Index: head/sys/vm/vm_map.c =================================================================== --- head/sys/vm/vm_map.c (revision 355063) +++ head/sys/vm/vm_map.c (revision 355064) @@ -1,4991 +1,4990 @@ /*- * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Authors: Avadis Tevanian, Jr., Michael Wayne Young * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ /* * Virtual memory mapping module. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Virtual memory maps provide for the mapping, protection, * and sharing of virtual memory objects. In addition, * this module provides for an efficient virtual copy of * memory from one map to another. * * Synchronization is required prior to most operations. * * Maps consist of an ordered doubly-linked list of simple * entries; a self-adjusting binary search tree of these * entries is used to speed up lookups. * * Since portions of maps are specified by start/end addresses, * which may not align with existing map entries, all * routines merely "clip" entries to these start/end values. * [That is, an entry is split into two, bordering at a * start or end value.] Note that these clippings may not * always be necessary (as the two resulting entries are then * not changed); however, the clipping is done for convenience. * * As mentioned above, virtual copy operations are performed * by copying VM object references from one map to * another, and then marking both regions as copy-on-write. */ static struct mtx map_sleep_mtx; static uma_zone_t mapentzone; static uma_zone_t kmapentzone; static uma_zone_t mapzone; static uma_zone_t vmspace_zone; static int vmspace_zinit(void *mem, int size, int flags); static int vm_map_zinit(void *mem, int ize, int flags); static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max); static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map); static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry); static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry); static int vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry); static void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags); #ifdef INVARIANTS static void vm_map_zdtor(void *mem, int size, void *arg); static void vmspace_zdtor(void *mem, int size, void *arg); #endif static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow); static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, vm_offset_t failed_addr); #define ENTRY_CHARGED(e) ((e)->cred != NULL || \ ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \ !((e)->eflags & MAP_ENTRY_NEEDS_COPY))) /* * PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type * stable. */ #define PROC_VMSPACE_LOCK(p) do { } while (0) #define PROC_VMSPACE_UNLOCK(p) do { } while (0) /* * VM_MAP_RANGE_CHECK: [ internal use only ] * * Asserts that the starting and ending region * addresses fall within the valid range of the map. */ #define VM_MAP_RANGE_CHECK(map, start, end) \ { \ if (start < vm_map_min(map)) \ start = vm_map_min(map); \ if (end > vm_map_max(map)) \ end = vm_map_max(map); \ if (start > end) \ start = end; \ } /* * vm_map_startup: * * Initialize the vm_map module. Must be called before * any other vm_map routines. * * Map and entry structures are allocated from the general * purpose memory pool with some exceptions: * * - The kernel map and kmem submap are allocated statically. * - Kernel map entries are allocated out of a static pool. * * These restrictions are necessary since malloc() uses the * maps and requires map entries. */ void vm_map_startup(void) { mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF); mapzone = uma_zcreate("MAP", sizeof(struct vm_map), NULL, #ifdef INVARIANTS vm_map_zdtor, #else NULL, #endif vm_map_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); uma_prealloc(mapzone, MAX_KMAP); kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_MTXCLASS | UMA_ZONE_VM); mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL, #ifdef INVARIANTS vmspace_zdtor, #else NULL, #endif vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); } static int vmspace_zinit(void *mem, int size, int flags) { struct vmspace *vm; vm = (struct vmspace *)mem; vm->vm_map.pmap = NULL; (void)vm_map_zinit(&vm->vm_map, sizeof(vm->vm_map), flags); PMAP_LOCK_INIT(vmspace_pmap(vm)); return (0); } static int vm_map_zinit(void *mem, int size, int flags) { vm_map_t map; map = (vm_map_t)mem; memset(map, 0, sizeof(*map)); mtx_init(&map->system_mtx, "vm map (system)", NULL, MTX_DEF | MTX_DUPOK); sx_init(&map->lock, "vm map (user)"); return (0); } #ifdef INVARIANTS static void vmspace_zdtor(void *mem, int size, void *arg) { struct vmspace *vm; vm = (struct vmspace *)mem; vm_map_zdtor(&vm->vm_map, sizeof(vm->vm_map), arg); } static void vm_map_zdtor(void *mem, int size, void *arg) { vm_map_t map; map = (vm_map_t)mem; KASSERT(map->nentries == 0, ("map %p nentries == %d on free.", map, map->nentries)); KASSERT(map->size == 0, ("map %p size == %lu on free.", map, (unsigned long)map->size)); } #endif /* INVARIANTS */ /* * Allocate a vmspace structure, including a vm_map and pmap, * and initialize those structures. The refcnt is set to 1. * * If 'pinit' is NULL then the embedded pmap is initialized via pmap_pinit(). */ struct vmspace * vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit) { struct vmspace *vm; vm = uma_zalloc(vmspace_zone, M_WAITOK); KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL")); if (!pinit(vmspace_pmap(vm))) { uma_zfree(vmspace_zone, vm); return (NULL); } CTR1(KTR_VM, "vmspace_alloc: %p", vm); _vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max); vm->vm_refcnt = 1; vm->vm_shm = NULL; vm->vm_swrss = 0; vm->vm_tsize = 0; vm->vm_dsize = 0; vm->vm_ssize = 0; vm->vm_taddr = 0; vm->vm_daddr = 0; vm->vm_maxsaddr = 0; return (vm); } #ifdef RACCT static void vmspace_container_reset(struct proc *p) { PROC_LOCK(p); racct_set(p, RACCT_DATA, 0); racct_set(p, RACCT_STACK, 0); racct_set(p, RACCT_RSS, 0); racct_set(p, RACCT_MEMLOCK, 0); racct_set(p, RACCT_VMEM, 0); PROC_UNLOCK(p); } #endif static inline void vmspace_dofree(struct vmspace *vm) { CTR1(KTR_VM, "vmspace_free: %p", vm); /* * Make sure any SysV shm is freed, it might not have been in * exit1(). */ shmexit(vm); /* * Lock the map, to wait out all other references to it. * Delete all of the mappings and pages they hold, then call * the pmap module to reclaim anything left. */ (void)vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map), vm_map_max(&vm->vm_map)); pmap_release(vmspace_pmap(vm)); vm->vm_map.pmap = NULL; uma_zfree(vmspace_zone, vm); } void vmspace_free(struct vmspace *vm) { WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmspace_free() called"); if (vm->vm_refcnt == 0) panic("vmspace_free: attempt to free already freed vmspace"); if (atomic_fetchadd_int(&vm->vm_refcnt, -1) == 1) vmspace_dofree(vm); } void vmspace_exitfree(struct proc *p) { struct vmspace *vm; PROC_VMSPACE_LOCK(p); vm = p->p_vmspace; p->p_vmspace = NULL; PROC_VMSPACE_UNLOCK(p); KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace")); vmspace_free(vm); } void vmspace_exit(struct thread *td) { int refcnt; struct vmspace *vm; struct proc *p; /* * Release user portion of address space. * This releases references to vnodes, * which could cause I/O if the file has been unlinked. * Need to do this early enough that we can still sleep. * * The last exiting process to reach this point releases as * much of the environment as it can. vmspace_dofree() is the * slower fallback in case another process had a temporary * reference to the vmspace. */ p = td->td_proc; vm = p->p_vmspace; atomic_add_int(&vmspace0.vm_refcnt, 1); refcnt = vm->vm_refcnt; do { if (refcnt > 1 && p->p_vmspace != &vmspace0) { /* Switch now since other proc might free vmspace */ PROC_VMSPACE_LOCK(p); p->p_vmspace = &vmspace0; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); } } while (!atomic_fcmpset_int(&vm->vm_refcnt, &refcnt, refcnt - 1)); if (refcnt == 1) { if (p->p_vmspace != vm) { /* vmspace not yet freed, switch back */ PROC_VMSPACE_LOCK(p); p->p_vmspace = vm; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); } pmap_remove_pages(vmspace_pmap(vm)); /* Switch now since this proc will free vmspace */ PROC_VMSPACE_LOCK(p); p->p_vmspace = &vmspace0; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); vmspace_dofree(vm); } #ifdef RACCT if (racct_enable) vmspace_container_reset(p); #endif } /* Acquire reference to vmspace owned by another process. */ struct vmspace * vmspace_acquire_ref(struct proc *p) { struct vmspace *vm; int refcnt; PROC_VMSPACE_LOCK(p); vm = p->p_vmspace; if (vm == NULL) { PROC_VMSPACE_UNLOCK(p); return (NULL); } refcnt = vm->vm_refcnt; do { if (refcnt <= 0) { /* Avoid 0->1 transition */ PROC_VMSPACE_UNLOCK(p); return (NULL); } } while (!atomic_fcmpset_int(&vm->vm_refcnt, &refcnt, refcnt + 1)); if (vm != p->p_vmspace) { PROC_VMSPACE_UNLOCK(p); vmspace_free(vm); return (NULL); } PROC_VMSPACE_UNLOCK(p); return (vm); } /* * Switch between vmspaces in an AIO kernel process. * * The new vmspace is either the vmspace of a user process obtained * from an active AIO request or the initial vmspace of the AIO kernel * process (when it is idling). Because user processes will block to * drain any active AIO requests before proceeding in exit() or * execve(), the reference count for vmspaces from AIO requests can * never be 0. Similarly, AIO kernel processes hold an extra * reference on their initial vmspace for the life of the process. As * a result, the 'newvm' vmspace always has a non-zero reference * count. This permits an additional reference on 'newvm' to be * acquired via a simple atomic increment rather than the loop in * vmspace_acquire_ref() above. */ void vmspace_switch_aio(struct vmspace *newvm) { struct vmspace *oldvm; /* XXX: Need some way to assert that this is an aio daemon. */ KASSERT(newvm->vm_refcnt > 0, ("vmspace_switch_aio: newvm unreferenced")); oldvm = curproc->p_vmspace; if (oldvm == newvm) return; /* * Point to the new address space and refer to it. */ curproc->p_vmspace = newvm; atomic_add_int(&newvm->vm_refcnt, 1); /* Activate the new mapping. */ pmap_activate(curthread); vmspace_free(oldvm); } void _vm_map_lock(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_lock_flags_(&map->system_mtx, 0, file, line); else sx_xlock_(&map->lock, file, line); map->timestamp++; } void vm_map_entry_set_vnode_text(vm_map_entry_t entry, bool add) { vm_object_t object, object1; struct vnode *vp; if ((entry->eflags & MAP_ENTRY_VN_EXEC) == 0) return; KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, ("Submap with execs")); object = entry->object.vm_object; KASSERT(object != NULL, ("No object for text, entry %p", entry)); VM_OBJECT_RLOCK(object); while ((object1 = object->backing_object) != NULL) { VM_OBJECT_RLOCK(object1); VM_OBJECT_RUNLOCK(object); object = object1; } vp = NULL; if (object->type == OBJT_DEAD) { /* * For OBJT_DEAD objects, v_writecount was handled in * vnode_pager_dealloc(). */ } else if (object->type == OBJT_VNODE) { vp = object->handle; } else if (object->type == OBJT_SWAP) { KASSERT((object->flags & OBJ_TMPFS_NODE) != 0, ("vm_map_entry_set_vnode_text: swap and !TMPFS " "entry %p, object %p, add %d", entry, object, add)); /* * Tmpfs VREG node, which was reclaimed, has * OBJ_TMPFS_NODE flag set, but not OBJ_TMPFS. In * this case there is no v_writecount to adjust. */ if ((object->flags & OBJ_TMPFS) != 0) vp = object->un_pager.swp.swp_tmpfs; } else { KASSERT(0, ("vm_map_entry_set_vnode_text: wrong object type, " "entry %p, object %p, add %d", entry, object, add)); } if (vp != NULL) { if (add) { VOP_SET_TEXT_CHECKED(vp); VM_OBJECT_RUNLOCK(object); } else { vhold(vp); VM_OBJECT_RUNLOCK(object); vn_lock(vp, LK_SHARED | LK_RETRY); VOP_UNSET_TEXT_CHECKED(vp); VOP_UNLOCK(vp, 0); vdrop(vp); } } else { VM_OBJECT_RUNLOCK(object); } } /* * Use a different name for this vm_map_entry field when it's use * is not consistent with its use as part of an ordered search tree. */ #define defer_next right static void vm_map_process_deferred(void) { struct thread *td; vm_map_entry_t entry, next; vm_object_t object; td = curthread; entry = td->td_map_def_user; td->td_map_def_user = NULL; while (entry != NULL) { next = entry->defer_next; MPASS((entry->eflags & (MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC)) != (MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC)); if ((entry->eflags & MAP_ENTRY_WRITECNT) != 0) { /* * Decrement the object's writemappings and * possibly the vnode's v_writecount. */ KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, ("Submap with writecount")); object = entry->object.vm_object; KASSERT(object != NULL, ("No object for writecount")); vm_pager_release_writecount(object, entry->start, entry->end); } vm_map_entry_set_vnode_text(entry, false); vm_map_entry_deallocate(entry, FALSE); entry = next; } } #ifdef INVARIANTS static void _vm_map_assert_locked(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_assert_(&map->system_mtx, MA_OWNED, file, line); else sx_assert_(&map->lock, SA_XLOCKED, file, line); } #define VM_MAP_ASSERT_LOCKED(map) \ _vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE) enum { VMMAP_CHECK_NONE, VMMAP_CHECK_UNLOCK, VMMAP_CHECK_ALL }; #ifdef DIAGNOSTIC static int enable_vmmap_check = VMMAP_CHECK_UNLOCK; #else static int enable_vmmap_check = VMMAP_CHECK_NONE; #endif SYSCTL_INT(_debug, OID_AUTO, vmmap_check, CTLFLAG_RWTUN, &enable_vmmap_check, 0, "Enable vm map consistency checking"); static void _vm_map_assert_consistent(vm_map_t map, int check); #define VM_MAP_ASSERT_CONSISTENT(map) \ _vm_map_assert_consistent(map, VMMAP_CHECK_ALL) #ifdef DIAGNOSTIC #define VM_MAP_UNLOCK_CONSISTENT(map) do { \ if (map->nupdates > map->nentries) { \ _vm_map_assert_consistent(map, VMMAP_CHECK_UNLOCK); \ map->nupdates = 0; \ } \ } while (0) #else #define VM_MAP_UNLOCK_CONSISTENT(map) #endif #else #define VM_MAP_ASSERT_LOCKED(map) #define VM_MAP_ASSERT_CONSISTENT(map) #define VM_MAP_UNLOCK_CONSISTENT(map) #endif /* INVARIANTS */ void _vm_map_unlock(vm_map_t map, const char *file, int line) { VM_MAP_UNLOCK_CONSISTENT(map); if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else { sx_xunlock_(&map->lock, file, line); vm_map_process_deferred(); } } void _vm_map_lock_read(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_lock_flags_(&map->system_mtx, 0, file, line); else sx_slock_(&map->lock, file, line); } void _vm_map_unlock_read(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else { sx_sunlock_(&map->lock, file, line); vm_map_process_deferred(); } } int _vm_map_trylock(vm_map_t map, const char *file, int line) { int error; error = map->system_map ? !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : !sx_try_xlock_(&map->lock, file, line); if (error == 0) map->timestamp++; return (error == 0); } int _vm_map_trylock_read(vm_map_t map, const char *file, int line) { int error; error = map->system_map ? !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : !sx_try_slock_(&map->lock, file, line); return (error == 0); } /* * _vm_map_lock_upgrade: [ internal use only ] * * Tries to upgrade a read (shared) lock on the specified map to a write * (exclusive) lock. Returns the value "0" if the upgrade succeeds and a * non-zero value if the upgrade fails. If the upgrade fails, the map is * returned without a read or write lock held. * * Requires that the map be read locked. */ int _vm_map_lock_upgrade(vm_map_t map, const char *file, int line) { unsigned int last_timestamp; if (map->system_map) { mtx_assert_(&map->system_mtx, MA_OWNED, file, line); } else { if (!sx_try_upgrade_(&map->lock, file, line)) { last_timestamp = map->timestamp; sx_sunlock_(&map->lock, file, line); vm_map_process_deferred(); /* * If the map's timestamp does not change while the * map is unlocked, then the upgrade succeeds. */ sx_xlock_(&map->lock, file, line); if (last_timestamp != map->timestamp) { sx_xunlock_(&map->lock, file, line); return (1); } } } map->timestamp++; return (0); } void _vm_map_lock_downgrade(vm_map_t map, const char *file, int line) { if (map->system_map) { mtx_assert_(&map->system_mtx, MA_OWNED, file, line); } else { VM_MAP_UNLOCK_CONSISTENT(map); sx_downgrade_(&map->lock, file, line); } } /* * vm_map_locked: * * Returns a non-zero value if the caller holds a write (exclusive) lock * on the specified map and the value "0" otherwise. */ int vm_map_locked(vm_map_t map) { if (map->system_map) return (mtx_owned(&map->system_mtx)); else return (sx_xlocked(&map->lock)); } /* * _vm_map_unlock_and_wait: * * Atomically releases the lock on the specified map and puts the calling * thread to sleep. The calling thread will remain asleep until either * vm_map_wakeup() is performed on the map or the specified timeout is * exceeded. * * WARNING! This function does not perform deferred deallocations of * objects and map entries. Therefore, the calling thread is expected to * reacquire the map lock after reawakening and later perform an ordinary * unlock operation, such as vm_map_unlock(), before completing its * operation on the map. */ int _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line) { VM_MAP_UNLOCK_CONSISTENT(map); mtx_lock(&map_sleep_mtx); if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else sx_xunlock_(&map->lock, file, line); return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", timo)); } /* * vm_map_wakeup: * * Awaken any threads that have slept on the map using * vm_map_unlock_and_wait(). */ void vm_map_wakeup(vm_map_t map) { /* * Acquire and release map_sleep_mtx to prevent a wakeup() * from being performed (and lost) between the map unlock * and the msleep() in _vm_map_unlock_and_wait(). */ mtx_lock(&map_sleep_mtx); mtx_unlock(&map_sleep_mtx); wakeup(&map->root); } void vm_map_busy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); map->busy++; } void vm_map_unbusy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); KASSERT(map->busy, ("vm_map_unbusy: not busy")); if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) { vm_map_modflags(map, 0, MAP_BUSY_WAKEUP); wakeup(&map->busy); } } void vm_map_wait_busy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); while (map->busy) { vm_map_modflags(map, MAP_BUSY_WAKEUP, 0); if (map->system_map) msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0); else sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0); } map->timestamp++; } long vmspace_resident_count(struct vmspace *vmspace) { return pmap_resident_count(vmspace_pmap(vmspace)); } /* * vm_map_create: * * Creates and returns a new empty VM map with * the given physical map structure, and having * the given lower and upper address bounds. */ vm_map_t vm_map_create(pmap_t pmap, vm_offset_t min, vm_offset_t max) { vm_map_t result; result = uma_zalloc(mapzone, M_WAITOK); CTR1(KTR_VM, "vm_map_create: %p", result); _vm_map_init(result, pmap, min, max); return (result); } /* * Initialize an existing vm_map structure * such as that in the vmspace structure. */ static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) { map->header.next = map->header.prev = &map->header; map->header.eflags = MAP_ENTRY_HEADER; map->needs_wakeup = FALSE; map->system_map = 0; map->pmap = pmap; map->header.end = min; map->header.start = max; map->flags = 0; map->root = NULL; map->timestamp = 0; map->busy = 0; map->anon_loc = 0; #ifdef DIAGNOSTIC map->nupdates = 0; #endif } void vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) { _vm_map_init(map, pmap, min, max); mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK); sx_init(&map->lock, "user map"); } /* * vm_map_entry_dispose: [ internal use only ] * * Inverse of vm_map_entry_create. */ static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry) { uma_zfree(map->system_map ? kmapentzone : mapentzone, entry); } /* * vm_map_entry_create: [ internal use only ] * * Allocates a VM map entry for insertion. * No entry fields are filled in. */ static vm_map_entry_t vm_map_entry_create(vm_map_t map) { vm_map_entry_t new_entry; if (map->system_map) new_entry = uma_zalloc(kmapentzone, M_NOWAIT); else new_entry = uma_zalloc(mapentzone, M_WAITOK); if (new_entry == NULL) panic("vm_map_entry_create: kernel resources exhausted"); return (new_entry); } /* * vm_map_entry_set_behavior: * * Set the expected access behavior, either normal, random, or * sequential. */ static inline void vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior) { entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) | (behavior & MAP_ENTRY_BEHAV_MASK); } /* * vm_map_entry_max_free_{left,right}: * * Compute the size of the largest free gap between two entries, * one the root of a tree and the other the ancestor of that root * that is the least or greatest ancestor found on the search path. */ static inline vm_size_t vm_map_entry_max_free_left(vm_map_entry_t root, vm_map_entry_t left_ancestor) { return (root->left != NULL ? root->left->max_free : root->start - left_ancestor->end); } static inline vm_size_t vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor) { return (root->right != NULL ? root->right->max_free : right_ancestor->start - root->end); } /* * vm_map_entry_{pred,succ}: * * Find the {predecessor, successor} of the entry by taking one step * in the appropriate direction and backtracking as much as necessary. */ static inline vm_map_entry_t vm_map_entry_pred(vm_map_entry_t entry) { return (entry->prev); } /* vm_map_entry_succ is defined in vm_map.h. */ #define SPLAY_LEFT_STEP(root, y, rlist, test) do { \ vm_size_t max_free; \ \ /* \ * Infer root->right->max_free == root->max_free when \ * y->max_free < root->max_free || root->max_free == 0. \ * Otherwise, look right to find it. \ */ \ y = root->left; \ max_free = root->max_free; \ KASSERT(max_free >= vm_map_entry_max_free_right(root, rlist), \ ("%s: max_free invariant fails", __func__)); \ if (y == NULL ? max_free > 0 : max_free - 1 < y->max_free) \ max_free = vm_map_entry_max_free_right(root, rlist); \ if (y != NULL && (test)) { \ /* Rotate right and make y root. */ \ root->left = y->right; \ y->right = root; \ if (max_free < y->max_free) \ root->max_free = max_free = MAX(max_free, \ vm_map_entry_max_free_left(root, y)); \ root = y; \ y = root->left; \ } \ /* Copy right->max_free. Put root on rlist. */ \ root->max_free = max_free; \ KASSERT(max_free == vm_map_entry_max_free_right(root, rlist), \ ("%s: max_free not copied from right", __func__)); \ root->left = rlist; \ rlist = root; \ root = y; \ } while (0) #define SPLAY_RIGHT_STEP(root, y, llist, test) do { \ vm_size_t max_free; \ \ /* \ * Infer root->left->max_free == root->max_free when \ * y->max_free < root->max_free || root->max_free == 0. \ * Otherwise, look left to find it. \ */ \ y = root->right; \ max_free = root->max_free; \ KASSERT(max_free >= vm_map_entry_max_free_left(root, llist), \ ("%s: max_free invariant fails", __func__)); \ if (y == NULL ? max_free > 0 : max_free - 1 < y->max_free) \ max_free = vm_map_entry_max_free_left(root, llist); \ if (y != NULL && (test)) { \ /* Rotate left and make y root. */ \ root->right = y->left; \ y->left = root; \ if (max_free < y->max_free) \ root->max_free = max_free = MAX(max_free, \ vm_map_entry_max_free_right(root, y)); \ root = y; \ y = root->right; \ } \ /* Copy left->max_free. Put root on llist. */ \ root->max_free = max_free; \ KASSERT(max_free == vm_map_entry_max_free_left(root, llist), \ ("%s: max_free not copied from left", __func__)); \ root->right = llist; \ llist = root; \ root = y; \ } while (0) /* * Walk down the tree until we find addr or a NULL pointer where addr would go, * breaking off left and right subtrees of nodes less than, or greater than * addr. Treat pointers to nodes with max_free < length as NULL pointers. * llist and rlist are the two sides in reverse order (bottom-up), with llist * linked by the right pointer and rlist linked by the left pointer in the * vm_map_entry, and both lists terminated by &map->header. This function, and * the subsequent call to vm_map_splay_merge, rely on the start and end address * values in &map->header. */ static vm_map_entry_t vm_map_splay_split(vm_map_t map, vm_offset_t addr, vm_size_t length, vm_map_entry_t *out_llist, vm_map_entry_t *out_rlist) { vm_map_entry_t llist, rlist, root, y; llist = rlist = &map->header; root = map->root; while (root != NULL && root->max_free >= length) { KASSERT(llist->end <= root->start && root->end <= rlist->start, ("%s: root not within tree bounds", __func__)); if (addr < root->start) { SPLAY_LEFT_STEP(root, y, rlist, y->max_free >= length && addr < y->start); } else if (addr >= root->end) { SPLAY_RIGHT_STEP(root, y, llist, y->max_free >= length && addr >= y->end); } else break; } *out_llist = llist; *out_rlist = rlist; return (root); } static void vm_map_splay_findnext(vm_map_entry_t root, vm_map_entry_t *iolist) { vm_map_entry_t rlist, y; root = root->right; rlist = *iolist; while (root != NULL) SPLAY_LEFT_STEP(root, y, rlist, true); *iolist = rlist; } static void vm_map_splay_findprev(vm_map_entry_t root, vm_map_entry_t *iolist) { vm_map_entry_t llist, y; root = root->left; llist = *iolist; while (root != NULL) SPLAY_RIGHT_STEP(root, y, llist, true); *iolist = llist; } static inline void vm_map_entry_swap(vm_map_entry_t *a, vm_map_entry_t *b) { vm_map_entry_t tmp; tmp = *b; *b = *a; *a = tmp; } /* * Walk back up the two spines, flip the pointers and set max_free. The * subtrees of the root go at the bottom of llist and rlist. */ static void vm_map_splay_merge(vm_map_t map, vm_map_entry_t root, vm_map_entry_t llist, vm_map_entry_t rlist) { vm_map_entry_t prev; vm_size_t max_free_left, max_free_right; max_free_left = vm_map_entry_max_free_left(root, llist); if (llist != &map->header) { prev = root->left; do { /* * The max_free values of the children of llist are in * llist->max_free and max_free_left. Update with the * max value. */ llist->max_free = max_free_left = MAX(llist->max_free, max_free_left); vm_map_entry_swap(&llist->right, &prev); vm_map_entry_swap(&prev, &llist); } while (llist != &map->header); root->left = prev; } max_free_right = vm_map_entry_max_free_right(root, rlist); if (rlist != &map->header) { prev = root->right; do { /* * The max_free values of the children of rlist are in * rlist->max_free and max_free_right. Update with the * max value. */ rlist->max_free = max_free_right = MAX(rlist->max_free, max_free_right); vm_map_entry_swap(&rlist->left, &prev); vm_map_entry_swap(&prev, &rlist); } while (rlist != &map->header); root->right = prev; } root->max_free = MAX(max_free_left, max_free_right); map->root = root; #ifdef DIAGNOSTIC ++map->nupdates; #endif } /* * vm_map_splay: * * The Sleator and Tarjan top-down splay algorithm with the * following variation. Max_free must be computed bottom-up, so * on the downward pass, maintain the left and right spines in * reverse order. Then, make a second pass up each side to fix * the pointers and compute max_free. The time bound is O(log n) * amortized. * * The new root is the vm_map_entry containing "addr", or else an * adjacent entry (lower if possible) if addr is not in the tree. * * The map must be locked, and leaves it so. * * Returns: the new root. */ static vm_map_entry_t vm_map_splay(vm_map_t map, vm_offset_t addr) { vm_map_entry_t llist, rlist, root; root = vm_map_splay_split(map, addr, 0, &llist, &rlist); if (root != NULL) { /* do nothing */ } else if (llist != &map->header) { /* * Recover the greatest node in the left * subtree and make it the root. */ root = llist; llist = root->right; root->right = NULL; } else if (rlist != &map->header) { /* * Recover the least node in the right * subtree and make it the root. */ root = rlist; rlist = root->left; root->left = NULL; } else { /* There is no root. */ return (NULL); } vm_map_splay_merge(map, root, llist, rlist); VM_MAP_ASSERT_CONSISTENT(map); return (root); } /* * vm_map_entry_{un,}link: * * Insert/remove entries from maps. */ static void vm_map_entry_link(vm_map_t map, vm_map_entry_t entry) { vm_map_entry_t llist, rlist, root; CTR3(KTR_VM, "vm_map_entry_link: map %p, nentries %d, entry %p", map, map->nentries, entry); VM_MAP_ASSERT_LOCKED(map); map->nentries++; root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); KASSERT(root == NULL, ("vm_map_entry_link: link object already mapped")); entry->prev = llist; entry->next = rlist; llist->next = rlist->prev = entry; entry->left = entry->right = NULL; vm_map_splay_merge(map, entry, llist, rlist); VM_MAP_ASSERT_CONSISTENT(map); } enum unlink_merge_type { UNLINK_MERGE_NONE, UNLINK_MERGE_NEXT }; static void vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry, enum unlink_merge_type op) { vm_map_entry_t llist, rlist, root, y; VM_MAP_ASSERT_LOCKED(map); root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); KASSERT(root != NULL, ("vm_map_entry_unlink: unlink object not mapped")); vm_map_splay_findnext(root, &rlist); switch (op) { case UNLINK_MERGE_NEXT: rlist->start = root->start; rlist->offset = root->offset; y = root->left; root = rlist; rlist = root->left; root->left = y; break; case UNLINK_MERGE_NONE: vm_map_splay_findprev(root, &llist); if (llist != &map->header) { root = llist; llist = root->right; root->right = NULL; } else if (rlist != &map->header) { root = rlist; rlist = root->left; root->left = NULL; } else root = NULL; break; } y = entry->next; y->prev = entry->prev; y->prev->next = y; if (root != NULL) vm_map_splay_merge(map, root, llist, rlist); else map->root = NULL; VM_MAP_ASSERT_CONSISTENT(map); map->nentries--; CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map, map->nentries, entry); } /* * vm_map_entry_resize: * * Resize a vm_map_entry, recompute the amount of free space that * follows it and propagate that value up the tree. * * The map must be locked, and leaves it so. */ static void vm_map_entry_resize(vm_map_t map, vm_map_entry_t entry, vm_size_t grow_amount) { vm_map_entry_t llist, rlist, root; VM_MAP_ASSERT_LOCKED(map); root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist); KASSERT(root != NULL, ("%s: resize object not mapped", __func__)); vm_map_splay_findnext(root, &rlist); root->right = NULL; entry->end += grow_amount; vm_map_splay_merge(map, root, llist, rlist); VM_MAP_ASSERT_CONSISTENT(map); CTR4(KTR_VM, "%s: map %p, nentries %d, entry %p", __func__, map, map->nentries, entry); } /* * vm_map_lookup_entry: [ internal use only ] * * Finds the map entry containing (or * immediately preceding) the specified address * in the given map; the entry is returned * in the "entry" parameter. The boolean * result indicates whether the address is * actually contained in the map. */ boolean_t vm_map_lookup_entry( vm_map_t map, vm_offset_t address, vm_map_entry_t *entry) /* OUT */ { vm_map_entry_t cur, lbound; boolean_t locked; /* * If the map is empty, then the map entry immediately preceding * "address" is the map's header. */ cur = map->root; if (cur == NULL) { *entry = &map->header; return (FALSE); } if (address >= cur->start && cur->end > address) { *entry = cur; return (TRUE); } if ((locked = vm_map_locked(map)) || sx_try_upgrade(&map->lock)) { /* * Splay requires a write lock on the map. However, it only * restructures the binary search tree; it does not otherwise * change the map. Thus, the map's timestamp need not change * on a temporary upgrade. */ cur = vm_map_splay(map, address); if (!locked) { VM_MAP_UNLOCK_CONSISTENT(map); sx_downgrade(&map->lock); } /* * If "address" is contained within a map entry, the new root * is that map entry. Otherwise, the new root is a map entry * immediately before or after "address". */ if (address < cur->start) { *entry = &map->header; return (FALSE); } *entry = cur; return (address < cur->end); } /* * Since the map is only locked for read access, perform a * standard binary search tree lookup for "address". */ lbound = &map->header; do { if (address < cur->start) { cur = cur->left; } else if (cur->end <= address) { lbound = cur; cur = cur->right; } else { *entry = cur; return (TRUE); } } while (cur != NULL); *entry = lbound; return (FALSE); } /* * vm_map_insert: * * Inserts the given whole VM object into the target * map at the specified address range. The object's * size should match that of the address range. * * Requires that the map be locked, and leaves it so. * * If object is non-NULL, ref count must be bumped by caller * prior to making call to account for the new entry. */ int vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow) { vm_map_entry_t new_entry, next_entry, prev_entry; struct ucred *cred; vm_eflags_t protoeflags; vm_inherit_t inheritance; VM_MAP_ASSERT_LOCKED(map); KASSERT(object != kernel_object || (cow & MAP_COPY_ON_WRITE) == 0, ("vm_map_insert: kernel object and COW")); KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0, ("vm_map_insert: paradoxical MAP_NOFAULT request")); KASSERT((prot & ~max) == 0, ("prot %#x is not subset of max_prot %#x", prot, max)); /* * Check that the start and end points are not bogus. */ if (start < vm_map_min(map) || end > vm_map_max(map) || start >= end) return (KERN_INVALID_ADDRESS); /* * Find the entry prior to the proposed starting address; if it's part * of an existing entry, this range is bogus. */ if (vm_map_lookup_entry(map, start, &prev_entry)) return (KERN_NO_SPACE); /* * Assert that the next entry doesn't overlap the end point. */ next_entry = vm_map_entry_succ(prev_entry); if (next_entry->start < end) return (KERN_NO_SPACE); if ((cow & MAP_CREATE_GUARD) != 0 && (object != NULL || max != VM_PROT_NONE)) return (KERN_INVALID_ARGUMENT); protoeflags = 0; if (cow & MAP_COPY_ON_WRITE) protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY; if (cow & MAP_NOFAULT) protoeflags |= MAP_ENTRY_NOFAULT; if (cow & MAP_DISABLE_SYNCER) protoeflags |= MAP_ENTRY_NOSYNC; if (cow & MAP_DISABLE_COREDUMP) protoeflags |= MAP_ENTRY_NOCOREDUMP; if (cow & MAP_STACK_GROWS_DOWN) protoeflags |= MAP_ENTRY_GROWS_DOWN; if (cow & MAP_STACK_GROWS_UP) protoeflags |= MAP_ENTRY_GROWS_UP; if (cow & MAP_WRITECOUNT) protoeflags |= MAP_ENTRY_WRITECNT; if (cow & MAP_VN_EXEC) protoeflags |= MAP_ENTRY_VN_EXEC; if ((cow & MAP_CREATE_GUARD) != 0) protoeflags |= MAP_ENTRY_GUARD; if ((cow & MAP_CREATE_STACK_GAP_DN) != 0) protoeflags |= MAP_ENTRY_STACK_GAP_DN; if ((cow & MAP_CREATE_STACK_GAP_UP) != 0) protoeflags |= MAP_ENTRY_STACK_GAP_UP; if (cow & MAP_INHERIT_SHARE) inheritance = VM_INHERIT_SHARE; else inheritance = VM_INHERIT_DEFAULT; cred = NULL; if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0) goto charged; if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) && ((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) { if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start)) return (KERN_RESOURCE_SHORTAGE); KASSERT(object == NULL || (protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 || object->cred == NULL, ("overcommit: vm_map_insert o %p", object)); cred = curthread->td_ucred; } charged: /* Expand the kernel pmap, if necessary. */ if (map == kernel_map && end > kernel_vm_end) pmap_growkernel(end); if (object != NULL) { /* * OBJ_ONEMAPPING must be cleared unless this mapping * is trivially proven to be the only mapping for any * of the object's pages. (Object granularity * reference counting is insufficient to recognize * aliases with precision.) */ if ((object->flags & OBJ_ANON) != 0) { VM_OBJECT_WLOCK(object); if (object->ref_count > 1 || object->shadow_count != 0) vm_object_clear_flag(object, OBJ_ONEMAPPING); VM_OBJECT_WUNLOCK(object); } } else if ((prev_entry->eflags & ~MAP_ENTRY_USER_WIRED) == protoeflags && (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP | MAP_VN_EXEC)) == 0 && prev_entry->end == start && (prev_entry->cred == cred || (prev_entry->object.vm_object != NULL && prev_entry->object.vm_object->cred == cred)) && vm_object_coalesce(prev_entry->object.vm_object, prev_entry->offset, (vm_size_t)(prev_entry->end - prev_entry->start), (vm_size_t)(end - prev_entry->end), cred != NULL && (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) { /* * We were able to extend the object. Determine if we * can extend the previous map entry to include the * new range as well. */ if (prev_entry->inheritance == inheritance && prev_entry->protection == prot && prev_entry->max_protection == max && prev_entry->wired_count == 0) { KASSERT((prev_entry->eflags & MAP_ENTRY_USER_WIRED) == 0, ("prev_entry %p has incoherent wiring", prev_entry)); if ((prev_entry->eflags & MAP_ENTRY_GUARD) == 0) map->size += end - prev_entry->end; vm_map_entry_resize(map, prev_entry, end - prev_entry->end); vm_map_try_merge_entries(map, prev_entry, next_entry); return (KERN_SUCCESS); } /* * If we can extend the object but cannot extend the * map entry, we have to create a new map entry. We * must bump the ref count on the extended object to * account for it. object may be NULL. */ object = prev_entry->object.vm_object; offset = prev_entry->offset + (prev_entry->end - prev_entry->start); vm_object_reference(object); if (cred != NULL && object != NULL && object->cred != NULL && !(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { /* Object already accounts for this uid. */ cred = NULL; } } if (cred != NULL) crhold(cred); /* * Create a new entry */ new_entry = vm_map_entry_create(map); new_entry->start = start; new_entry->end = end; new_entry->cred = NULL; new_entry->eflags = protoeflags; new_entry->object.vm_object = object; new_entry->offset = offset; new_entry->inheritance = inheritance; new_entry->protection = prot; new_entry->max_protection = max; new_entry->wired_count = 0; new_entry->wiring_thread = NULL; new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT; new_entry->next_read = start; KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry), ("overcommit: vm_map_insert leaks vm_map %p", new_entry)); new_entry->cred = cred; /* * Insert the new entry into the list */ vm_map_entry_link(map, new_entry); if ((new_entry->eflags & MAP_ENTRY_GUARD) == 0) map->size += new_entry->end - new_entry->start; /* * Try to coalesce the new entry with both the previous and next * entries in the list. Previously, we only attempted to coalesce * with the previous entry when object is NULL. Here, we handle the * other cases, which are less common. */ vm_map_try_merge_entries(map, prev_entry, new_entry); vm_map_try_merge_entries(map, new_entry, next_entry); if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) { vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset), end - start, cow & MAP_PREFAULT_PARTIAL); } return (KERN_SUCCESS); } /* * vm_map_findspace: * * Find the first fit (lowest VM address) for "length" free bytes * beginning at address >= start in the given map. * * In a vm_map_entry, "max_free" is the maximum amount of * contiguous free space between an entry in its subtree and a * neighbor of that entry. This allows finding a free region in * one path down the tree, so O(log n) amortized with splay * trees. * * The map must be locked, and leaves it so. * * Returns: starting address if sufficient space, * vm_map_max(map)-length+1 if insufficient space. */ vm_offset_t vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length) { vm_map_entry_t llist, rlist, root, y; vm_size_t left_length; vm_offset_t gap_end; /* * Request must fit within min/max VM address and must avoid * address wrap. */ start = MAX(start, vm_map_min(map)); if (start >= vm_map_max(map) || length > vm_map_max(map) - start) return (vm_map_max(map) - length + 1); /* Empty tree means wide open address space. */ if (map->root == NULL) return (start); /* * After splay_split, if start is within an entry, push it to the start * of the following gap. If rlist is at the end of the gap containing * start, save the end of that gap in gap_end to see if the gap is big * enough; otherwise set gap_end to start skip gap-checking and move * directly to a search of the right subtree. */ root = vm_map_splay_split(map, start, length, &llist, &rlist); gap_end = rlist->start; if (root != NULL) { start = root->end; if (root->right != NULL) gap_end = start; } else if (rlist != &map->header) { root = rlist; rlist = root->left; root->left = NULL; } else { root = llist; llist = root->right; root->right = NULL; } vm_map_splay_merge(map, root, llist, rlist); VM_MAP_ASSERT_CONSISTENT(map); if (length <= gap_end - start) return (start); /* With max_free, can immediately tell if no solution. */ if (root->right == NULL || length > root->right->max_free) return (vm_map_max(map) - length + 1); /* * Splay for the least large-enough gap in the right subtree. */ llist = rlist = &map->header; for (left_length = 0;; left_length = vm_map_entry_max_free_left(root, llist)) { if (length <= left_length) SPLAY_LEFT_STEP(root, y, rlist, length <= vm_map_entry_max_free_left(y, llist)); else SPLAY_RIGHT_STEP(root, y, llist, length > vm_map_entry_max_free_left(y, root)); if (root == NULL) break; } root = llist; llist = root->right; root->right = NULL; if (rlist != &map->header) { y = rlist; rlist = y->left; y->left = NULL; vm_map_splay_merge(map, y, &map->header, rlist); y->max_free = MAX( vm_map_entry_max_free_left(y, root), vm_map_entry_max_free_right(y, &map->header)); root->right = y; } vm_map_splay_merge(map, root, llist, &map->header); VM_MAP_ASSERT_CONSISTENT(map); return (root->end); } int vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t start, vm_size_t length, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t end; int result; end = start + length; KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || object == NULL, ("vm_map_fixed: non-NULL backing object for stack")); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if ((cow & MAP_CHECK_EXCL) == 0) vm_map_delete(map, start, end); if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { result = vm_map_stack_locked(map, start, length, sgrowsiz, prot, max, cow); } else { result = vm_map_insert(map, object, offset, start, end, prot, max, cow); } vm_map_unlock(map); return (result); } static const int aslr_pages_rnd_64[2] = {0x1000, 0x10}; static const int aslr_pages_rnd_32[2] = {0x100, 0x4}; static int cluster_anon = 1; SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW, &cluster_anon, 0, "Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always"); static bool clustering_anon_allowed(vm_offset_t addr) { switch (cluster_anon) { case 0: return (false); case 1: return (addr == 0); case 2: default: return (true); } } static long aslr_restarts; SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD, &aslr_restarts, 0, "Number of aslr failures"); #define MAP_32BIT_MAX_ADDR ((vm_offset_t)1 << 31) /* * Searches for the specified amount of free space in the given map with the * specified alignment. Performs an address-ordered, first-fit search from * the given address "*addr", with an optional upper bound "max_addr". If the * parameter "alignment" is zero, then the alignment is computed from the * given (object, offset) pair so as to enable the greatest possible use of * superpage mappings. Returns KERN_SUCCESS and the address of the free space * in "*addr" if successful. Otherwise, returns KERN_NO_SPACE. * * The map must be locked. Initially, there must be at least "length" bytes * of free space at the given address. */ static int vm_map_alignspace(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t *addr, vm_size_t length, vm_offset_t max_addr, vm_offset_t alignment) { vm_offset_t aligned_addr, free_addr; VM_MAP_ASSERT_LOCKED(map); free_addr = *addr; KASSERT(free_addr == vm_map_findspace(map, free_addr, length), ("caller failed to provide space %#jx at address %p", (uintmax_t)length, (void *)free_addr)); for (;;) { /* * At the start of every iteration, the free space at address * "*addr" is at least "length" bytes. */ if (alignment == 0) pmap_align_superpage(object, offset, addr, length); else if ((*addr & (alignment - 1)) != 0) { *addr &= ~(alignment - 1); *addr += alignment; } aligned_addr = *addr; if (aligned_addr == free_addr) { /* * Alignment did not change "*addr", so "*addr" must * still provide sufficient free space. */ return (KERN_SUCCESS); } /* * Test for address wrap on "*addr". A wrapped "*addr" could * be a valid address, in which case vm_map_findspace() cannot * be relied upon to fail. */ if (aligned_addr < free_addr) return (KERN_NO_SPACE); *addr = vm_map_findspace(map, aligned_addr, length); if (*addr + length > vm_map_max(map) || (max_addr != 0 && *addr + length > max_addr)) return (KERN_NO_SPACE); free_addr = *addr; if (free_addr == aligned_addr) { /* * If a successful call to vm_map_findspace() did not * change "*addr", then "*addr" must still be aligned * and provide sufficient free space. */ return (KERN_SUCCESS); } } } /* * vm_map_find finds an unallocated region in the target address * map with the given length. The search is defined to be * first-fit from the specified address; the region found is * returned in the same parameter. * * If object is non-NULL, ref count must be bumped by caller * prior to making call to account for the new entry. */ int vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t *addr, /* IN/OUT */ vm_size_t length, vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t alignment, curr_min_addr, min_addr; int gap, pidx, rv, try; bool cluster, en_aslr, update_anon; KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || object == NULL, ("vm_map_find: non-NULL backing object for stack")); MPASS((cow & MAP_REMAP) == 0 || (find_space == VMFS_NO_SPACE && (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0)); if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL || (object->flags & OBJ_COLORED) == 0)) find_space = VMFS_ANY_SPACE; if (find_space >> 8 != 0) { KASSERT((find_space & 0xff) == 0, ("bad VMFS flags")); alignment = (vm_offset_t)1 << (find_space >> 8); } else alignment = 0; en_aslr = (map->flags & MAP_ASLR) != 0; update_anon = cluster = clustering_anon_allowed(*addr) && (map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 && find_space != VMFS_NO_SPACE && object == NULL && (cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP | MAP_STACK_GROWS_DOWN)) == 0 && prot != PROT_NONE; curr_min_addr = min_addr = *addr; if (en_aslr && min_addr == 0 && !cluster && find_space != VMFS_NO_SPACE && (map->flags & MAP_ASLR_IGNSTART) != 0) curr_min_addr = min_addr = vm_map_min(map); try = 0; vm_map_lock(map); if (cluster) { curr_min_addr = map->anon_loc; if (curr_min_addr == 0) cluster = false; } if (find_space != VMFS_NO_SPACE) { KASSERT(find_space == VMFS_ANY_SPACE || find_space == VMFS_OPTIMAL_SPACE || find_space == VMFS_SUPER_SPACE || alignment != 0, ("unexpected VMFS flag")); again: /* * When creating an anonymous mapping, try clustering * with an existing anonymous mapping first. * * We make up to two attempts to find address space * for a given find_space value. The first attempt may * apply randomization or may cluster with an existing * anonymous mapping. If this first attempt fails, * perform a first-fit search of the available address * space. * * If all tries failed, and find_space is * VMFS_OPTIMAL_SPACE, fallback to VMFS_ANY_SPACE. * Again enable clustering and randomization. */ try++; MPASS(try <= 2); if (try == 2) { /* * Second try: we failed either to find a * suitable region for randomizing the * allocation, or to cluster with an existing * mapping. Retry with free run. */ curr_min_addr = (map->flags & MAP_ASLR_IGNSTART) != 0 ? vm_map_min(map) : min_addr; atomic_add_long(&aslr_restarts, 1); } if (try == 1 && en_aslr && !cluster) { /* * Find space for allocation, including * gap needed for later randomization. */ pidx = MAXPAGESIZES > 1 && pagesizes[1] != 0 && (find_space == VMFS_SUPER_SPACE || find_space == VMFS_OPTIMAL_SPACE) ? 1 : 0; gap = vm_map_max(map) > MAP_32BIT_MAX_ADDR && (max_addr == 0 || max_addr > MAP_32BIT_MAX_ADDR) ? aslr_pages_rnd_64[pidx] : aslr_pages_rnd_32[pidx]; *addr = vm_map_findspace(map, curr_min_addr, length + gap * pagesizes[pidx]); if (*addr + length + gap * pagesizes[pidx] > vm_map_max(map)) goto again; /* And randomize the start address. */ *addr += (arc4random() % gap) * pagesizes[pidx]; if (max_addr != 0 && *addr + length > max_addr) goto again; } else { *addr = vm_map_findspace(map, curr_min_addr, length); if (*addr + length > vm_map_max(map) || (max_addr != 0 && *addr + length > max_addr)) { if (cluster) { cluster = false; MPASS(try == 1); goto again; } rv = KERN_NO_SPACE; goto done; } } if (find_space != VMFS_ANY_SPACE && (rv = vm_map_alignspace(map, object, offset, addr, length, max_addr, alignment)) != KERN_SUCCESS) { if (find_space == VMFS_OPTIMAL_SPACE) { find_space = VMFS_ANY_SPACE; curr_min_addr = min_addr; cluster = update_anon; try = 0; goto again; } goto done; } } else if ((cow & MAP_REMAP) != 0) { if (*addr < vm_map_min(map) || *addr + length > vm_map_max(map) || *addr + length <= length) { rv = KERN_INVALID_ADDRESS; goto done; } vm_map_delete(map, *addr, *addr + length); } if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { rv = vm_map_stack_locked(map, *addr, length, sgrowsiz, prot, max, cow); } else { rv = vm_map_insert(map, object, offset, *addr, *addr + length, prot, max, cow); } if (rv == KERN_SUCCESS && update_anon) map->anon_loc = *addr + length; done: vm_map_unlock(map); return (rv); } /* * vm_map_find_min() is a variant of vm_map_find() that takes an * additional parameter (min_addr) and treats the given address * (*addr) differently. Specifically, it treats *addr as a hint * and not as the minimum address where the mapping is created. * * This function works in two phases. First, it tries to * allocate above the hint. If that fails and the hint is * greater than min_addr, it performs a second pass, replacing * the hint with min_addr as the minimum address for the * allocation. */ int vm_map_find_min(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t *addr, vm_size_t length, vm_offset_t min_addr, vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t hint; int rv; hint = *addr; for (;;) { rv = vm_map_find(map, object, offset, addr, length, max_addr, find_space, prot, max, cow); if (rv == KERN_SUCCESS || min_addr >= hint) return (rv); *addr = hint = min_addr; } } /* * A map entry with any of the following flags set must not be merged with * another entry. */ #define MAP_ENTRY_NOMERGE_MASK (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP | \ MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_VN_EXEC) static bool vm_map_mergeable_neighbors(vm_map_entry_t prev, vm_map_entry_t entry) { KASSERT((prev->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 || (entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0, ("vm_map_mergeable_neighbors: neither %p nor %p are mergeable", prev, entry)); return (prev->end == entry->start && prev->object.vm_object == entry->object.vm_object && (prev->object.vm_object == NULL || prev->offset + (prev->end - prev->start) == entry->offset) && prev->eflags == entry->eflags && prev->protection == entry->protection && prev->max_protection == entry->max_protection && prev->inheritance == entry->inheritance && prev->wired_count == entry->wired_count && prev->cred == entry->cred); } static void vm_map_merged_neighbor_dispose(vm_map_t map, vm_map_entry_t entry) { /* * If the backing object is a vnode object, vm_object_deallocate() * calls vrele(). However, vrele() does not lock the vnode because * the vnode has additional references. Thus, the map lock can be * kept without causing a lock-order reversal with the vnode lock. * * Since we count the number of virtual page mappings in * object->un_pager.vnp.writemappings, the writemappings value * should not be adjusted when the entry is disposed of. */ if (entry->object.vm_object != NULL) vm_object_deallocate(entry->object.vm_object); if (entry->cred != NULL) crfree(entry->cred); vm_map_entry_dispose(map, entry); } /* * vm_map_try_merge_entries: * * Compare the given map entry to its predecessor, and merge its precessor * into it if possible. The entry remains valid, and may be extended. * The predecessor may be deleted. * * The map must be locked. */ void vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev, vm_map_entry_t entry) { VM_MAP_ASSERT_LOCKED(map); if ((entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 && vm_map_mergeable_neighbors(prev, entry)) { vm_map_entry_unlink(map, prev, UNLINK_MERGE_NEXT); vm_map_merged_neighbor_dispose(map, prev); } } /* * vm_map_entry_back: * * Allocate an object to back a map entry. */ static inline void vm_map_entry_back(vm_map_entry_t entry) { vm_object_t object; KASSERT(entry->object.vm_object == NULL, ("map entry %p has backing object", entry)); KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, ("map entry %p is a submap", entry)); object = vm_object_allocate_anon(atop(entry->end - entry->start)); entry->object.vm_object = object; entry->offset = 0; if (entry->cred != NULL) { object->cred = entry->cred; object->charge = entry->end - entry->start; entry->cred = NULL; } } /* * vm_map_entry_charge_object * * If there is no object backing this entry, create one. Otherwise, if * the entry has cred, give it to the backing object. */ static inline void vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry) { VM_MAP_ASSERT_LOCKED(map); KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, ("map entry %p is a submap", entry)); if (entry->object.vm_object == NULL && !map->system_map && (entry->eflags & MAP_ENTRY_GUARD) == 0) vm_map_entry_back(entry); else if (entry->object.vm_object != NULL && ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && entry->cred != NULL) { VM_OBJECT_WLOCK(entry->object.vm_object); KASSERT(entry->object.vm_object->cred == NULL, ("OVERCOMMIT: %s: both cred e %p", __func__, entry)); entry->object.vm_object->cred = entry->cred; entry->object.vm_object->charge = entry->end - entry->start; VM_OBJECT_WUNLOCK(entry->object.vm_object); entry->cred = NULL; } } /* * vm_map_clip_start: [ internal use only ] * * Asserts that the given entry begins at or after * the specified address; if necessary, * it splits the entry into two. */ #define vm_map_clip_start(map, entry, startaddr) \ { \ if (startaddr > entry->start) \ _vm_map_clip_start(map, entry, startaddr); \ } /* * This routine is called only when it is known that * the entry must be split. */ static void _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start) { vm_map_entry_t new_entry; VM_MAP_ASSERT_LOCKED(map); KASSERT(entry->end > start && entry->start < start, ("_vm_map_clip_start: invalid clip of entry %p", entry)); /* * Create a backing object now, if none exists, so that more individual * objects won't be created after the map entry is split. */ vm_map_entry_charge_object(map, entry); /* Clone the entry. */ new_entry = vm_map_entry_create(map); *new_entry = *entry; /* * Split off the front portion. Insert the new entry BEFORE this one, * so that this entry has the specified starting address. */ new_entry->end = start; entry->offset += (start - entry->start); entry->start = start; if (new_entry->cred != NULL) crhold(entry->cred); vm_map_entry_link(map, new_entry); if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { vm_object_reference(new_entry->object.vm_object); vm_map_entry_set_vnode_text(new_entry, true); /* * The object->un_pager.vnp.writemappings for the * object of MAP_ENTRY_WRITECNT type entry shall be * kept as is here. The virtual pages are * re-distributed among the clipped entries, so the sum is * left the same. */ } } /* * vm_map_clip_end: [ internal use only ] * * Asserts that the given entry ends at or before * the specified address; if necessary, * it splits the entry into two. */ #define vm_map_clip_end(map, entry, endaddr) \ { \ if ((endaddr) < (entry->end)) \ _vm_map_clip_end((map), (entry), (endaddr)); \ } /* * This routine is called only when it is known that * the entry must be split. */ static void _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end) { vm_map_entry_t new_entry; VM_MAP_ASSERT_LOCKED(map); KASSERT(entry->start < end && entry->end > end, ("_vm_map_clip_end: invalid clip of entry %p", entry)); /* * Create a backing object now, if none exists, so that more individual * objects won't be created after the map entry is split. */ vm_map_entry_charge_object(map, entry); /* Clone the entry. */ new_entry = vm_map_entry_create(map); *new_entry = *entry; /* * Split off the back portion. Insert the new entry AFTER this one, * so that this entry has the specified ending address. */ new_entry->start = entry->end = end; new_entry->offset += (end - entry->start); if (new_entry->cred != NULL) crhold(entry->cred); vm_map_entry_link(map, new_entry); if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { vm_object_reference(new_entry->object.vm_object); vm_map_entry_set_vnode_text(new_entry, true); } } /* * vm_map_submap: [ kernel use only ] * * Mark the given range as handled by a subordinate map. * * This range must have been created with vm_map_find, * and no other operations may have been performed on this * range prior to calling vm_map_submap. * * Only a limited number of operations can be performed * within this rage after calling vm_map_submap: * vm_fault * [Don't try vm_map_copy!] * * To remove a submapping, one must first remove the * range from the superior map, and then destroy the * submap (if desired). [Better yet, don't try it.] */ int vm_map_submap( vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) { vm_map_entry_t entry; int result; result = KERN_INVALID_ARGUMENT; vm_map_lock(submap); submap->flags |= MAP_IS_SUB_MAP; vm_map_unlock(submap); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &entry)) { vm_map_clip_start(map, entry, start); } else entry = vm_map_entry_succ(entry); vm_map_clip_end(map, entry, end); if ((entry->start == start) && (entry->end == end) && ((entry->eflags & MAP_ENTRY_COW) == 0) && (entry->object.vm_object == NULL)) { entry->object.sub_map = submap; entry->eflags |= MAP_ENTRY_IS_SUB_MAP; result = KERN_SUCCESS; } vm_map_unlock(map); if (result != KERN_SUCCESS) { vm_map_lock(submap); submap->flags &= ~MAP_IS_SUB_MAP; vm_map_unlock(submap); } return (result); } /* * The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified */ #define MAX_INIT_PT 96 /* * vm_map_pmap_enter: * * Preload the specified map's pmap with mappings to the specified * object's memory-resident pages. No further physical pages are * allocated, and no further virtual pages are retrieved from secondary * storage. If the specified flags include MAP_PREFAULT_PARTIAL, then a * limited number of page mappings are created at the low-end of the * specified address range. (For this purpose, a superpage mapping * counts as one page mapping.) Otherwise, all resident pages within * the specified address range are mapped. */ static void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags) { vm_offset_t start; vm_page_t p, p_start; vm_pindex_t mask, psize, threshold, tmpidx; if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL) return; VM_OBJECT_RLOCK(object); if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { VM_OBJECT_RUNLOCK(object); VM_OBJECT_WLOCK(object); if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { pmap_object_init_pt(map->pmap, addr, object, pindex, size); VM_OBJECT_WUNLOCK(object); return; } VM_OBJECT_LOCK_DOWNGRADE(object); } psize = atop(size); if (psize + pindex > object->size) { if (object->size < pindex) { VM_OBJECT_RUNLOCK(object); return; } psize = object->size - pindex; } start = 0; p_start = NULL; threshold = MAX_INIT_PT; p = vm_page_find_least(object, pindex); /* * Assert: the variable p is either (1) the page with the * least pindex greater than or equal to the parameter pindex * or (2) NULL. */ for (; p != NULL && (tmpidx = p->pindex - pindex) < psize; p = TAILQ_NEXT(p, listq)) { /* * don't allow an madvise to blow away our really * free pages allocating pv entries. */ if (((flags & MAP_PREFAULT_MADVISE) != 0 && vm_page_count_severe()) || ((flags & MAP_PREFAULT_PARTIAL) != 0 && tmpidx >= threshold)) { psize = tmpidx; break; } if (vm_page_all_valid(p)) { if (p_start == NULL) { start = addr + ptoa(tmpidx); p_start = p; } /* Jump ahead if a superpage mapping is possible. */ if (p->psind > 0 && ((addr + ptoa(tmpidx)) & (pagesizes[p->psind] - 1)) == 0) { mask = atop(pagesizes[p->psind]) - 1; if (tmpidx + mask < psize && vm_page_ps_test(p, PS_ALL_VALID, NULL)) { p += mask; threshold += mask; } } } else if (p_start != NULL) { pmap_enter_object(map->pmap, start, addr + ptoa(tmpidx), p_start, prot); p_start = NULL; } } if (p_start != NULL) pmap_enter_object(map->pmap, start, addr + ptoa(psize), p_start, prot); VM_OBJECT_RUNLOCK(object); } /* * vm_map_protect: * * Sets the protection of the specified address * region in the target map. If "set_max" is * specified, the maximum protection is to be set; * otherwise, only the current protection is affected. */ int vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_prot_t new_prot, boolean_t set_max) { vm_map_entry_t current, entry, in_tran, prev_entry; vm_object_t obj; struct ucred *cred; vm_prot_t old_prot; int rv; if (start == end) return (KERN_SUCCESS); again: in_tran = NULL; vm_map_lock(map); /* * Ensure that we are not concurrently wiring pages. vm_map_wire() may * need to fault pages into the map and will drop the map lock while * doing so, and the VM object may end up in an inconsistent state if we * update the protection on the map entry in between faults. */ vm_map_wait_busy(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &entry)) entry = vm_map_entry_succ(entry); /* * Make a first pass to check for protection violations. */ for (current = entry; current->start < end; current = vm_map_entry_succ(current)) { if ((current->eflags & MAP_ENTRY_GUARD) != 0) continue; if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_unlock(map); return (KERN_INVALID_ARGUMENT); } if ((new_prot & current->max_protection) != new_prot) { vm_map_unlock(map); return (KERN_PROTECTION_FAILURE); } if ((current->eflags & MAP_ENTRY_IN_TRANSITION) != 0) in_tran = current; } /* * Postpone the operation until all in-transition map entries have * stabilized. An in-transition entry might already have its pages * wired and wired_count incremented, but not yet have its * MAP_ENTRY_USER_WIRED flag set. In which case, we would fail to call * vm_fault_copy_entry() in the final loop below. */ if (in_tran != NULL) { in_tran->eflags |= MAP_ENTRY_NEEDS_WAKEUP; vm_map_unlock_and_wait(map, 0); goto again; } /* * Before changing the protections, try to reserve swap space for any * private (i.e., copy-on-write) mappings that are transitioning from * read-only to read/write access. If a reservation fails, break out * of this loop early and let the next loop simplify the entries, since * some may now be mergeable. */ rv = KERN_SUCCESS; vm_map_clip_start(map, entry, start); for (current = entry; current->start < end; current = vm_map_entry_succ(current)) { vm_map_clip_end(map, current, end); if (set_max || ((new_prot & ~(current->protection)) & VM_PROT_WRITE) == 0 || ENTRY_CHARGED(current) || (current->eflags & MAP_ENTRY_GUARD) != 0) { continue; } cred = curthread->td_ucred; obj = current->object.vm_object; if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) { if (!swap_reserve(current->end - current->start)) { rv = KERN_RESOURCE_SHORTAGE; end = current->end; break; } crhold(cred); current->cred = cred; continue; } VM_OBJECT_WLOCK(obj); if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP) { VM_OBJECT_WUNLOCK(obj); continue; } /* * Charge for the whole object allocation now, since * we cannot distinguish between non-charged and * charged clipped mapping of the same object later. */ KASSERT(obj->charge == 0, ("vm_map_protect: object %p overcharged (entry %p)", obj, current)); if (!swap_reserve(ptoa(obj->size))) { VM_OBJECT_WUNLOCK(obj); rv = KERN_RESOURCE_SHORTAGE; end = current->end; break; } crhold(cred); obj->cred = cred; obj->charge = ptoa(obj->size); VM_OBJECT_WUNLOCK(obj); } /* * If enough swap space was available, go back and fix up protections. * Otherwise, just simplify entries, since some may have been modified. * [Note that clipping is not necessary the second time.] */ for (prev_entry = vm_map_entry_pred(entry), current = entry; current->start < end; vm_map_try_merge_entries(map, prev_entry, current), prev_entry = current, current = vm_map_entry_succ(current)) { if (rv != KERN_SUCCESS || (current->eflags & MAP_ENTRY_GUARD) != 0) continue; old_prot = current->protection; if (set_max) current->protection = (current->max_protection = new_prot) & old_prot; else current->protection = new_prot; /* * For user wired map entries, the normal lazy evaluation of * write access upgrades through soft page faults is * undesirable. Instead, immediately copy any pages that are * copy-on-write and enable write access in the physical map. */ if ((current->eflags & MAP_ENTRY_USER_WIRED) != 0 && (current->protection & VM_PROT_WRITE) != 0 && (old_prot & VM_PROT_WRITE) == 0) vm_fault_copy_entry(map, map, current, current, NULL); /* * When restricting access, update the physical map. Worry * about copy-on-write here. */ if ((old_prot & ~current->protection) != 0) { #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ VM_PROT_ALL) pmap_protect(map->pmap, current->start, current->end, current->protection & MASK(current)); #undef MASK } } vm_map_try_merge_entries(map, prev_entry, current); vm_map_unlock(map); return (rv); } /* * vm_map_madvise: * * This routine traverses a processes map handling the madvise * system call. Advisories are classified as either those effecting * the vm_map_entry structure, or those effecting the underlying * objects. */ int vm_map_madvise( vm_map_t map, vm_offset_t start, vm_offset_t end, int behav) { vm_map_entry_t current, prev_entry; bool modify_map; /* * Some madvise calls directly modify the vm_map_entry, in which case * we need to use an exclusive lock on the map and we need to perform * various clipping operations. Otherwise we only need a read-lock * on the map. */ switch(behav) { case MADV_NORMAL: case MADV_SEQUENTIAL: case MADV_RANDOM: case MADV_NOSYNC: case MADV_AUTOSYNC: case MADV_NOCORE: case MADV_CORE: if (start == end) return (0); modify_map = true; vm_map_lock(map); break; case MADV_WILLNEED: case MADV_DONTNEED: case MADV_FREE: if (start == end) return (0); modify_map = false; vm_map_lock_read(map); break; default: return (EINVAL); } /* * Locate starting entry and clip if necessary. */ VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, ¤t)) { if (modify_map) vm_map_clip_start(map, current, start); prev_entry = vm_map_entry_pred(current); } else { prev_entry = current; current = vm_map_entry_succ(current); } if (modify_map) { /* * madvise behaviors that are implemented in the vm_map_entry. * * We clip the vm_map_entry so that behavioral changes are * limited to the specified address range. */ for (; current->start < end; prev_entry = current, current = vm_map_entry_succ(current)) { if (current->eflags & MAP_ENTRY_IS_SUB_MAP) continue; vm_map_clip_end(map, current, end); switch (behav) { case MADV_NORMAL: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); break; case MADV_SEQUENTIAL: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); break; case MADV_RANDOM: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); break; case MADV_NOSYNC: current->eflags |= MAP_ENTRY_NOSYNC; break; case MADV_AUTOSYNC: current->eflags &= ~MAP_ENTRY_NOSYNC; break; case MADV_NOCORE: current->eflags |= MAP_ENTRY_NOCOREDUMP; break; case MADV_CORE: current->eflags &= ~MAP_ENTRY_NOCOREDUMP; break; default: break; } vm_map_try_merge_entries(map, prev_entry, current); } vm_map_try_merge_entries(map, prev_entry, current); vm_map_unlock(map); } else { vm_pindex_t pstart, pend; /* * madvise behaviors that are implemented in the underlying * vm_object. * * Since we don't clip the vm_map_entry, we have to clip * the vm_object pindex and count. */ for (; current->start < end; current = vm_map_entry_succ(current)) { vm_offset_t useEnd, useStart; if (current->eflags & MAP_ENTRY_IS_SUB_MAP) continue; /* * MADV_FREE would otherwise rewind time to * the creation of the shadow object. Because * we hold the VM map read-locked, neither the * entry's object nor the presence of a * backing object can change. */ if (behav == MADV_FREE && current->object.vm_object != NULL && current->object.vm_object->backing_object != NULL) continue; pstart = OFF_TO_IDX(current->offset); pend = pstart + atop(current->end - current->start); useStart = current->start; useEnd = current->end; if (current->start < start) { pstart += atop(start - current->start); useStart = start; } if (current->end > end) { pend -= atop(current->end - end); useEnd = end; } if (pstart >= pend) continue; /* * Perform the pmap_advise() before clearing * PGA_REFERENCED in vm_page_advise(). Otherwise, a * concurrent pmap operation, such as pmap_remove(), * could clear a reference in the pmap and set * PGA_REFERENCED on the page before the pmap_advise() * had completed. Consequently, the page would appear * referenced based upon an old reference that * occurred before this pmap_advise() ran. */ if (behav == MADV_DONTNEED || behav == MADV_FREE) pmap_advise(map->pmap, useStart, useEnd, behav); vm_object_madvise(current->object.vm_object, pstart, pend, behav); /* * Pre-populate paging structures in the * WILLNEED case. For wired entries, the * paging structures are already populated. */ if (behav == MADV_WILLNEED && current->wired_count == 0) { vm_map_pmap_enter(map, useStart, current->protection, current->object.vm_object, pstart, ptoa(pend - pstart), MAP_PREFAULT_MADVISE ); } } vm_map_unlock_read(map); } return (0); } /* * vm_map_inherit: * * Sets the inheritance of the specified address * range in the target map. Inheritance * affects how the map will be shared with * child maps at the time of vmspace_fork. */ int vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_inherit_t new_inheritance) { vm_map_entry_t entry, prev_entry; switch (new_inheritance) { case VM_INHERIT_NONE: case VM_INHERIT_COPY: case VM_INHERIT_SHARE: case VM_INHERIT_ZERO: break; default: return (KERN_INVALID_ARGUMENT); } if (start == end) return (KERN_SUCCESS); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &prev_entry)) { entry = prev_entry; vm_map_clip_start(map, entry, start); prev_entry = vm_map_entry_pred(entry); } else entry = vm_map_entry_succ(prev_entry); for (; entry->start < end; prev_entry = entry, entry = vm_map_entry_succ(entry)) { vm_map_clip_end(map, entry, end); if ((entry->eflags & MAP_ENTRY_GUARD) == 0 || new_inheritance != VM_INHERIT_ZERO) entry->inheritance = new_inheritance; vm_map_try_merge_entries(map, prev_entry, entry); } vm_map_try_merge_entries(map, prev_entry, entry); vm_map_unlock(map); return (KERN_SUCCESS); } /* * vm_map_entry_in_transition: * * Release the map lock, and sleep until the entry is no longer in * transition. Awake and acquire the map lock. If the map changed while * another held the lock, lookup a possibly-changed entry at or after the * 'start' position of the old entry. */ static vm_map_entry_t vm_map_entry_in_transition(vm_map_t map, vm_offset_t in_start, vm_offset_t *io_end, bool holes_ok, vm_map_entry_t in_entry) { vm_map_entry_t entry; vm_offset_t start; u_int last_timestamp; VM_MAP_ASSERT_LOCKED(map); KASSERT((in_entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, ("not in-tranition map entry %p", in_entry)); /* * We have not yet clipped the entry. */ start = MAX(in_start, in_entry->start); in_entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; last_timestamp = map->timestamp; if (vm_map_unlock_and_wait(map, 0)) { /* * Allow interruption of user wiring/unwiring? */ } vm_map_lock(map); if (last_timestamp + 1 == map->timestamp) return (in_entry); /* * Look again for the entry because the map was modified while it was * unlocked. Specifically, the entry may have been clipped, merged, or * deleted. */ if (!vm_map_lookup_entry(map, start, &entry)) { if (!holes_ok) { *io_end = start; return (NULL); } entry = vm_map_entry_succ(entry); } return (entry); } /* * vm_map_unwire: * * Implements both kernel and user unwiring. */ int vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) { vm_map_entry_t entry, first_entry, next_entry, prev_entry; int rv; bool holes_ok, need_wakeup, user_unwire; if (start == end) return (KERN_SUCCESS); holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0; user_unwire = (flags & VM_MAP_WIRE_USER) != 0; vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &first_entry)) { if (holes_ok) first_entry = vm_map_entry_succ(first_entry); else { vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } } rv = KERN_SUCCESS; for (entry = first_entry; entry->start < end; entry = next_entry) { if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { /* * We have not yet clipped the entry. */ next_entry = vm_map_entry_in_transition(map, start, &end, holes_ok, entry); if (next_entry == NULL) { if (entry == first_entry) { vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } rv = KERN_INVALID_ADDRESS; break; } first_entry = (entry == first_entry) ? next_entry : NULL; continue; } vm_map_clip_start(map, entry, start); vm_map_clip_end(map, entry, end); /* * Mark the entry in case the map lock is released. (See * above.) */ KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && entry->wiring_thread == NULL, ("owned map entry %p", entry)); entry->eflags |= MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = curthread; next_entry = vm_map_entry_succ(entry); /* * Check the map for holes in the specified region. * If holes_ok, skip this check. */ if (!holes_ok && entry->end < end && next_entry->start > entry->end) { end = entry->end; rv = KERN_INVALID_ADDRESS; break; } /* * If system unwiring, require that the entry is system wired. */ if (!user_unwire && vm_map_entry_system_wired_count(entry) == 0) { end = entry->end; rv = KERN_INVALID_ARGUMENT; break; } } need_wakeup = false; if (first_entry == NULL && !vm_map_lookup_entry(map, start, &first_entry)) { KASSERT(holes_ok, ("vm_map_unwire: lookup failed")); prev_entry = first_entry; entry = vm_map_entry_succ(first_entry); } else { prev_entry = vm_map_entry_pred(first_entry); entry = first_entry; } for (; entry->start < end; prev_entry = entry, entry = vm_map_entry_succ(entry)) { /* * If holes_ok was specified, an empty * space in the unwired region could have been mapped * while the map lock was dropped for draining * MAP_ENTRY_IN_TRANSITION. Moreover, another thread * could be simultaneously wiring this new mapping * entry. Detect these cases and skip any entries * marked as in transition by us. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || entry->wiring_thread != curthread) { KASSERT(holes_ok, ("vm_map_unwire: !HOLESOK and new/changed entry")); continue; } if (rv == KERN_SUCCESS && (!user_unwire || (entry->eflags & MAP_ENTRY_USER_WIRED))) { if (entry->wired_count == 1) vm_map_entry_unwire(map, entry); else entry->wired_count--; if (user_unwire) entry->eflags &= ~MAP_ENTRY_USER_WIRED; } KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, ("vm_map_unwire: in-transition flag missing %p", entry)); KASSERT(entry->wiring_thread == curthread, ("vm_map_unwire: alien wire %p", entry)); entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = NULL; if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; need_wakeup = true; } vm_map_try_merge_entries(map, prev_entry, entry); } vm_map_try_merge_entries(map, prev_entry, entry); vm_map_unlock(map); if (need_wakeup) vm_map_wakeup(map); return (rv); } static void vm_map_wire_user_count_sub(u_long npages) { atomic_subtract_long(&vm_user_wire_count, npages); } static bool vm_map_wire_user_count_add(u_long npages) { u_long wired; wired = vm_user_wire_count; do { if (npages + wired > vm_page_max_user_wired) return (false); } while (!atomic_fcmpset_long(&vm_user_wire_count, &wired, npages + wired)); return (true); } /* * vm_map_wire_entry_failure: * * Handle a wiring failure on the given entry. * * The map should be locked. */ static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, vm_offset_t failed_addr) { VM_MAP_ASSERT_LOCKED(map); KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 && entry->wired_count == 1, ("vm_map_wire_entry_failure: entry %p isn't being wired", entry)); KASSERT(failed_addr < entry->end, ("vm_map_wire_entry_failure: entry %p was fully wired", entry)); /* * If any pages at the start of this entry were successfully wired, * then unwire them. */ if (failed_addr > entry->start) { pmap_unwire(map->pmap, entry->start, failed_addr); vm_object_unwire(entry->object.vm_object, entry->offset, failed_addr - entry->start, PQ_ACTIVE); } /* * Assign an out-of-range value to represent the failure to wire this * entry. */ entry->wired_count = -1; } int vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) { int rv; vm_map_lock(map); rv = vm_map_wire_locked(map, start, end, flags); vm_map_unlock(map); return (rv); } /* * vm_map_wire_locked: * * Implements both kernel and user wiring. Returns with the map locked, * the map lock may be dropped. */ int vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) { vm_map_entry_t entry, first_entry, next_entry, prev_entry; vm_offset_t faddr, saved_end, saved_start; u_long npages; u_int last_timestamp; int rv; bool holes_ok, need_wakeup, user_wire; vm_prot_t prot; VM_MAP_ASSERT_LOCKED(map); if (start == end) return (KERN_SUCCESS); prot = 0; if (flags & VM_MAP_WIRE_WRITE) prot |= VM_PROT_WRITE; holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0; user_wire = (flags & VM_MAP_WIRE_USER) != 0; VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &first_entry)) { if (holes_ok) first_entry = vm_map_entry_succ(first_entry); else return (KERN_INVALID_ADDRESS); } for (entry = first_entry; entry->start < end; entry = next_entry) { if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { /* * We have not yet clipped the entry. */ next_entry = vm_map_entry_in_transition(map, start, &end, holes_ok, entry); if (next_entry == NULL) { if (entry == first_entry) return (KERN_INVALID_ADDRESS); rv = KERN_INVALID_ADDRESS; goto done; } first_entry = (entry == first_entry) ? next_entry : NULL; continue; } vm_map_clip_start(map, entry, start); vm_map_clip_end(map, entry, end); /* * Mark the entry in case the map lock is released. (See * above.) */ KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && entry->wiring_thread == NULL, ("owned map entry %p", entry)); entry->eflags |= MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = curthread; if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || (entry->protection & prot) != prot) { entry->eflags |= MAP_ENTRY_WIRE_SKIPPED; if (!holes_ok) { end = entry->end; rv = KERN_INVALID_ADDRESS; goto done; } } else if (entry->wired_count == 0) { entry->wired_count++; npages = atop(entry->end - entry->start); if (user_wire && !vm_map_wire_user_count_add(npages)) { vm_map_wire_entry_failure(map, entry, entry->start); end = entry->end; rv = KERN_RESOURCE_SHORTAGE; goto done; } /* * Release the map lock, relying on the in-transition * mark. Mark the map busy for fork. */ saved_start = entry->start; saved_end = entry->end; last_timestamp = map->timestamp; vm_map_busy(map); vm_map_unlock(map); faddr = saved_start; do { /* * Simulate a fault to get the page and enter * it into the physical map. */ if ((rv = vm_fault(map, faddr, VM_PROT_NONE, VM_FAULT_WIRE, NULL)) != KERN_SUCCESS) break; } while ((faddr += PAGE_SIZE) < saved_end); vm_map_lock(map); vm_map_unbusy(map); if (last_timestamp + 1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. The entry * may have been clipped, but NOT merged or * deleted. */ if (!vm_map_lookup_entry(map, saved_start, &next_entry)) KASSERT(false, ("vm_map_wire: lookup failed")); first_entry = (entry == first_entry) ? next_entry : NULL; for (entry = next_entry; entry->end < saved_end; entry = vm_map_entry_succ(entry)) { /* * In case of failure, handle entries * that were not fully wired here; * fully wired entries are handled * later. */ if (rv != KERN_SUCCESS && faddr < entry->end) vm_map_wire_entry_failure(map, entry, faddr); } } if (rv != KERN_SUCCESS) { vm_map_wire_entry_failure(map, entry, faddr); if (user_wire) vm_map_wire_user_count_sub(npages); end = entry->end; goto done; } } else if (!user_wire || (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { entry->wired_count++; } /* * Check the map for holes in the specified region. * If holes_ok was specified, skip this check. */ next_entry = vm_map_entry_succ(entry); if (!holes_ok && entry->end < end && next_entry->start > entry->end) { end = entry->end; rv = KERN_INVALID_ADDRESS; goto done; } } rv = KERN_SUCCESS; done: need_wakeup = false; if (first_entry == NULL && !vm_map_lookup_entry(map, start, &first_entry)) { KASSERT(holes_ok, ("vm_map_wire: lookup failed")); prev_entry = first_entry; entry = vm_map_entry_succ(first_entry); } else { prev_entry = vm_map_entry_pred(first_entry); entry = first_entry; } for (; entry->start < end; prev_entry = entry, entry = vm_map_entry_succ(entry)) { /* * If holes_ok was specified, an empty * space in the unwired region could have been mapped * while the map lock was dropped for faulting in the * pages or draining MAP_ENTRY_IN_TRANSITION. * Moreover, another thread could be simultaneously * wiring this new mapping entry. Detect these cases * and skip any entries marked as in transition not by us. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || entry->wiring_thread != curthread) { KASSERT(holes_ok, ("vm_map_wire: !HOLESOK and new/changed entry")); continue; } if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) { /* do nothing */ } else if (rv == KERN_SUCCESS) { if (user_wire) entry->eflags |= MAP_ENTRY_USER_WIRED; } else if (entry->wired_count == -1) { /* * Wiring failed on this entry. Thus, unwiring is * unnecessary. */ entry->wired_count = 0; } else if (!user_wire || (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { /* * Undo the wiring. Wiring succeeded on this entry * but failed on a later entry. */ if (entry->wired_count == 1) { vm_map_entry_unwire(map, entry); if (user_wire) vm_map_wire_user_count_sub( atop(entry->end - entry->start)); } else entry->wired_count--; } KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, ("vm_map_wire: in-transition flag missing %p", entry)); KASSERT(entry->wiring_thread == curthread, ("vm_map_wire: alien wire %p", entry)); entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WIRE_SKIPPED); entry->wiring_thread = NULL; if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; need_wakeup = true; } vm_map_try_merge_entries(map, prev_entry, entry); } vm_map_try_merge_entries(map, prev_entry, entry); if (need_wakeup) vm_map_wakeup(map); return (rv); } /* * vm_map_sync * * Push any dirty cached pages in the address range to their pager. * If syncio is TRUE, dirty pages are written synchronously. * If invalidate is TRUE, any cached pages are freed as well. * * If the size of the region from start to end is zero, we are * supposed to flush all modified pages within the region containing * start. Unfortunately, a region can be split or coalesced with * neighboring regions, making it difficult to determine what the * original region was. Therefore, we approximate this requirement by * flushing the current region containing start. * * Returns an error if any part of the specified range is not mapped. */ int vm_map_sync( vm_map_t map, vm_offset_t start, vm_offset_t end, boolean_t syncio, boolean_t invalidate) { vm_map_entry_t current, entry, next_entry; vm_size_t size; vm_object_t object; vm_ooffset_t offset; unsigned int last_timestamp; boolean_t failed; vm_map_lock_read(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &entry)) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } else if (start == end) { start = entry->start; end = entry->end; } /* * Make a first pass to check for user-wired memory and holes. */ for (current = entry; current->start < end; current = next_entry) { if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) { vm_map_unlock_read(map); return (KERN_INVALID_ARGUMENT); } next_entry = vm_map_entry_succ(current); if (end > current->end && current->end != next_entry->start) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } } if (invalidate) pmap_remove(map->pmap, start, end); failed = FALSE; /* * Make a second pass, cleaning/uncaching pages from the indicated * objects as we go. */ for (current = entry; current->start < end;) { offset = current->offset + (start - current->start); size = (end <= current->end ? end : current->end) - start; if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_t smap; vm_map_entry_t tentry; vm_size_t tsize; smap = current->object.sub_map; vm_map_lock_read(smap); (void) vm_map_lookup_entry(smap, offset, &tentry); tsize = tentry->end - offset; if (tsize < size) size = tsize; object = tentry->object.vm_object; offset = tentry->offset + (offset - tentry->start); vm_map_unlock_read(smap); } else { object = current->object.vm_object; } vm_object_reference(object); last_timestamp = map->timestamp; vm_map_unlock_read(map); if (!vm_object_sync(object, offset, size, syncio, invalidate)) failed = TRUE; start += size; vm_object_deallocate(object); vm_map_lock_read(map); if (last_timestamp == map->timestamp || !vm_map_lookup_entry(map, start, ¤t)) current = vm_map_entry_succ(current); } vm_map_unlock_read(map); return (failed ? KERN_FAILURE : KERN_SUCCESS); } /* * vm_map_entry_unwire: [ internal use only ] * * Make the region specified by this entry pageable. * * The map in question should be locked. * [This is the reason for this routine's existence.] */ static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) { vm_size_t size; VM_MAP_ASSERT_LOCKED(map); KASSERT(entry->wired_count > 0, ("vm_map_entry_unwire: entry %p isn't wired", entry)); size = entry->end - entry->start; if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0) vm_map_wire_user_count_sub(atop(size)); pmap_unwire(map->pmap, entry->start, entry->end); vm_object_unwire(entry->object.vm_object, entry->offset, size, PQ_ACTIVE); entry->wired_count = 0; } static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map) { if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) vm_object_deallocate(entry->object.vm_object); uma_zfree(system_map ? kmapentzone : mapentzone, entry); } /* * vm_map_entry_delete: [ internal use only ] * * Deallocate the given entry from the target map. */ static void vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry) { vm_object_t object; vm_pindex_t offidxstart, offidxend, count, size1; vm_size_t size; vm_map_entry_unlink(map, entry, UNLINK_MERGE_NONE); object = entry->object.vm_object; if ((entry->eflags & MAP_ENTRY_GUARD) != 0) { MPASS(entry->cred == NULL); MPASS((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0); MPASS(object == NULL); vm_map_entry_deallocate(entry, map->system_map); return; } size = entry->end - entry->start; map->size -= size; if (entry->cred != NULL) { swap_release_by_cred(size, entry->cred); crfree(entry->cred); } if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || object == NULL) { entry->object.vm_object = NULL; } else if ((object->flags & OBJ_ANON) != 0 || object == kernel_object) { KASSERT(entry->cred == NULL || object->cred == NULL || (entry->eflags & MAP_ENTRY_NEEDS_COPY), ("OVERCOMMIT vm_map_entry_delete: both cred %p", entry)); count = atop(size); offidxstart = OFF_TO_IDX(entry->offset); offidxend = offidxstart + count; VM_OBJECT_WLOCK(object); if (object->ref_count != 1 && ((object->flags & OBJ_ONEMAPPING) != 0 || object == kernel_object)) { vm_object_collapse(object); /* * The option OBJPR_NOTMAPPED can be passed here * because vm_map_delete() already performed * pmap_remove() on the only mapping to this range * of pages. */ vm_object_page_remove(object, offidxstart, offidxend, OBJPR_NOTMAPPED); if (object->type == OBJT_SWAP) swap_pager_freespace(object, offidxstart, count); if (offidxend >= object->size && offidxstart < object->size) { size1 = object->size; object->size = offidxstart; if (object->cred != NULL) { size1 -= object->size; KASSERT(object->charge >= ptoa(size1), ("object %p charge < 0", object)); swap_release_by_cred(ptoa(size1), object->cred); object->charge -= ptoa(size1); } } } VM_OBJECT_WUNLOCK(object); } if (map->system_map) vm_map_entry_deallocate(entry, TRUE); else { entry->defer_next = curthread->td_map_def_user; curthread->td_map_def_user = entry; } } /* * vm_map_delete: [ internal use only ] * * Deallocates the given address range from the target * map. */ int vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end) { vm_map_entry_t entry; vm_map_entry_t first_entry; VM_MAP_ASSERT_LOCKED(map); if (start == end) return (KERN_SUCCESS); /* * Find the start of the region, and clip it */ if (!vm_map_lookup_entry(map, start, &first_entry)) entry = vm_map_entry_succ(first_entry); else { entry = first_entry; vm_map_clip_start(map, entry, start); } /* * Step through all entries in this region */ while (entry->start < end) { vm_map_entry_t next; /* * Wait for wiring or unwiring of an entry to complete. * Also wait for any system wirings to disappear on * user maps. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 || (vm_map_pmap(map) != kernel_pmap && vm_map_entry_system_wired_count(entry) != 0)) { unsigned int last_timestamp; vm_offset_t saved_start; vm_map_entry_t tmp_entry; saved_start = entry->start; entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; last_timestamp = map->timestamp; (void) vm_map_unlock_and_wait(map, 0); vm_map_lock(map); if (last_timestamp + 1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. * Specifically, the entry may have been * clipped, merged, or deleted. */ if (!vm_map_lookup_entry(map, saved_start, &tmp_entry)) entry = vm_map_entry_succ(tmp_entry); else { entry = tmp_entry; vm_map_clip_start(map, entry, saved_start); } } continue; } vm_map_clip_end(map, entry, end); next = vm_map_entry_succ(entry); /* * Unwire before removing addresses from the pmap; otherwise, * unwiring will put the entries back in the pmap. */ if (entry->wired_count != 0) vm_map_entry_unwire(map, entry); /* * Remove mappings for the pages, but only if the * mappings could exist. For instance, it does not * make sense to call pmap_remove() for guard entries. */ if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || entry->object.vm_object != NULL) pmap_remove(map->pmap, entry->start, entry->end); if (entry->end == map->anon_loc) map->anon_loc = entry->start; /* * Delete the entry only after removing all pmap * entries pointing to its pages. (Otherwise, its * page frames may be reallocated, and any modify bits * will be set in the wrong object!) */ vm_map_entry_delete(map, entry); entry = next; } return (KERN_SUCCESS); } /* * vm_map_remove: * * Remove the given address range from the target map. * This is the exported form of vm_map_delete. */ int vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) { int result; vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); result = vm_map_delete(map, start, end); vm_map_unlock(map); return (result); } /* * vm_map_check_protection: * * Assert that the target map allows the specified privilege on the * entire address region given. The entire region must be allocated. * * WARNING! This code does not and should not check whether the * contents of the region is accessible. For example a smaller file * might be mapped into a larger address space. * * NOTE! This code is also called by munmap(). * * The map must be locked. A read lock is sufficient. */ boolean_t vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_prot_t protection) { vm_map_entry_t entry; vm_map_entry_t tmp_entry; if (!vm_map_lookup_entry(map, start, &tmp_entry)) return (FALSE); entry = tmp_entry; while (start < end) { /* * No holes allowed! */ if (start < entry->start) return (FALSE); /* * Check protection associated with entry. */ if ((entry->protection & protection) != protection) return (FALSE); /* go to next entry */ start = entry->end; entry = vm_map_entry_succ(entry); } return (TRUE); } /* * vm_map_copy_entry: * * Copies the contents of the source entry to the destination * entry. The entries *must* be aligned properly. */ static void vm_map_copy_entry( vm_map_t src_map, vm_map_t dst_map, vm_map_entry_t src_entry, vm_map_entry_t dst_entry, vm_ooffset_t *fork_charge) { vm_object_t src_object; vm_map_entry_t fake_entry; vm_offset_t size; struct ucred *cred; int charged; VM_MAP_ASSERT_LOCKED(dst_map); if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP) return; if (src_entry->wired_count == 0 || (src_entry->protection & VM_PROT_WRITE) == 0) { /* * If the source entry is marked needs_copy, it is already * write-protected. */ if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 && (src_entry->protection & VM_PROT_WRITE) != 0) { pmap_protect(src_map->pmap, src_entry->start, src_entry->end, src_entry->protection & ~VM_PROT_WRITE); } /* * Make a copy of the object. */ size = src_entry->end - src_entry->start; if ((src_object = src_entry->object.vm_object) != NULL) { VM_OBJECT_WLOCK(src_object); charged = ENTRY_CHARGED(src_entry); - if (src_object->handle == NULL && - (src_object->flags & OBJ_ANON) != 0) { + if ((src_object->flags & OBJ_ANON) != 0) { vm_object_collapse(src_object); if ((src_object->flags & OBJ_ONEMAPPING) != 0) { vm_object_split(src_entry); src_object = src_entry->object.vm_object; } } vm_object_reference_locked(src_object); vm_object_clear_flag(src_object, OBJ_ONEMAPPING); if (src_entry->cred != NULL && !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { KASSERT(src_object->cred == NULL, ("OVERCOMMIT: vm_map_copy_entry: cred %p", src_object)); src_object->cred = src_entry->cred; src_object->charge = size; } VM_OBJECT_WUNLOCK(src_object); dst_entry->object.vm_object = src_object; if (charged) { cred = curthread->td_ucred; crhold(cred); dst_entry->cred = cred; *fork_charge += size; if (!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { crhold(cred); src_entry->cred = cred; *fork_charge += size; } } src_entry->eflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY; dst_entry->eflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY; dst_entry->offset = src_entry->offset; if (src_entry->eflags & MAP_ENTRY_WRITECNT) { /* * MAP_ENTRY_WRITECNT cannot * indicate write reference from * src_entry, since the entry is * marked as needs copy. Allocate a * fake entry that is used to * decrement object->un_pager writecount * at the appropriate time. Attach * fake_entry to the deferred list. */ fake_entry = vm_map_entry_create(dst_map); fake_entry->eflags = MAP_ENTRY_WRITECNT; src_entry->eflags &= ~MAP_ENTRY_WRITECNT; vm_object_reference(src_object); fake_entry->object.vm_object = src_object; fake_entry->start = src_entry->start; fake_entry->end = src_entry->end; fake_entry->defer_next = curthread->td_map_def_user; curthread->td_map_def_user = fake_entry; } pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, dst_entry->end - dst_entry->start, src_entry->start); } else { dst_entry->object.vm_object = NULL; dst_entry->offset = 0; if (src_entry->cred != NULL) { dst_entry->cred = curthread->td_ucred; crhold(dst_entry->cred); *fork_charge += size; } } } else { /* * We don't want to make writeable wired pages copy-on-write. * Immediately copy these pages into the new map by simulating * page faults. The new pages are pageable. */ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry, fork_charge); } } /* * vmspace_map_entry_forked: * Update the newly-forked vmspace each time a map entry is inherited * or copied. The values for vm_dsize and vm_tsize are approximate * (and mostly-obsolete ideas in the face of mmap(2) et al.) */ static void vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2, vm_map_entry_t entry) { vm_size_t entrysize; vm_offset_t newend; if ((entry->eflags & MAP_ENTRY_GUARD) != 0) return; entrysize = entry->end - entry->start; vm2->vm_map.size += entrysize; if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) { vm2->vm_ssize += btoc(entrysize); } else if (entry->start >= (vm_offset_t)vm1->vm_daddr && entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) { newend = MIN(entry->end, (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)); vm2->vm_dsize += btoc(newend - entry->start); } else if (entry->start >= (vm_offset_t)vm1->vm_taddr && entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) { newend = MIN(entry->end, (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)); vm2->vm_tsize += btoc(newend - entry->start); } } /* * vmspace_fork: * Create a new process vmspace structure and vm_map * based on those of an existing process. The new map * is based on the old map, according to the inheritance * values on the regions in that map. * * XXX It might be worth coalescing the entries added to the new vmspace. * * The source map must not be locked. */ struct vmspace * vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge) { struct vmspace *vm2; vm_map_t new_map, old_map; vm_map_entry_t new_entry, old_entry; vm_object_t object; int error, locked; vm_inherit_t inh; old_map = &vm1->vm_map; /* Copy immutable fields of vm1 to vm2. */ vm2 = vmspace_alloc(vm_map_min(old_map), vm_map_max(old_map), pmap_pinit); if (vm2 == NULL) return (NULL); vm2->vm_taddr = vm1->vm_taddr; vm2->vm_daddr = vm1->vm_daddr; vm2->vm_maxsaddr = vm1->vm_maxsaddr; vm_map_lock(old_map); if (old_map->busy) vm_map_wait_busy(old_map); new_map = &vm2->vm_map; locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */ KASSERT(locked, ("vmspace_fork: lock failed")); error = pmap_vmspace_copy(new_map->pmap, old_map->pmap); if (error != 0) { sx_xunlock(&old_map->lock); sx_xunlock(&new_map->lock); vm_map_process_deferred(); vmspace_free(vm2); return (NULL); } new_map->anon_loc = old_map->anon_loc; old_entry = vm_map_entry_first(old_map); while (old_entry != &old_map->header) { if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) panic("vm_map_fork: encountered a submap"); inh = old_entry->inheritance; if ((old_entry->eflags & MAP_ENTRY_GUARD) != 0 && inh != VM_INHERIT_NONE) inh = VM_INHERIT_COPY; switch (inh) { case VM_INHERIT_NONE: break; case VM_INHERIT_SHARE: /* * Clone the entry, creating the shared object if necessary. */ object = old_entry->object.vm_object; if (object == NULL) { vm_map_entry_back(old_entry); object = old_entry->object.vm_object; } /* * Add the reference before calling vm_object_shadow * to insure that a shadow object is created. */ vm_object_reference(object); if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { vm_object_shadow(&old_entry->object.vm_object, &old_entry->offset, old_entry->end - old_entry->start); old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; /* Transfer the second reference too. */ vm_object_reference( old_entry->object.vm_object); /* * As in vm_map_merged_neighbor_dispose(), * the vnode lock will not be acquired in * this call to vm_object_deallocate(). */ vm_object_deallocate(object); object = old_entry->object.vm_object; } VM_OBJECT_WLOCK(object); vm_object_clear_flag(object, OBJ_ONEMAPPING); if (old_entry->cred != NULL) { KASSERT(object->cred == NULL, ("vmspace_fork both cred")); object->cred = old_entry->cred; object->charge = old_entry->end - old_entry->start; old_entry->cred = NULL; } /* * Assert the correct state of the vnode * v_writecount while the object is locked, to * not relock it later for the assertion * correctness. */ if (old_entry->eflags & MAP_ENTRY_WRITECNT && object->type == OBJT_VNODE) { KASSERT(((struct vnode *)object->handle)-> v_writecount > 0, ("vmspace_fork: v_writecount %p", object)); KASSERT(object->un_pager.vnp.writemappings > 0, ("vmspace_fork: vnp.writecount %p", object)); } VM_OBJECT_WUNLOCK(object); /* * Clone the entry, referencing the shared object. */ new_entry = vm_map_entry_create(new_map); *new_entry = *old_entry; new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION); new_entry->wiring_thread = NULL; new_entry->wired_count = 0; if (new_entry->eflags & MAP_ENTRY_WRITECNT) { vm_pager_update_writecount(object, new_entry->start, new_entry->end); } vm_map_entry_set_vnode_text(new_entry, true); /* * Insert the entry into the new map -- we know we're * inserting at the end of the new map. */ vm_map_entry_link(new_map, new_entry); vmspace_map_entry_forked(vm1, vm2, new_entry); /* * Update the physical map */ pmap_copy(new_map->pmap, old_map->pmap, new_entry->start, (old_entry->end - old_entry->start), old_entry->start); break; case VM_INHERIT_COPY: /* * Clone the entry and link into the map. */ new_entry = vm_map_entry_create(new_map); *new_entry = *old_entry; /* * Copied entry is COW over the old object. */ new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WRITECNT); new_entry->wiring_thread = NULL; new_entry->wired_count = 0; new_entry->object.vm_object = NULL; new_entry->cred = NULL; vm_map_entry_link(new_map, new_entry); vmspace_map_entry_forked(vm1, vm2, new_entry); vm_map_copy_entry(old_map, new_map, old_entry, new_entry, fork_charge); vm_map_entry_set_vnode_text(new_entry, true); break; case VM_INHERIT_ZERO: /* * Create a new anonymous mapping entry modelled from * the old one. */ new_entry = vm_map_entry_create(new_map); memset(new_entry, 0, sizeof(*new_entry)); new_entry->start = old_entry->start; new_entry->end = old_entry->end; new_entry->eflags = old_entry->eflags & ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC); new_entry->protection = old_entry->protection; new_entry->max_protection = old_entry->max_protection; new_entry->inheritance = VM_INHERIT_ZERO; vm_map_entry_link(new_map, new_entry); vmspace_map_entry_forked(vm1, vm2, new_entry); new_entry->cred = curthread->td_ucred; crhold(new_entry->cred); *fork_charge += (new_entry->end - new_entry->start); break; } old_entry = vm_map_entry_succ(old_entry); } /* * Use inlined vm_map_unlock() to postpone handling the deferred * map entries, which cannot be done until both old_map and * new_map locks are released. */ sx_xunlock(&old_map->lock); sx_xunlock(&new_map->lock); vm_map_process_deferred(); return (vm2); } /* * Create a process's stack for exec_new_vmspace(). This function is never * asked to wire the newly created stack. */ int vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_prot_t prot, vm_prot_t max, int cow) { vm_size_t growsize, init_ssize; rlim_t vmemlim; int rv; MPASS((map->flags & MAP_WIREFUTURE) == 0); growsize = sgrowsiz; init_ssize = (max_ssize < growsize) ? max_ssize : growsize; vm_map_lock(map); vmemlim = lim_cur(curthread, RLIMIT_VMEM); /* If we would blow our VMEM resource limit, no go */ if (map->size + init_ssize > vmemlim) { rv = KERN_NO_SPACE; goto out; } rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot, max, cow); out: vm_map_unlock(map); return (rv); } static int stack_guard_page = 1; SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RWTUN, &stack_guard_page, 0, "Specifies the number of guard pages for a stack that grows"); static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow) { vm_map_entry_t new_entry, prev_entry; vm_offset_t bot, gap_bot, gap_top, top; vm_size_t init_ssize, sgp; int orient, rv; /* * The stack orientation is piggybacked with the cow argument. * Extract it into orient and mask the cow argument so that we * don't pass it around further. */ orient = cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP); KASSERT(orient != 0, ("No stack grow direction")); KASSERT(orient != (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP), ("bi-dir stack")); if (addrbos < vm_map_min(map) || addrbos + max_ssize > vm_map_max(map) || addrbos + max_ssize <= addrbos) return (KERN_INVALID_ADDRESS); sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 || (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 : (vm_size_t)stack_guard_page * PAGE_SIZE; if (sgp >= max_ssize) return (KERN_INVALID_ARGUMENT); init_ssize = growsize; if (max_ssize < init_ssize + sgp) init_ssize = max_ssize - sgp; /* If addr is already mapped, no go */ if (vm_map_lookup_entry(map, addrbos, &prev_entry)) return (KERN_NO_SPACE); /* * If we can't accommodate max_ssize in the current mapping, no go. */ if (vm_map_entry_succ(prev_entry)->start < addrbos + max_ssize) return (KERN_NO_SPACE); /* * We initially map a stack of only init_ssize. We will grow as * needed later. Depending on the orientation of the stack (i.e. * the grow direction) we either map at the top of the range, the * bottom of the range or in the middle. * * Note: we would normally expect prot and max to be VM_PROT_ALL, * and cow to be 0. Possibly we should eliminate these as input * parameters, and just pass these values here in the insert call. */ if (orient == MAP_STACK_GROWS_DOWN) { bot = addrbos + max_ssize - init_ssize; top = bot + init_ssize; gap_bot = addrbos; gap_top = bot; } else /* if (orient == MAP_STACK_GROWS_UP) */ { bot = addrbos; top = bot + init_ssize; gap_bot = top; gap_top = addrbos + max_ssize; } rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow); if (rv != KERN_SUCCESS) return (rv); new_entry = vm_map_entry_succ(prev_entry); KASSERT(new_entry->end == top || new_entry->start == bot, ("Bad entry start/end for new stack entry")); KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 || (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0, ("new entry lacks MAP_ENTRY_GROWS_DOWN")); KASSERT((orient & MAP_STACK_GROWS_UP) == 0 || (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0, ("new entry lacks MAP_ENTRY_GROWS_UP")); if (gap_bot == gap_top) return (KERN_SUCCESS); rv = vm_map_insert(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE, VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ? MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP)); if (rv == KERN_SUCCESS) { /* * Gap can never successfully handle a fault, so * read-ahead logic is never used for it. Re-use * next_read of the gap entry to store * stack_guard_page for vm_map_growstack(). */ if (orient == MAP_STACK_GROWS_DOWN) vm_map_entry_pred(new_entry)->next_read = sgp; else vm_map_entry_succ(new_entry)->next_read = sgp; } else { (void)vm_map_delete(map, bot, top); } return (rv); } /* * Attempts to grow a vm stack entry. Returns KERN_SUCCESS if we * successfully grow the stack. */ static int vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry) { vm_map_entry_t stack_entry; struct proc *p; struct vmspace *vm; struct ucred *cred; vm_offset_t gap_end, gap_start, grow_start; vm_size_t grow_amount, guard, max_grow; rlim_t lmemlim, stacklim, vmemlim; int rv, rv1; bool gap_deleted, grow_down, is_procstack; #ifdef notyet uint64_t limit; #endif #ifdef RACCT int error; #endif p = curproc; vm = p->p_vmspace; /* * Disallow stack growth when the access is performed by a * debugger or AIO daemon. The reason is that the wrong * resource limits are applied. */ if (p != initproc && (map != &p->p_vmspace->vm_map || p->p_textvp == NULL)) return (KERN_FAILURE); MPASS(!map->system_map); lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK); stacklim = lim_cur(curthread, RLIMIT_STACK); vmemlim = lim_cur(curthread, RLIMIT_VMEM); retry: /* If addr is not in a hole for a stack grow area, no need to grow. */ if (gap_entry == NULL && !vm_map_lookup_entry(map, addr, &gap_entry)) return (KERN_FAILURE); if ((gap_entry->eflags & MAP_ENTRY_GUARD) == 0) return (KERN_SUCCESS); if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) { stack_entry = vm_map_entry_succ(gap_entry); if ((stack_entry->eflags & MAP_ENTRY_GROWS_DOWN) == 0 || stack_entry->start != gap_entry->end) return (KERN_FAILURE); grow_amount = round_page(stack_entry->start - addr); grow_down = true; } else if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_UP) != 0) { stack_entry = vm_map_entry_pred(gap_entry); if ((stack_entry->eflags & MAP_ENTRY_GROWS_UP) == 0 || stack_entry->end != gap_entry->start) return (KERN_FAILURE); grow_amount = round_page(addr + 1 - stack_entry->end); grow_down = false; } else { return (KERN_FAILURE); } guard = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 || (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 : gap_entry->next_read; max_grow = gap_entry->end - gap_entry->start; if (guard > max_grow) return (KERN_NO_SPACE); max_grow -= guard; if (grow_amount > max_grow) return (KERN_NO_SPACE); /* * If this is the main process stack, see if we're over the stack * limit. */ is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr && addr < (vm_offset_t)p->p_sysent->sv_usrstack; if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) return (KERN_NO_SPACE); #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (is_procstack && racct_set(p, RACCT_STACK, ctob(vm->vm_ssize) + grow_amount)) { PROC_UNLOCK(p); return (KERN_NO_SPACE); } PROC_UNLOCK(p); } #endif grow_amount = roundup(grow_amount, sgrowsiz); if (grow_amount > max_grow) grow_amount = max_grow; if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { grow_amount = trunc_page((vm_size_t)stacklim) - ctob(vm->vm_ssize); } #ifdef notyet PROC_LOCK(p); limit = racct_get_available(p, RACCT_STACK); PROC_UNLOCK(p); if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit)) grow_amount = limit - ctob(vm->vm_ssize); #endif if (!old_mlock && (map->flags & MAP_WIREFUTURE) != 0) { if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) { rv = KERN_NO_SPACE; goto out; } #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (racct_set(p, RACCT_MEMLOCK, ptoa(pmap_wired_count(map->pmap)) + grow_amount)) { PROC_UNLOCK(p); rv = KERN_NO_SPACE; goto out; } PROC_UNLOCK(p); } #endif } /* If we would blow our VMEM resource limit, no go */ if (map->size + grow_amount > vmemlim) { rv = KERN_NO_SPACE; goto out; } #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) { PROC_UNLOCK(p); rv = KERN_NO_SPACE; goto out; } PROC_UNLOCK(p); } #endif if (vm_map_lock_upgrade(map)) { gap_entry = NULL; vm_map_lock_read(map); goto retry; } if (grow_down) { grow_start = gap_entry->end - grow_amount; if (gap_entry->start + grow_amount == gap_entry->end) { gap_start = gap_entry->start; gap_end = gap_entry->end; vm_map_entry_delete(map, gap_entry); gap_deleted = true; } else { MPASS(gap_entry->start < gap_entry->end - grow_amount); vm_map_entry_resize(map, gap_entry, -grow_amount); gap_deleted = false; } rv = vm_map_insert(map, NULL, 0, grow_start, grow_start + grow_amount, stack_entry->protection, stack_entry->max_protection, MAP_STACK_GROWS_DOWN); if (rv != KERN_SUCCESS) { if (gap_deleted) { rv1 = vm_map_insert(map, NULL, 0, gap_start, gap_end, VM_PROT_NONE, VM_PROT_NONE, MAP_CREATE_GUARD | MAP_CREATE_STACK_GAP_DN); MPASS(rv1 == KERN_SUCCESS); } else vm_map_entry_resize(map, gap_entry, grow_amount); } } else { grow_start = stack_entry->end; cred = stack_entry->cred; if (cred == NULL && stack_entry->object.vm_object != NULL) cred = stack_entry->object.vm_object->cred; if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred)) rv = KERN_NO_SPACE; /* Grow the underlying object if applicable. */ else if (stack_entry->object.vm_object == NULL || vm_object_coalesce(stack_entry->object.vm_object, stack_entry->offset, (vm_size_t)(stack_entry->end - stack_entry->start), grow_amount, cred != NULL)) { if (gap_entry->start + grow_amount == gap_entry->end) { vm_map_entry_delete(map, gap_entry); vm_map_entry_resize(map, stack_entry, grow_amount); } else { gap_entry->start += grow_amount; stack_entry->end += grow_amount; } map->size += grow_amount; rv = KERN_SUCCESS; } else rv = KERN_FAILURE; } if (rv == KERN_SUCCESS && is_procstack) vm->vm_ssize += btoc(grow_amount); /* * Heed the MAP_WIREFUTURE flag if it was set for this process. */ if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE) != 0) { rv = vm_map_wire_locked(map, grow_start, grow_start + grow_amount, VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES); } vm_map_lock_downgrade(map); out: #ifdef RACCT if (racct_enable && rv != KERN_SUCCESS) { PROC_LOCK(p); error = racct_set(p, RACCT_VMEM, map->size); KASSERT(error == 0, ("decreasing RACCT_VMEM failed")); if (!old_mlock) { error = racct_set(p, RACCT_MEMLOCK, ptoa(pmap_wired_count(map->pmap))); KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed")); } error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize)); KASSERT(error == 0, ("decreasing RACCT_STACK failed")); PROC_UNLOCK(p); } #endif return (rv); } /* * Unshare the specified VM space for exec. If other processes are * mapped to it, then create a new one. The new vmspace is null. */ int vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0, ("vmspace_exec recursed")); newvmspace = vmspace_alloc(minuser, maxuser, pmap_pinit); if (newvmspace == NULL) return (ENOMEM); newvmspace->vm_swrss = oldvmspace->vm_swrss; /* * This code is written like this for prototype purposes. The * goal is to avoid running down the vmspace here, but let the * other process's that are still using the vmspace to finally * run it down. Even though there is little or no chance of blocking * here, it is a good idea to keep this form for future mods. */ PROC_VMSPACE_LOCK(p); p->p_vmspace = newvmspace; PROC_VMSPACE_UNLOCK(p); if (p == curthread->td_proc) pmap_activate(curthread); curthread->td_pflags |= TDP_EXECVMSPC; return (0); } /* * Unshare the specified VM space for forcing COW. This * is called by rfork, for the (RFMEM|RFPROC) == 0 case. */ int vmspace_unshare(struct proc *p) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; vm_ooffset_t fork_charge; if (oldvmspace->vm_refcnt == 1) return (0); fork_charge = 0; newvmspace = vmspace_fork(oldvmspace, &fork_charge); if (newvmspace == NULL) return (ENOMEM); if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) { vmspace_free(newvmspace); return (ENOMEM); } PROC_VMSPACE_LOCK(p); p->p_vmspace = newvmspace; PROC_VMSPACE_UNLOCK(p); if (p == curthread->td_proc) pmap_activate(curthread); vmspace_free(oldvmspace); return (0); } /* * vm_map_lookup: * * Finds the VM object, offset, and * protection for a given virtual address in the * specified map, assuming a page fault of the * type specified. * * Leaves the map in question locked for read; return * values are guaranteed until a vm_map_lookup_done * call is performed. Note that the map argument * is in/out; the returned map must be used in * the call to vm_map_lookup_done. * * A handle (out_entry) is returned for use in * vm_map_lookup_done, to make that fast. * * If a lookup is requested with "write protection" * specified, the map may be changed to perform virtual * copying operations, although the data referenced will * remain the same. */ int vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ vm_offset_t vaddr, vm_prot_t fault_typea, vm_map_entry_t *out_entry, /* OUT */ vm_object_t *object, /* OUT */ vm_pindex_t *pindex, /* OUT */ vm_prot_t *out_prot, /* OUT */ boolean_t *wired) /* OUT */ { vm_map_entry_t entry; vm_map_t map = *var_map; vm_prot_t prot; vm_prot_t fault_type = fault_typea; vm_object_t eobject; vm_size_t size; struct ucred *cred; RetryLookup: vm_map_lock_read(map); RetryLookupLocked: /* * Lookup the faulting address. */ if (!vm_map_lookup_entry(map, vaddr, out_entry)) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } entry = *out_entry; /* * Handle submaps. */ if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_t old_map = map; *var_map = map = entry->object.sub_map; vm_map_unlock_read(old_map); goto RetryLookup; } /* * Check whether this task is allowed to have this page. */ prot = entry->protection; if ((fault_typea & VM_PROT_FAULT_LOOKUP) != 0) { fault_typea &= ~VM_PROT_FAULT_LOOKUP; if (prot == VM_PROT_NONE && map != kernel_map && (entry->eflags & MAP_ENTRY_GUARD) != 0 && (entry->eflags & (MAP_ENTRY_STACK_GAP_DN | MAP_ENTRY_STACK_GAP_UP)) != 0 && vm_map_growstack(map, vaddr, entry) == KERN_SUCCESS) goto RetryLookupLocked; } fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE; if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) { vm_map_unlock_read(map); return (KERN_PROTECTION_FAILURE); } KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags & (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) != (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY), ("entry %p flags %x", entry, entry->eflags)); if ((fault_typea & VM_PROT_COPY) != 0 && (entry->max_protection & VM_PROT_WRITE) == 0 && (entry->eflags & MAP_ENTRY_COW) == 0) { vm_map_unlock_read(map); return (KERN_PROTECTION_FAILURE); } /* * If this page is not pageable, we have to get it for all possible * accesses. */ *wired = (entry->wired_count != 0); if (*wired) fault_type = entry->protection; size = entry->end - entry->start; /* * If the entry was copy-on-write, we either ... */ if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { /* * If we want to write the page, we may as well handle that * now since we've got the map locked. * * If we don't need to write the page, we just demote the * permissions allowed. */ if ((fault_type & VM_PROT_WRITE) != 0 || (fault_typea & VM_PROT_COPY) != 0) { /* * Make a new object, and place it in the object * chain. Note that no new references have appeared * -- one just moved from the map to the new * object. */ if (vm_map_lock_upgrade(map)) goto RetryLookup; if (entry->cred == NULL) { /* * The debugger owner is charged for * the memory. */ cred = curthread->td_ucred; crhold(cred); if (!swap_reserve_by_cred(size, cred)) { crfree(cred); vm_map_unlock(map); return (KERN_RESOURCE_SHORTAGE); } entry->cred = cred; } vm_object_shadow(&entry->object.vm_object, &entry->offset, size); entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; eobject = entry->object.vm_object; if (eobject->cred != NULL) { /* * The object was not shadowed. */ swap_release_by_cred(size, entry->cred); crfree(entry->cred); entry->cred = NULL; } else if (entry->cred != NULL) { VM_OBJECT_WLOCK(eobject); eobject->cred = entry->cred; eobject->charge = size; VM_OBJECT_WUNLOCK(eobject); entry->cred = NULL; } vm_map_lock_downgrade(map); } else { /* * We're attempting to read a copy-on-write page -- * don't allow writes. */ prot &= ~VM_PROT_WRITE; } } /* * Create an object if necessary. */ if (entry->object.vm_object == NULL && !map->system_map) { if (vm_map_lock_upgrade(map)) goto RetryLookup; entry->object.vm_object = vm_object_allocate_anon(atop(size)); entry->offset = 0; if (entry->cred != NULL) { VM_OBJECT_WLOCK(entry->object.vm_object); entry->object.vm_object->cred = entry->cred; entry->object.vm_object->charge = size; VM_OBJECT_WUNLOCK(entry->object.vm_object); entry->cred = NULL; } vm_map_lock_downgrade(map); } /* * Return the object/offset from this entry. If the entry was * copy-on-write or empty, it has been fixed up. */ *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); *object = entry->object.vm_object; *out_prot = prot; return (KERN_SUCCESS); } /* * vm_map_lookup_locked: * * Lookup the faulting address. A version of vm_map_lookup that returns * KERN_FAILURE instead of blocking on map lock or memory allocation. */ int vm_map_lookup_locked(vm_map_t *var_map, /* IN/OUT */ vm_offset_t vaddr, vm_prot_t fault_typea, vm_map_entry_t *out_entry, /* OUT */ vm_object_t *object, /* OUT */ vm_pindex_t *pindex, /* OUT */ vm_prot_t *out_prot, /* OUT */ boolean_t *wired) /* OUT */ { vm_map_entry_t entry; vm_map_t map = *var_map; vm_prot_t prot; vm_prot_t fault_type = fault_typea; /* * Lookup the faulting address. */ if (!vm_map_lookup_entry(map, vaddr, out_entry)) return (KERN_INVALID_ADDRESS); entry = *out_entry; /* * Fail if the entry refers to a submap. */ if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) return (KERN_FAILURE); /* * Check whether this task is allowed to have this page. */ prot = entry->protection; fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE; if ((fault_type & prot) != fault_type) return (KERN_PROTECTION_FAILURE); /* * If this page is not pageable, we have to get it for all possible * accesses. */ *wired = (entry->wired_count != 0); if (*wired) fault_type = entry->protection; if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { /* * Fail if the entry was copy-on-write for a write fault. */ if (fault_type & VM_PROT_WRITE) return (KERN_FAILURE); /* * We're attempting to read a copy-on-write page -- * don't allow writes. */ prot &= ~VM_PROT_WRITE; } /* * Fail if an object should be created. */ if (entry->object.vm_object == NULL && !map->system_map) return (KERN_FAILURE); /* * Return the object/offset from this entry. If the entry was * copy-on-write or empty, it has been fixed up. */ *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); *object = entry->object.vm_object; *out_prot = prot; return (KERN_SUCCESS); } /* * vm_map_lookup_done: * * Releases locks acquired by a vm_map_lookup * (according to the handle returned by that lookup). */ void vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry) { /* * Unlock the main-level map */ vm_map_unlock_read(map); } vm_offset_t vm_map_max_KBI(const struct vm_map *map) { return (vm_map_max(map)); } vm_offset_t vm_map_min_KBI(const struct vm_map *map) { return (vm_map_min(map)); } pmap_t vm_map_pmap_KBI(vm_map_t map) { return (map->pmap); } #ifdef INVARIANTS static void _vm_map_assert_consistent(vm_map_t map, int check) { vm_map_entry_t entry, prev; vm_size_t max_left, max_right; if (enable_vmmap_check != check) return; prev = &map->header; VM_MAP_ENTRY_FOREACH(entry, map) { KASSERT(prev->end <= entry->start, ("map %p prev->end = %jx, start = %jx", map, (uintmax_t)prev->end, (uintmax_t)entry->start)); KASSERT(entry->start < entry->end, ("map %p start = %jx, end = %jx", map, (uintmax_t)entry->start, (uintmax_t)entry->end)); KASSERT(entry->end <= vm_map_entry_succ(entry)->start, ("map %p end = %jx, next->start = %jx", map, (uintmax_t)entry->end, (uintmax_t)vm_map_entry_succ(entry)->start)); KASSERT(entry->left == NULL || entry->left->start < entry->start, ("map %p left->start = %jx, start = %jx", map, (uintmax_t)entry->left->start, (uintmax_t)entry->start)); KASSERT(entry->right == NULL || entry->start < entry->right->start, ("map %p start = %jx, right->start = %jx", map, (uintmax_t)entry->start, (uintmax_t)entry->right->start)); max_left = vm_map_entry_max_free_left(entry, vm_map_entry_pred(entry)); max_right = vm_map_entry_max_free_right(entry, vm_map_entry_succ(entry)); KASSERT(entry->max_free == MAX(max_left, max_right), ("map %p max = %jx, max_left = %jx, max_right = %jx", map, (uintmax_t)entry->max_free, (uintmax_t)max_left, (uintmax_t)max_right)); prev = entry; } KASSERT(prev->end <= entry->start, ("map %p prev->end = %jx, start = %jx", map, (uintmax_t)prev->end, (uintmax_t)entry->start)); } #endif #include "opt_ddb.h" #ifdef DDB #include #include static void vm_map_print(vm_map_t map) { vm_map_entry_t entry, prev; db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", (void *)map, (void *)map->pmap, map->nentries, map->timestamp); db_indent += 2; prev = &map->header; VM_MAP_ENTRY_FOREACH(entry, map) { db_iprintf("map entry %p: start=%p, end=%p, eflags=%#x, \n", (void *)entry, (void *)entry->start, (void *)entry->end, entry->eflags); { static char *inheritance_name[4] = {"share", "copy", "none", "donate_copy"}; db_iprintf(" prot=%x/%x/%s", entry->protection, entry->max_protection, inheritance_name[(int)(unsigned char) entry->inheritance]); if (entry->wired_count != 0) db_printf(", wired"); } if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { db_printf(", share=%p, offset=0x%jx\n", (void *)entry->object.sub_map, (uintmax_t)entry->offset); if (prev == &map->header || prev->object.sub_map != entry->object.sub_map) { db_indent += 2; vm_map_print((vm_map_t)entry->object.sub_map); db_indent -= 2; } } else { if (entry->cred != NULL) db_printf(", ruid %d", entry->cred->cr_ruid); db_printf(", object=%p, offset=0x%jx", (void *)entry->object.vm_object, (uintmax_t)entry->offset); if (entry->object.vm_object && entry->object.vm_object->cred) db_printf(", obj ruid %d charge %jx", entry->object.vm_object->cred->cr_ruid, (uintmax_t)entry->object.vm_object->charge); if (entry->eflags & MAP_ENTRY_COW) db_printf(", copy (%s)", (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); db_printf("\n"); if (prev == &map->header || prev->object.vm_object != entry->object.vm_object) { db_indent += 2; vm_object_print((db_expr_t)(intptr_t) entry->object.vm_object, 0, 0, (char *)0); db_indent -= 2; } } prev = entry; } db_indent -= 2; } DB_SHOW_COMMAND(map, map) { if (!have_addr) { db_printf("usage: show map \n"); return; } vm_map_print((vm_map_t)addr); } DB_SHOW_COMMAND(procvm, procvm) { struct proc *p; if (have_addr) { p = db_lookup_proc(addr); } else { p = curproc; } db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, (void *)vmspace_pmap(p->p_vmspace)); vm_map_print((vm_map_t)&p->p_vmspace->vm_map); } #endif /* DDB */ Index: head/sys/vm/vm_object.c =================================================================== --- head/sys/vm/vm_object.c (revision 355063) +++ head/sys/vm/vm_object.c (revision 355064) @@ -1,2709 +1,2703 @@ /*- * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vm_object.c 8.5 (Berkeley) 3/22/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Authors: Avadis Tevanian, Jr., Michael Wayne Young * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ /* * Virtual memory object module. */ #include __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include #include #include #include #include #include #include #include #include #include #include /* for curproc, pageproc */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int old_msync; SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, "Use old (insecure) msync behavior"); static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, int flags, boolean_t *allclean, boolean_t *eio); static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean); static void vm_object_qcollapse(vm_object_t object); static void vm_object_vndeallocate(vm_object_t object); static void vm_object_backing_remove(vm_object_t object); /* * Virtual memory objects maintain the actual data * associated with allocated virtual memory. A given * page of memory exists within exactly one object. * * An object is only deallocated when all "references" * are given up. Only one "reference" to a given * region of an object should be writeable. * * Associated with each object is a list of all resident * memory pages belonging to that object; this list is * maintained by the "vm_page" module, and locked by the object's * lock. * * Each object also records a "pager" routine which is * used to retrieve (and store) pages to the proper backing * storage. In addition, objects may be backed by other * objects from which they were virtual-copied. * * The only items within the object structure which are * modified after time of creation are: * reference count locked by object's lock * pager routine locked by object's lock * */ struct object_q vm_object_list; struct mtx vm_object_list_mtx; /* lock for object list and count */ struct vm_object kernel_object_store; static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats"); static counter_u64_t object_collapses = EARLY_COUNTER; SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, &object_collapses, "VM object collapses"); static counter_u64_t object_bypasses = EARLY_COUNTER; SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, &object_bypasses, "VM object bypasses"); static void counter_startup(void) { object_collapses = counter_u64_alloc(M_WAITOK); object_bypasses = counter_u64_alloc(M_WAITOK); } SYSINIT(object_counters, SI_SUB_CPU, SI_ORDER_ANY, counter_startup, NULL); static uma_zone_t obj_zone; static int vm_object_zinit(void *mem, int size, int flags); #ifdef INVARIANTS static void vm_object_zdtor(void *mem, int size, void *arg); static void vm_object_zdtor(void *mem, int size, void *arg) { vm_object_t object; object = (vm_object_t)mem; KASSERT(object->ref_count == 0, ("object %p ref_count = %d", object, object->ref_count)); KASSERT(TAILQ_EMPTY(&object->memq), ("object %p has resident pages in its memq", object)); KASSERT(vm_radix_is_empty(&object->rtree), ("object %p has resident pages in its trie", object)); #if VM_NRESERVLEVEL > 0 KASSERT(LIST_EMPTY(&object->rvq), ("object %p has reservations", object)); #endif KASSERT(REFCOUNT_COUNT(object->paging_in_progress) == 0, ("object %p paging_in_progress = %d", object, REFCOUNT_COUNT(object->paging_in_progress))); KASSERT(object->busy == 0, ("object %p busy = %d", object, object->busy)); KASSERT(object->resident_page_count == 0, ("object %p resident_page_count = %d", object, object->resident_page_count)); KASSERT(object->shadow_count == 0, ("object %p shadow_count = %d", object, object->shadow_count)); KASSERT(object->type == OBJT_DEAD, ("object %p has non-dead type %d", object, object->type)); } #endif static int vm_object_zinit(void *mem, int size, int flags) { vm_object_t object; object = (vm_object_t)mem; rw_init_flags(&object->lock, "vm object", RW_DUPOK | RW_NEW); /* These are true for any object that has been freed */ object->type = OBJT_DEAD; vm_radix_init(&object->rtree); refcount_init(&object->ref_count, 0); refcount_init(&object->paging_in_progress, 0); refcount_init(&object->busy, 0); object->resident_page_count = 0; object->shadow_count = 0; object->flags = OBJ_DEAD; mtx_lock(&vm_object_list_mtx); TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); mtx_unlock(&vm_object_list_mtx); return (0); } static void _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, vm_object_t object) { TAILQ_INIT(&object->memq); LIST_INIT(&object->shadow_head); object->type = type; if (type == OBJT_SWAP) pctrie_init(&object->un_pager.swp.swp_blks); /* * Ensure that swap_pager_swapoff() iteration over object_list * sees up to date type and pctrie head if it observed * non-dead object. */ atomic_thread_fence_rel(); object->pg_color = 0; object->flags = flags; object->size = size; object->domain.dr_policy = NULL; object->generation = 1; object->cleangeneration = 1; refcount_init(&object->ref_count, 1); object->memattr = VM_MEMATTR_DEFAULT; object->cred = NULL; object->charge = 0; object->handle = NULL; object->backing_object = NULL; object->backing_object_offset = (vm_ooffset_t) 0; #if VM_NRESERVLEVEL > 0 LIST_INIT(&object->rvq); #endif umtx_shm_object_init(object); } /* * vm_object_init: * * Initialize the VM objects module. */ void vm_object_init(void) { TAILQ_INIT(&vm_object_list); mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); rw_init(&kernel_object->lock, "kernel vm object"); _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object); #if VM_NRESERVLEVEL > 0 kernel_object->flags |= OBJ_COLORED; kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); #endif /* * The lock portion of struct vm_object must be type stable due * to vm_pageout_fallback_object_lock locking a vm object * without holding any references to it. */ obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, #ifdef INVARIANTS vm_object_zdtor, #else NULL, #endif vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); vm_radix_zinit(); } void vm_object_clear_flag(vm_object_t object, u_short bits) { VM_OBJECT_ASSERT_WLOCKED(object); object->flags &= ~bits; } /* * Sets the default memory attribute for the specified object. Pages * that are allocated to this object are by default assigned this memory * attribute. * * Presently, this function must be called before any pages are allocated * to the object. In the future, this requirement may be relaxed for * "default" and "swap" objects. */ int vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) { VM_OBJECT_ASSERT_WLOCKED(object); switch (object->type) { case OBJT_DEFAULT: case OBJT_DEVICE: case OBJT_MGTDEVICE: case OBJT_PHYS: case OBJT_SG: case OBJT_SWAP: case OBJT_VNODE: if (!TAILQ_EMPTY(&object->memq)) return (KERN_FAILURE); break; case OBJT_DEAD: return (KERN_INVALID_ARGUMENT); default: panic("vm_object_set_memattr: object %p is of undefined type", object); } object->memattr = memattr; return (KERN_SUCCESS); } void vm_object_pip_add(vm_object_t object, short i) { refcount_acquiren(&object->paging_in_progress, i); } void vm_object_pip_wakeup(vm_object_t object) { refcount_release(&object->paging_in_progress); } void vm_object_pip_wakeupn(vm_object_t object, short i) { refcount_releasen(&object->paging_in_progress, i); } void vm_object_pip_wait(vm_object_t object, char *waitid) { VM_OBJECT_ASSERT_WLOCKED(object); while (REFCOUNT_COUNT(object->paging_in_progress) > 0) { VM_OBJECT_WUNLOCK(object); refcount_wait(&object->paging_in_progress, waitid, PVM); VM_OBJECT_WLOCK(object); } } void vm_object_pip_wait_unlocked(vm_object_t object, char *waitid) { VM_OBJECT_ASSERT_UNLOCKED(object); while (REFCOUNT_COUNT(object->paging_in_progress) > 0) refcount_wait(&object->paging_in_progress, waitid, PVM); } /* * vm_object_allocate: * * Returns a new object with the given size. */ vm_object_t vm_object_allocate(objtype_t type, vm_pindex_t size) { vm_object_t object; u_short flags; switch (type) { case OBJT_DEAD: panic("vm_object_allocate: can't create OBJT_DEAD"); case OBJT_DEFAULT: case OBJT_SWAP: flags = OBJ_COLORED; break; case OBJT_DEVICE: case OBJT_SG: flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; break; case OBJT_MGTDEVICE: flags = OBJ_FICTITIOUS; break; case OBJT_PHYS: flags = OBJ_UNMANAGED; break; case OBJT_VNODE: flags = 0; break; default: panic("vm_object_allocate: type %d is undefined", type); } object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); _vm_object_allocate(type, size, flags, object); return (object); } /* * vm_object_allocate_anon: * * Returns a new default object of the given size and marked as * anonymous memory for special split/collapse handling. Color * to be initialized by the caller. */ vm_object_t vm_object_allocate_anon(vm_pindex_t size) { vm_object_t object; object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); _vm_object_allocate(OBJT_DEFAULT, size, OBJ_ANON | OBJ_ONEMAPPING, object); return (object); } /* * vm_object_reference: * * Gets another reference to the given object. Note: OBJ_DEAD * objects can be referenced during final cleaning. */ void vm_object_reference(vm_object_t object) { if (object == NULL) return; VM_OBJECT_RLOCK(object); vm_object_reference_locked(object); VM_OBJECT_RUNLOCK(object); } /* * vm_object_reference_locked: * * Gets another reference to the given object. * * The object must be locked. */ void vm_object_reference_locked(vm_object_t object) { struct vnode *vp; VM_OBJECT_ASSERT_LOCKED(object); refcount_acquire(&object->ref_count); if (object->type == OBJT_VNODE) { vp = object->handle; vref(vp); } } /* * Handle deallocating an object of type OBJT_VNODE. */ static void vm_object_vndeallocate(vm_object_t object) { struct vnode *vp = (struct vnode *) object->handle; KASSERT(object->type == OBJT_VNODE, ("vm_object_vndeallocate: not a vnode object")); KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); if (refcount_release(&object->ref_count) && !umtx_shm_vnobj_persistent) umtx_shm_object_terminated(object); VM_OBJECT_RUNLOCK(object); /* vrele may need the vnode lock. */ vrele(vp); } /* * vm_object_deallocate: * * Release a reference to the specified object, * gained either through a vm_object_allocate * or a vm_object_reference call. When all references * are gone, storage associated with this object * may be relinquished. * * No object may be locked. */ void vm_object_deallocate(vm_object_t object) { - vm_object_t temp; + vm_object_t robject, temp; bool released; while (object != NULL) { VM_OBJECT_RLOCK(object); if (object->type == OBJT_VNODE) { vm_object_vndeallocate(object); return; } /* * If the reference count goes to 0 we start calling * vm_object_terminate() on the object chain. A ref count * of 1 may be a special case depending on the shadow count * being 0 or 1. These cases require a write lock on the * object. */ if ((object->flags & OBJ_ANON) == 0) released = refcount_release_if_gt(&object->ref_count, 1); else released = refcount_release_if_gt(&object->ref_count, 2); VM_OBJECT_RUNLOCK(object); if (released) return; VM_OBJECT_WLOCK(object); KASSERT(object->ref_count != 0, ("vm_object_deallocate: object deallocated too many times: %d", object->type)); refcount_release(&object->ref_count); if (object->ref_count > 1) { VM_OBJECT_WUNLOCK(object); return; } else if (object->ref_count == 1) { if (object->shadow_count == 0 && - object->handle == NULL && (object->flags & OBJ_ANON) != 0) { vm_object_set_flag(object, OBJ_ONEMAPPING); - } else if ((object->shadow_count == 1) && - (object->handle == NULL) && - (object->flags & OBJ_ANON) != 0) { - vm_object_t robject; - + } else if (object->shadow_count == 1) { + KASSERT((object->flags & OBJ_ANON) != 0, + ("obj %p with shadow_count > 0 is not anon", + object)); robject = LIST_FIRST(&object->shadow_head); KASSERT(robject != NULL, - ("vm_object_deallocate: ref_count: %d, shadow_count: %d", - object->ref_count, - object->shadow_count)); + ("vm_object_deallocate: ref_count: %d, " + "shadow_count: %d", object->ref_count, + object->shadow_count)); KASSERT((robject->flags & OBJ_TMPFS_NODE) == 0, ("shadowed tmpfs v_object %p", object)); if (!VM_OBJECT_TRYWLOCK(robject)) { /* * Avoid a potential deadlock. */ refcount_acquire(&object->ref_count); VM_OBJECT_WUNLOCK(object); /* * More likely than not the thread * holding robject's lock has lower * priority than the current thread. * Let the lower priority thread run. */ pause("vmo_de", 1); continue; } /* * Collapse object into its shadow unless its * shadow is dead. In that case, object will * be deallocated by the thread that is * deallocating its shadow. */ if ((robject->flags & - (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON && - robject->handle == NULL) { + (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON) { refcount_acquire(&robject->ref_count); retry: if (REFCOUNT_COUNT(robject->paging_in_progress) > 0) { VM_OBJECT_WUNLOCK(object); vm_object_pip_wait(robject, "objde1"); temp = robject->backing_object; if (object == temp) { VM_OBJECT_WLOCK(object); goto retry; } } else if (REFCOUNT_COUNT(object->paging_in_progress) > 0) { VM_OBJECT_WUNLOCK(robject); VM_OBJECT_WUNLOCK(object); refcount_wait( &object->paging_in_progress, "objde2", PVM); VM_OBJECT_WLOCK(robject); temp = robject->backing_object; if (object == temp) { VM_OBJECT_WLOCK(object); goto retry; } } else VM_OBJECT_WUNLOCK(object); if (robject->ref_count == 1) { robject->ref_count--; object = robject; goto doterm; } object = robject; vm_object_collapse(object); VM_OBJECT_WUNLOCK(object); continue; } VM_OBJECT_WUNLOCK(robject); } VM_OBJECT_WUNLOCK(object); return; } doterm: umtx_shm_object_terminated(object); temp = object->backing_object; if (temp != NULL) { KASSERT((object->flags & OBJ_TMPFS_NODE) == 0, ("shadowed tmpfs v_object 2 %p", object)); vm_object_backing_remove(object); } /* * Don't double-terminate, we could be in a termination * recursion due to the terminate having to sync data * to disk. */ if ((object->flags & OBJ_DEAD) == 0) { vm_object_set_flag(object, OBJ_DEAD); vm_object_terminate(object); } else VM_OBJECT_WUNLOCK(object); object = temp; } } /* * vm_object_destroy removes the object from the global object list * and frees the space for the object. */ void vm_object_destroy(vm_object_t object) { /* * Release the allocation charge. */ if (object->cred != NULL) { swap_release_by_cred(object->charge, object->cred); object->charge = 0; crfree(object->cred); object->cred = NULL; } /* * Free the space for the object. */ uma_zfree(obj_zone, object); } static void vm_object_backing_remove_locked(vm_object_t object) { vm_object_t backing_object; backing_object = object->backing_object; VM_OBJECT_ASSERT_WLOCKED(object); VM_OBJECT_ASSERT_WLOCKED(backing_object); if ((object->flags & OBJ_SHADOWLIST) != 0) { LIST_REMOVE(object, shadow_list); backing_object->shadow_count--; object->flags &= ~OBJ_SHADOWLIST; } object->backing_object = NULL; } static void vm_object_backing_remove(vm_object_t object) { vm_object_t backing_object; VM_OBJECT_ASSERT_WLOCKED(object); if ((object->flags & OBJ_SHADOWLIST) != 0) { backing_object = object->backing_object; VM_OBJECT_WLOCK(backing_object); vm_object_backing_remove_locked(object); VM_OBJECT_WUNLOCK(backing_object); } else object->backing_object = NULL; } static void vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) { VM_OBJECT_ASSERT_WLOCKED(object); if ((backing_object->flags & OBJ_ANON) != 0) { VM_OBJECT_ASSERT_WLOCKED(backing_object); LIST_INSERT_HEAD(&backing_object->shadow_head, object, shadow_list); backing_object->shadow_count++; object->flags |= OBJ_SHADOWLIST; } object->backing_object = backing_object; } static void vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) { VM_OBJECT_ASSERT_WLOCKED(object); if ((backing_object->flags & OBJ_ANON) != 0) { VM_OBJECT_WLOCK(backing_object); vm_object_backing_insert_locked(object, backing_object); VM_OBJECT_WUNLOCK(backing_object); } else object->backing_object = backing_object; } /* * vm_object_terminate_pages removes any remaining pageable pages * from the object and resets the object to an empty state. */ static void vm_object_terminate_pages(vm_object_t object) { vm_page_t p, p_next; VM_OBJECT_ASSERT_WLOCKED(object); /* * Free any remaining pageable pages. This also removes them from the * paging queues. However, don't free wired pages, just remove them * from the object. Rather than incrementally removing each page from * the object, the page and object are reset to any empty state. */ TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) { vm_page_assert_unbusied(p); KASSERT(p->object == object && (p->ref_count & VPRC_OBJREF) != 0, ("vm_object_terminate_pages: page %p is inconsistent", p)); p->object = NULL; if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { VM_CNT_INC(v_pfree); vm_page_free(p); } } /* * If the object contained any pages, then reset it to an empty state. * None of the object's fields, including "resident_page_count", were * modified by the preceding loop. */ if (object->resident_page_count != 0) { vm_radix_reclaim_allnodes(&object->rtree); TAILQ_INIT(&object->memq); object->resident_page_count = 0; if (object->type == OBJT_VNODE) vdrop(object->handle); } } /* * vm_object_terminate actually destroys the specified object, freeing * up all previously used resources. * * The object must be locked. * This routine may block. */ void vm_object_terminate(vm_object_t object) { VM_OBJECT_ASSERT_WLOCKED(object); KASSERT((object->flags & OBJ_DEAD) != 0, ("terminating non-dead obj %p", object)); /* * wait for the pageout daemon to be done with the object */ vm_object_pip_wait(object, "objtrm"); KASSERT(!REFCOUNT_COUNT(object->paging_in_progress), ("vm_object_terminate: pageout in progress")); KASSERT(object->ref_count == 0, ("vm_object_terminate: object with references, ref_count=%d", object->ref_count)); if ((object->flags & OBJ_PG_DTOR) == 0) vm_object_terminate_pages(object); #if VM_NRESERVLEVEL > 0 if (__predict_false(!LIST_EMPTY(&object->rvq))) vm_reserv_break_all(object); #endif KASSERT(object->cred == NULL || object->type == OBJT_DEFAULT || object->type == OBJT_SWAP, ("%s: non-swap obj %p has cred", __func__, object)); /* * Let the pager know object is dead. */ vm_pager_deallocate(object); VM_OBJECT_WUNLOCK(object); vm_object_destroy(object); } /* * Make the page read-only so that we can clear the object flags. However, if * this is a nosync mmap then the object is likely to stay dirty so do not * mess with the page and do not clear the object flags. Returns TRUE if the * page should be flushed, and FALSE otherwise. */ static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) { vm_page_assert_busied(p); /* * If we have been asked to skip nosync pages and this is a * nosync page, skip it. Note that the object flags were not * cleared in this case so we do not have to set them. */ if ((flags & OBJPC_NOSYNC) != 0 && (p->aflags & PGA_NOSYNC) != 0) { *allclean = FALSE; return (FALSE); } else { pmap_remove_write(p); return (p->dirty != 0); } } /* * vm_object_page_clean * * Clean all dirty pages in the specified range of object. Leaves page * on whatever queue it is currently on. If NOSYNC is set then do not * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), * leaving the object dirty. * * When stuffing pages asynchronously, allow clustering. XXX we need a * synchronous clustering mode implementation. * * Odd semantics: if start == end, we clean everything. * * The object must be locked. * * Returns FALSE if some page from the range was not written, as * reported by the pager, and TRUE otherwise. */ boolean_t vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, int flags) { vm_page_t np, p; vm_pindex_t pi, tend, tstart; int curgeneration, n, pagerflags; boolean_t eio, res, allclean; VM_OBJECT_ASSERT_WLOCKED(object); if (object->type != OBJT_VNODE || !vm_object_mightbedirty(object) || object->resident_page_count == 0) return (TRUE); pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; tstart = OFF_TO_IDX(start); tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); allclean = tstart == 0 && tend >= object->size; res = TRUE; rescan: curgeneration = object->generation; for (p = vm_page_find_least(object, tstart); p != NULL; p = np) { pi = p->pindex; if (pi >= tend) break; np = TAILQ_NEXT(p, listq); if (vm_page_none_valid(p)) continue; if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) { if (object->generation != curgeneration && (flags & OBJPC_SYNC) != 0) goto rescan; np = vm_page_find_least(object, pi); continue; } if (!vm_object_page_remove_write(p, flags, &allclean)) { vm_page_xunbusy(p); continue; } n = vm_object_page_collect_flush(object, p, pagerflags, flags, &allclean, &eio); if (eio) { res = FALSE; allclean = FALSE; } if (object->generation != curgeneration && (flags & OBJPC_SYNC) != 0) goto rescan; /* * If the VOP_PUTPAGES() did a truncated write, so * that even the first page of the run is not fully * written, vm_pageout_flush() returns 0 as the run * length. Since the condition that caused truncated * write may be permanent, e.g. exhausted free space, * accepting n == 0 would cause an infinite loop. * * Forwarding the iterator leaves the unwritten page * behind, but there is not much we can do there if * filesystem refuses to write it. */ if (n == 0) { n = 1; allclean = FALSE; } np = vm_page_find_least(object, pi + n); } #if 0 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); #endif if (allclean) object->cleangeneration = curgeneration; return (res); } static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags, int flags, boolean_t *allclean, boolean_t *eio) { vm_page_t ma[vm_pageout_page_count], p_first, tp; int count, i, mreq, runlen; vm_page_lock_assert(p, MA_NOTOWNED); vm_page_assert_xbusied(p); VM_OBJECT_ASSERT_WLOCKED(object); count = 1; mreq = 0; for (tp = p; count < vm_pageout_page_count; count++) { tp = vm_page_next(tp); if (tp == NULL || vm_page_tryxbusy(tp) == 0) break; if (!vm_object_page_remove_write(tp, flags, allclean)) { vm_page_xunbusy(tp); break; } } for (p_first = p; count < vm_pageout_page_count; count++) { tp = vm_page_prev(p_first); if (tp == NULL || vm_page_tryxbusy(tp) == 0) break; if (!vm_object_page_remove_write(tp, flags, allclean)) { vm_page_xunbusy(tp); break; } p_first = tp; mreq++; } for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++) ma[i] = tp; vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio); return (runlen); } /* * Note that there is absolutely no sense in writing out * anonymous objects, so we track down the vnode object * to write out. * We invalidate (remove) all pages from the address space * for semantic correctness. * * If the backing object is a device object with unmanaged pages, then any * mappings to the specified range of pages must be removed before this * function is called. * * Note: certain anonymous maps, such as MAP_NOSYNC maps, * may start out with a NULL object. */ boolean_t vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, boolean_t syncio, boolean_t invalidate) { vm_object_t backing_object; struct vnode *vp; struct mount *mp; int error, flags, fsync_after; boolean_t res; if (object == NULL) return (TRUE); res = TRUE; error = 0; VM_OBJECT_WLOCK(object); while ((backing_object = object->backing_object) != NULL) { VM_OBJECT_WLOCK(backing_object); offset += object->backing_object_offset; VM_OBJECT_WUNLOCK(object); object = backing_object; if (object->size < OFF_TO_IDX(offset + size)) size = IDX_TO_OFF(object->size) - offset; } /* * Flush pages if writing is allowed, invalidate them * if invalidation requested. Pages undergoing I/O * will be ignored by vm_object_page_remove(). * * We cannot lock the vnode and then wait for paging * to complete without deadlocking against vm_fault. * Instead we simply call vm_object_page_remove() and * allow it to block internally on a page-by-page * basis when it encounters pages undergoing async * I/O. */ if (object->type == OBJT_VNODE && vm_object_mightbedirty(object) != 0 && ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { VM_OBJECT_WUNLOCK(object); (void) vn_start_write(vp, &mp, V_WAIT); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); if (syncio && !invalidate && offset == 0 && atop(size) == object->size) { /* * If syncing the whole mapping of the file, * it is faster to schedule all the writes in * async mode, also allowing the clustering, * and then wait for i/o to complete. */ flags = 0; fsync_after = TRUE; } else { flags = (syncio || invalidate) ? OBJPC_SYNC : 0; flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; fsync_after = FALSE; } VM_OBJECT_WLOCK(object); res = vm_object_page_clean(object, offset, offset + size, flags); VM_OBJECT_WUNLOCK(object); if (fsync_after) error = VOP_FSYNC(vp, MNT_WAIT, curthread); VOP_UNLOCK(vp, 0); vn_finished_write(mp); if (error != 0) res = FALSE; VM_OBJECT_WLOCK(object); } if ((object->type == OBJT_VNODE || object->type == OBJT_DEVICE) && invalidate) { if (object->type == OBJT_DEVICE) /* * The option OBJPR_NOTMAPPED must be passed here * because vm_object_page_remove() cannot remove * unmanaged mappings. */ flags = OBJPR_NOTMAPPED; else if (old_msync) flags = 0; else flags = OBJPR_CLEANONLY; vm_object_page_remove(object, OFF_TO_IDX(offset), OFF_TO_IDX(offset + size + PAGE_MASK), flags); } VM_OBJECT_WUNLOCK(object); return (res); } /* * Determine whether the given advice can be applied to the object. Advice is * not applied to unmanaged pages since they never belong to page queues, and * since MADV_FREE is destructive, it can apply only to anonymous pages that * have been mapped at most once. */ static bool vm_object_advice_applies(vm_object_t object, int advice) { if ((object->flags & OBJ_UNMANAGED) != 0) return (false); if (advice != MADV_FREE) return (true); return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == (OBJ_ONEMAPPING | OBJ_ANON)); } static void vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, vm_size_t size) { if (advice == MADV_FREE && object->type == OBJT_SWAP) swap_pager_freespace(object, pindex, size); } /* * vm_object_madvise: * * Implements the madvise function at the object/page level. * * MADV_WILLNEED (any object) * * Activate the specified pages if they are resident. * * MADV_DONTNEED (any object) * * Deactivate the specified pages if they are resident. * * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, * OBJ_ONEMAPPING only) * * Deactivate and clean the specified pages if they are * resident. This permits the process to reuse the pages * without faulting or the kernel to reclaim the pages * without I/O. */ void vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, int advice) { vm_pindex_t tpindex; vm_object_t backing_object, tobject; vm_page_t m, tm; if (object == NULL) return; relookup: VM_OBJECT_WLOCK(object); if (!vm_object_advice_applies(object, advice)) { VM_OBJECT_WUNLOCK(object); return; } for (m = vm_page_find_least(object, pindex); pindex < end; pindex++) { tobject = object; /* * If the next page isn't resident in the top-level object, we * need to search the shadow chain. When applying MADV_FREE, we * take care to release any swap space used to store * non-resident pages. */ if (m == NULL || pindex < m->pindex) { /* * Optimize a common case: if the top-level object has * no backing object, we can skip over the non-resident * range in constant time. */ if (object->backing_object == NULL) { tpindex = (m != NULL && m->pindex < end) ? m->pindex : end; vm_object_madvise_freespace(object, advice, pindex, tpindex - pindex); if ((pindex = tpindex) == end) break; goto next_page; } tpindex = pindex; do { vm_object_madvise_freespace(tobject, advice, tpindex, 1); /* * Prepare to search the next object in the * chain. */ backing_object = tobject->backing_object; if (backing_object == NULL) goto next_pindex; VM_OBJECT_WLOCK(backing_object); tpindex += OFF_TO_IDX(tobject->backing_object_offset); if (tobject != object) VM_OBJECT_WUNLOCK(tobject); tobject = backing_object; if (!vm_object_advice_applies(tobject, advice)) goto next_pindex; } while ((tm = vm_page_lookup(tobject, tpindex)) == NULL); } else { next_page: tm = m; m = TAILQ_NEXT(m, listq); } /* * If the page is not in a normal state, skip it. The page * can not be invalidated while the object lock is held. */ if (!vm_page_all_valid(tm) || vm_page_wired(tm)) goto next_pindex; KASSERT((tm->flags & PG_FICTITIOUS) == 0, ("vm_object_madvise: page %p is fictitious", tm)); KASSERT((tm->oflags & VPO_UNMANAGED) == 0, ("vm_object_madvise: page %p is not managed", tm)); if (vm_page_tryxbusy(tm) == 0) { if (object != tobject) VM_OBJECT_WUNLOCK(object); if (advice == MADV_WILLNEED) { /* * Reference the page before unlocking and * sleeping so that the page daemon is less * likely to reclaim it. */ vm_page_aflag_set(tm, PGA_REFERENCED); } vm_page_busy_sleep(tm, "madvpo", false); goto relookup; } vm_page_lock(tm); vm_page_advise(tm, advice); vm_page_unlock(tm); vm_page_xunbusy(tm); vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); next_pindex: if (tobject != object) VM_OBJECT_WUNLOCK(tobject); } VM_OBJECT_WUNLOCK(object); } /* * vm_object_shadow: * * Create a new object which is backed by the * specified existing object range. The source * object reference is deallocated. * * The new object and offset into that object * are returned in the source parameters. */ void vm_object_shadow( vm_object_t *object, /* IN/OUT */ vm_ooffset_t *offset, /* IN/OUT */ vm_size_t length) { vm_object_t source; vm_object_t result; source = *object; /* * Don't create the new object if the old object isn't shared. * * If we hold the only reference we can guarantee that it won't * increase while we have the map locked. Otherwise the race is * harmless and we will end up with an extra shadow object that * will be collapsed later. */ if (source != NULL && source->ref_count == 1 && - source->handle == NULL && (source->flags & OBJ_ANON) != 0) + (source->flags & OBJ_ANON) != 0) return; /* * Allocate a new object with the given length. */ result = vm_object_allocate_anon(atop(length)); /* * Store the offset into the source object, and fix up the offset into * the new object. */ result->backing_object_offset = *offset; /* * The new object shadows the source object, adding a reference to it. * Our caller changes his reference to point to the new object, * removing a reference to the source object. Net result: no change * of reference count. * * Try to optimize the result object's page color when shadowing * in order to maintain page coloring consistency in the combined * shadowed object. */ if (source != NULL) { VM_OBJECT_WLOCK(result); vm_object_backing_insert(result, source); result->domain = source->domain; #if VM_NRESERVLEVEL > 0 result->flags |= source->flags & OBJ_COLORED; result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1)) - 1); #endif VM_OBJECT_WUNLOCK(result); } /* * Return the new things */ *offset = 0; *object = result; } /* * vm_object_split: * * Split the pages in a map entry into a new object. This affords * easier removal of unused pages, and keeps object inheritance from * being a negative impact on memory usage. */ void vm_object_split(vm_map_entry_t entry) { vm_page_t m, m_next; vm_object_t orig_object, new_object, source; vm_pindex_t idx, offidxstart; vm_size_t size; orig_object = entry->object.vm_object; if ((orig_object->flags & OBJ_ANON) == 0) return; if (orig_object->ref_count <= 1) return; VM_OBJECT_WUNLOCK(orig_object); offidxstart = OFF_TO_IDX(entry->offset); size = atop(entry->end - entry->start); /* * If swap_pager_copy() is later called, it will convert new_object * into a swap object. */ new_object = vm_object_allocate_anon(size); /* * At this point, the new object is still private, so the order in * which the original and new objects are locked does not matter. */ VM_OBJECT_WLOCK(new_object); VM_OBJECT_WLOCK(orig_object); new_object->domain = orig_object->domain; source = orig_object->backing_object; if (source != NULL) { if ((source->flags & (OBJ_ANON | OBJ_DEAD)) != 0) { VM_OBJECT_WLOCK(source); if ((source->flags & OBJ_DEAD) != 0) { VM_OBJECT_WUNLOCK(source); VM_OBJECT_WUNLOCK(orig_object); VM_OBJECT_WUNLOCK(new_object); vm_object_deallocate(new_object); VM_OBJECT_WLOCK(orig_object); return; } vm_object_backing_insert_locked(new_object, source); vm_object_reference_locked(source); /* for new_object */ vm_object_clear_flag(source, OBJ_ONEMAPPING); VM_OBJECT_WUNLOCK(source); } else { vm_object_backing_insert(new_object, source); vm_object_reference(source); } new_object->backing_object_offset = orig_object->backing_object_offset + entry->offset; } if (orig_object->cred != NULL) { new_object->cred = orig_object->cred; crhold(orig_object->cred); new_object->charge = ptoa(size); KASSERT(orig_object->charge >= ptoa(size), ("orig_object->charge < 0")); orig_object->charge -= ptoa(size); } retry: m = vm_page_find_least(orig_object, offidxstart); for (; m != NULL && (idx = m->pindex - offidxstart) < size; m = m_next) { m_next = TAILQ_NEXT(m, listq); /* * We must wait for pending I/O to complete before we can * rename the page. * * We do not have to VM_PROT_NONE the page as mappings should * not be changed by this operation. */ if (vm_page_tryxbusy(m) == 0) { VM_OBJECT_WUNLOCK(new_object); vm_page_sleep_if_busy(m, "spltwt"); VM_OBJECT_WLOCK(new_object); goto retry; } /* vm_page_rename() will dirty the page. */ if (vm_page_rename(m, new_object, idx)) { vm_page_xunbusy(m); VM_OBJECT_WUNLOCK(new_object); VM_OBJECT_WUNLOCK(orig_object); vm_radix_wait(); VM_OBJECT_WLOCK(orig_object); VM_OBJECT_WLOCK(new_object); goto retry; } #if VM_NRESERVLEVEL > 0 /* * If some of the reservation's allocated pages remain with * the original object, then transferring the reservation to * the new object is neither particularly beneficial nor * particularly harmful as compared to leaving the reservation * with the original object. If, however, all of the * reservation's allocated pages are transferred to the new * object, then transferring the reservation is typically * beneficial. Determining which of these two cases applies * would be more costly than unconditionally renaming the * reservation. */ vm_reserv_rename(m, new_object, orig_object, offidxstart); #endif if (orig_object->type != OBJT_SWAP) vm_page_xunbusy(m); } if (orig_object->type == OBJT_SWAP) { /* * swap_pager_copy() can sleep, in which case the orig_object's * and new_object's locks are released and reacquired. */ swap_pager_copy(orig_object, new_object, offidxstart, 0); TAILQ_FOREACH(m, &new_object->memq, listq) vm_page_xunbusy(m); } VM_OBJECT_WUNLOCK(orig_object); VM_OBJECT_WUNLOCK(new_object); entry->object.vm_object = new_object; entry->offset = 0LL; vm_object_deallocate(orig_object); VM_OBJECT_WLOCK(new_object); } #define OBSC_COLLAPSE_NOWAIT 0x0002 #define OBSC_COLLAPSE_WAIT 0x0004 static vm_page_t vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p, vm_page_t next, int op) { vm_object_t backing_object; VM_OBJECT_ASSERT_WLOCKED(object); backing_object = object->backing_object; VM_OBJECT_ASSERT_WLOCKED(backing_object); KASSERT(p == NULL || p->object == object || p->object == backing_object, ("invalid ownership %p %p %p", p, object, backing_object)); if ((op & OBSC_COLLAPSE_NOWAIT) != 0) return (next); /* The page is only NULL when rename fails. */ if (p == NULL) { vm_radix_wait(); } else { if (p->object == object) VM_OBJECT_WUNLOCK(backing_object); else VM_OBJECT_WUNLOCK(object); vm_page_busy_sleep(p, "vmocol", false); } VM_OBJECT_WLOCK(object); VM_OBJECT_WLOCK(backing_object); return (TAILQ_FIRST(&backing_object->memq)); } static bool vm_object_scan_all_shadowed(vm_object_t object) { vm_object_t backing_object; vm_page_t p, pp; vm_pindex_t backing_offset_index, new_pindex, pi, ps; VM_OBJECT_ASSERT_WLOCKED(object); VM_OBJECT_ASSERT_WLOCKED(object->backing_object); backing_object = object->backing_object; if ((backing_object->flags & OBJ_ANON) == 0) return (false); pi = backing_offset_index = OFF_TO_IDX(object->backing_object_offset); p = vm_page_find_least(backing_object, pi); ps = swap_pager_find_least(backing_object, pi); /* * Only check pages inside the parent object's range and * inside the parent object's mapping of the backing object. */ for (;; pi++) { if (p != NULL && p->pindex < pi) p = TAILQ_NEXT(p, listq); if (ps < pi) ps = swap_pager_find_least(backing_object, pi); if (p == NULL && ps >= backing_object->size) break; else if (p == NULL) pi = ps; else pi = MIN(p->pindex, ps); new_pindex = pi - backing_offset_index; if (new_pindex >= object->size) break; /* * See if the parent has the page or if the parent's object * pager has the page. If the parent has the page but the page * is not valid, the parent's object pager must have the page. * * If this fails, the parent does not completely shadow the * object and we might as well give up now. */ pp = vm_page_lookup(object, new_pindex); /* * The valid check here is stable due to object lock being * required to clear valid and initiate paging. */ if ((pp == NULL || vm_page_none_valid(pp)) && !vm_pager_has_page(object, new_pindex, NULL, NULL)) return (false); } return (true); } static bool vm_object_collapse_scan(vm_object_t object, int op) { vm_object_t backing_object; vm_page_t next, p, pp; vm_pindex_t backing_offset_index, new_pindex; VM_OBJECT_ASSERT_WLOCKED(object); VM_OBJECT_ASSERT_WLOCKED(object->backing_object); backing_object = object->backing_object; backing_offset_index = OFF_TO_IDX(object->backing_object_offset); /* * Initial conditions */ if ((op & OBSC_COLLAPSE_WAIT) != 0) vm_object_set_flag(backing_object, OBJ_DEAD); /* * Our scan */ for (p = TAILQ_FIRST(&backing_object->memq); p != NULL; p = next) { next = TAILQ_NEXT(p, listq); new_pindex = p->pindex - backing_offset_index; /* * Check for busy page */ if (vm_page_tryxbusy(p) == 0) { next = vm_object_collapse_scan_wait(object, p, next, op); continue; } KASSERT(p->object == backing_object, ("vm_object_collapse_scan: object mismatch")); if (p->pindex < backing_offset_index || new_pindex >= object->size) { if (backing_object->type == OBJT_SWAP) swap_pager_freespace(backing_object, p->pindex, 1); KASSERT(!pmap_page_is_mapped(p), ("freeing mapped page %p", p)); if (vm_page_remove(p)) vm_page_free(p); else vm_page_xunbusy(p); continue; } pp = vm_page_lookup(object, new_pindex); if (pp != NULL && vm_page_tryxbusy(pp) == 0) { vm_page_xunbusy(p); /* * The page in the parent is busy and possibly not * (yet) valid. Until its state is finalized by the * busy bit owner, we can't tell whether it shadows the * original page. Therefore, we must either skip it * and the original (backing_object) page or wait for * its state to be finalized. * * This is due to a race with vm_fault() where we must * unbusy the original (backing_obj) page before we can * (re)lock the parent. Hence we can get here. */ next = vm_object_collapse_scan_wait(object, pp, next, op); continue; } KASSERT(pp == NULL || !vm_page_none_valid(pp), ("unbusy invalid page %p", pp)); if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, NULL)) { /* * The page already exists in the parent OR swap exists * for this location in the parent. Leave the parent's * page alone. Destroy the original page from the * backing object. */ if (backing_object->type == OBJT_SWAP) swap_pager_freespace(backing_object, p->pindex, 1); KASSERT(!pmap_page_is_mapped(p), ("freeing mapped page %p", p)); if (vm_page_remove(p)) vm_page_free(p); else vm_page_xunbusy(p); if (pp != NULL) vm_page_xunbusy(pp); continue; } /* * Page does not exist in parent, rename the page from the * backing object to the main object. * * If the page was mapped to a process, it can remain mapped * through the rename. vm_page_rename() will dirty the page. */ if (vm_page_rename(p, object, new_pindex)) { vm_page_xunbusy(p); if (pp != NULL) vm_page_xunbusy(pp); next = vm_object_collapse_scan_wait(object, NULL, next, op); continue; } /* Use the old pindex to free the right page. */ if (backing_object->type == OBJT_SWAP) swap_pager_freespace(backing_object, new_pindex + backing_offset_index, 1); #if VM_NRESERVLEVEL > 0 /* * Rename the reservation. */ vm_reserv_rename(p, object, backing_object, backing_offset_index); #endif vm_page_xunbusy(p); } return (true); } /* * this version of collapse allows the operation to occur earlier and * when paging_in_progress is true for an object... This is not a complete * operation, but should plug 99.9% of the rest of the leaks. */ static void vm_object_qcollapse(vm_object_t object) { vm_object_t backing_object = object->backing_object; VM_OBJECT_ASSERT_WLOCKED(object); VM_OBJECT_ASSERT_WLOCKED(backing_object); if (backing_object->ref_count != 1) return; vm_object_collapse_scan(object, OBSC_COLLAPSE_NOWAIT); } /* * vm_object_collapse: * * Collapse an object with the object backing it. * Pages in the backing object are moved into the * parent, and the backing object is deallocated. */ void vm_object_collapse(vm_object_t object) { vm_object_t backing_object, new_backing_object; VM_OBJECT_ASSERT_WLOCKED(object); while (TRUE) { /* * Verify that the conditions are right for collapse: * * The object exists and the backing object exists. */ if ((backing_object = object->backing_object) == NULL) break; /* * we check the backing object first, because it is most likely * not collapsable. */ if ((backing_object->flags & OBJ_ANON) == 0) break; VM_OBJECT_WLOCK(backing_object); - if (backing_object->handle != NULL || - (backing_object->flags & OBJ_DEAD) != 0 || - object->handle != NULL || - (object->flags & OBJ_DEAD) != 0) { + if ((backing_object->flags & OBJ_DEAD) != 0 || + (object->flags & (OBJ_DEAD | OBJ_ANON)) != OBJ_ANON) { VM_OBJECT_WUNLOCK(backing_object); break; } if (REFCOUNT_COUNT(object->paging_in_progress) > 0 || REFCOUNT_COUNT(backing_object->paging_in_progress) > 0) { vm_object_qcollapse(object); VM_OBJECT_WUNLOCK(backing_object); break; } /* * We know that we can either collapse the backing object (if * the parent is the only reference to it) or (perhaps) have * the parent bypass the object if the parent happens to shadow * all the resident pages in the entire backing object. * * This is ignoring pager-backed pages such as swap pages. * vm_object_collapse_scan fails the shadowing test in this * case. */ if (backing_object->ref_count == 1) { vm_object_pip_add(object, 1); vm_object_pip_add(backing_object, 1); /* * If there is exactly one reference to the backing * object, we can collapse it into the parent. */ vm_object_collapse_scan(object, OBSC_COLLAPSE_WAIT); #if VM_NRESERVLEVEL > 0 /* * Break any reservations from backing_object. */ if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) vm_reserv_break_all(backing_object); #endif /* * Move the pager from backing_object to object. */ if (backing_object->type == OBJT_SWAP) { /* * swap_pager_copy() can sleep, in which case * the backing_object's and object's locks are * released and reacquired. * Since swap_pager_copy() is being asked to * destroy the source, it will change the * backing_object's type to OBJT_DEFAULT. */ swap_pager_copy( backing_object, object, OFF_TO_IDX(object->backing_object_offset), TRUE); } /* * Object now shadows whatever backing_object did. * Note that the reference to * backing_object->backing_object moves from within * backing_object to within object. */ vm_object_backing_remove_locked(object); new_backing_object = backing_object->backing_object; if (new_backing_object != NULL) { VM_OBJECT_WLOCK(new_backing_object); vm_object_backing_remove_locked(backing_object); vm_object_backing_insert_locked(object, new_backing_object); VM_OBJECT_WUNLOCK(new_backing_object); } object->backing_object_offset += backing_object->backing_object_offset; /* * Discard backing_object. * * Since the backing object has no pages, no pager left, * and no object references within it, all that is * necessary is to dispose of it. */ KASSERT(backing_object->ref_count == 1, ( "backing_object %p was somehow re-referenced during collapse!", backing_object)); vm_object_pip_wakeup(backing_object); backing_object->type = OBJT_DEAD; backing_object->ref_count = 0; VM_OBJECT_WUNLOCK(backing_object); vm_object_destroy(backing_object); vm_object_pip_wakeup(object); counter_u64_add(object_collapses, 1); } else { /* * If we do not entirely shadow the backing object, * there is nothing we can do so we give up. */ if (object->resident_page_count != object->size && !vm_object_scan_all_shadowed(object)) { VM_OBJECT_WUNLOCK(backing_object); break; } /* * Make the parent shadow the next object in the * chain. Deallocating backing_object will not remove * it, since its reference count is at least 2. */ vm_object_backing_remove_locked(object); new_backing_object = backing_object->backing_object; if (new_backing_object != NULL) { vm_object_backing_insert(object, new_backing_object); vm_object_reference(new_backing_object); object->backing_object_offset += backing_object->backing_object_offset; } /* * Drop the reference count on backing_object. Since * its ref_count was at least 2, it will not vanish. */ refcount_release(&backing_object->ref_count); VM_OBJECT_WUNLOCK(backing_object); counter_u64_add(object_bypasses, 1); } /* * Try again with this object's new backing object. */ } } /* * vm_object_page_remove: * * For the given object, either frees or invalidates each of the * specified pages. In general, a page is freed. However, if a page is * wired for any reason other than the existence of a managed, wired * mapping, then it may be invalidated but not removed from the object. * Pages are specified by the given range ["start", "end") and the option * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range * extends from "start" to the end of the object. If the option * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the * specified range are affected. If the option OBJPR_NOTMAPPED is * specified, then the pages within the specified range must have no * mappings. Otherwise, if this option is not specified, any mappings to * the specified pages are removed before the pages are freed or * invalidated. * * In general, this operation should only be performed on objects that * contain managed pages. There are, however, two exceptions. First, it * is performed on the kernel and kmem objects by vm_map_entry_delete(). * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- * backed pages. In both of these cases, the option OBJPR_CLEANONLY must * not be specified and the option OBJPR_NOTMAPPED must be specified. * * The object must be locked. */ void vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int options) { vm_page_t p, next; VM_OBJECT_ASSERT_WLOCKED(object); KASSERT((object->flags & OBJ_UNMANAGED) == 0 || (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, ("vm_object_page_remove: illegal options for object %p", object)); if (object->resident_page_count == 0) return; vm_object_pip_add(object, 1); again: p = vm_page_find_least(object, start); /* * Here, the variable "p" is either (1) the page with the least pindex * greater than or equal to the parameter "start" or (2) NULL. */ for (; p != NULL && (p->pindex < end || end == 0); p = next) { next = TAILQ_NEXT(p, listq); /* * If the page is wired for any reason besides the existence * of managed, wired mappings, then it cannot be freed. For * example, fictitious pages, which represent device memory, * are inherently wired and cannot be freed. They can, * however, be invalidated if the option OBJPR_CLEANONLY is * not specified. */ if (vm_page_tryxbusy(p) == 0) { vm_page_sleep_if_busy(p, "vmopar"); goto again; } if (vm_page_wired(p)) { wired: if ((options & OBJPR_NOTMAPPED) == 0 && object->ref_count != 0) pmap_remove_all(p); if ((options & OBJPR_CLEANONLY) == 0) { vm_page_invalid(p); vm_page_undirty(p); } vm_page_xunbusy(p); continue; } KASSERT((p->flags & PG_FICTITIOUS) == 0, ("vm_object_page_remove: page %p is fictitious", p)); if ((options & OBJPR_CLEANONLY) != 0 && !vm_page_none_valid(p)) { if ((options & OBJPR_NOTMAPPED) == 0 && object->ref_count != 0 && !vm_page_try_remove_write(p)) goto wired; if (p->dirty != 0) { vm_page_xunbusy(p); continue; } } if ((options & OBJPR_NOTMAPPED) == 0 && object->ref_count != 0 && !vm_page_try_remove_all(p)) goto wired; vm_page_free(p); } vm_object_pip_wakeup(object); } /* * vm_object_page_noreuse: * * For the given object, attempt to move the specified pages to * the head of the inactive queue. This bypasses regular LRU * operation and allows the pages to be reused quickly under memory * pressure. If a page is wired for any reason, then it will not * be queued. Pages are specified by the range ["start", "end"). * As a special case, if "end" is zero, then the range extends from * "start" to the end of the object. * * This operation should only be performed on objects that * contain non-fictitious, managed pages. * * The object must be locked. */ void vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) { struct mtx *mtx; vm_page_t p, next; VM_OBJECT_ASSERT_LOCKED(object); KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, ("vm_object_page_noreuse: illegal object %p", object)); if (object->resident_page_count == 0) return; p = vm_page_find_least(object, start); /* * Here, the variable "p" is either (1) the page with the least pindex * greater than or equal to the parameter "start" or (2) NULL. */ mtx = NULL; for (; p != NULL && (p->pindex < end || end == 0); p = next) { next = TAILQ_NEXT(p, listq); vm_page_change_lock(p, &mtx); vm_page_deactivate_noreuse(p); } if (mtx != NULL) mtx_unlock(mtx); } /* * Populate the specified range of the object with valid pages. Returns * TRUE if the range is successfully populated and FALSE otherwise. * * Note: This function should be optimized to pass a larger array of * pages to vm_pager_get_pages() before it is applied to a non- * OBJT_DEVICE object. * * The object must be locked. */ boolean_t vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) { vm_page_t m; vm_pindex_t pindex; int rv; VM_OBJECT_ASSERT_WLOCKED(object); for (pindex = start; pindex < end; pindex++) { rv = vm_page_grab_valid(&m, object, pindex, VM_ALLOC_NORMAL); if (rv != VM_PAGER_OK) break; /* * Keep "m" busy because a subsequent iteration may unlock * the object. */ } if (pindex > start) { m = vm_page_lookup(object, start); while (m != NULL && m->pindex < pindex) { vm_page_xunbusy(m); m = TAILQ_NEXT(m, listq); } } return (pindex == end); } /* * Routine: vm_object_coalesce * Function: Coalesces two objects backing up adjoining * regions of memory into a single object. * * returns TRUE if objects were combined. * * NOTE: Only works at the moment if the second object is NULL - * if it's not, which object do we lock first? * * Parameters: * prev_object First object to coalesce * prev_offset Offset into prev_object * prev_size Size of reference to prev_object * next_size Size of reference to the second object * reserved Indicator that extension region has * swap accounted for * * Conditions: * The object must *not* be locked. */ boolean_t vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) { vm_pindex_t next_pindex; if (prev_object == NULL) return (TRUE); if ((prev_object->flags & OBJ_ANON) == 0) return (FALSE); VM_OBJECT_WLOCK(prev_object); /* * Try to collapse the object first */ vm_object_collapse(prev_object); /* * Can't coalesce if: . more than one reference . paged out . shadows * another object . has a copy elsewhere (any of which mean that the * pages not mapped to prev_entry may be in use anyway) */ if (prev_object->backing_object != NULL) { VM_OBJECT_WUNLOCK(prev_object); return (FALSE); } prev_size >>= PAGE_SHIFT; next_size >>= PAGE_SHIFT; next_pindex = OFF_TO_IDX(prev_offset) + prev_size; if (prev_object->ref_count > 1 && prev_object->size != next_pindex && (prev_object->flags & OBJ_ONEMAPPING) == 0) { VM_OBJECT_WUNLOCK(prev_object); return (FALSE); } /* * Account for the charge. */ if (prev_object->cred != NULL) { /* * If prev_object was charged, then this mapping, * although not charged now, may become writable * later. Non-NULL cred in the object would prevent * swap reservation during enabling of the write * access, so reserve swap now. Failed reservation * cause allocation of the separate object for the map * entry, and swap reservation for this entry is * managed in appropriate time. */ if (!reserved && !swap_reserve_by_cred(ptoa(next_size), prev_object->cred)) { VM_OBJECT_WUNLOCK(prev_object); return (FALSE); } prev_object->charge += ptoa(next_size); } /* * Remove any pages that may still be in the object from a previous * deallocation. */ if (next_pindex < prev_object->size) { vm_object_page_remove(prev_object, next_pindex, next_pindex + next_size, 0); if (prev_object->type == OBJT_SWAP) swap_pager_freespace(prev_object, next_pindex, next_size); #if 0 if (prev_object->cred != NULL) { KASSERT(prev_object->charge >= ptoa(prev_object->size - next_pindex), ("object %p overcharged 1 %jx %jx", prev_object, (uintmax_t)next_pindex, (uintmax_t)next_size)); prev_object->charge -= ptoa(prev_object->size - next_pindex); } #endif } /* * Extend the object if necessary. */ if (next_pindex + next_size > prev_object->size) prev_object->size = next_pindex + next_size; VM_OBJECT_WUNLOCK(prev_object); return (TRUE); } void vm_object_set_writeable_dirty(vm_object_t object) { VM_OBJECT_ASSERT_LOCKED(object); /* Only set for vnodes & tmpfs */ if (object->type != OBJT_VNODE && (object->flags & OBJ_TMPFS_NODE) == 0) return; atomic_add_int(&object->generation, 1); } /* * vm_object_unwire: * * For each page offset within the specified range of the given object, * find the highest-level page in the shadow chain and unwire it. A page * must exist at every page offset, and the highest-level page must be * wired. */ void vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, uint8_t queue) { vm_object_t tobject, t1object; vm_page_t m, tm; vm_pindex_t end_pindex, pindex, tpindex; int depth, locked_depth; KASSERT((offset & PAGE_MASK) == 0, ("vm_object_unwire: offset is not page aligned")); KASSERT((length & PAGE_MASK) == 0, ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); /* The wired count of a fictitious page never changes. */ if ((object->flags & OBJ_FICTITIOUS) != 0) return; pindex = OFF_TO_IDX(offset); end_pindex = pindex + atop(length); again: locked_depth = 1; VM_OBJECT_RLOCK(object); m = vm_page_find_least(object, pindex); while (pindex < end_pindex) { if (m == NULL || pindex < m->pindex) { /* * The first object in the shadow chain doesn't * contain a page at the current index. Therefore, * the page must exist in a backing object. */ tobject = object; tpindex = pindex; depth = 0; do { tpindex += OFF_TO_IDX(tobject->backing_object_offset); tobject = tobject->backing_object; KASSERT(tobject != NULL, ("vm_object_unwire: missing page")); if ((tobject->flags & OBJ_FICTITIOUS) != 0) goto next_page; depth++; if (depth == locked_depth) { locked_depth++; VM_OBJECT_RLOCK(tobject); } } while ((tm = vm_page_lookup(tobject, tpindex)) == NULL); } else { tm = m; m = TAILQ_NEXT(m, listq); } if (vm_page_trysbusy(tm) == 0) { for (tobject = object; locked_depth >= 1; locked_depth--) { t1object = tobject->backing_object; if (tm->object != tobject) VM_OBJECT_RUNLOCK(tobject); tobject = t1object; } vm_page_busy_sleep(tm, "unwbo", true); goto again; } vm_page_unwire(tm, queue); vm_page_sunbusy(tm); next_page: pindex++; } /* Release the accumulated object locks. */ for (tobject = object; locked_depth >= 1; locked_depth--) { t1object = tobject->backing_object; VM_OBJECT_RUNLOCK(tobject); tobject = t1object; } } /* * Return the vnode for the given object, or NULL if none exists. * For tmpfs objects, the function may return NULL if there is * no vnode allocated at the time of the call. */ struct vnode * vm_object_vnode(vm_object_t object) { struct vnode *vp; VM_OBJECT_ASSERT_LOCKED(object); if (object->type == OBJT_VNODE) { vp = object->handle; KASSERT(vp != NULL, ("%s: OBJT_VNODE has no vnode", __func__)); } else if (object->type == OBJT_SWAP && (object->flags & OBJ_TMPFS) != 0) { vp = object->un_pager.swp.swp_tmpfs; KASSERT(vp != NULL, ("%s: OBJT_TMPFS has no vnode", __func__)); } else { vp = NULL; } return (vp); } /* * Busy the vm object. This prevents new pages belonging to the object from * becoming busy. Existing pages persist as busy. Callers are responsible * for checking page state before proceeding. */ void vm_object_busy(vm_object_t obj) { VM_OBJECT_ASSERT_LOCKED(obj); refcount_acquire(&obj->busy); /* The fence is required to order loads of page busy. */ atomic_thread_fence_acq_rel(); } void vm_object_unbusy(vm_object_t obj) { refcount_release(&obj->busy); } void vm_object_busy_wait(vm_object_t obj, const char *wmesg) { VM_OBJECT_ASSERT_UNLOCKED(obj); if (obj->busy) refcount_sleep(&obj->busy, wmesg, PVM); } /* * Return the kvme type of the given object. * If vpp is not NULL, set it to the object's vm_object_vnode() or NULL. */ int vm_object_kvme_type(vm_object_t object, struct vnode **vpp) { VM_OBJECT_ASSERT_LOCKED(object); if (vpp != NULL) *vpp = vm_object_vnode(object); switch (object->type) { case OBJT_DEFAULT: return (KVME_TYPE_DEFAULT); case OBJT_VNODE: return (KVME_TYPE_VNODE); case OBJT_SWAP: if ((object->flags & OBJ_TMPFS_NODE) != 0) return (KVME_TYPE_VNODE); return (KVME_TYPE_SWAP); case OBJT_DEVICE: return (KVME_TYPE_DEVICE); case OBJT_PHYS: return (KVME_TYPE_PHYS); case OBJT_DEAD: return (KVME_TYPE_DEAD); case OBJT_SG: return (KVME_TYPE_SG); case OBJT_MGTDEVICE: return (KVME_TYPE_MGTDEVICE); default: return (KVME_TYPE_UNKNOWN); } } static int sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) { struct kinfo_vmobject *kvo; char *fullpath, *freepath; struct vnode *vp; struct vattr va; vm_object_t obj; vm_page_t m; int count, error; if (req->oldptr == NULL) { /* * If an old buffer has not been provided, generate an * estimate of the space needed for a subsequent call. */ mtx_lock(&vm_object_list_mtx); count = 0; TAILQ_FOREACH(obj, &vm_object_list, object_list) { if (obj->type == OBJT_DEAD) continue; count++; } mtx_unlock(&vm_object_list_mtx); return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * count * 11 / 10)); } kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK); error = 0; /* * VM objects are type stable and are never removed from the * list once added. This allows us to safely read obj->object_list * after reacquiring the VM object lock. */ mtx_lock(&vm_object_list_mtx); TAILQ_FOREACH(obj, &vm_object_list, object_list) { if (obj->type == OBJT_DEAD) continue; VM_OBJECT_RLOCK(obj); if (obj->type == OBJT_DEAD) { VM_OBJECT_RUNLOCK(obj); continue; } mtx_unlock(&vm_object_list_mtx); kvo->kvo_size = ptoa(obj->size); kvo->kvo_resident = obj->resident_page_count; kvo->kvo_ref_count = obj->ref_count; kvo->kvo_shadow_count = obj->shadow_count; kvo->kvo_memattr = obj->memattr; kvo->kvo_active = 0; kvo->kvo_inactive = 0; TAILQ_FOREACH(m, &obj->memq, listq) { /* * A page may belong to the object but be * dequeued and set to PQ_NONE while the * object lock is not held. This makes the * reads of m->queue below racy, and we do not * count pages set to PQ_NONE. However, this * sysctl is only meant to give an * approximation of the system anyway. */ if (m->queue == PQ_ACTIVE) kvo->kvo_active++; else if (m->queue == PQ_INACTIVE) kvo->kvo_inactive++; } kvo->kvo_vn_fileid = 0; kvo->kvo_vn_fsid = 0; kvo->kvo_vn_fsid_freebsd11 = 0; freepath = NULL; fullpath = ""; kvo->kvo_type = vm_object_kvme_type(obj, &vp); if (vp != NULL) vref(vp); VM_OBJECT_RUNLOCK(obj); if (vp != NULL) { vn_fullpath(curthread, vp, &fullpath, &freepath); vn_lock(vp, LK_SHARED | LK_RETRY); if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { kvo->kvo_vn_fileid = va.va_fileid; kvo->kvo_vn_fsid = va.va_fsid; kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; /* truncate */ } vput(vp); } strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); if (freepath != NULL) free(freepath, M_TEMP); /* Pack record size down */ kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) + strlen(kvo->kvo_path) + 1; kvo->kvo_structsize = roundup(kvo->kvo_structsize, sizeof(uint64_t)); error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); mtx_lock(&vm_object_list_mtx); if (error) break; } mtx_unlock(&vm_object_list_mtx); free(kvo, M_TEMP); return (error); } SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", "List of VM objects"); #include "opt_ddb.h" #ifdef DDB #include #include #include static int _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) { vm_map_t tmpm; vm_map_entry_t tmpe; vm_object_t obj; if (map == 0) return 0; if (entry == 0) { VM_MAP_ENTRY_FOREACH(tmpe, map) { if (_vm_object_in_map(map, object, tmpe)) { return 1; } } } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { tmpm = entry->object.sub_map; VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { if (_vm_object_in_map(tmpm, object, tmpe)) { return 1; } } } else if ((obj = entry->object.vm_object) != NULL) { for (; obj; obj = obj->backing_object) if (obj == object) { return 1; } } return 0; } static int vm_object_in_map(vm_object_t object) { struct proc *p; /* sx_slock(&allproc_lock); */ FOREACH_PROC_IN_SYSTEM(p) { if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) continue; if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { /* sx_sunlock(&allproc_lock); */ return 1; } } /* sx_sunlock(&allproc_lock); */ if (_vm_object_in_map(kernel_map, object, 0)) return 1; return 0; } DB_SHOW_COMMAND(vmochk, vm_object_check) { vm_object_t object; /* * make sure that internal objs are in a map somewhere * and none have zero ref counts. */ TAILQ_FOREACH(object, &vm_object_list, object_list) { - if (object->handle == NULL && - (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { + if ((object->flags & OBJ_ANON) != 0) { if (object->ref_count == 0) { db_printf("vmochk: internal obj has zero ref count: %ld\n", (long)object->size); } if (!vm_object_in_map(object)) { db_printf( "vmochk: internal obj is not in a map: " "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", object->ref_count, (u_long)object->size, (u_long)object->size, (void *)object->backing_object); } } } } /* * vm_object_print: [ debug ] */ DB_SHOW_COMMAND(object, vm_object_print_static) { /* XXX convert args. */ vm_object_t object = (vm_object_t)addr; boolean_t full = have_addr; vm_page_t p; /* XXX count is an (unused) arg. Avoid shadowing it. */ #define count was_count int count; if (object == NULL) return; db_iprintf( "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n", object, (int)object->type, (uintmax_t)object->size, object->resident_page_count, object->ref_count, object->flags, object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge); db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", object->shadow_count, object->backing_object ? object->backing_object->ref_count : 0, object->backing_object, (uintmax_t)object->backing_object_offset); if (!full) return; db_indent += 2; count = 0; TAILQ_FOREACH(p, &object->memq, listq) { if (count == 0) db_iprintf("memory:="); else if (count == 6) { db_printf("\n"); db_iprintf(" ..."); count = 0; } else db_printf(","); count++; db_printf("(off=0x%jx,page=0x%jx)", (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); } if (count != 0) db_printf("\n"); db_indent -= 2; } /* XXX. */ #undef count /* XXX need this non-static entry for calling from vm_map_print. */ void vm_object_print( /* db_expr_t */ long addr, boolean_t have_addr, /* db_expr_t */ long count, char *modif) { vm_object_print_static(addr, have_addr, count, modif); } DB_SHOW_COMMAND(vmopag, vm_object_print_pages) { vm_object_t object; vm_pindex_t fidx; vm_paddr_t pa; vm_page_t m, prev_m; int rcount, nl, c; nl = 0; TAILQ_FOREACH(object, &vm_object_list, object_list) { db_printf("new object: %p\n", (void *)object); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; rcount = 0; fidx = 0; pa = -1; TAILQ_FOREACH(m, &object->memq, listq) { if (m->pindex > 128) break; if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && prev_m->pindex + 1 != m->pindex) { if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; rcount = 0; } } if (rcount && (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { ++rcount; continue; } if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; } fidx = m->pindex; pa = VM_PAGE_TO_PHYS(m); rcount = 1; } if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; } } } #endif /* DDB */