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Index: head/sys/i386/i386/pmap.c
===================================================================
--- head/sys/i386/i386/pmap.c
+++ head/sys/i386/i386/pmap.c
@@ -3575,20 +3575,41 @@
pv_entry_t pv;
vm_paddr_t opa, pa;
vm_page_t mpte, om;
- boolean_t invlva, wired;
+ int rv;
va = trunc_page(va);
- mpte = NULL;
- wired = (flags & PMAP_ENTER_WIRED) != 0;
-
KASSERT((pmap == kernel_pmap && va < VM_MAX_KERNEL_ADDRESS) ||
(pmap != kernel_pmap && va < VM_MAXUSER_ADDRESS),
("pmap_enter: toobig k%d %#x", pmap == kernel_pmap, va));
KASSERT(va < PMAP_TRM_MIN_ADDRESS,
("pmap_enter: invalid to pmap_enter into trampoline (va: 0x%x)",
va));
+ KASSERT(pmap != kernel_pmap || (m->oflags & VPO_UNMANAGED) != 0 ||
+ va < kmi.clean_sva || va >= kmi.clean_eva,
+ ("pmap_enter: managed mapping within the clean submap"));
if ((m->oflags & VPO_UNMANAGED) == 0 && !vm_page_xbusied(m))
VM_OBJECT_ASSERT_LOCKED(m->object);
+ KASSERT((flags & PMAP_ENTER_RESERVED) == 0,
+ ("pmap_enter: flags %u has reserved bits set", flags));
+ pa = VM_PAGE_TO_PHYS(m);
+ newpte = (pt_entry_t)(pa | PG_A | PG_V);
+ if ((flags & VM_PROT_WRITE) != 0)
+ newpte |= PG_M;
+ if ((prot & VM_PROT_WRITE) != 0)
+ newpte |= PG_RW;
+ KASSERT((newpte & (PG_M | PG_RW)) != PG_M,
+ ("pmap_enter: flags includes VM_PROT_WRITE but prot doesn't"));
+#if defined(PAE) || defined(PAE_TABLES)
+ if ((prot & VM_PROT_EXECUTE) == 0)
+ newpte |= pg_nx;
+#endif
+ if ((flags & PMAP_ENTER_WIRED) != 0)
+ newpte |= PG_W;
+ if (pmap != kernel_pmap)
+ newpte |= PG_U;
+ newpte |= pmap_cache_bits(m->md.pat_mode, psind > 0);
+ if ((m->oflags & VPO_UNMANAGED) == 0)
+ newpte |= PG_MANAGED;
rw_wlock(&pvh_global_lock);
PMAP_LOCK(pmap);
@@ -3606,10 +3627,8 @@
if (mpte == NULL) {
KASSERT((flags & PMAP_ENTER_NOSLEEP) != 0,
("pmap_allocpte failed with sleep allowed"));
- sched_unpin();
- rw_wunlock(&pvh_global_lock);
- PMAP_UNLOCK(pmap);
- return (KERN_RESOURCE_SHORTAGE);
+ rv = KERN_RESOURCE_SHORTAGE;
+ goto out;
}
} else {
/*
@@ -3617,6 +3636,7 @@
* to install a page table page. PG_V is also
* asserted by pmap_demote_pde().
*/
+ mpte = NULL;
KASSERT(pde != NULL && (*pde & PG_V) != 0,
("KVA %#x invalid pde pdir %#jx", va,
(uintmax_t)pmap->pm_pdir[PTDPTDI]));
@@ -3635,55 +3655,64 @@
(uintmax_t)pmap->pm_pdir[PTDPTDI], va);
}
- pa = VM_PAGE_TO_PHYS(m);
origpte = *pte;
- opa = origpte & PG_FRAME;
+ pv = NULL;
/*
- * Mapping has not changed, must be protection or wiring change.
+ * Is the specified virtual address already mapped?
*/
- if (origpte && (opa == pa)) {
+ if ((origpte & PG_V) != 0) {
/*
* Wiring change, just update stats. We don't worry about
* wiring PT pages as they remain resident as long as there
* are valid mappings in them. Hence, if a user page is wired,
* the PT page will be also.
*/
- if (wired && ((origpte & PG_W) == 0))
+ if ((newpte & PG_W) != 0 && (origpte & PG_W) == 0)
pmap->pm_stats.wired_count++;
- else if (!wired && (origpte & PG_W))
+ else if ((newpte & PG_W) == 0 && (origpte & PG_W) != 0)
pmap->pm_stats.wired_count--;
/*
- * Remove extra pte reference
+ * Remove the extra PT page reference.
*/
- if (mpte)
+ if (mpte != NULL) {
mpte->wire_count--;
+ KASSERT(mpte->wire_count > 0,
+ ("pmap_enter: missing reference to page table page,"
+ " va: 0x%x", va));
+ }
- if (origpte & PG_MANAGED)
- pa |= PG_MANAGED;
- goto validate;
- }
+ /*
+ * Has the physical page changed?
+ */
+ opa = origpte & PG_FRAME;
+ if (opa == pa) {
+ /*
+ * No, might be a protection or wiring change.
+ */
+ if ((origpte & PG_MANAGED) != 0 &&
+ (newpte & PG_RW) != 0)
+ vm_page_aflag_set(m, PGA_WRITEABLE);
+ if (((origpte ^ newpte) & ~(PG_M | PG_A)) == 0)
+ goto unchanged;
+ goto validate;
+ }
- pv = NULL;
-
- /*
- * Mapping has changed, invalidate old range and fall through to
- * handle validating new mapping. This ensures that all threads
- * sharing the pmap keep a consistent view of the mapping, which is
- * necessary for the correct handling of COW faults. It
- * also permits reuse of the old mapping's PV entry,
- * avoiding an allocation.
- *
- * For consistency, handle unmanaged mappings the same way.
- */
- if (opa) {
+ /*
+ * The physical page has changed. Temporarily invalidate
+ * the mapping. This ensures that all threads sharing the
+ * pmap keep a consistent view of the mapping, which is
+ * necessary for the correct handling of COW faults. It
+ * also permits reuse of the old mapping's PV entry,
+ * avoiding an allocation.
+ *
+ * For consistency, handle unmanaged mappings the same way.
+ */
origpte = pte_load_clear(pte);
KASSERT((origpte & PG_FRAME) == opa,
("pmap_enter: unexpected pa update for %#x", va));
- if (origpte & PG_W)
- pmap->pm_stats.wired_count--;
- if (origpte & PG_MANAGED) {
+ if ((origpte & PG_MANAGED) != 0) {
om = PHYS_TO_VM_PAGE(opa);
/*
@@ -3696,6 +3725,8 @@
if ((origpte & PG_A) != 0)
vm_page_aflag_set(om, PGA_REFERENCED);
pv = pmap_pvh_remove(&om->md, pmap, va);
+ if ((newpte & PG_MANAGED) == 0)
+ free_pv_entry(pmap, pv);
if ((om->aflags & PGA_WRITEABLE) != 0 &&
TAILQ_EMPTY(&om->md.pv_list) &&
((om->flags & PG_FICTITIOUS) != 0 ||
@@ -3705,86 +3736,62 @@
if ((origpte & PG_A) != 0)
pmap_invalidate_page(pmap, va);
origpte = 0;
- if (mpte != NULL) {
- mpte->wire_count--;
- KASSERT(mpte->wire_count > 0,
- ("pmap_enter: missing reference to page table page,"
- " va: 0x%x", va));
- }
- } else
+ } else {
+ /*
+ * Increment the counters.
+ */
+ if ((newpte & PG_W) != 0)
+ pmap->pm_stats.wired_count++;
pmap->pm_stats.resident_count++;
+ }
/*
* Enter on the PV list if part of our managed memory.
*/
- if ((m->oflags & VPO_UNMANAGED) == 0) {
- KASSERT(pmap != kernel_pmap || va < kmi.clean_sva ||
- va >= kmi.clean_eva,
- ("pmap_enter: managed mapping within the clean submap"));
+ if ((newpte & PG_MANAGED) != 0) {
if (pv == NULL) {
pv = get_pv_entry(pmap, FALSE);
pv->pv_va = va;
}
TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_next);
- pa |= PG_MANAGED;
- } else if (pv != NULL)
- free_pv_entry(pmap, pv);
-
- /*
- * Increment counters
- */
- if (wired)
- pmap->pm_stats.wired_count++;
-
-validate:
- /*
- * Now validate mapping with desired protection/wiring.
- */
- newpte = (pt_entry_t)(pa | pmap_cache_bits(m->md.pat_mode, 0) | PG_V);
- if ((prot & VM_PROT_WRITE) != 0) {
- newpte |= PG_RW;
- if ((newpte & PG_MANAGED) != 0)
+ if ((newpte & PG_RW) != 0)
vm_page_aflag_set(m, PGA_WRITEABLE);
}
-#if defined(PAE) || defined(PAE_TABLES)
- if ((prot & VM_PROT_EXECUTE) == 0)
- newpte |= pg_nx;
-#endif
- if (wired)
- newpte |= PG_W;
- if (pmap != kernel_pmap)
- newpte |= PG_U;
/*
- * if the mapping or permission bits are different, we need
- * to update the pte.
+ * Update the PTE.
*/
- if ((origpte & ~(PG_M|PG_A)) != newpte) {
- newpte |= PG_A;
- if ((flags & VM_PROT_WRITE) != 0)
- newpte |= PG_M;
- if (origpte & PG_V) {
- invlva = FALSE;
- origpte = pte_load_store(pte, newpte);
- KASSERT((origpte & PG_FRAME) == VM_PAGE_TO_PHYS(m),
- ("pmap_enter: unexpected pa update for %#x", va));
- if ((origpte & (PG_M | PG_RW)) == (PG_M | PG_RW) &&
- (newpte & PG_M) == 0) {
- if ((origpte & PG_MANAGED) != 0)
- vm_page_dirty(m);
- invlva = TRUE;
- }
+ if ((origpte & PG_V) != 0) {
+validate:
+ origpte = pte_load_store(pte, newpte);
+ KASSERT((origpte & PG_FRAME) == pa,
+ ("pmap_enter: unexpected pa update for %#x", va));
+ if ((newpte & PG_M) == 0 && (origpte & (PG_M | PG_RW)) ==
+ (PG_M | PG_RW)) {
+ if ((origpte & PG_MANAGED) != 0)
+ vm_page_dirty(m);
+
+ /*
+ * Although the PTE may still have PG_RW set, TLB
+ * invalidation may nonetheless be required because
+ * the PTE no longer has PG_M set.
+ */
+ }
#if defined(PAE) || defined(PAE_TABLES)
- else if ((origpte & (PG_A | PG_NX)) == PG_A &&
- (newpte & PG_NX) != 0)
- invlva = TRUE;
+ else if ((origpte & PG_NX) != 0 || (newpte & PG_NX) == 0) {
+ /*
+ * This PTE change does not require TLB invalidation.
+ */
+ goto unchanged;
+ }
#endif
- if (invlva)
- pmap_invalidate_page(pmap, va);
- } else
- pte_store(pte, newpte);
- }
+ if ((origpte & PG_A) != 0)
+ pmap_invalidate_page(pmap, va);
+ } else
+ pte_store(pte, newpte);
+unchanged:
+
#if VM_NRESERVLEVEL > 0
/*
* If both the page table page and the reservation are fully
@@ -3796,10 +3803,12 @@
pmap_promote_pde(pmap, pde, va);
#endif
+ rv = KERN_SUCCESS;
+out:
sched_unpin();
rw_wunlock(&pvh_global_lock);
PMAP_UNLOCK(pmap);
- return (KERN_SUCCESS);
+ return (rv);
}
/*

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