diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c index 04f767b8aed0..71ea8e320d73 100644 --- a/sys/compat/linux/linux_futex.c +++ b/sys/compat/linux/linux_futex.c @@ -1,1240 +1,1252 @@ /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */ /*- * SPDX-License-Identifier: BSD-4-Clause * * Copyright (c) 2005 Emmanuel Dreyfus * All rights reserved. * Copyright (c) 2009-2016 Dmitry Chagin * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Emmanuel Dreyfus * 4. The name of the author may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR 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 AUTHOR 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. */ #include __FBSDID("$FreeBSD$"); #if 0 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $"); #endif #include "opt_compat.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef COMPAT_LINUX32 #include #include #else #include #include #endif #include #include #include #include #include /* DTrace init */ LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); /** * Futex part for the special DTrace module "locks". */ LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *"); LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *"); /** * Per futex probes. */ LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *"); LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *"); /** * DTrace probes in this module. */ LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t", "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t", "int"); LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t", "int"); LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *"); LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int"); LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *", "struct waiting_proc *", "uint32_t *", "uint32_t"); LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *", "struct waiting_proc *"); LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t", "struct waiting_proc *", "uint32_t"); LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *"); LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *"); LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *", "struct waiting_proc *", "uint32_t"); LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", "int"); LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_clockswitch); LIN_SDT_PROBE_DEFINE1(futex, linux_futex, copyin_error, "int"); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, invalid_cmp_requeue_use); LIN_SDT_PROBE_DEFINE3(futex, linux_futex, debug_wait, "uint32_t *", "uint32_t", "uint32_t"); LIN_SDT_PROBE_DEFINE4(futex, linux_futex, debug_wait_value_neq, "uint32_t *", "uint32_t", "int", "uint32_t"); LIN_SDT_PROBE_DEFINE3(futex, linux_futex, debug_wake, "uint32_t *", "uint32_t", "uint32_t"); LIN_SDT_PROBE_DEFINE5(futex, linux_futex, debug_cmp_requeue, "uint32_t *", "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); LIN_SDT_PROBE_DEFINE2(futex, linux_futex, debug_cmp_requeue_value_neq, "uint32_t", "int"); LIN_SDT_PROBE_DEFINE5(futex, linux_futex, debug_wake_op, "uint32_t *", "int", "uint32_t", "uint32_t *", "uint32_t"); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unhandled_efault); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_lock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_unlock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_trylock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, deprecated_requeue); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_wait_requeue_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_futex, unimplemented_cmp_requeue_pi); LIN_SDT_PROBE_DEFINE1(futex, linux_futex, unknown_operation, "int"); LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); struct futex; struct waiting_proc { uint32_t wp_flags; struct futex *wp_futex; TAILQ_ENTRY(waiting_proc) wp_list; }; struct futex { struct mtx f_lck; uint32_t *f_uaddr; /* user-supplied value, for debug */ struct umtx_key f_key; uint32_t f_refcount; uint32_t f_bitset; LIST_ENTRY(futex) f_list; TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; }; #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck) #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck) #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck) #define FUTEX_INIT(f) do { \ mtx_init(&(f)->f_lck, "ftlk", NULL, \ MTX_DUPOK); \ LIN_SDT_PROBE1(futex, futex, create, \ &(f)->f_lck); \ } while (0) #define FUTEX_DESTROY(f) do { \ LIN_SDT_PROBE1(futex, futex, destroy, \ &(f)->f_lck); \ mtx_destroy(&(f)->f_lck); \ } while (0) #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED) #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED) #define FUTEXES_LOCK do { \ mtx_lock(&futex_mtx); \ LIN_SDT_PROBE1(locks, futex_mtx, \ locked, &futex_mtx); \ } while (0) #define FUTEXES_UNLOCK do { \ LIN_SDT_PROBE1(locks, futex_mtx, \ unlock, &futex_mtx); \ mtx_unlock(&futex_mtx); \ } while (0) /* flags for futex_get() */ #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ #define FUTEX_SHARED 0x8 /* shared futex */ #define FUTEX_DONTLOCK 0x10 /* don't lock futex */ /* wp_flags */ #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list * of futex where thread sleep to wp_list * of another futex. */ #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex * wp_list to prevent double wakeup. */ static void futex_put(struct futex *, struct waiting_proc *); static int futex_get0(uint32_t *, struct futex **f, uint32_t); static int futex_get(uint32_t *, struct waiting_proc **, struct futex **, uint32_t); static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *); static int futex_wake(struct futex *, int, uint32_t); static int futex_requeue(struct futex *, int, struct futex *, int); static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *, uint32_t); static void futex_lock(struct futex *); static void futex_unlock(struct futex *); static int futex_atomic_op(struct thread *, int, uint32_t *); static int handle_futex_death(struct linux_emuldata *, uint32_t *, unsigned int); static int fetch_robust_entry(struct linux_robust_list **, struct linux_robust_list **, unsigned int *); struct linux_futex_args { uint32_t *uaddr; int32_t op; uint32_t flags; bool clockrt; uint32_t val; struct timespec *ts; uint32_t *uaddr2; uint32_t val3; struct timespec kts; }; static int linux_futex(struct thread *, struct linux_futex_args *); static int linux_futex_wait(struct thread *, struct linux_futex_args *); static int linux_futex_wake(struct thread *, struct linux_futex_args *); +static int linux_futex_requeue(struct thread *, struct linux_futex_args *); static void futex_put(struct futex *f, struct waiting_proc *wp) { if (wp != NULL) { if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); free(wp, M_FUTEX_WP); } FUTEXES_LOCK; if (--f->f_refcount == 0) { LIST_REMOVE(f, f_list); FUTEXES_UNLOCK; if (FUTEX_LOCKED(f)) futex_unlock(f); LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr, f->f_refcount, f->f_key.shared); LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d " "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); umtx_key_release(&f->f_key); FUTEX_DESTROY(f); free(f, M_FUTEX); return; } LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount, f->f_key.shared); LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); if (FUTEX_LOCKED(f)) futex_unlock(f); FUTEXES_UNLOCK; } static int futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) { struct futex *f, *tmpf; struct umtx_key key; int error; *newf = tmpf = NULL; error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? AUTO_SHARE : THREAD_SHARE, &key); if (error) { LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error); return (error); } retry: FUTEXES_LOCK; LIST_FOREACH(f, &futex_list, f_list) { if (umtx_key_match(&f->f_key, &key)) { if (tmpf != NULL) { if (FUTEX_LOCKED(tmpf)) futex_unlock(tmpf); FUTEX_DESTROY(tmpf); free(tmpf, M_FUTEX); } if (flags & FUTEX_DONTEXISTS) { FUTEXES_UNLOCK; umtx_key_release(&key); return (EINVAL); } /* * Increment refcount of the found futex to * prevent it from deallocation before FUTEX_LOCK() */ ++f->f_refcount; FUTEXES_UNLOCK; umtx_key_release(&key); if ((flags & FUTEX_DONTLOCK) == 0) futex_lock(f); *newf = f; LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr, f->f_refcount, f->f_key.shared); LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d", uaddr, f->f_refcount, f->f_key.shared); return (0); } } if (flags & FUTEX_DONTCREATE) { FUTEXES_UNLOCK; umtx_key_release(&key); LIN_SDT_PROBE1(futex, futex_get0, null, uaddr); LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); return (0); } if (tmpf == NULL) { FUTEXES_UNLOCK; tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); tmpf->f_uaddr = uaddr; tmpf->f_key = key; tmpf->f_refcount = 1; tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY; FUTEX_INIT(tmpf); TAILQ_INIT(&tmpf->f_waiting_proc); /* * Lock the new futex before an insert into the futex_list * to prevent futex usage by other. */ if ((flags & FUTEX_DONTLOCK) == 0) futex_lock(tmpf); goto retry; } LIST_INSERT_HEAD(&futex_list, tmpf, f_list); FUTEXES_UNLOCK; LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount, tmpf->f_key.shared); LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new", uaddr, tmpf->f_refcount, tmpf->f_key.shared); *newf = tmpf; return (0); } static int futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, uint32_t flags) { int error; if (flags & FUTEX_CREATE_WP) { *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); (*wp)->wp_flags = 0; } error = futex_get0(uaddr, f, flags); if (error) { LIN_SDT_PROBE0(futex, futex_get, error); if (flags & FUTEX_CREATE_WP) free(*wp, M_FUTEX_WP); return (error); } if (flags & FUTEX_CREATE_WP) { TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); (*wp)->wp_futex = *f; } return (error); } static inline void futex_lock(struct futex *f) { LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); FUTEX_ASSERT_UNLOCKED(f); FUTEX_LOCK(f); } static inline void futex_unlock(struct futex *f) { LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); FUTEX_ASSERT_LOCKED(f); FUTEX_UNLOCK(f); } static int futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts) { sbintime_t sbt, prec, tmp; time_t over; int error; FUTEX_ASSERT_LOCKED(f); if (ts != NULL) { if (ts->tv_sec > INT32_MAX / 2) { over = ts->tv_sec - INT32_MAX / 2; ts->tv_sec -= over; } tmp = tstosbt(*ts); if (TIMESEL(&sbt, tmp)) sbt += tc_tick_sbt; sbt += tmp; prec = tmp; prec >>= tc_precexp; } else { sbt = 0; prec = 0; } LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d", f->f_uaddr, wp, sbt, f->f_refcount); error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE); if (wp->wp_flags & FUTEX_WP_REQUEUED) { KASSERT(f != wp->wp_futex, ("futex != wp_futex")); if (error) { LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, wp->wp_futex->f_refcount); } LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp" " %p requeued uaddr %p ref %d", error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, wp->wp_futex->f_refcount); futex_put(f, NULL); f = wp->wp_futex; futex_lock(f); } else { if (error) { LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error, f->f_uaddr, wp); } LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", error, f->f_uaddr, wp); } futex_put(f, wp); return (error); } static int futex_wake(struct futex *f, int n, uint32_t bitset) { struct waiting_proc *wp, *wpt; int count = 0; if (bitset == 0) return (EINVAL); FUTEX_ASSERT_LOCKED(f); TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp, f->f_refcount); LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", f->f_uaddr, wp, f->f_refcount); /* * Unless we find a matching bit in * the bitset, continue searching. */ if (!(wp->wp_futex->f_bitset & bitset)) continue; wp->wp_flags |= FUTEX_WP_REMOVED; TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp); wakeup_one(wp); if (++count == n) break; } return (count); } static int futex_requeue(struct futex *f, int nrwake, struct futex *f2, int nrrequeue) { struct waiting_proc *wp, *wpt; int count = 0; FUTEX_ASSERT_LOCKED(f); FUTEX_ASSERT_LOCKED(f2); TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { if (++count <= nrwake) { LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", f->f_uaddr, wp); wp->wp_flags |= FUTEX_WP_REMOVED; TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); wakeup_one(wp); } else { LIN_SDT_PROBE3(futex, futex_requeue, requeue, f->f_uaddr, wp, f2->f_uaddr); LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", f->f_uaddr, wp, f2->f_uaddr); wp->wp_flags |= FUTEX_WP_REQUEUED; /* Move wp to wp_list of f2 futex */ TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); /* * Thread which sleeps on wp after waking should * acquire f2 lock, so increment refcount of f2 to * prevent it from premature deallocation. */ wp->wp_futex = f2; FUTEXES_LOCK; ++f2->f_refcount; FUTEXES_UNLOCK; if (count - nrwake >= nrrequeue) break; } } return (count); } static int futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts, uint32_t bitset) { int error; if (bitset == 0) { futex_put(f, wp); return (EINVAL); } f->f_bitset = bitset; error = futex_sleep(f, wp, ts); if (error) LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); if (error == EWOULDBLOCK) error = ETIMEDOUT; return (error); } static int futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) { int op = (encoded_op >> 28) & 7; int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; int oldval = 0, ret; if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, cmparg); /* XXX: Linux verifies access here and returns EFAULT */ LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); switch (op) { case FUTEX_OP_SET: ret = futex_xchgl(oparg, uaddr, &oldval); break; case FUTEX_OP_ADD: ret = futex_addl(oparg, uaddr, &oldval); break; case FUTEX_OP_OR: ret = futex_orl(oparg, uaddr, &oldval); break; case FUTEX_OP_ANDN: ret = futex_andl(~oparg, uaddr, &oldval); break; case FUTEX_OP_XOR: ret = futex_xorl(oparg, uaddr, &oldval); break; default: LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); ret = -ENOSYS; break; } if (ret) return (ret); switch (cmp) { case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; default: LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); ret = -ENOSYS; } return (ret); } static int linux_futex(struct thread *td, struct linux_futex_args *args) { - int nrwake, nrrequeue, op_ret, ret; + int nrwake, op_ret, ret; struct linux_pemuldata *pem; struct futex *f, *f2; int error, save; uint32_t val; if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { args->flags = 0; args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; } else args->flags = FUTEX_SHARED; /* * Currently support for switching between CLOCK_MONOTONIC and * CLOCK_REALTIME is not present. However Linux forbids the use of * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and * FUTEX_WAIT_REQUEUE_PI. */ args->clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; if (args->clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { LIN_SDT_PROBE0(futex, linux_futex, unimplemented_clockswitch); return (ENOSYS); } error = 0; f = f2 = NULL; switch (args->op) { case LINUX_FUTEX_WAIT: args->val3 = FUTEX_BITSET_MATCH_ANY; /* FALLTHROUGH */ case LINUX_FUTEX_WAIT_BITSET: LIN_SDT_PROBE3(futex, linux_futex, debug_wait, args->uaddr, args->val, args->val3); LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", args->uaddr, args->val, args->val3); return (linux_futex_wait(td, args)); case LINUX_FUTEX_WAKE: args->val3 = FUTEX_BITSET_MATCH_ANY; /* FALLTHROUGH */ case LINUX_FUTEX_WAKE_BITSET: LIN_SDT_PROBE3(futex, linux_futex, debug_wake, args->uaddr, args->val, args->val3); LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", args->uaddr, args->val, args->val3); return (linux_futex_wake(td, args)); case LINUX_FUTEX_CMP_REQUEUE: LIN_SDT_PROBE5(futex, linux_futex, debug_cmp_requeue, args->uaddr, args->val, args->val3, args->uaddr2, args->ts); LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", args->uaddr, args->val, args->val3, args->uaddr2, args->ts); - /* - * Linux allows this, we would not, it is an incorrect - * usage of declared ABI, so return EINVAL. - */ - if (args->uaddr == args->uaddr2) { - LIN_SDT_PROBE0(futex, linux_futex, - invalid_cmp_requeue_use); - return (EINVAL); - } - - nrrequeue = (int)(unsigned long)args->ts; - nrwake = args->val; - /* - * Sanity check to prevent signed integer overflow, - * see Linux CVE-2018-6927 - */ - if (nrwake < 0 || nrrequeue < 0) - return (EINVAL); - -retry1: - error = futex_get(args->uaddr, NULL, &f, - args->flags | FUTEX_DONTLOCK); - if (error) - return (error); - - /* - * To avoid deadlocks return EINVAL if second futex - * exists at this time. - * - * Glibc fall back to FUTEX_WAKE in case of any error - * returned by FUTEX_CMP_REQUEUE. - */ - error = futex_get(args->uaddr2, NULL, &f2, - args->flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); - if (error) { - futex_put(f, NULL); - return (error); - } - futex_lock(f); - futex_lock(f2); - error = copyin_nofault(args->uaddr, &val, sizeof(val)); - if (error) { - futex_put(f2, NULL); - futex_put(f, NULL); - error = copyin(args->uaddr, &val, sizeof(val)); - if (error == 0) - goto retry1; - LIN_SDT_PROBE1(futex, linux_futex, copyin_error, - error); - LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", - error); - return (error); - } - if (val != args->val3) { - LIN_SDT_PROBE2(futex, linux_futex, - debug_cmp_requeue_value_neq, args->val, val); - LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", - args->val, val); - futex_put(f2, NULL); - futex_put(f, NULL); - return (EAGAIN); - } - - td->td_retval[0] = futex_requeue(f, nrwake, f2, nrrequeue); - futex_put(f2, NULL); - futex_put(f, NULL); - break; + return (linux_futex_requeue(td, args)); case LINUX_FUTEX_WAKE_OP: LIN_SDT_PROBE5(futex, linux_futex, debug_wake_op, args->uaddr, args->op, args->val, args->uaddr2, args->val3); LINUX_CTR5(sys_futex, "WAKE_OP " "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", args->uaddr, args->val, args->uaddr2, args->val3, args->ts); if (args->uaddr == args->uaddr2) return (EINVAL); retry2: error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTLOCK); if (error) return (error); error = futex_get(args->uaddr2, NULL, &f2, args->flags | FUTEX_DONTLOCK); if (error) { futex_put(f, NULL); return (error); } futex_lock(f); futex_lock(f2); /* * This function returns positive number as results and * negative as errors */ save = vm_fault_disable_pagefaults(); op_ret = futex_atomic_op(td, args->val3, args->uaddr2); vm_fault_enable_pagefaults(save); LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", args->uaddr, op_ret); if (op_ret < 0) { if (f2 != NULL) futex_put(f2, NULL); futex_put(f, NULL); error = copyin(args->uaddr2, &val, sizeof(val)); if (error == 0) goto retry2; return (error); } ret = futex_wake(f, args->val, args->val3); if (op_ret > 0) { op_ret = 0; nrwake = (int)(unsigned long)args->ts; if (f2 != NULL) op_ret += futex_wake(f2, nrwake, args->val3); else op_ret += futex_wake(f, nrwake, args->val3); ret += op_ret; } if (f2 != NULL) futex_put(f2, NULL); futex_put(f, NULL); td->td_retval[0] = ret; break; case LINUX_FUTEX_LOCK_PI: /* not yet implemented */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { linux_msg(td, "unsupported FUTEX_LOCK_PI"); pem->flags |= LINUX_XUNSUP_FUTEXPIOP; LIN_SDT_PROBE0(futex, linux_futex, unimplemented_lock_pi); } return (ENOSYS); case LINUX_FUTEX_UNLOCK_PI: /* not yet implemented */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { linux_msg(td, "unsupported FUTEX_UNLOCK_PI"); pem->flags |= LINUX_XUNSUP_FUTEXPIOP; LIN_SDT_PROBE0(futex, linux_futex, unimplemented_unlock_pi); } return (ENOSYS); case LINUX_FUTEX_TRYLOCK_PI: /* not yet implemented */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { linux_msg(td, "unsupported FUTEX_TRYLOCK_PI"); pem->flags |= LINUX_XUNSUP_FUTEXPIOP; LIN_SDT_PROBE0(futex, linux_futex, unimplemented_trylock_pi); } return (ENOSYS); case LINUX_FUTEX_REQUEUE: /* * Glibc does not use this operation since version 2.3.3, * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when * FUTEX_REQUEUE returned EINVAL. */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { linux_msg(td, "unsupported FUTEX_REQUEUE"); pem->flags |= LINUX_XDEPR_REQUEUEOP; LIN_SDT_PROBE0(futex, linux_futex, deprecated_requeue); } return (EINVAL); case LINUX_FUTEX_WAIT_REQUEUE_PI: /* not yet implemented */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { linux_msg(td, "unsupported FUTEX_WAIT_REQUEUE_PI"); pem->flags |= LINUX_XUNSUP_FUTEXPIOP; LIN_SDT_PROBE0(futex, linux_futex, unimplemented_wait_requeue_pi); } return (ENOSYS); case LINUX_FUTEX_CMP_REQUEUE_PI: /* not yet implemented */ pem = pem_find(td->td_proc); if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { linux_msg(td, "unsupported FUTEX_CMP_REQUEUE_PI"); pem->flags |= LINUX_XUNSUP_FUTEXPIOP; LIN_SDT_PROBE0(futex, linux_futex, unimplemented_cmp_requeue_pi); } return (ENOSYS); default: linux_msg(td, "unsupported futex op %d", args->op); LIN_SDT_PROBE1(futex, linux_futex, unknown_operation, args->op); return (ENOSYS); } return (error); } +static int +linux_futex_requeue(struct thread *td, struct linux_futex_args *args) +{ + int nrwake, nrrequeue; + struct futex *f, *f2; + int error; + uint32_t val; + + /* + * Linux allows this, we would not, it is an incorrect + * usage of declared ABI, so return EINVAL. + */ + if (args->uaddr == args->uaddr2) { + LIN_SDT_PROBE0(futex, linux_futex, + invalid_cmp_requeue_use); + return (EINVAL); + } + + nrrequeue = (int)(unsigned long)args->ts; + nrwake = args->val; + /* + * Sanity check to prevent signed integer overflow, + * see Linux CVE-2018-6927 + */ + if (nrwake < 0 || nrrequeue < 0) + return (EINVAL); + +retry: + f = f2 = NULL; + error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTLOCK); + if (error != 0) + return (error); + + /* + * To avoid deadlocks return EINVAL if second futex + * exists at this time. + * + * Glibc fall back to FUTEX_WAKE in case of any error + * returned by FUTEX_CMP_REQUEUE. + */ + error = futex_get(args->uaddr2, NULL, &f2, + args->flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); + if (error != 0) { + futex_put(f, NULL); + return (error); + } + futex_lock(f); + futex_lock(f2); + error = copyin_nofault(args->uaddr, &val, sizeof(val)); + if (error != 0) { + futex_put(f2, NULL); + futex_put(f, NULL); + error = copyin(args->uaddr, &val, sizeof(val)); + if (error == 0) + goto retry; + LIN_SDT_PROBE1(futex, linux_futex, copyin_error, + error); + LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", + error); + return (error); + } + if (val != args->val3) { + LIN_SDT_PROBE2(futex, linux_futex, + debug_cmp_requeue_value_neq, args->val, val); + LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", + args->val, val); + futex_put(f2, NULL); + futex_put(f, NULL); + return (EAGAIN); + } + + td->td_retval[0] = futex_requeue(f, nrwake, f2, nrrequeue); + futex_put(f2, NULL); + futex_put(f, NULL); + return (0); +} + static int linux_futex_wake(struct thread *td, struct linux_futex_args *args) { struct futex *f; int error; f = NULL; error = futex_get(args->uaddr, NULL, &f, args->flags | FUTEX_DONTCREATE); if (error != 0) return (error); if (f == NULL) { td->td_retval[0] = 0; return (error); } td->td_retval[0] = futex_wake(f, args->val, args->val3); futex_put(f, NULL); return (0); } static int linux_futex_wait(struct thread *td, struct linux_futex_args *args) { struct waiting_proc *wp; struct timespec kts; struct futex *f; int error; uint32_t val; if (args->ts != NULL) { if (args->clockrt) { nanotime(&kts); timespecsub(args->ts, &kts, args->ts); } else if (args->op == LINUX_FUTEX_WAIT_BITSET) { nanouptime(&kts); timespecsub(args->ts, &kts, args->ts); } } retry: f = NULL; error = futex_get(args->uaddr, &wp, &f, args->flags | FUTEX_CREATE_WP); if (error != 0) return (error); error = copyin_nofault(args->uaddr, &val, sizeof(val)); if (error != 0) { futex_put(f, wp); error = copyin(args->uaddr, &val, sizeof(val)); if (error == 0) goto retry; LIN_SDT_PROBE1(futex, linux_futex, copyin_error, error); LINUX_CTR1(sys_futex, "WAIT copyin failed %d", error); return (error); } if (val != args->val) { LIN_SDT_PROBE4(futex, linux_futex, debug_wait_value_neq, args->uaddr, args->val, val, args->val3); LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x != uval 0x%x", args->uaddr, args->val, val); futex_put(f, wp); return (EWOULDBLOCK); } return (futex_wait(f, wp, args->ts, args->val3)); } int linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) { struct linux_futex_args fargs = { .uaddr = args->uaddr, .op = args->op, .val = args->val, .ts = NULL, .uaddr2 = args->uaddr2, .val3 = args->val3, }; struct l_timespec lts; int error; switch (args->op & LINUX_FUTEX_CMD_MASK) { case LINUX_FUTEX_WAIT: case LINUX_FUTEX_WAIT_BITSET: if (args->timeout != NULL) { error = copyin(args->timeout, <s, sizeof(lts)); if (error != 0) return (error); error = linux_to_native_timespec(&fargs.kts, <s); if (error != 0) return (error); fargs.ts = &fargs.kts; } break; default: fargs.ts = PTRIN(args->timeout); } return (linux_futex(td, &fargs)); } #if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32)) int linux_sys_futex_time64(struct thread *td, struct linux_sys_futex_time64_args *args) { struct linux_futex_args fargs = { .uaddr = args->uaddr, .op = args->op, .val = args->val, .ts = NULL, .uaddr2 = args->uaddr2, .val3 = args->val3, }; struct l_timespec64 lts; int error; switch (args->op & LINUX_FUTEX_CMD_MASK) { case LINUX_FUTEX_WAIT: case LINUX_FUTEX_WAIT_BITSET: if (args->timeout != NULL) { error = copyin(args->timeout, <s, sizeof(lts)); if (error != 0) return (error); error = linux_to_native_timespec64(&fargs.kts, <s); if (error != 0) return (error); fargs.ts = &fargs.kts; } break; default: fargs.ts = PTRIN(args->timeout); } return (linux_futex(td, &fargs)); } #endif int linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) { struct linux_emuldata *em; if (args->len != sizeof(struct linux_robust_list_head)) { LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); return (EINVAL); } em = em_find(td); em->robust_futexes = args->head; return (0); } int linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) { struct linux_emuldata *em; struct linux_robust_list_head *head; l_size_t len = sizeof(struct linux_robust_list_head); struct thread *td2; int error = 0; if (!args->pid) { em = em_find(td); KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); head = em->robust_futexes; } else { td2 = tdfind(args->pid, -1); if (td2 == NULL) return (ESRCH); if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) { PROC_UNLOCK(td2->td_proc); return (EPERM); } em = em_find(td2); KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); /* XXX: ptrace? */ if (priv_check(td, PRIV_CRED_SETUID) || priv_check(td, PRIV_CRED_SETEUID) || p_candebug(td, td2->td_proc)) { PROC_UNLOCK(td2->td_proc); return (EPERM); } head = em->robust_futexes; PROC_UNLOCK(td2->td_proc); } error = copyout(&len, args->len, sizeof(l_size_t)); if (error) { LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, error); return (EFAULT); } error = copyout(&head, args->head, sizeof(head)); if (error) { LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, error); } return (error); } static int handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, unsigned int pi) { uint32_t uval, nval, mval; struct futex *f; int error; retry: error = copyin(uaddr, &uval, 4); if (error) { LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); return (EFAULT); } if ((uval & FUTEX_TID_MASK) == em->em_tid) { mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; nval = casuword32(uaddr, uval, mval); if (nval == -1) return (EFAULT); if (nval != uval) goto retry; if (!pi && (uval & FUTEX_WAITERS)) { error = futex_get(uaddr, NULL, &f, FUTEX_DONTCREATE | FUTEX_SHARED); if (error) return (error); if (f != NULL) { futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); futex_put(f, NULL); } } } return (0); } static int fetch_robust_entry(struct linux_robust_list **entry, struct linux_robust_list **head, unsigned int *pi) { l_ulong uentry; int error; error = copyin((const void *)head, &uentry, sizeof(l_ulong)); if (error) { LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); return (EFAULT); } *entry = (void *)(uentry & ~1UL); *pi = uentry & 1; return (0); } /* This walks the list of robust futexes releasing them. */ void release_futexes(struct thread *td, struct linux_emuldata *em) { struct linux_robust_list_head *head = NULL; struct linux_robust_list *entry, *next_entry, *pending; unsigned int limit = 2048, pi, next_pi, pip; l_long futex_offset; int rc, error; head = em->robust_futexes; if (head == NULL) return; if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) return; error = copyin(&head->futex_offset, &futex_offset, sizeof(futex_offset)); if (error) { LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); return; } if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) return; while (entry != &head->list) { rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); if (entry != pending) if (handle_futex_death(em, (uint32_t *)((caddr_t)entry + futex_offset), pi)) { return; } if (rc) return; entry = next_entry; pi = next_pi; if (!--limit) break; sched_relinquish(curthread); } if (pending) handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); }