/* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */ /*- * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved. * * 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 /* DTrace init */ LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); /* Linuxulator-global DTrace probes */ LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked); LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock); /** * 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_DEFINE2(futex, futex_put, entry, "struct futex *", "struct waiting_proc *"); 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_DEFINE0(futex, futex_put, return); LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **", "uint32_t"); 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_DEFINE1(futex, futex_get0, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *", "struct waiting_proc **", "struct futex **"); LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *", "struct waiting_proc **", "int"); 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_DEFINE1(futex, futex_sleep, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int", "uint32_t"); 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_wake, return, "int"); LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int", "struct futex *", "int"); 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_requeue, return, "int"); LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *", "struct waiting_proc **", "int", "uint32_t"); LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", "int", "uint32_t"); 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_DEFINE1(futex, futex_atomic_op, return, "int"); LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", "struct linux_sys_futex_args *"); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int"); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use); LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *", "uint32_t", "uint32_t"); LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq, "uint32_t *", "uint32_t", "int", "uint32_t"); LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *", "uint32_t", "uint32_t"); LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *", "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq, "uint32_t", "int"); LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *", "int", "uint32_t", "uint32_t *", "uint32_t"); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int"); LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int"); LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *", "struct linux_set_robust_list_args *"); LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int"); LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *", "struct linux_get_robust_list_args *"); LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, "struct proc *", "uint32_t *", "int"); LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int"); LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry, "struct linux_robust_list **", "struct linux_robust_list **", "int *"); LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int"); LIN_SDT_PROBE_DEFINE1(futex, release_futexes, entry, "struct proc *"); LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes"); static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp"); struct futex; struct waiting_proc { uint32_t wp_flags; struct futex *wp_futex; TAILQ_ENTRY(waiting_proc) wp_list; }; struct futex { struct sx 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; }; struct futex_list futex_list; #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck) #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck) #define FUTEX_INIT(f) do { \ sx_init_flags(&(f)->f_lck, "ftlk", \ SX_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); \ sx_destroy(&(f)->f_lck); \ } while (0) #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED) struct mtx futex_mtx; /* protects the futex list */ #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 */ /* 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. */ /* support.s */ int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); int futex_addl(int oparg, uint32_t *uaddr, int *oldval); int futex_orl(int oparg, uint32_t *uaddr, int *oldval); int futex_andl(int oparg, uint32_t *uaddr, int *oldval); int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); static void futex_put(struct futex *f, struct waiting_proc *wp) { LIN_SDT_PROBE2(futex, futex_put, entry, f, wp); FUTEX_ASSERT_LOCKED(f); 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; 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); LIN_SDT_PROBE0(futex, futex_put, return); 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); FUTEXES_UNLOCK; FUTEX_UNLOCK(f); LIN_SDT_PROBE0(futex, futex_put, return); } static int futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) { struct futex *f, *tmpf; struct umtx_key key; int error; LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags); *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); LIN_SDT_PROBE1(futex, futex_get0, return, error); return (error); } retry: FUTEXES_LOCK; LIST_FOREACH(f, &futex_list, f_list) { if (umtx_key_match(&f->f_key, &key)) { if (tmpf != NULL) { FUTEX_UNLOCK(tmpf); FUTEX_DESTROY(tmpf); free(tmpf, M_FUTEX); } if (flags & FUTEX_DONTEXISTS) { FUTEXES_UNLOCK; umtx_key_release(&key); LIN_SDT_PROBE1(futex, futex_get0, return, EINVAL); 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); 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); LIN_SDT_PROBE1(futex, futex_get0, return, 0); 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); LIN_SDT_PROBE1(futex, futex_get0, return, 0); 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. */ 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; LIN_SDT_PROBE1(futex, futex_get0, return, 0); return (0); } static int futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, uint32_t flags) { int error; LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f); 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); LIN_SDT_PROBE1(futex, futex_get, return, error); return (error); } if (flags & FUTEX_CREATE_WP) { TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); (*wp)->wp_futex = *f; } LIN_SDT_PROBE1(futex, futex_get, return, error); return (error); } static int futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout) { int error; FUTEX_ASSERT_LOCKED(f); LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout); LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d", f->f_uaddr, wp, timeout, f->f_refcount); error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout); 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); LIN_SDT_PROBE1(futex, futex_sleep, return, error); return (error); } static int futex_wake(struct futex *f, int n, uint32_t bitset) { struct waiting_proc *wp, *wpt; int count = 0; LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset); if (bitset == 0) { LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL); 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; } LIN_SDT_PROBE1(futex, futex_wake, return, count); return (count); } static int futex_requeue(struct futex *f, int n, struct futex *f2, int n2) { struct waiting_proc *wp, *wpt; int count = 0; LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2); FUTEX_ASSERT_LOCKED(f); FUTEX_ASSERT_LOCKED(f2); TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { if (++count <= n) { 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 - n >= n2) break; } } LIN_SDT_PROBE1(futex, futex_requeue, return, count); return (count); } static int futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz, uint32_t bitset) { int error; LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset); if (bitset == 0) { LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); return (EINVAL); } f->f_bitset = bitset; error = futex_sleep(f, wp, timeout_hz); if (error) LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); if (error == EWOULDBLOCK) error = ETIMEDOUT; LIN_SDT_PROBE1(futex, futex_wait, return, error); 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; LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 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) { LIN_SDT_PROBE1(futex, futex_atomic_op, return, 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; } LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); return (ret); } int linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) { int clockrt, nrwake, op_ret, ret; struct linux_emuldata *em; struct waiting_proc *wp; struct futex *f, *f2; struct l_timespec timeout; struct timeval utv, ctv; int timeout_hz; int error; uint32_t flags, val; LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { flags = 0; args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; } else 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. */ clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_clockswitch); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 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_sys_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); error = futex_get(args->uaddr, &wp, &f, flags | FUTEX_CREATE_WP); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } error = copyin(args->uaddr, &val, sizeof(val)); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, error); LINUX_CTR1(sys_futex, "WAIT copyin failed %d", error); futex_put(f, wp); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } if (val != args->val) { LIN_SDT_PROBE4(futex, linux_sys_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); LIN_SDT_PROBE1(futex, linux_sys_futex, return, EWOULDBLOCK); return (EWOULDBLOCK); } if (args->timeout != NULL) { error = copyin(args->timeout, &timeout, sizeof(timeout)); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, error); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); futex_put(f, wp); return (error); } TIMESPEC_TO_TIMEVAL(&utv, &timeout); error = itimerfix(&utv); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error, error); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); futex_put(f, wp); return (error); } if (clockrt) { microtime(&ctv); timevalsub(&utv, &ctv); } else if (args->op == LINUX_FUTEX_WAIT_BITSET) { microuptime(&ctv); timevalsub(&utv, &ctv); } if (utv.tv_sec < 0) timevalclear(&utv); timeout_hz = tvtohz(&utv); } else timeout_hz = 0; error = futex_wait(f, wp, timeout_hz, args->val3); break; case LINUX_FUTEX_WAKE: args->val3 = FUTEX_BITSET_MATCH_ANY; /* FALLTHROUGH */ case LINUX_FUTEX_WAKE_BITSET: LIN_SDT_PROBE3(futex, linux_sys_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); error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTCREATE); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } if (f == NULL) { td->td_retval[0] = 0; LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } td->td_retval[0] = futex_wake(f, args->val, args->val3); futex_put(f, NULL); break; case LINUX_FUTEX_CMP_REQUEUE: LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, args->uaddr, args->val, args->val3, args->uaddr2, args->timeout); 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->timeout); /* * 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_sys_futex, invalid_cmp_requeue_use); LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); return (EINVAL); } error = futex_get(args->uaddr, NULL, &f, flags); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, return, 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, flags | FUTEX_DONTEXISTS); if (error) { futex_put(f, NULL); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } error = copyin(args->uaddr, &val, sizeof(val)); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, error); LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", error); futex_put(f2, NULL); futex_put(f, NULL); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } if (val != args->val3) { LIN_SDT_PROBE2(futex, linux_sys_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); LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); return (EAGAIN); } nrwake = (int)(unsigned long)args->timeout; td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); futex_put(f2, NULL); futex_put(f, NULL); break; case LINUX_FUTEX_WAKE_OP: LIN_SDT_PROBE5(futex, linux_sys_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->timeout); error = futex_get(args->uaddr, NULL, &f, flags); if (error) { LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } if (args->uaddr != args->uaddr2) error = futex_get(args->uaddr2, NULL, &f2, flags); if (error) { futex_put(f, NULL); LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } /* * This function returns positive number as results and * negative as errors */ op_ret = futex_atomic_op(td, args->val3, args->uaddr2); LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", args->uaddr, op_ret); if (op_ret < 0) { /* XXX: We don't handle the EFAULT yet. */ if (op_ret != -EFAULT) { if (f2 != NULL) futex_put(f2, NULL); futex_put(f, NULL); LIN_SDT_PROBE1(futex, linux_sys_futex, return, -op_ret); return (-op_ret); } else { LIN_SDT_PROBE0(futex, linux_sys_futex, unhandled_efault); } if (f2 != NULL) futex_put(f2, NULL); futex_put(f, NULL); LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT); return (EFAULT); } ret = futex_wake(f, args->val, args->val3); if (op_ret > 0) { op_ret = 0; nrwake = (int)(unsigned long)args->timeout; 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 */ linux_msg(td, "linux_sys_futex: " "op LINUX_FUTEX_LOCK_PI not implemented\n"); LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); return (ENOSYS); case LINUX_FUTEX_UNLOCK_PI: /* not yet implemented */ linux_msg(td, "linux_sys_futex: " "op LINUX_FUTEX_UNLOCK_PI not implemented\n"); LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); return (ENOSYS); case LINUX_FUTEX_TRYLOCK_PI: /* not yet implemented */ linux_msg(td, "linux_sys_futex: " "op LINUX_FUTEX_TRYLOCK_PI not implemented\n"); LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_trylock_pi); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 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. */ em = em_find(td->td_proc, EMUL_DONTLOCK); if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) { linux_msg(td, "linux_sys_futex: " "unsupported futex_requeue op\n"); em->flags |= LINUX_XDEPR_REQUEUEOP; LIN_SDT_PROBE0(futex, linux_sys_futex, deprecated_requeue); } LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); return (EINVAL); case LINUX_FUTEX_WAIT_REQUEUE_PI: /* not yet implemented */ linux_msg(td, "linux_sys_futex: " "op FUTEX_WAIT_REQUEUE_PI not implemented\n"); LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); return (ENOSYS); case LINUX_FUTEX_CMP_REQUEUE_PI: /* not yet implemented */ linux_msg(td, "linux_sys_futex: " "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n"); LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); return (ENOSYS); default: linux_msg(td, "linux_sys_futex: unknown op %d\n", args->op); LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, args->op); LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); return (ENOSYS); } LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); return (error); } int linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) { struct linux_emuldata *em; LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); if (args->len != sizeof(struct linux_robust_list_head)) { LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); return (EINVAL); } em = em_find(td->td_proc, EMUL_DOLOCK); em->robust_futexes = args->head; EMUL_UNLOCK(&emul_lock); LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 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); int error = 0; LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); if (!args->pid) { em = em_find(td->td_proc, EMUL_DONTLOCK); head = em->robust_futexes; } else { struct proc *p; p = pfind(args->pid); if (p == NULL) { LIN_SDT_PROBE1(futex, linux_get_robust_list, return, ESRCH); return (ESRCH); } em = em_find(p, EMUL_DONTLOCK); /* XXX: ptrace? */ if (priv_check(td, PRIV_CRED_SETUID) || priv_check(td, PRIV_CRED_SETEUID) || p_candebug(td, p)) { PROC_UNLOCK(p); LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EPERM); return (EPERM); } head = em->robust_futexes; PROC_UNLOCK(p); } error = copyout(&len, args->len, sizeof(l_size_t)); if (error) { LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, error); LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); return (EFAULT); } error = copyout(head, args->head, sizeof(struct linux_robust_list_head)); if (error) { LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, error); } LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); return (error); } static int handle_futex_death(struct proc *p, uint32_t *uaddr, int pi) { uint32_t uval, nval, mval; struct futex *f; int error; LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi); retry: error = copyin(uaddr, &uval, 4); if (error) { LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); return (EFAULT); } if ((uval & FUTEX_TID_MASK) == p->p_pid) { mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; nval = casuword32(uaddr, uval, mval); if (nval == -1) { LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); return (EFAULT); } if (nval != uval) goto retry; if (!pi && (uval & FUTEX_WAITERS)) { error = futex_get(uaddr, NULL, &f, FUTEX_DONTCREATE | FUTEX_SHARED); if (error) { LIN_SDT_PROBE1(futex, handle_futex_death, return, error); return (error); } if (f != NULL) { futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); futex_put(f, NULL); } } } LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); return (0); } static int fetch_robust_entry(struct linux_robust_list **entry, struct linux_robust_list **head, int *pi) { l_ulong uentry; int error; LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); error = copyin((const void *)head, &uentry, sizeof(l_ulong)); if (error) { LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); return (EFAULT); } *entry = (void *)(uentry & ~1UL); *pi = uentry & 1; LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); return (0); } /* This walks the list of robust futexes releasing them. */ void release_futexes(struct proc *p) { struct linux_robust_list_head *head = NULL; struct linux_robust_list *entry, *next_entry, *pending; unsigned int limit = 2048, pi, next_pi, pip; struct linux_emuldata *em; l_long futex_offset; int rc, error; LIN_SDT_PROBE1(futex, release_futexes, entry, p); em = em_find(p, EMUL_DONTLOCK); head = em->robust_futexes; if (head == NULL) { LIN_SDT_PROBE0(futex, release_futexes, return); return; } if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { LIN_SDT_PROBE0(futex, release_futexes, return); return; } error = copyin(&head->futex_offset, &futex_offset, sizeof(futex_offset)); if (error) { LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); LIN_SDT_PROBE0(futex, release_futexes, return); return; } if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { LIN_SDT_PROBE0(futex, release_futexes, return); return; } while (entry != &head->list) { rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); if (entry != pending) if (handle_futex_death(p, (uint32_t *)((caddr_t)entry + futex_offset), pi)) { LIN_SDT_PROBE0(futex, release_futexes, return); return; } if (rc) { LIN_SDT_PROBE0(futex, release_futexes, return); return; } entry = next_entry; pi = next_pi; if (!--limit) break; sched_relinquish(curthread); } if (pending) handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip); LIN_SDT_PROBE0(futex, release_futexes, return); }