The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/compat/linux/linux_futex.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*      $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
    2 
    3 /*-
    4  * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  * 3. All advertising materials mentioning features or use of this software
   15  *    must display the following acknowledgement:
   16  *      This product includes software developed by Emmanuel Dreyfus
   17  * 4. The name of the author may not be used to endorse or promote
   18  *    products derived from this software without specific prior written
   19  *    permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
   22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   23  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
   25  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   31  * POSSIBILITY OF SUCH DAMAGE.
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD: releng/10.0/sys/compat/linux/linux_futex.c 255971 2013-10-01 15:40:27Z markj $");
   36 #if 0
   37 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
   38 #endif
   39 
   40 #include "opt_compat.h"
   41 #include "opt_kdtrace.h"
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/imgact.h>
   46 #include <sys/kernel.h>
   47 #include <sys/ktr.h>
   48 #include <sys/lock.h>
   49 #include <sys/malloc.h>
   50 #include <sys/mutex.h>
   51 #include <sys/priv.h>
   52 #include <sys/proc.h>
   53 #include <sys/queue.h>
   54 #include <sys/sched.h>
   55 #include <sys/sdt.h>
   56 #include <sys/sx.h>
   57 #include <sys/umtx.h>
   58 
   59 #ifdef COMPAT_LINUX32
   60 #include <machine/../linux32/linux.h>
   61 #include <machine/../linux32/linux32_proto.h>
   62 #else
   63 #include <machine/../linux/linux.h>
   64 #include <machine/../linux/linux_proto.h>
   65 #endif
   66 #include <compat/linux/linux_dtrace.h>
   67 #include <compat/linux/linux_emul.h>
   68 #include <compat/linux/linux_futex.h>
   69 #include <compat/linux/linux_util.h>
   70 
   71 /* DTrace init */
   72 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
   73 
   74 /* Linuxulator-global DTrace probes */
   75 LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked);
   76 LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock);
   77 
   78 /**
   79  * Futex part for the special DTrace module "locks".
   80  */
   81 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
   82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
   83 
   84 /**
   85  * Per futex probes.
   86  */
   87 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
   88 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
   89 
   90 /**
   91  * DTrace probes in this module.
   92  */
   93 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
   94     "struct waiting_proc *");
   95 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
   96     "int");
   97 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
   98     "int");
   99 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
  100 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
  101     "uint32_t");
  102 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
  103 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
  104     "int");
  105 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
  106 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
  107 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
  108 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
  109     "struct waiting_proc **", "struct futex **");
  110 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
  111 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
  112 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
  113     "struct waiting_proc **", "int");
  114 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
  115     "struct waiting_proc *", "uint32_t *", "uint32_t");
  116 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
  117     "struct waiting_proc *");
  118 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
  119 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
  120     "uint32_t");
  121 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
  122     "struct waiting_proc *", "uint32_t");
  123 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
  124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
  125 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
  126     "struct futex *", "int");
  127 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
  128 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
  129     "struct waiting_proc *", "uint32_t");
  130 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
  131 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
  132     "struct waiting_proc **", "struct l_timespec *", "uint32_t");
  133 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, copyin_error, "int");
  134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, itimerfix_error, "int");
  135 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
  136 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
  137 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
  138     "int", "uint32_t");
  139 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
  140     "int");
  141 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
  142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
  143 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
  144 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
  145 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
  146     "struct linux_sys_futex_args *");
  147 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
  148 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
  149 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
  150 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
  151     "uint32_t", "uint32_t");
  152 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
  153     "uint32_t *", "uint32_t", "int", "uint32_t");
  154 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
  155     "uint32_t", "uint32_t");
  156 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
  157     "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
  158 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
  159     "uint32_t", "int");
  160 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
  161     "int", "uint32_t", "uint32_t *", "uint32_t");
  162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
  163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
  164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
  165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
  166 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
  167 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
  168 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
  169 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
  170 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
  171 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
  172     "struct linux_set_robust_list_args *");
  173 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
  174 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
  175 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
  176     "struct linux_get_robust_list_args *");
  177 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
  178 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
  179 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, "struct proc *",
  180     "uint32_t *", "int");
  181 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
  182 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
  183 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
  184     "struct linux_robust_list **", "struct linux_robust_list **", "int *");
  185 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
  186 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
  187 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, entry, "struct proc *");
  188 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
  189 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
  190 
  191 static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes");
  192 static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp");
  193 
  194 struct futex;
  195 
  196 struct waiting_proc {
  197         uint32_t        wp_flags;
  198         struct futex    *wp_futex;
  199         TAILQ_ENTRY(waiting_proc) wp_list;
  200 };
  201 
  202 struct futex {
  203         struct sx       f_lck;
  204         uint32_t        *f_uaddr;       /* user-supplied value, for debug */
  205         struct umtx_key f_key;
  206         uint32_t        f_refcount;
  207         uint32_t        f_bitset;
  208         LIST_ENTRY(futex) f_list;
  209         TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
  210 };
  211 
  212 struct futex_list futex_list;
  213 
  214 #define FUTEX_LOCK(f)           sx_xlock(&(f)->f_lck)
  215 #define FUTEX_UNLOCK(f)         sx_xunlock(&(f)->f_lck)
  216 #define FUTEX_INIT(f)           do { \
  217                                     sx_init_flags(&(f)->f_lck, "ftlk", \
  218                                         SX_DUPOK); \
  219                                     LIN_SDT_PROBE1(futex, futex, create, \
  220                                         &(f)->f_lck); \
  221                                 } while (0)
  222 #define FUTEX_DESTROY(f)        do { \
  223                                     LIN_SDT_PROBE1(futex, futex, destroy, \
  224                                         &(f)->f_lck); \
  225                                     sx_destroy(&(f)->f_lck); \
  226                                 } while (0)
  227 #define FUTEX_ASSERT_LOCKED(f)  sx_assert(&(f)->f_lck, SA_XLOCKED)
  228 
  229 struct mtx futex_mtx;                   /* protects the futex list */
  230 #define FUTEXES_LOCK            do { \
  231                                     mtx_lock(&futex_mtx); \
  232                                     LIN_SDT_PROBE1(locks, futex_mtx, \
  233                                         locked, &futex_mtx); \
  234                                 } while (0)
  235 #define FUTEXES_UNLOCK          do { \
  236                                     LIN_SDT_PROBE1(locks, futex_mtx, \
  237                                         unlock, &futex_mtx); \
  238                                     mtx_unlock(&futex_mtx); \
  239                                 } while (0)
  240 
  241 /* flags for futex_get() */
  242 #define FUTEX_CREATE_WP         0x1     /* create waiting_proc */
  243 #define FUTEX_DONTCREATE        0x2     /* don't create futex if not exists */
  244 #define FUTEX_DONTEXISTS        0x4     /* return EINVAL if futex exists */
  245 #define FUTEX_SHARED            0x8     /* shared futex */
  246 
  247 /* wp_flags */
  248 #define FUTEX_WP_REQUEUED       0x1     /* wp requeued - wp moved from wp_list
  249                                          * of futex where thread sleep to wp_list
  250                                          * of another futex.
  251                                          */
  252 #define FUTEX_WP_REMOVED        0x2     /* wp is woken up and removed from futex
  253                                          * wp_list to prevent double wakeup.
  254                                          */
  255 
  256 /* support.s */
  257 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
  258 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
  259 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
  260 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
  261 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
  262 
  263 static void
  264 futex_put(struct futex *f, struct waiting_proc *wp)
  265 {
  266         LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
  267 
  268         FUTEX_ASSERT_LOCKED(f);
  269         if (wp != NULL) {
  270                 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
  271                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
  272                 free(wp, M_FUTEX_WP);
  273         }
  274 
  275         FUTEXES_LOCK;
  276         if (--f->f_refcount == 0) {
  277                 LIST_REMOVE(f, f_list);
  278                 FUTEXES_UNLOCK;
  279                 FUTEX_UNLOCK(f);
  280 
  281                 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
  282                     f->f_refcount, f->f_key.shared);
  283                 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
  284                     "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
  285                 umtx_key_release(&f->f_key);
  286                 FUTEX_DESTROY(f);
  287                 free(f, M_FUTEX);
  288 
  289                 LIN_SDT_PROBE0(futex, futex_put, return);
  290                 return;
  291         }
  292 
  293         LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
  294             f->f_key.shared);
  295         LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
  296             f->f_uaddr, f->f_refcount, f->f_key.shared);
  297         FUTEXES_UNLOCK;
  298         FUTEX_UNLOCK(f);
  299 
  300         LIN_SDT_PROBE0(futex, futex_put, return);
  301 }
  302 
  303 static int
  304 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
  305 {
  306         struct futex *f, *tmpf;
  307         struct umtx_key key;
  308         int error;
  309 
  310         LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
  311 
  312         *newf = tmpf = NULL;
  313 
  314         error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
  315             AUTO_SHARE : THREAD_SHARE, &key);
  316         if (error) {
  317                 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
  318                 LIN_SDT_PROBE1(futex, futex_get0, return, error);
  319                 return (error);
  320         }
  321 retry:
  322         FUTEXES_LOCK;
  323         LIST_FOREACH(f, &futex_list, f_list) {
  324                 if (umtx_key_match(&f->f_key, &key)) {
  325                         if (tmpf != NULL) {
  326                                 FUTEX_UNLOCK(tmpf);
  327                                 FUTEX_DESTROY(tmpf);
  328                                 free(tmpf, M_FUTEX);
  329                         }
  330                         if (flags & FUTEX_DONTEXISTS) {
  331                                 FUTEXES_UNLOCK;
  332                                 umtx_key_release(&key);
  333 
  334                                 LIN_SDT_PROBE1(futex, futex_get0, return,
  335                                     EINVAL);
  336                                 return (EINVAL);
  337                         }
  338 
  339                         /*
  340                          * Increment refcount of the found futex to
  341                          * prevent it from deallocation before FUTEX_LOCK()
  342                          */
  343                         ++f->f_refcount;
  344                         FUTEXES_UNLOCK;
  345                         umtx_key_release(&key);
  346 
  347                         FUTEX_LOCK(f);
  348                         *newf = f;
  349                         LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
  350                             f->f_refcount, f->f_key.shared);
  351                         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
  352                             uaddr, f->f_refcount, f->f_key.shared);
  353 
  354                         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
  355                         return (0);
  356                 }
  357         }
  358 
  359         if (flags & FUTEX_DONTCREATE) {
  360                 FUTEXES_UNLOCK;
  361                 umtx_key_release(&key);
  362                 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
  363                 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
  364 
  365                 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
  366                 return (0);
  367         }
  368 
  369         if (tmpf == NULL) {
  370                 FUTEXES_UNLOCK;
  371                 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
  372                 tmpf->f_uaddr = uaddr;
  373                 tmpf->f_key = key;
  374                 tmpf->f_refcount = 1;
  375                 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
  376                 FUTEX_INIT(tmpf);
  377                 TAILQ_INIT(&tmpf->f_waiting_proc);
  378 
  379                 /*
  380                  * Lock the new futex before an insert into the futex_list
  381                  * to prevent futex usage by other.
  382                  */
  383                 FUTEX_LOCK(tmpf);
  384                 goto retry;
  385         }
  386 
  387         LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
  388         FUTEXES_UNLOCK;
  389 
  390         LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
  391             tmpf->f_key.shared);
  392         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
  393             uaddr, tmpf->f_refcount, tmpf->f_key.shared);
  394         *newf = tmpf;
  395 
  396         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
  397         return (0);
  398 }
  399 
  400 static int
  401 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
  402     uint32_t flags)
  403 {
  404         int error;
  405 
  406         LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
  407 
  408         if (flags & FUTEX_CREATE_WP) {
  409                 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
  410                 (*wp)->wp_flags = 0;
  411         }
  412         error = futex_get0(uaddr, f, flags);
  413         if (error) {
  414                 LIN_SDT_PROBE0(futex, futex_get, error);
  415 
  416                 if (flags & FUTEX_CREATE_WP)
  417                         free(*wp, M_FUTEX_WP);
  418 
  419                 LIN_SDT_PROBE1(futex, futex_get, return, error);
  420                 return (error);
  421         }
  422         if (flags & FUTEX_CREATE_WP) {
  423                 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
  424                 (*wp)->wp_futex = *f;
  425         }
  426 
  427         LIN_SDT_PROBE1(futex, futex_get, return, error);
  428         return (error);
  429 }
  430 
  431 static int
  432 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
  433 {
  434         int error;
  435 
  436         FUTEX_ASSERT_LOCKED(f);
  437         LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout);
  438         LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
  439             f->f_uaddr, wp, timeout, f->f_refcount);
  440         error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
  441         if (wp->wp_flags & FUTEX_WP_REQUEUED) {
  442                 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
  443 
  444                 if (error) {
  445                         LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
  446                             f->f_uaddr, wp, wp->wp_futex->f_uaddr,
  447                             wp->wp_futex->f_refcount);
  448                 }
  449 
  450                 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
  451                     " %p requeued uaddr %p ref %d",
  452                     error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
  453                     wp->wp_futex->f_refcount);
  454                 futex_put(f, NULL);
  455                 f = wp->wp_futex;
  456                 FUTEX_LOCK(f);
  457         } else {
  458                 if (error) {
  459                         LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
  460                             f->f_uaddr, wp);
  461                 }
  462                 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
  463                     error, f->f_uaddr, wp);
  464         }
  465 
  466         futex_put(f, wp);
  467 
  468         LIN_SDT_PROBE1(futex, futex_sleep, return, error);
  469         return (error);
  470 }
  471 
  472 static int
  473 futex_wake(struct futex *f, int n, uint32_t bitset)
  474 {
  475         struct waiting_proc *wp, *wpt;
  476         int count = 0;
  477 
  478         LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
  479 
  480         if (bitset == 0) {
  481                 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
  482                 return (EINVAL);
  483         }
  484 
  485         FUTEX_ASSERT_LOCKED(f);
  486         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
  487                 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
  488                     f->f_refcount);
  489                 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
  490                     f->f_uaddr, wp, f->f_refcount);
  491                 /*
  492                  * Unless we find a matching bit in
  493                  * the bitset, continue searching.
  494                  */
  495                 if (!(wp->wp_futex->f_bitset & bitset))
  496                         continue;
  497 
  498                 wp->wp_flags |= FUTEX_WP_REMOVED;
  499                 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
  500                 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
  501                 wakeup_one(wp);
  502                 if (++count == n)
  503                         break;
  504         }
  505 
  506         LIN_SDT_PROBE1(futex, futex_wake, return, count);
  507         return (count);
  508 }
  509 
  510 static int
  511 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
  512 {
  513         struct waiting_proc *wp, *wpt;
  514         int count = 0;
  515 
  516         LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
  517 
  518         FUTEX_ASSERT_LOCKED(f);
  519         FUTEX_ASSERT_LOCKED(f2);
  520 
  521         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
  522                 if (++count <= n) {
  523                         LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
  524                             f->f_uaddr, wp);
  525                         wp->wp_flags |= FUTEX_WP_REMOVED;
  526                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
  527                         LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
  528                         wakeup_one(wp);
  529                 } else {
  530                         LIN_SDT_PROBE3(futex, futex_requeue, requeue,
  531                             f->f_uaddr, wp, f2->f_uaddr);
  532                         LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
  533                             f->f_uaddr, wp, f2->f_uaddr);
  534                         wp->wp_flags |= FUTEX_WP_REQUEUED;
  535                         /* Move wp to wp_list of f2 futex */
  536                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
  537                         TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
  538 
  539                         /*
  540                          * Thread which sleeps on wp after waking should
  541                          * acquire f2 lock, so increment refcount of f2 to
  542                          * prevent it from premature deallocation.
  543                          */
  544                         wp->wp_futex = f2;
  545                         FUTEXES_LOCK;
  546                         ++f2->f_refcount;
  547                         FUTEXES_UNLOCK;
  548                         if (count - n >= n2)
  549                                 break;
  550                 }
  551         }
  552 
  553         LIN_SDT_PROBE1(futex, futex_requeue, return, count);
  554         return (count);
  555 }
  556 
  557 static int
  558 futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts,
  559     uint32_t bitset)
  560 {
  561         struct l_timespec timeout;
  562         struct timeval tv;
  563         int timeout_hz;
  564         int error;
  565 
  566         LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
  567 
  568         if (bitset == 0) {
  569                 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
  570                 return (EINVAL);
  571         }
  572 
  573         f->f_bitset = bitset;
  574 
  575         if (ts != NULL) {
  576                 error = copyin(ts, &timeout, sizeof(timeout));
  577                 if (error) {
  578                         LIN_SDT_PROBE1(futex, futex_wait, copyin_error, error);
  579                         LIN_SDT_PROBE1(futex, futex_wait, return, error);
  580                         return (error);
  581                 }
  582                 TIMESPEC_TO_TIMEVAL(&tv, &timeout);
  583                 error = itimerfix(&tv);
  584                 if (error) {
  585                         LIN_SDT_PROBE1(futex, futex_wait, itimerfix_error,
  586                             error);
  587                         LIN_SDT_PROBE1(futex, futex_wait, return, error);
  588                         return (error);
  589                 }
  590                 timeout_hz = tvtohz(&tv);
  591         } else
  592                 timeout_hz = 0;
  593 
  594         error = futex_sleep(f, wp, timeout_hz);
  595         if (error) {
  596                 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
  597         }
  598         if (error == EWOULDBLOCK)
  599                 error = ETIMEDOUT;
  600 
  601         LIN_SDT_PROBE1(futex, futex_wait, return, error);
  602         return (error);
  603 }
  604 
  605 static int
  606 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
  607 {
  608         int op = (encoded_op >> 28) & 7;
  609         int cmp = (encoded_op >> 24) & 15;
  610         int oparg = (encoded_op << 8) >> 20;
  611         int cmparg = (encoded_op << 20) >> 20;
  612         int oldval = 0, ret;
  613 
  614         LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
  615 
  616         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
  617                 oparg = 1 << oparg;
  618 
  619         LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
  620             cmparg);
  621         
  622         /* XXX: Linux verifies access here and returns EFAULT */
  623         LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
  624 
  625         switch (op) {
  626         case FUTEX_OP_SET:
  627                 ret = futex_xchgl(oparg, uaddr, &oldval);
  628                 break;
  629         case FUTEX_OP_ADD:
  630                 ret = futex_addl(oparg, uaddr, &oldval);
  631                 break;
  632         case FUTEX_OP_OR:
  633                 ret = futex_orl(oparg, uaddr, &oldval);
  634                 break;
  635         case FUTEX_OP_ANDN:
  636                 ret = futex_andl(~oparg, uaddr, &oldval);
  637                 break;
  638         case FUTEX_OP_XOR:
  639                 ret = futex_xorl(oparg, uaddr, &oldval);
  640                 break;
  641         default:
  642                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
  643                 ret = -ENOSYS;
  644                 break;
  645         }
  646 
  647         if (ret) {
  648                 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
  649                 return (ret);
  650         }
  651 
  652         switch (cmp) {
  653         case FUTEX_OP_CMP_EQ:
  654                 ret = (oldval == cmparg);
  655                 break;
  656         case FUTEX_OP_CMP_NE:
  657                 ret = (oldval != cmparg);
  658                 break;
  659         case FUTEX_OP_CMP_LT:
  660                 ret = (oldval < cmparg);
  661                 break;
  662         case FUTEX_OP_CMP_GE:
  663                 ret = (oldval >= cmparg);
  664                 break;
  665         case FUTEX_OP_CMP_LE:
  666                 ret = (oldval <= cmparg);
  667                 break;
  668         case FUTEX_OP_CMP_GT:
  669                 ret = (oldval > cmparg);
  670                 break;
  671         default:
  672                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
  673                 ret = -ENOSYS;
  674         }
  675 
  676         LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
  677         return (ret);
  678 }
  679 
  680 int
  681 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
  682 {
  683         int clockrt, nrwake, op_ret, ret, val;
  684         struct linux_emuldata *em;
  685         struct waiting_proc *wp;
  686         struct futex *f, *f2;
  687         int error;
  688         uint32_t flags;
  689 
  690         LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
  691 
  692         if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
  693                 flags = 0;
  694                 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
  695         } else
  696                 flags = FUTEX_SHARED;
  697 
  698         /*
  699          * Currently support for switching between CLOCK_MONOTONIC and
  700          * CLOCK_REALTIME is not present. However Linux forbids the use of
  701          * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
  702          * FUTEX_WAIT_REQUEUE_PI.
  703          */
  704         clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
  705         args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
  706         if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
  707                 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
  708                 LIN_SDT_PROBE0(futex, linux_sys_futex,
  709                     unimplemented_clockswitch);
  710                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  711                 return (ENOSYS);
  712         }
  713 
  714         error = 0;
  715         f = f2 = NULL;
  716 
  717         switch (args->op) {
  718         case LINUX_FUTEX_WAIT:
  719                 args->val3 = FUTEX_BITSET_MATCH_ANY;
  720                 /* FALLTHROUGH */
  721 
  722         case LINUX_FUTEX_WAIT_BITSET:
  723                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
  724                     args->val, args->val3);
  725                 LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d val3 %d",
  726                     args->uaddr, args->val, args->val3);
  727 
  728                 error = futex_get(args->uaddr, &wp, &f,
  729                     flags | FUTEX_CREATE_WP);
  730                 if (error) {
  731                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  732                         return (error);
  733                 }
  734 
  735                 error = copyin(args->uaddr, &val, sizeof(val));
  736                 if (error) {
  737                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
  738                             error);
  739                         LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
  740                             error);
  741                         futex_put(f, wp);
  742 
  743                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  744                         return (error);
  745                 }
  746                 if (val != args->val) {
  747                         LIN_SDT_PROBE4(futex, linux_sys_futex,
  748                             debug_wait_value_neq, args->uaddr, args->val, val,
  749                             args->val3);
  750                         LINUX_CTR4(sys_futex,
  751                             "WAIT uaddr %p val %d != uval %d val3 %d",
  752                             args->uaddr, args->val, val, args->val3);
  753                         futex_put(f, wp);
  754 
  755                         LIN_SDT_PROBE1(futex, linux_sys_futex, return,
  756                             EWOULDBLOCK);
  757                         return (EWOULDBLOCK);
  758                 }
  759 
  760                 error = futex_wait(f, wp, args->timeout, args->val3);
  761                 break;
  762 
  763         case LINUX_FUTEX_WAKE:
  764                 args->val3 = FUTEX_BITSET_MATCH_ANY;
  765                 /* FALLTHROUGH */
  766 
  767         case LINUX_FUTEX_WAKE_BITSET:
  768                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
  769                     args->val, args->val3);
  770                 LINUX_CTR3(sys_futex, "WAKE uaddr %p val % d val3 %d",
  771                     args->uaddr, args->val, args->val3);
  772 
  773                 error = futex_get(args->uaddr, NULL, &f,
  774                     flags | FUTEX_DONTCREATE);
  775                 if (error) {
  776                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  777                         return (error);
  778                 }
  779 
  780                 if (f == NULL) {
  781                         td->td_retval[0] = 0;
  782 
  783                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  784                         return (error);
  785                 }
  786                 td->td_retval[0] = futex_wake(f, args->val, args->val3);
  787                 futex_put(f, NULL);
  788                 break;
  789 
  790         case LINUX_FUTEX_CMP_REQUEUE:
  791                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
  792                     args->uaddr, args->val, args->val3, args->uaddr2,
  793                     args->timeout);
  794                 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
  795                     "val %d val3 %d uaddr2 %p val2 %d",
  796                     args->uaddr, args->val, args->val3, args->uaddr2,
  797                     (int)(unsigned long)args->timeout);
  798 
  799                 /*
  800                  * Linux allows this, we would not, it is an incorrect
  801                  * usage of declared ABI, so return EINVAL.
  802                  */
  803                 if (args->uaddr == args->uaddr2) {
  804                         LIN_SDT_PROBE0(futex, linux_sys_futex,
  805                             invalid_cmp_requeue_use);
  806                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
  807                         return (EINVAL);
  808                 }
  809 
  810                 error = futex_get(args->uaddr, NULL, &f, flags);
  811                 if (error) {
  812                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  813                         return (error);
  814                 }
  815 
  816                 /*
  817                  * To avoid deadlocks return EINVAL if second futex
  818                  * exists at this time.
  819                  *
  820                  * Glibc fall back to FUTEX_WAKE in case of any error
  821                  * returned by FUTEX_CMP_REQUEUE.
  822                  */
  823                 error = futex_get(args->uaddr2, NULL, &f2,
  824                     flags | FUTEX_DONTEXISTS);
  825                 if (error) {
  826                         futex_put(f, NULL);
  827 
  828                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  829                         return (error);
  830                 }
  831                 error = copyin(args->uaddr, &val, sizeof(val));
  832                 if (error) {
  833                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
  834                             error);
  835                         LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
  836                             error);
  837                         futex_put(f2, NULL);
  838                         futex_put(f, NULL);
  839 
  840                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  841                         return (error);
  842                 }
  843                 if (val != args->val3) {
  844                         LIN_SDT_PROBE2(futex, linux_sys_futex,
  845                             debug_cmp_requeue_value_neq, args->val, val);
  846                         LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d",
  847                             args->val, val);
  848                         futex_put(f2, NULL);
  849                         futex_put(f, NULL);
  850 
  851                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
  852                         return (EAGAIN);
  853                 }
  854 
  855                 nrwake = (int)(unsigned long)args->timeout;
  856                 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
  857                 futex_put(f2, NULL);
  858                 futex_put(f, NULL);
  859                 break;
  860 
  861         case LINUX_FUTEX_WAKE_OP:
  862                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
  863                     args->uaddr, args->op, args->val, args->uaddr2, args->val3);
  864                 LINUX_CTR5(sys_futex, "WAKE_OP "
  865                     "uaddr %p op %d val %x uaddr2 %p val3 %x",
  866                     args->uaddr, args->op, args->val,
  867                     args->uaddr2, args->val3);
  868 
  869                 error = futex_get(args->uaddr, NULL, &f, flags);
  870                 if (error) {
  871                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  872                         return (error);
  873                 }
  874 
  875                 if (args->uaddr != args->uaddr2)
  876                         error = futex_get(args->uaddr2, NULL, &f2, flags);
  877                 if (error) {
  878                         futex_put(f, NULL);
  879 
  880                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
  881                         return (error);
  882                 }
  883 
  884                 /*
  885                  * This function returns positive number as results and
  886                  * negative as errors
  887                  */
  888                 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
  889 
  890                 if (op_ret < 0) {
  891                         /* XXX: We don't handle the EFAULT yet. */
  892                         if (op_ret != -EFAULT) {
  893                                 if (f2 != NULL)
  894                                         futex_put(f2, NULL);
  895                                 futex_put(f, NULL);
  896 
  897                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
  898                                     -op_ret);
  899                                 return (-op_ret);
  900                         } else {
  901                                 LIN_SDT_PROBE0(futex, linux_sys_futex,
  902                                     unhandled_efault);
  903                         }
  904                         if (f2 != NULL)
  905                                 futex_put(f2, NULL);
  906                         futex_put(f, NULL);
  907 
  908                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT);
  909                         return (EFAULT);
  910                 }
  911 
  912                 ret = futex_wake(f, args->val, args->val3);
  913 
  914                 if (op_ret > 0) {
  915                         op_ret = 0;
  916                         nrwake = (int)(unsigned long)args->timeout;
  917 
  918                         if (f2 != NULL)
  919                                 op_ret += futex_wake(f2, nrwake, args->val3);
  920                         else
  921                                 op_ret += futex_wake(f, nrwake, args->val3);
  922                         ret += op_ret;
  923 
  924                 }
  925                 if (f2 != NULL)
  926                         futex_put(f2, NULL);
  927                 futex_put(f, NULL);
  928                 td->td_retval[0] = ret;
  929                 break;
  930 
  931         case LINUX_FUTEX_LOCK_PI:
  932                 /* not yet implemented */
  933                 linux_msg(td,
  934                           "linux_sys_futex: "
  935                           "op LINUX_FUTEX_LOCK_PI not implemented\n");
  936                 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi);
  937                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  938                 return (ENOSYS);
  939 
  940         case LINUX_FUTEX_UNLOCK_PI:
  941                 /* not yet implemented */
  942                 linux_msg(td,
  943                           "linux_sys_futex: "
  944                           "op LINUX_FUTEX_UNLOCK_PI not implemented\n");
  945                 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi);
  946                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  947                 return (ENOSYS);
  948 
  949         case LINUX_FUTEX_TRYLOCK_PI:
  950                 /* not yet implemented */
  951                 linux_msg(td,
  952                           "linux_sys_futex: "
  953                           "op LINUX_FUTEX_TRYLOCK_PI not implemented\n");
  954                 LIN_SDT_PROBE0(futex, linux_sys_futex,
  955                     unimplemented_trylock_pi);
  956                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  957                 return (ENOSYS);
  958 
  959         case LINUX_FUTEX_REQUEUE:
  960 
  961                 /*
  962                  * Glibc does not use this operation since version 2.3.3,
  963                  * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
  964                  * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
  965                  * FUTEX_REQUEUE returned EINVAL.
  966                  */
  967                 em = em_find(td->td_proc, EMUL_DONTLOCK);
  968                 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
  969                         linux_msg(td,
  970                                   "linux_sys_futex: "
  971                                   "unsupported futex_requeue op\n");
  972                         em->flags |= LINUX_XDEPR_REQUEUEOP;
  973                         LIN_SDT_PROBE0(futex, linux_sys_futex,
  974                             deprecated_requeue);
  975                 }
  976 
  977                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
  978                 return (EINVAL);
  979 
  980         case LINUX_FUTEX_WAIT_REQUEUE_PI:
  981                 /* not yet implemented */
  982                 linux_msg(td,
  983                           "linux_sys_futex: "
  984                           "op FUTEX_WAIT_REQUEUE_PI not implemented\n");
  985                 LIN_SDT_PROBE0(futex, linux_sys_futex,
  986                     unimplemented_wait_requeue_pi);
  987                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  988                 return (ENOSYS);
  989 
  990         case LINUX_FUTEX_CMP_REQUEUE_PI:
  991                 /* not yet implemented */
  992                 linux_msg(td,
  993                             "linux_sys_futex: "
  994                             "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n");
  995                 LIN_SDT_PROBE0(futex, linux_sys_futex,
  996                     unimplemented_cmp_requeue_pi);
  997                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
  998                 return (ENOSYS);
  999 
 1000         default:
 1001                 linux_msg(td,
 1002                           "linux_sys_futex: unknown op %d\n", args->op);
 1003                 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
 1004                     args->op);
 1005                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 1006                 return (ENOSYS);
 1007         }
 1008 
 1009         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 1010         return (error);
 1011 }
 1012 
 1013 int
 1014 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
 1015 {
 1016         struct linux_emuldata *em;
 1017 
 1018         LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
 1019 
 1020         if (args->len != sizeof(struct linux_robust_list_head)) {
 1021                 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
 1022                 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
 1023                 return (EINVAL);
 1024         }
 1025 
 1026         em = em_find(td->td_proc, EMUL_DOLOCK);
 1027         em->robust_futexes = args->head;
 1028         EMUL_UNLOCK(&emul_lock);
 1029 
 1030         LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
 1031         return (0);
 1032 }
 1033 
 1034 int
 1035 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
 1036 {
 1037         struct linux_emuldata *em;
 1038         struct linux_robust_list_head *head;
 1039         l_size_t len = sizeof(struct linux_robust_list_head);
 1040         int error = 0;
 1041 
 1042         LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
 1043 
 1044         if (!args->pid) {
 1045                 em = em_find(td->td_proc, EMUL_DONTLOCK);
 1046                 head = em->robust_futexes;
 1047         } else {
 1048                 struct proc *p;
 1049 
 1050                 p = pfind(args->pid);
 1051                 if (p == NULL) {
 1052                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
 1053                             ESRCH);
 1054                         return (ESRCH);
 1055                 }
 1056 
 1057                 em = em_find(p, EMUL_DONTLOCK);
 1058                 /* XXX: ptrace? */
 1059                 if (priv_check(td, PRIV_CRED_SETUID) ||
 1060                     priv_check(td, PRIV_CRED_SETEUID) ||
 1061                     p_candebug(td, p)) {
 1062                         PROC_UNLOCK(p);
 1063 
 1064                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
 1065                             EPERM);
 1066                         return (EPERM);
 1067                 }
 1068                 head = em->robust_futexes;
 1069 
 1070                 PROC_UNLOCK(p);
 1071         }
 1072 
 1073         error = copyout(&len, args->len, sizeof(l_size_t));
 1074         if (error) {
 1075                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
 1076                     error);
 1077                 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
 1078                 return (EFAULT);
 1079         }
 1080 
 1081         error = copyout(head, args->head, sizeof(struct linux_robust_list_head));
 1082         if (error) {
 1083                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
 1084                     error);
 1085         }
 1086 
 1087         LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
 1088         return (error);
 1089 }
 1090 
 1091 static int
 1092 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi)
 1093 {
 1094         uint32_t uval, nval, mval;
 1095         struct futex *f;
 1096         int error;
 1097 
 1098         LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi);
 1099 
 1100 retry:
 1101         error = copyin(uaddr, &uval, 4);
 1102         if (error) {
 1103                 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
 1104                 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
 1105                 return (EFAULT);
 1106         }
 1107         if ((uval & FUTEX_TID_MASK) == p->p_pid) {
 1108                 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
 1109                 nval = casuword32(uaddr, uval, mval);
 1110 
 1111                 if (nval == -1) {
 1112                         LIN_SDT_PROBE1(futex, handle_futex_death, return,
 1113                             EFAULT);
 1114                         return (EFAULT);
 1115                 }
 1116 
 1117                 if (nval != uval)
 1118                         goto retry;
 1119 
 1120                 if (!pi && (uval & FUTEX_WAITERS)) {
 1121                         error = futex_get(uaddr, NULL, &f,
 1122                             FUTEX_DONTCREATE | FUTEX_SHARED);
 1123                         if (error) {
 1124                                 LIN_SDT_PROBE1(futex, handle_futex_death,
 1125                                     return, error);
 1126                                 return (error);
 1127                         }
 1128                         if (f != NULL) {
 1129                                 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
 1130                                 futex_put(f, NULL);
 1131                         }
 1132                 }
 1133         }
 1134 
 1135         LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
 1136         return (0);
 1137 }
 1138 
 1139 static int
 1140 fetch_robust_entry(struct linux_robust_list **entry,
 1141     struct linux_robust_list **head, int *pi)
 1142 {
 1143         l_ulong uentry;
 1144         int error;
 1145 
 1146         LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
 1147 
 1148         error = copyin((const void *)head, &uentry, sizeof(l_ulong));
 1149         if (error) {
 1150                 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
 1151                 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
 1152                 return (EFAULT);
 1153         }
 1154 
 1155         *entry = (void *)(uentry & ~1UL);
 1156         *pi = uentry & 1;
 1157 
 1158         LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
 1159         return (0);
 1160 }
 1161 
 1162 /* This walks the list of robust futexes releasing them. */
 1163 void
 1164 release_futexes(struct proc *p)
 1165 {
 1166         struct linux_robust_list_head *head = NULL;
 1167         struct linux_robust_list *entry, *next_entry, *pending;
 1168         unsigned int limit = 2048, pi, next_pi, pip;
 1169         struct linux_emuldata *em;
 1170         l_long futex_offset;
 1171         int rc, error;
 1172 
 1173         LIN_SDT_PROBE1(futex, release_futexes, entry, p);
 1174 
 1175         em = em_find(p, EMUL_DONTLOCK);
 1176         head = em->robust_futexes;
 1177 
 1178         if (head == NULL) {
 1179                 LIN_SDT_PROBE0(futex, release_futexes, return);
 1180                 return;
 1181         }
 1182 
 1183         if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
 1184                 LIN_SDT_PROBE0(futex, release_futexes, return);
 1185                 return;
 1186         }
 1187 
 1188         error = copyin(&head->futex_offset, &futex_offset,
 1189             sizeof(futex_offset));
 1190         if (error) {
 1191                 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
 1192                 LIN_SDT_PROBE0(futex, release_futexes, return);
 1193                 return;
 1194         }
 1195 
 1196         if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
 1197                 LIN_SDT_PROBE0(futex, release_futexes, return);
 1198                 return;
 1199         }
 1200 
 1201         while (entry != &head->list) {
 1202                 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
 1203 
 1204                 if (entry != pending)
 1205                         if (handle_futex_death(p,
 1206                             (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
 1207                                 LIN_SDT_PROBE0(futex, release_futexes, return);
 1208                                 return;
 1209                         }
 1210                 if (rc) {
 1211                         LIN_SDT_PROBE0(futex, release_futexes, return);
 1212                         return;
 1213                 }
 1214 
 1215                 entry = next_entry;
 1216                 pi = next_pi;
 1217 
 1218                 if (!--limit)
 1219                         break;
 1220 
 1221                 sched_relinquish(curthread);
 1222         }
 1223 
 1224         if (pending)
 1225                 handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip);
 1226 
 1227         LIN_SDT_PROBE0(futex, release_futexes, return);
 1228 }

Cache object: f5f25db448c376ffda0af0e721f46a86


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.