sys/compat/linux/linux_futex.c

   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("$FreeBSD$");
  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 }