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
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/imgact.h>
  45 #include <sys/kernel.h>
  46 #include <sys/ktr.h>
  47 #include <sys/lock.h>
  48 #include <sys/malloc.h>
  49 #include <sys/mutex.h>
  50 #include <sys/priv.h>
  51 #include <sys/proc.h>
  52 #include <sys/queue.h>
  53 #include <sys/sched.h>
  54 #include <sys/sdt.h>
  55 #include <sys/sx.h>
  56 #include <sys/umtx.h>
  57
  58 #ifdef COMPAT_LINUX32
  59 #include <machine/../linux32/linux.h>
  60 #include <machine/../linux32/linux32_proto.h>
  61 #else
  62 #include <machine/../linux/linux.h>
  63 #include <machine/../linux/linux_proto.h>
  64 #endif
  65 #include <compat/linux/linux_dtrace.h>
  66 #include <compat/linux/linux_emul.h>
  67 #include <compat/linux/linux_futex.h>
  68 #include <compat/linux/linux_timer.h>
  69 #include <compat/linux/linux_util.h>
  70
  71 /* DTrace init */
  72 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
  73
  74 /**
  75  * Futex part for the special DTrace module "locks".
  76  */
  77 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
  78 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
  79
  80 /**
  81  * Per futex probes.
  82  */
  83 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
  84 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
  85
  86 /**
  87  * DTrace probes in this module.
  88  */
  89 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
  90     "struct waiting_proc *");
  91 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
  92     "int");
  93 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
  94     "int");
  95 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
  96 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
  97     "uint32_t");
  98 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
  99 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
 100     "int");
 101 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
 102 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
 103 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
 104 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
 105     "struct waiting_proc **", "struct futex **");
 106 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
 107 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
 108 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
 109     "struct waiting_proc **", "int");
 110 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
 111     "struct waiting_proc *", "uint32_t *", "uint32_t");
 112 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
 113     "struct waiting_proc *");
 114 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
 115 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
 116     "uint32_t");
 117 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
 118     "struct waiting_proc *", "uint32_t");
 119 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
 120 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
 121 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
 122     "struct futex *", "int");
 123 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
 124 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
 125     "struct waiting_proc *", "uint32_t");
 126 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
 127 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
 128     "struct waiting_proc **", "int", "uint32_t");
 129 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
 130 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
 131 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
 132     "int", "uint32_t");
 133 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
 134     "int");
 135 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
 136 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
 137 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
 138 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
 139 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
 140     "struct linux_sys_futex_args *");
 141 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
 142 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int");
 143 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
 144 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
 145 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
 146     "uint32_t", "uint32_t");
 147 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
 148     "uint32_t *", "uint32_t", "int", "uint32_t");
 149 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
 150     "uint32_t", "uint32_t");
 151 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
 152     "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
 153 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
 154     "uint32_t", "int");
 155 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
 156     "int", "uint32_t", "uint32_t *", "uint32_t");
 157 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
 158 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
 159 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
 160 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
 161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
 162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
 163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
 164 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
 165 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
 166 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
 167     "struct linux_set_robust_list_args *");
 168 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
 169 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
 170 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
 171     "struct linux_get_robust_list_args *");
 172 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
 173 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
 174 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry,
 175     "struct linux_emuldata *", "uint32_t *", "unsigned int");
 176 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
 177 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
 178 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
 179     "struct linux_robust_list **", "struct linux_robust_list **",
 180     "unsigned int *");
 181 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
 182 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
 183 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *",
 184     "struct linux_emuldata *");
 185 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
 186 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
 187
 188 struct futex;
 189
 190 struct waiting_proc {
 191         uint32_t        wp_flags;
 192         struct futex    *wp_futex;
 193         TAILQ_ENTRY(waiting_proc) wp_list;
 194 };
 195
 196 struct futex {
 197         struct sx       f_lck;
 198         uint32_t        *f_uaddr;       /* user-supplied value, for debug */
 199         struct umtx_key f_key;
 200         uint32_t        f_refcount;
 201         uint32_t        f_bitset;
 202         LIST_ENTRY(futex) f_list;
 203         TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
 204 };
 205
 206 struct futex_list futex_list;
 207
 208 #define FUTEX_LOCK(f)           sx_xlock(&(f)->f_lck)
 209 #define FUTEX_UNLOCK(f)         sx_xunlock(&(f)->f_lck)
 210 #define FUTEX_INIT(f)           do { \
 211                                     sx_init_flags(&(f)->f_lck, "ftlk", \
 212                                         SX_DUPOK); \
 213                                     LIN_SDT_PROBE1(futex, futex, create, \
 214                                         &(f)->f_lck); \
 215                                 } while (0)
 216 #define FUTEX_DESTROY(f)        do { \
 217                                     LIN_SDT_PROBE1(futex, futex, destroy, \
 218                                         &(f)->f_lck); \
 219                                     sx_destroy(&(f)->f_lck); \
 220                                 } while (0)
 221 #define FUTEX_ASSERT_LOCKED(f)  sx_assert(&(f)->f_lck, SA_XLOCKED)
 222
 223 struct mtx futex_mtx;                   /* protects the futex list */
 224 #define FUTEXES_LOCK            do { \
 225                                     mtx_lock(&futex_mtx); \
 226                                     LIN_SDT_PROBE1(locks, futex_mtx, \
 227                                         locked, &futex_mtx); \
 228                                 } while (0)
 229 #define FUTEXES_UNLOCK          do { \
 230                                     LIN_SDT_PROBE1(locks, futex_mtx, \
 231                                         unlock, &futex_mtx); \
 232                                     mtx_unlock(&futex_mtx); \
 233                                 } while (0)
 234
 235 /* flags for futex_get() */
 236 #define FUTEX_CREATE_WP         0x1     /* create waiting_proc */
 237 #define FUTEX_DONTCREATE        0x2     /* don't create futex if not exists */
 238 #define FUTEX_DONTEXISTS        0x4     /* return EINVAL if futex exists */
 239 #define FUTEX_SHARED            0x8     /* shared futex */
 240
 241 /* wp_flags */
 242 #define FUTEX_WP_REQUEUED       0x1     /* wp requeued - wp moved from wp_list
 243                                          * of futex where thread sleep to wp_list
 244                                          * of another futex.
 245                                          */
 246 #define FUTEX_WP_REMOVED        0x2     /* wp is woken up and removed from futex
 247                                          * wp_list to prevent double wakeup.
 248                                          */
 249
 250 static void futex_put(struct futex *, struct waiting_proc *);
 251 static int futex_get0(uint32_t *, struct futex **f, uint32_t);
 252 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
 253     uint32_t);
 254 static int futex_sleep(struct futex *, struct waiting_proc *, int);
 255 static int futex_wake(struct futex *, int, uint32_t);
 256 static int futex_requeue(struct futex *, int, struct futex *, int);
 257 static int futex_wait(struct futex *, struct waiting_proc *, int,
 258     uint32_t);
 259 static int futex_atomic_op(struct thread *, int, uint32_t *);
 260 static int handle_futex_death(struct linux_emuldata *, uint32_t *,
 261     unsigned int);
 262 static int fetch_robust_entry(struct linux_robust_list **,
 263     struct linux_robust_list **, unsigned int *);
 264
 265 /* support.s */
 266 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
 267 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
 268 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
 269 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
 270 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
 271
 272
 273 static void
 274 futex_put(struct futex *f, struct waiting_proc *wp)
 275 {
 276         LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
 277
 278         FUTEX_ASSERT_LOCKED(f);
 279         if (wp != NULL) {
 280                 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
 281                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 282                 free(wp, M_FUTEX_WP);
 283         }
 284
 285         FUTEXES_LOCK;
 286         if (--f->f_refcount == 0) {
 287                 LIST_REMOVE(f, f_list);
 288                 FUTEXES_UNLOCK;
 289                 FUTEX_UNLOCK(f);
 290
 291                 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
 292                     f->f_refcount, f->f_key.shared);
 293                 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
 294                     "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
 295                 umtx_key_release(&f->f_key);
 296                 FUTEX_DESTROY(f);
 297                 free(f, M_FUTEX);
 298
 299                 LIN_SDT_PROBE0(futex, futex_put, return);
 300                 return;
 301         }
 302
 303         LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
 304             f->f_key.shared);
 305         LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
 306             f->f_uaddr, f->f_refcount, f->f_key.shared);
 307         FUTEXES_UNLOCK;
 308         FUTEX_UNLOCK(f);
 309
 310         LIN_SDT_PROBE0(futex, futex_put, return);
 311 }
 312
 313 static int
 314 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
 315 {
 316         struct futex *f, *tmpf;
 317         struct umtx_key key;
 318         int error;
 319
 320         LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
 321
 322         *newf = tmpf = NULL;
 323
 324         error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
 325             AUTO_SHARE : THREAD_SHARE, &key);
 326         if (error) {
 327                 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
 328                 LIN_SDT_PROBE1(futex, futex_get0, return, error);
 329                 return (error);
 330         }
 331 retry:
 332         FUTEXES_LOCK;
 333         LIST_FOREACH(f, &futex_list, f_list) {
 334                 if (umtx_key_match(&f->f_key, &key)) {
 335                         if (tmpf != NULL) {
 336                                 FUTEX_UNLOCK(tmpf);
 337                                 FUTEX_DESTROY(tmpf);
 338                                 free(tmpf, M_FUTEX);
 339                         }
 340                         if (flags & FUTEX_DONTEXISTS) {
 341                                 FUTEXES_UNLOCK;
 342                                 umtx_key_release(&key);
 343
 344                                 LIN_SDT_PROBE1(futex, futex_get0, return,
 345                                     EINVAL);
 346                                 return (EINVAL);
 347                         }
 348
 349                         /*
 350                          * Increment refcount of the found futex to
 351                          * prevent it from deallocation before FUTEX_LOCK()
 352                          */
 353                         ++f->f_refcount;
 354                         FUTEXES_UNLOCK;
 355                         umtx_key_release(&key);
 356
 357                         FUTEX_LOCK(f);
 358                         *newf = f;
 359                         LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
 360                             f->f_refcount, f->f_key.shared);
 361                         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
 362                             uaddr, f->f_refcount, f->f_key.shared);
 363
 364                         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 365                         return (0);
 366                 }
 367         }
 368
 369         if (flags & FUTEX_DONTCREATE) {
 370                 FUTEXES_UNLOCK;
 371                 umtx_key_release(&key);
 372                 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
 373                 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
 374
 375                 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 376                 return (0);
 377         }
 378
 379         if (tmpf == NULL) {
 380                 FUTEXES_UNLOCK;
 381                 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
 382                 tmpf->f_uaddr = uaddr;
 383                 tmpf->f_key = key;
 384                 tmpf->f_refcount = 1;
 385                 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
 386                 FUTEX_INIT(tmpf);
 387                 TAILQ_INIT(&tmpf->f_waiting_proc);
 388
 389                 /*
 390                  * Lock the new futex before an insert into the futex_list
 391                  * to prevent futex usage by other.
 392                  */
 393                 FUTEX_LOCK(tmpf);
 394                 goto retry;
 395         }
 396
 397         LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
 398         FUTEXES_UNLOCK;
 399
 400         LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
 401             tmpf->f_key.shared);
 402         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
 403             uaddr, tmpf->f_refcount, tmpf->f_key.shared);
 404         *newf = tmpf;
 405
 406         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 407         return (0);
 408 }
 409
 410 static int
 411 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
 412     uint32_t flags)
 413 {
 414         int error;
 415
 416         LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
 417
 418         if (flags & FUTEX_CREATE_WP) {
 419                 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
 420                 (*wp)->wp_flags = 0;
 421         }
 422         error = futex_get0(uaddr, f, flags);
 423         if (error) {
 424                 LIN_SDT_PROBE0(futex, futex_get, error);
 425
 426                 if (flags & FUTEX_CREATE_WP)
 427                         free(*wp, M_FUTEX_WP);
 428
 429                 LIN_SDT_PROBE1(futex, futex_get, return, error);
 430                 return (error);
 431         }
 432         if (flags & FUTEX_CREATE_WP) {
 433                 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
 434                 (*wp)->wp_futex = *f;
 435         }
 436
 437         LIN_SDT_PROBE1(futex, futex_get, return, error);
 438         return (error);
 439 }
 440
 441 static int
 442 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
 443 {
 444         int error;
 445
 446         FUTEX_ASSERT_LOCKED(f);
 447         LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout);
 448         LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
 449             f->f_uaddr, wp, timeout, f->f_refcount);
 450         error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
 451         if (wp->wp_flags & FUTEX_WP_REQUEUED) {
 452                 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
 453
 454                 if (error) {
 455                         LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
 456                             f->f_uaddr, wp, wp->wp_futex->f_uaddr,
 457                             wp->wp_futex->f_refcount);
 458                 }
 459
 460                 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
 461                     " %p requeued uaddr %p ref %d",
 462                     error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
 463                     wp->wp_futex->f_refcount);
 464                 futex_put(f, NULL);
 465                 f = wp->wp_futex;
 466                 FUTEX_LOCK(f);
 467         } else {
 468                 if (error) {
 469                         LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
 470                             f->f_uaddr, wp);
 471                 }
 472                 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
 473                     error, f->f_uaddr, wp);
 474         }
 475
 476         futex_put(f, wp);
 477
 478         LIN_SDT_PROBE1(futex, futex_sleep, return, error);
 479         return (error);
 480 }
 481
 482 static int
 483 futex_wake(struct futex *f, int n, uint32_t bitset)
 484 {
 485         struct waiting_proc *wp, *wpt;
 486         int count = 0;
 487
 488         LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
 489
 490         if (bitset == 0) {
 491                 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
 492                 return (EINVAL);
 493         }
 494
 495         FUTEX_ASSERT_LOCKED(f);
 496         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
 497                 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
 498                     f->f_refcount);
 499                 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
 500                     f->f_uaddr, wp, f->f_refcount);
 501                 /*
 502                  * Unless we find a matching bit in
 503                  * the bitset, continue searching.
 504                  */
 505                 if (!(wp->wp_futex->f_bitset & bitset))
 506                         continue;
 507
 508                 wp->wp_flags |= FUTEX_WP_REMOVED;
 509                 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 510                 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
 511                 wakeup_one(wp);
 512                 if (++count == n)
 513                         break;
 514         }
 515
 516         LIN_SDT_PROBE1(futex, futex_wake, return, count);
 517         return (count);
 518 }
 519
 520 static int
 521 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
 522 {
 523         struct waiting_proc *wp, *wpt;
 524         int count = 0;
 525
 526         LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
 527
 528         FUTEX_ASSERT_LOCKED(f);
 529         FUTEX_ASSERT_LOCKED(f2);
 530
 531         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
 532                 if (++count <= n) {
 533                         LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
 534                             f->f_uaddr, wp);
 535                         wp->wp_flags |= FUTEX_WP_REMOVED;
 536                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 537                         LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
 538                         wakeup_one(wp);
 539                 } else {
 540                         LIN_SDT_PROBE3(futex, futex_requeue, requeue,
 541                             f->f_uaddr, wp, f2->f_uaddr);
 542                         LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
 543                             f->f_uaddr, wp, f2->f_uaddr);
 544                         wp->wp_flags |= FUTEX_WP_REQUEUED;
 545                         /* Move wp to wp_list of f2 futex */
 546                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 547                         TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
 548
 549                         /*
 550                          * Thread which sleeps on wp after waking should
 551                          * acquire f2 lock, so increment refcount of f2 to
 552                          * prevent it from premature deallocation.
 553                          */
 554                         wp->wp_futex = f2;
 555                         FUTEXES_LOCK;
 556                         ++f2->f_refcount;
 557                         FUTEXES_UNLOCK;
 558                         if (count - n >= n2)
 559                                 break;
 560                 }
 561         }
 562
 563         LIN_SDT_PROBE1(futex, futex_requeue, return, count);
 564         return (count);
 565 }
 566
 567 static int
 568 futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz,
 569     uint32_t bitset)
 570 {
 571         int error;
 572
 573         LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset);
 574
 575         if (bitset == 0) {
 576                 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
 577                 return (EINVAL);
 578         }
 579
 580         f->f_bitset = bitset;
 581         error = futex_sleep(f, wp, timeout_hz);
 582         if (error)
 583                 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
 584         if (error == EWOULDBLOCK)
 585                 error = ETIMEDOUT;
 586
 587         LIN_SDT_PROBE1(futex, futex_wait, return, error);
 588         return (error);
 589 }
 590
 591 static int
 592 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
 593 {
 594         int op = (encoded_op >> 28) & 7;
 595         int cmp = (encoded_op >> 24) & 15;
 596         int oparg = (encoded_op << 8) >> 20;
 597         int cmparg = (encoded_op << 20) >> 20;
 598         int oldval = 0, ret;
 599
 600         LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
 601
 602         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
 603                 oparg = 1 << oparg;
 604
 605         LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
 606             cmparg);
 607
 608         /* XXX: Linux verifies access here and returns EFAULT */
 609         LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
 610
 611         switch (op) {
 612         case FUTEX_OP_SET:
 613                 ret = futex_xchgl(oparg, uaddr, &oldval);
 614                 break;
 615         case FUTEX_OP_ADD:
 616                 ret = futex_addl(oparg, uaddr, &oldval);
 617                 break;
 618         case FUTEX_OP_OR:
 619                 ret = futex_orl(oparg, uaddr, &oldval);
 620                 break;
 621         case FUTEX_OP_ANDN:
 622                 ret = futex_andl(~oparg, uaddr, &oldval);
 623                 break;
 624         case FUTEX_OP_XOR:
 625                 ret = futex_xorl(oparg, uaddr, &oldval);
 626                 break;
 627         default:
 628                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
 629                 ret = -ENOSYS;
 630                 break;
 631         }
 632
 633         if (ret) {
 634                 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
 635                 return (ret);
 636         }
 637
 638         switch (cmp) {
 639         case FUTEX_OP_CMP_EQ:
 640                 ret = (oldval == cmparg);
 641                 break;
 642         case FUTEX_OP_CMP_NE:
 643                 ret = (oldval != cmparg);
 644                 break;
 645         case FUTEX_OP_CMP_LT:
 646                 ret = (oldval < cmparg);
 647                 break;
 648         case FUTEX_OP_CMP_GE:
 649                 ret = (oldval >= cmparg);
 650                 break;
 651         case FUTEX_OP_CMP_LE:
 652                 ret = (oldval <= cmparg);
 653                 break;
 654         case FUTEX_OP_CMP_GT:
 655                 ret = (oldval > cmparg);
 656                 break;
 657         default:
 658                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
 659                 ret = -ENOSYS;
 660         }
 661
 662         LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
 663         return (ret);
 664 }
 665
 666 int
 667 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 668 {
 669         int clockrt, nrwake, op_ret, ret;
 670         struct linux_pemuldata *pem;
 671         struct waiting_proc *wp;
 672         struct futex *f, *f2;
 673         struct l_timespec ltimeout;
 674         struct timespec timeout;
 675         struct timeval utv, ctv;
 676         int timeout_hz;
 677         int error;
 678         uint32_t flags, val;
 679
 680         LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
 681
 682         if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
 683                 flags = 0;
 684                 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
 685         } else
 686                 flags = FUTEX_SHARED;
 687
 688         /*
 689          * Currently support for switching between CLOCK_MONOTONIC and
 690          * CLOCK_REALTIME is not present. However Linux forbids the use of
 691          * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
 692          * FUTEX_WAIT_REQUEUE_PI.
 693          */
 694         clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
 695         args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
 696         if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
 697                 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
 698                 LIN_SDT_PROBE0(futex, linux_sys_futex,
 699                     unimplemented_clockswitch);
 700                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 701                 return (ENOSYS);
 702         }
 703
 704         error = 0;
 705         f = f2 = NULL;
 706
 707         switch (args->op) {
 708         case LINUX_FUTEX_WAIT:
 709                 args->val3 = FUTEX_BITSET_MATCH_ANY;
 710                 /* FALLTHROUGH */
 711
 712         case LINUX_FUTEX_WAIT_BITSET:
 713                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
 714                     args->val, args->val3);
 715                 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
 716                     args->uaddr, args->val, args->val3);
 717
 718                 if (args->timeout != NULL) {
 719                         error = copyin(args->timeout, &ltimeout, sizeof(ltimeout));
 720                         if (error) {
 721                                 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 722                                     error);
 723                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 724                                 return (error);
 725                         }
 726                         error = linux_to_native_timespec(&timeout, &ltimeout);
 727                         if (error)
 728                                 return (error);
 729                         TIMESPEC_TO_TIMEVAL(&utv, &timeout);
 730                         error = itimerfix(&utv);
 731                         if (error) {
 732                                 LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error,
 733                                     error);
 734                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 735                                 return (error);
 736                         }
 737                         if (clockrt) {
 738                                 microtime(&ctv);
 739                                 timevalsub(&utv, &ctv);
 740                         } else if (args->op == LINUX_FUTEX_WAIT_BITSET) {
 741                                 microuptime(&ctv);
 742                                 timevalsub(&utv, &ctv);
 743                         }
 744                         if (utv.tv_sec < 0)
 745                                 timevalclear(&utv);
 746                         timeout_hz = tvtohz(&utv);
 747                 } else
 748                         timeout_hz = 0;
 749
 750                 error = futex_get(args->uaddr, &wp, &f,
 751                     flags | FUTEX_CREATE_WP);
 752                 if (error) {
 753                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 754                         return (error);
 755                 }
 756
 757                 error = copyin(args->uaddr, &val, sizeof(val));
 758                 if (error) {
 759                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 760                             error);
 761                         LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
 762                             error);
 763                         futex_put(f, wp);
 764
 765                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 766                         return (error);
 767                 }
 768                 if (val != args->val) {
 769                         LIN_SDT_PROBE4(futex, linux_sys_futex,
 770                             debug_wait_value_neq, args->uaddr, args->val, val,
 771                             args->val3);
 772                         LINUX_CTR3(sys_futex,
 773                             "WAIT uaddr %p val 0x%x != uval 0x%x",
 774                             args->uaddr, args->val, val);
 775                         futex_put(f, wp);
 776
 777                         LIN_SDT_PROBE1(futex, linux_sys_futex, return,
 778                             EWOULDBLOCK);
 779                         return (EWOULDBLOCK);
 780                 }
 781
 782                 error = futex_wait(f, wp, timeout_hz, args->val3);
 783                 break;
 784
 785         case LINUX_FUTEX_WAKE:
 786                 args->val3 = FUTEX_BITSET_MATCH_ANY;
 787                 /* FALLTHROUGH */
 788
 789         case LINUX_FUTEX_WAKE_BITSET:
 790                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
 791                     args->val, args->val3);
 792                 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
 793                     args->uaddr, args->val, args->val3);
 794
 795                 error = futex_get(args->uaddr, NULL, &f,
 796                     flags | FUTEX_DONTCREATE);
 797                 if (error) {
 798                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 799                         return (error);
 800                 }
 801
 802                 if (f == NULL) {
 803                         td->td_retval[0] = 0;
 804
 805                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 806                         return (error);
 807                 }
 808                 td->td_retval[0] = futex_wake(f, args->val, args->val3);
 809                 futex_put(f, NULL);
 810                 break;
 811
 812         case LINUX_FUTEX_CMP_REQUEUE:
 813                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
 814                     args->uaddr, args->val, args->val3, args->uaddr2,
 815                     args->timeout);
 816                 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
 817                     "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
 818                     args->uaddr, args->val, args->val3, args->uaddr2,
 819                     args->timeout);
 820
 821                 /*
 822                  * Linux allows this, we would not, it is an incorrect
 823                  * usage of declared ABI, so return EINVAL.
 824                  */
 825                 if (args->uaddr == args->uaddr2) {
 826                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 827                             invalid_cmp_requeue_use);
 828                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
 829                         return (EINVAL);
 830                 }
 831
 832                 error = futex_get(args->uaddr, NULL, &f, flags);
 833                 if (error) {
 834                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 835                         return (error);
 836                 }
 837
 838                 /*
 839                  * To avoid deadlocks return EINVAL if second futex
 840                  * exists at this time.
 841                  *
 842                  * Glibc fall back to FUTEX_WAKE in case of any error
 843                  * returned by FUTEX_CMP_REQUEUE.
 844                  */
 845                 error = futex_get(args->uaddr2, NULL, &f2,
 846                     flags | FUTEX_DONTEXISTS);
 847                 if (error) {
 848                         futex_put(f, NULL);
 849
 850                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 851                         return (error);
 852                 }
 853                 error = copyin(args->uaddr, &val, sizeof(val));
 854                 if (error) {
 855                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 856                             error);
 857                         LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
 858                             error);
 859                         futex_put(f2, NULL);
 860                         futex_put(f, NULL);
 861
 862                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 863                         return (error);
 864                 }
 865                 if (val != args->val3) {
 866                         LIN_SDT_PROBE2(futex, linux_sys_futex,
 867                             debug_cmp_requeue_value_neq, args->val, val);
 868                         LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
 869                             args->val, val);
 870                         futex_put(f2, NULL);
 871                         futex_put(f, NULL);
 872
 873                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
 874                         return (EAGAIN);
 875                 }
 876
 877                 nrwake = (int)(unsigned long)args->timeout;
 878                 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
 879                 futex_put(f2, NULL);
 880                 futex_put(f, NULL);
 881                 break;
 882
 883         case LINUX_FUTEX_WAKE_OP:
 884                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
 885                     args->uaddr, args->op, args->val, args->uaddr2, args->val3);
 886                 LINUX_CTR5(sys_futex, "WAKE_OP "
 887                     "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
 888                     args->uaddr, args->val, args->uaddr2, args->val3,
 889                     args->timeout);
 890
 891                 error = futex_get(args->uaddr, NULL, &f, flags);
 892                 if (error) {
 893                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 894                         return (error);
 895                 }
 896
 897                 if (args->uaddr != args->uaddr2)
 898                         error = futex_get(args->uaddr2, NULL, &f2, flags);
 899                 if (error) {
 900                         futex_put(f, NULL);
 901
 902                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 903                         return (error);
 904                 }
 905
 906                 /*
 907                  * This function returns positive number as results and
 908                  * negative as errors
 909                  */
 910                 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
 911
 912                 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
 913                     args->uaddr, op_ret);
 914
 915                 if (op_ret < 0) {
 916                         /* XXX: We don't handle the EFAULT yet. */
 917                         if (op_ret != -EFAULT) {
 918                                 if (f2 != NULL)
 919                                         futex_put(f2, NULL);
 920                                 futex_put(f, NULL);
 921
 922                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
 923                                     -op_ret);
 924                                 return (-op_ret);
 925                         } else {
 926                                 LIN_SDT_PROBE0(futex, linux_sys_futex,
 927                                     unhandled_efault);
 928                         }
 929                         if (f2 != NULL)
 930                                 futex_put(f2, NULL);
 931                         futex_put(f, NULL);
 932
 933                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT);
 934                         return (EFAULT);
 935                 }
 936
 937                 ret = futex_wake(f, args->val, args->val3);
 938
 939                 if (op_ret > 0) {
 940                         op_ret = 0;
 941                         nrwake = (int)(unsigned long)args->timeout;
 942
 943                         if (f2 != NULL)
 944                                 op_ret += futex_wake(f2, nrwake, args->val3);
 945                         else
 946                                 op_ret += futex_wake(f, nrwake, args->val3);
 947                         ret += op_ret;
 948
 949                 }
 950                 if (f2 != NULL)
 951                         futex_put(f2, NULL);
 952                 futex_put(f, NULL);
 953                 td->td_retval[0] = ret;
 954                 break;
 955
 956         case LINUX_FUTEX_LOCK_PI:
 957                 /* not yet implemented */
 958                 pem = pem_find(td->td_proc);
 959                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 960                         linux_msg(td,
 961                                   "linux_sys_futex: "
 962                                   "unsupported futex_pi op\n");
 963                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 964                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 965                             unimplemented_lock_pi);
 966                 }
 967                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 968                 return (ENOSYS);
 969
 970         case LINUX_FUTEX_UNLOCK_PI:
 971                 /* not yet implemented */
 972                 pem = pem_find(td->td_proc);
 973                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 974                         linux_msg(td,
 975                                   "linux_sys_futex: "
 976                                   "unsupported futex_pi op\n");
 977                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 978                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 979                             unimplemented_unlock_pi);
 980                 }
 981                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 982                 return (ENOSYS);
 983
 984         case LINUX_FUTEX_TRYLOCK_PI:
 985                 /* not yet implemented */
 986                 pem = pem_find(td->td_proc);
 987                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 988                         linux_msg(td,
 989                                   "linux_sys_futex: "
 990                                   "unsupported futex_pi op\n");
 991                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 992                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 993                             unimplemented_trylock_pi);
 994                 }
 995                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 996                 return (ENOSYS);
 997
 998         case LINUX_FUTEX_REQUEUE:
 999
1000                 /*
1001                  * Glibc does not use this operation since version 2.3.3,
1002                  * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
1003                  * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
1004                  * FUTEX_REQUEUE returned EINVAL.
1005                  */
1006                 pem = pem_find(td->td_proc);
1007                 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
1008                         linux_msg(td,
1009                                   "linux_sys_futex: "
1010                                   "unsupported futex_requeue op\n");
1011                         pem->flags |= LINUX_XDEPR_REQUEUEOP;
1012                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1013                             deprecated_requeue);
1014                 }
1015
1016                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
1017                 return (EINVAL);
1018
1019         case LINUX_FUTEX_WAIT_REQUEUE_PI:
1020                 /* not yet implemented */
1021                 pem = pem_find(td->td_proc);
1022                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1023                         linux_msg(td,
1024                                   "linux_sys_futex: "
1025                                   "unsupported futex_pi op\n");
1026                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1027                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1028                             unimplemented_wait_requeue_pi);
1029                 }
1030                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1031                 return (ENOSYS);
1032
1033         case LINUX_FUTEX_CMP_REQUEUE_PI:
1034                 /* not yet implemented */
1035                 pem = pem_find(td->td_proc);
1036                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1037                         linux_msg(td,
1038                                   "linux_sys_futex: "
1039                                   "unsupported futex_pi op\n");
1040                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1041                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1042                             unimplemented_cmp_requeue_pi);
1043                 }
1044                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1045                 return (ENOSYS);
1046
1047         default:
1048                 linux_msg(td,
1049                           "linux_sys_futex: unknown op %d\n", args->op);
1050                 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1051                     args->op);
1052                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1053                 return (ENOSYS);
1054         }
1055
1056         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1057         return (error);
1058 }
1059
1060 int
1061 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1062 {
1063         struct linux_emuldata *em;
1064
1065         LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1066
1067         if (args->len != sizeof(struct linux_robust_list_head)) {
1068                 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1069                 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1070                 return (EINVAL);
1071         }
1072
1073         em = em_find(td);
1074         em->robust_futexes = args->head;
1075
1076         LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1077         return (0);
1078 }
1079
1080 int
1081 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1082 {
1083         struct linux_emuldata *em;
1084         struct linux_robust_list_head *head;
1085         l_size_t len = sizeof(struct linux_robust_list_head);
1086         struct thread *td2;
1087         int error = 0;
1088
1089         LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1090
1091         if (!args->pid) {
1092                 em = em_find(td);
1093                 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1094                 head = em->robust_futexes;
1095         } else {
1096                 td2 = tdfind(args->pid, -1);
1097                 if (td2 == NULL) {
1098                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1099                             ESRCH);
1100                         return (ESRCH);
1101                 }
1102                 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) {
1103                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1104                             EPERM);
1105                         PROC_UNLOCK(td2->td_proc);
1106                         return (EPERM);
1107                 }
1108
1109                 em = em_find(td2);
1110                 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1111                 /* XXX: ptrace? */
1112                 if (priv_check(td, PRIV_CRED_SETUID) ||
1113                     priv_check(td, PRIV_CRED_SETEUID) ||
1114                     p_candebug(td, td2->td_proc)) {
1115                         PROC_UNLOCK(td2->td_proc);
1116
1117                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1118                             EPERM);
1119                         return (EPERM);
1120                 }
1121                 head = em->robust_futexes;
1122
1123                 PROC_UNLOCK(td2->td_proc);
1124         }
1125
1126         error = copyout(&len, args->len, sizeof(l_size_t));
1127         if (error) {
1128                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1129                     error);
1130                 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1131                 return (EFAULT);
1132         }
1133
1134         error = copyout(&head, args->head, sizeof(head));
1135         if (error) {
1136                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1137                     error);
1138         }
1139
1140         LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1141         return (error);
1142 }
1143
1144 static int
1145 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
1146     unsigned int pi)
1147 {
1148         uint32_t uval, nval, mval;
1149         struct futex *f;
1150         int error;
1151
1152         LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi);
1153
1154 retry:
1155         error = copyin(uaddr, &uval, 4);
1156         if (error) {
1157                 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1158                 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1159                 return (EFAULT);
1160         }
1161         if ((uval & FUTEX_TID_MASK) == em->em_tid) {
1162                 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1163                 nval = casuword32(uaddr, uval, mval);
1164
1165                 if (nval == -1) {
1166                         LIN_SDT_PROBE1(futex, handle_futex_death, return,
1167                             EFAULT);
1168                         return (EFAULT);
1169                 }
1170
1171                 if (nval != uval)
1172                         goto retry;
1173
1174                 if (!pi && (uval & FUTEX_WAITERS)) {
1175                         error = futex_get(uaddr, NULL, &f,
1176                             FUTEX_DONTCREATE | FUTEX_SHARED);
1177                         if (error) {
1178                                 LIN_SDT_PROBE1(futex, handle_futex_death,
1179                                     return, error);
1180                                 return (error);
1181                         }
1182                         if (f != NULL) {
1183                                 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1184                                 futex_put(f, NULL);
1185                         }
1186                 }
1187         }
1188
1189         LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1190         return (0);
1191 }
1192
1193 static int
1194 fetch_robust_entry(struct linux_robust_list **entry,
1195     struct linux_robust_list **head, unsigned int *pi)
1196 {
1197         l_ulong uentry;
1198         int error;
1199
1200         LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1201
1202         error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1203         if (error) {
1204                 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1205                 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1206                 return (EFAULT);
1207         }
1208
1209         *entry = (void *)(uentry & ~1UL);
1210         *pi = uentry & 1;
1211
1212         LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1213         return (0);
1214 }
1215
1216 /* This walks the list of robust futexes releasing them. */
1217 void
1218 release_futexes(struct thread *td, struct linux_emuldata *em)
1219 {
1220         struct linux_robust_list_head *head = NULL;
1221         struct linux_robust_list *entry, *next_entry, *pending;
1222         unsigned int limit = 2048, pi, next_pi, pip;
1223         l_long futex_offset;
1224         int rc, error;
1225
1226         LIN_SDT_PROBE2(futex, release_futexes, entry, td, em);
1227
1228         head = em->robust_futexes;
1229
1230         if (head == NULL) {
1231                 LIN_SDT_PROBE0(futex, release_futexes, return);
1232                 return;
1233         }
1234
1235         if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1236                 LIN_SDT_PROBE0(futex, release_futexes, return);
1237                 return;
1238         }
1239
1240         error = copyin(&head->futex_offset, &futex_offset,
1241             sizeof(futex_offset));
1242         if (error) {
1243                 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1244                 LIN_SDT_PROBE0(futex, release_futexes, return);
1245                 return;
1246         }
1247
1248         if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1249                 LIN_SDT_PROBE0(futex, release_futexes, return);
1250                 return;
1251         }
1252
1253         while (entry != &head->list) {
1254                 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1255
1256                 if (entry != pending)
1257                         if (handle_futex_death(em,
1258                             (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1259                                 LIN_SDT_PROBE0(futex, release_futexes, return);
1260                                 return;
1261                         }
1262                 if (rc) {
1263                         LIN_SDT_PROBE0(futex, release_futexes, return);
1264                         return;
1265                 }
1266
1267                 entry = next_entry;
1268                 pi = next_pi;
1269
1270                 if (!--limit)
1271                         break;
1272
1273                 sched_relinquish(curthread);
1274         }
1275
1276         if (pending)
1277                 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1278
1279         LIN_SDT_PROBE0(futex, release_futexes, return);
1280 }