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_timer.h>
  70 #include <compat/linux/linux_util.h>
  71
  72 /* DTrace init */
  73 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
  74
  75 /**
  76  * Futex part for the special DTrace module "locks".
  77  */
  78 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
  79 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
  80
  81 /**
  82  * Per futex probes.
  83  */
  84 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
  85 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
  86
  87 /**
  88  * DTrace probes in this module.
  89  */
  90 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
  91     "struct waiting_proc *");
  92 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
  93     "int");
  94 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
  95     "int");
  96 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
  97 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
  98     "uint32_t");
  99 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
 100 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
 101     "int");
 102 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
 103 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
 104 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
 105 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
 106     "struct waiting_proc **", "struct futex **");
 107 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
 108 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
 109 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
 110     "struct waiting_proc **", "int");
 111 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
 112     "struct waiting_proc *", "uint32_t *", "uint32_t");
 113 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
 114     "struct waiting_proc *");
 115 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
 116 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
 117     "uint32_t");
 118 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
 119     "struct waiting_proc *", "uint32_t");
 120 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
 121 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
 122 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
 123     "struct futex *", "int");
 124 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
 125 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
 126     "struct waiting_proc *", "uint32_t");
 127 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
 128 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
 129     "struct waiting_proc **", "int", "uint32_t");
 130 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
 131 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
 132 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
 133     "int", "uint32_t");
 134 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
 135     "int");
 136 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
 137 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
 138 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
 139 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
 140 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
 141     "struct linux_sys_futex_args *");
 142 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
 143 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int");
 144 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
 145 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
 146 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
 147     "uint32_t", "uint32_t");
 148 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
 149     "uint32_t *", "uint32_t", "int", "uint32_t");
 150 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
 151     "uint32_t", "uint32_t");
 152 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
 153     "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
 154 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
 155     "uint32_t", "int");
 156 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
 157     "int", "uint32_t", "uint32_t *", "uint32_t");
 158 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
 159 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
 160 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
 161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
 162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
 163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
 164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
 165 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
 166 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
 167 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
 168     "struct linux_set_robust_list_args *");
 169 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
 170 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
 171 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
 172     "struct linux_get_robust_list_args *");
 173 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
 174 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
 175 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry,
 176     "struct linux_emuldata *", "uint32_t *", "unsigned int");
 177 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
 178 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
 179 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
 180     "struct linux_robust_list **", "struct linux_robust_list **",
 181     "unsigned int *");
 182 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
 183 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
 184 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *",
 185     "struct linux_emuldata *");
 186 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
 187 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
 188
 189 struct futex;
 190
 191 struct waiting_proc {
 192         uint32_t        wp_flags;
 193         struct futex    *wp_futex;
 194         TAILQ_ENTRY(waiting_proc) wp_list;
 195 };
 196
 197 struct futex {
 198         struct sx       f_lck;
 199         uint32_t        *f_uaddr;       /* user-supplied value, for debug */
 200         struct umtx_key f_key;
 201         uint32_t        f_refcount;
 202         uint32_t        f_bitset;
 203         LIST_ENTRY(futex) f_list;
 204         TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
 205 };
 206
 207 struct futex_list futex_list;
 208
 209 #define FUTEX_LOCK(f)           sx_xlock(&(f)->f_lck)
 210 #define FUTEX_UNLOCK(f)         sx_xunlock(&(f)->f_lck)
 211 #define FUTEX_INIT(f)           do { \
 212                                     sx_init_flags(&(f)->f_lck, "ftlk", \
 213                                         SX_DUPOK); \
 214                                     LIN_SDT_PROBE1(futex, futex, create, \
 215                                         &(f)->f_lck); \
 216                                 } while (0)
 217 #define FUTEX_DESTROY(f)        do { \
 218                                     LIN_SDT_PROBE1(futex, futex, destroy, \
 219                                         &(f)->f_lck); \
 220                                     sx_destroy(&(f)->f_lck); \
 221                                 } while (0)
 222 #define FUTEX_ASSERT_LOCKED(f)  sx_assert(&(f)->f_lck, SA_XLOCKED)
 223
 224 struct mtx futex_mtx;                   /* protects the futex list */
 225 #define FUTEXES_LOCK            do { \
 226                                     mtx_lock(&futex_mtx); \
 227                                     LIN_SDT_PROBE1(locks, futex_mtx, \
 228                                         locked, &futex_mtx); \
 229                                 } while (0)
 230 #define FUTEXES_UNLOCK          do { \
 231                                     LIN_SDT_PROBE1(locks, futex_mtx, \
 232                                         unlock, &futex_mtx); \
 233                                     mtx_unlock(&futex_mtx); \
 234                                 } while (0)
 235
 236 /* flags for futex_get() */
 237 #define FUTEX_CREATE_WP         0x1     /* create waiting_proc */
 238 #define FUTEX_DONTCREATE        0x2     /* don't create futex if not exists */
 239 #define FUTEX_DONTEXISTS        0x4     /* return EINVAL if futex exists */
 240 #define FUTEX_SHARED            0x8     /* shared futex */
 241
 242 /* wp_flags */
 243 #define FUTEX_WP_REQUEUED       0x1     /* wp requeued - wp moved from wp_list
 244                                          * of futex where thread sleep to wp_list
 245                                          * of another futex.
 246                                          */
 247 #define FUTEX_WP_REMOVED        0x2     /* wp is woken up and removed from futex
 248                                          * wp_list to prevent double wakeup.
 249                                          */
 250
 251 static void futex_put(struct futex *, struct waiting_proc *);
 252 static int futex_get0(uint32_t *, struct futex **f, uint32_t);
 253 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
 254     uint32_t);
 255 static int futex_sleep(struct futex *, struct waiting_proc *, int);
 256 static int futex_wake(struct futex *, int, uint32_t);
 257 static int futex_requeue(struct futex *, int, struct futex *, int);
 258 static int futex_wait(struct futex *, struct waiting_proc *, int,
 259     uint32_t);
 260 static int futex_atomic_op(struct thread *, int, uint32_t *);
 261 static int handle_futex_death(struct linux_emuldata *, uint32_t *,
 262     unsigned int);
 263 static int fetch_robust_entry(struct linux_robust_list **,
 264     struct linux_robust_list **, unsigned int *);
 265
 266 /* support.s */
 267 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
 268 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
 269 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
 270 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
 271 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
 272
 273
 274 static void
 275 futex_put(struct futex *f, struct waiting_proc *wp)
 276 {
 277         LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
 278
 279         FUTEX_ASSERT_LOCKED(f);
 280         if (wp != NULL) {
 281                 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
 282                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 283                 free(wp, M_FUTEX_WP);
 284         }
 285
 286         FUTEXES_LOCK;
 287         if (--f->f_refcount == 0) {
 288                 LIST_REMOVE(f, f_list);
 289                 FUTEXES_UNLOCK;
 290                 FUTEX_UNLOCK(f);
 291
 292                 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
 293                     f->f_refcount, f->f_key.shared);
 294                 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
 295                     "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
 296                 umtx_key_release(&f->f_key);
 297                 FUTEX_DESTROY(f);
 298                 free(f, M_FUTEX);
 299
 300                 LIN_SDT_PROBE0(futex, futex_put, return);
 301                 return;
 302         }
 303
 304         LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
 305             f->f_key.shared);
 306         LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
 307             f->f_uaddr, f->f_refcount, f->f_key.shared);
 308         FUTEXES_UNLOCK;
 309         FUTEX_UNLOCK(f);
 310
 311         LIN_SDT_PROBE0(futex, futex_put, return);
 312 }
 313
 314 static int
 315 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
 316 {
 317         struct futex *f, *tmpf;
 318         struct umtx_key key;
 319         int error;
 320
 321         LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
 322
 323         *newf = tmpf = NULL;
 324
 325         error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
 326             AUTO_SHARE : THREAD_SHARE, &key);
 327         if (error) {
 328                 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
 329                 LIN_SDT_PROBE1(futex, futex_get0, return, error);
 330                 return (error);
 331         }
 332 retry:
 333         FUTEXES_LOCK;
 334         LIST_FOREACH(f, &futex_list, f_list) {
 335                 if (umtx_key_match(&f->f_key, &key)) {
 336                         if (tmpf != NULL) {
 337                                 FUTEX_UNLOCK(tmpf);
 338                                 FUTEX_DESTROY(tmpf);
 339                                 free(tmpf, M_FUTEX);
 340                         }
 341                         if (flags & FUTEX_DONTEXISTS) {
 342                                 FUTEXES_UNLOCK;
 343                                 umtx_key_release(&key);
 344
 345                                 LIN_SDT_PROBE1(futex, futex_get0, return,
 346                                     EINVAL);
 347                                 return (EINVAL);
 348                         }
 349
 350                         /*
 351                          * Increment refcount of the found futex to
 352                          * prevent it from deallocation before FUTEX_LOCK()
 353                          */
 354                         ++f->f_refcount;
 355                         FUTEXES_UNLOCK;
 356                         umtx_key_release(&key);
 357
 358                         FUTEX_LOCK(f);
 359                         *newf = f;
 360                         LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
 361                             f->f_refcount, f->f_key.shared);
 362                         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
 363                             uaddr, f->f_refcount, f->f_key.shared);
 364
 365                         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 366                         return (0);
 367                 }
 368         }
 369
 370         if (flags & FUTEX_DONTCREATE) {
 371                 FUTEXES_UNLOCK;
 372                 umtx_key_release(&key);
 373                 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
 374                 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
 375
 376                 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 377                 return (0);
 378         }
 379
 380         if (tmpf == NULL) {
 381                 FUTEXES_UNLOCK;
 382                 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
 383                 tmpf->f_uaddr = uaddr;
 384                 tmpf->f_key = key;
 385                 tmpf->f_refcount = 1;
 386                 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
 387                 FUTEX_INIT(tmpf);
 388                 TAILQ_INIT(&tmpf->f_waiting_proc);
 389
 390                 /*
 391                  * Lock the new futex before an insert into the futex_list
 392                  * to prevent futex usage by other.
 393                  */
 394                 FUTEX_LOCK(tmpf);
 395                 goto retry;
 396         }
 397
 398         LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
 399         FUTEXES_UNLOCK;
 400
 401         LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
 402             tmpf->f_key.shared);
 403         LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
 404             uaddr, tmpf->f_refcount, tmpf->f_key.shared);
 405         *newf = tmpf;
 406
 407         LIN_SDT_PROBE1(futex, futex_get0, return, 0);
 408         return (0);
 409 }
 410
 411 static int
 412 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
 413     uint32_t flags)
 414 {
 415         int error;
 416
 417         LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
 418
 419         if (flags & FUTEX_CREATE_WP) {
 420                 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
 421                 (*wp)->wp_flags = 0;
 422         }
 423         error = futex_get0(uaddr, f, flags);
 424         if (error) {
 425                 LIN_SDT_PROBE0(futex, futex_get, error);
 426
 427                 if (flags & FUTEX_CREATE_WP)
 428                         free(*wp, M_FUTEX_WP);
 429
 430                 LIN_SDT_PROBE1(futex, futex_get, return, error);
 431                 return (error);
 432         }
 433         if (flags & FUTEX_CREATE_WP) {
 434                 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
 435                 (*wp)->wp_futex = *f;
 436         }
 437
 438         LIN_SDT_PROBE1(futex, futex_get, return, error);
 439         return (error);
 440 }
 441
 442 static int
 443 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
 444 {
 445         int error;
 446
 447         FUTEX_ASSERT_LOCKED(f);
 448         LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout);
 449         LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
 450             f->f_uaddr, wp, timeout, f->f_refcount);
 451         error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
 452         if (wp->wp_flags & FUTEX_WP_REQUEUED) {
 453                 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
 454
 455                 if (error) {
 456                         LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
 457                             f->f_uaddr, wp, wp->wp_futex->f_uaddr,
 458                             wp->wp_futex->f_refcount);
 459                 }
 460
 461                 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
 462                     " %p requeued uaddr %p ref %d",
 463                     error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
 464                     wp->wp_futex->f_refcount);
 465                 futex_put(f, NULL);
 466                 f = wp->wp_futex;
 467                 FUTEX_LOCK(f);
 468         } else {
 469                 if (error) {
 470                         LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
 471                             f->f_uaddr, wp);
 472                 }
 473                 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
 474                     error, f->f_uaddr, wp);
 475         }
 476
 477         futex_put(f, wp);
 478
 479         LIN_SDT_PROBE1(futex, futex_sleep, return, error);
 480         return (error);
 481 }
 482
 483 static int
 484 futex_wake(struct futex *f, int n, uint32_t bitset)
 485 {
 486         struct waiting_proc *wp, *wpt;
 487         int count = 0;
 488
 489         LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
 490
 491         if (bitset == 0) {
 492                 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
 493                 return (EINVAL);
 494         }
 495
 496         FUTEX_ASSERT_LOCKED(f);
 497         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
 498                 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
 499                     f->f_refcount);
 500                 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
 501                     f->f_uaddr, wp, f->f_refcount);
 502                 /*
 503                  * Unless we find a matching bit in
 504                  * the bitset, continue searching.
 505                  */
 506                 if (!(wp->wp_futex->f_bitset & bitset))
 507                         continue;
 508
 509                 wp->wp_flags |= FUTEX_WP_REMOVED;
 510                 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 511                 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
 512                 wakeup_one(wp);
 513                 if (++count == n)
 514                         break;
 515         }
 516
 517         LIN_SDT_PROBE1(futex, futex_wake, return, count);
 518         return (count);
 519 }
 520
 521 static int
 522 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
 523 {
 524         struct waiting_proc *wp, *wpt;
 525         int count = 0;
 526
 527         LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
 528
 529         FUTEX_ASSERT_LOCKED(f);
 530         FUTEX_ASSERT_LOCKED(f2);
 531
 532         TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
 533                 if (++count <= n) {
 534                         LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
 535                             f->f_uaddr, wp);
 536                         wp->wp_flags |= FUTEX_WP_REMOVED;
 537                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 538                         LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
 539                         wakeup_one(wp);
 540                 } else {
 541                         LIN_SDT_PROBE3(futex, futex_requeue, requeue,
 542                             f->f_uaddr, wp, f2->f_uaddr);
 543                         LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
 544                             f->f_uaddr, wp, f2->f_uaddr);
 545                         wp->wp_flags |= FUTEX_WP_REQUEUED;
 546                         /* Move wp to wp_list of f2 futex */
 547                         TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
 548                         TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
 549
 550                         /*
 551                          * Thread which sleeps on wp after waking should
 552                          * acquire f2 lock, so increment refcount of f2 to
 553                          * prevent it from premature deallocation.
 554                          */
 555                         wp->wp_futex = f2;
 556                         FUTEXES_LOCK;
 557                         ++f2->f_refcount;
 558                         FUTEXES_UNLOCK;
 559                         if (count - n >= n2)
 560                                 break;
 561                 }
 562         }
 563
 564         LIN_SDT_PROBE1(futex, futex_requeue, return, count);
 565         return (count);
 566 }
 567
 568 static int
 569 futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz,
 570     uint32_t bitset)
 571 {
 572         int error;
 573
 574         LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset);
 575
 576         if (bitset == 0) {
 577                 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
 578                 return (EINVAL);
 579         }
 580
 581         f->f_bitset = bitset;
 582         error = futex_sleep(f, wp, timeout_hz);
 583         if (error)
 584                 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
 585         if (error == EWOULDBLOCK)
 586                 error = ETIMEDOUT;
 587
 588         LIN_SDT_PROBE1(futex, futex_wait, return, error);
 589         return (error);
 590 }
 591
 592 static int
 593 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
 594 {
 595         int op = (encoded_op >> 28) & 7;
 596         int cmp = (encoded_op >> 24) & 15;
 597         int oparg = (encoded_op << 8) >> 20;
 598         int cmparg = (encoded_op << 20) >> 20;
 599         int oldval = 0, ret;
 600
 601         LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
 602
 603         if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
 604                 oparg = 1 << oparg;
 605
 606         LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
 607             cmparg);
 608
 609         /* XXX: Linux verifies access here and returns EFAULT */
 610         LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
 611
 612         switch (op) {
 613         case FUTEX_OP_SET:
 614                 ret = futex_xchgl(oparg, uaddr, &oldval);
 615                 break;
 616         case FUTEX_OP_ADD:
 617                 ret = futex_addl(oparg, uaddr, &oldval);
 618                 break;
 619         case FUTEX_OP_OR:
 620                 ret = futex_orl(oparg, uaddr, &oldval);
 621                 break;
 622         case FUTEX_OP_ANDN:
 623                 ret = futex_andl(~oparg, uaddr, &oldval);
 624                 break;
 625         case FUTEX_OP_XOR:
 626                 ret = futex_xorl(oparg, uaddr, &oldval);
 627                 break;
 628         default:
 629                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
 630                 ret = -ENOSYS;
 631                 break;
 632         }
 633
 634         if (ret) {
 635                 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
 636                 return (ret);
 637         }
 638
 639         switch (cmp) {
 640         case FUTEX_OP_CMP_EQ:
 641                 ret = (oldval == cmparg);
 642                 break;
 643         case FUTEX_OP_CMP_NE:
 644                 ret = (oldval != cmparg);
 645                 break;
 646         case FUTEX_OP_CMP_LT:
 647                 ret = (oldval < cmparg);
 648                 break;
 649         case FUTEX_OP_CMP_GE:
 650                 ret = (oldval >= cmparg);
 651                 break;
 652         case FUTEX_OP_CMP_LE:
 653                 ret = (oldval <= cmparg);
 654                 break;
 655         case FUTEX_OP_CMP_GT:
 656                 ret = (oldval > cmparg);
 657                 break;
 658         default:
 659                 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
 660                 ret = -ENOSYS;
 661         }
 662
 663         LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
 664         return (ret);
 665 }
 666
 667 int
 668 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 669 {
 670         int clockrt, nrwake, op_ret, ret;
 671         struct linux_pemuldata *pem;
 672         struct waiting_proc *wp;
 673         struct futex *f, *f2;
 674         struct l_timespec ltimeout;
 675         struct timespec timeout;
 676         struct timeval utv, ctv;
 677         int timeout_hz;
 678         int error;
 679         uint32_t flags, val;
 680
 681         LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
 682
 683         if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
 684                 flags = 0;
 685                 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
 686         } else
 687                 flags = FUTEX_SHARED;
 688
 689         /*
 690          * Currently support for switching between CLOCK_MONOTONIC and
 691          * CLOCK_REALTIME is not present. However Linux forbids the use of
 692          * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
 693          * FUTEX_WAIT_REQUEUE_PI.
 694          */
 695         clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
 696         args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
 697         if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
 698                 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
 699                 LIN_SDT_PROBE0(futex, linux_sys_futex,
 700                     unimplemented_clockswitch);
 701                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 702                 return (ENOSYS);
 703         }
 704
 705         error = 0;
 706         f = f2 = NULL;
 707
 708         switch (args->op) {
 709         case LINUX_FUTEX_WAIT:
 710                 args->val3 = FUTEX_BITSET_MATCH_ANY;
 711                 /* FALLTHROUGH */
 712
 713         case LINUX_FUTEX_WAIT_BITSET:
 714                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
 715                     args->val, args->val3);
 716                 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
 717                     args->uaddr, args->val, args->val3);
 718
 719                 if (args->timeout != NULL) {
 720                         error = copyin(args->timeout, &ltimeout, sizeof(ltimeout));
 721                         if (error) {
 722                                 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 723                                     error);
 724                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 725                                 return (error);
 726                         }
 727                         error = linux_to_native_timespec(&timeout, &ltimeout);
 728                         if (error)
 729                                 return (error);
 730                         TIMESPEC_TO_TIMEVAL(&utv, &timeout);
 731                         error = itimerfix(&utv);
 732                         if (error) {
 733                                 LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error,
 734                                     error);
 735                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 736                                 return (error);
 737                         }
 738                         if (clockrt) {
 739                                 microtime(&ctv);
 740                                 timevalsub(&utv, &ctv);
 741                         } else if (args->op == LINUX_FUTEX_WAIT_BITSET) {
 742                                 microuptime(&ctv);
 743                                 timevalsub(&utv, &ctv);
 744                         }
 745                         if (utv.tv_sec < 0)
 746                                 timevalclear(&utv);
 747                         timeout_hz = tvtohz(&utv);
 748                 } else
 749                         timeout_hz = 0;
 750
 751                 error = futex_get(args->uaddr, &wp, &f,
 752                     flags | FUTEX_CREATE_WP);
 753                 if (error) {
 754                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 755                         return (error);
 756                 }
 757
 758                 error = copyin(args->uaddr, &val, sizeof(val));
 759                 if (error) {
 760                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 761                             error);
 762                         LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
 763                             error);
 764                         futex_put(f, wp);
 765
 766                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 767                         return (error);
 768                 }
 769                 if (val != args->val) {
 770                         LIN_SDT_PROBE4(futex, linux_sys_futex,
 771                             debug_wait_value_neq, args->uaddr, args->val, val,
 772                             args->val3);
 773                         LINUX_CTR3(sys_futex,
 774                             "WAIT uaddr %p val 0x%x != uval 0x%x",
 775                             args->uaddr, args->val, val);
 776                         futex_put(f, wp);
 777
 778                         LIN_SDT_PROBE1(futex, linux_sys_futex, return,
 779                             EWOULDBLOCK);
 780                         return (EWOULDBLOCK);
 781                 }
 782
 783                 error = futex_wait(f, wp, timeout_hz, args->val3);
 784                 break;
 785
 786         case LINUX_FUTEX_WAKE:
 787                 args->val3 = FUTEX_BITSET_MATCH_ANY;
 788                 /* FALLTHROUGH */
 789
 790         case LINUX_FUTEX_WAKE_BITSET:
 791                 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
 792                     args->val, args->val3);
 793                 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
 794                     args->uaddr, args->val, args->val3);
 795
 796                 error = futex_get(args->uaddr, NULL, &f,
 797                     flags | FUTEX_DONTCREATE);
 798                 if (error) {
 799                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 800                         return (error);
 801                 }
 802
 803                 if (f == NULL) {
 804                         td->td_retval[0] = 0;
 805
 806                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 807                         return (error);
 808                 }
 809                 td->td_retval[0] = futex_wake(f, args->val, args->val3);
 810                 futex_put(f, NULL);
 811                 break;
 812
 813         case LINUX_FUTEX_CMP_REQUEUE:
 814                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
 815                     args->uaddr, args->val, args->val3, args->uaddr2,
 816                     args->timeout);
 817                 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
 818                     "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
 819                     args->uaddr, args->val, args->val3, args->uaddr2,
 820                     args->timeout);
 821
 822                 /*
 823                  * Linux allows this, we would not, it is an incorrect
 824                  * usage of declared ABI, so return EINVAL.
 825                  */
 826                 if (args->uaddr == args->uaddr2) {
 827                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 828                             invalid_cmp_requeue_use);
 829                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
 830                         return (EINVAL);
 831                 }
 832
 833                 error = futex_get(args->uaddr, NULL, &f, flags);
 834                 if (error) {
 835                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 836                         return (error);
 837                 }
 838
 839                 /*
 840                  * To avoid deadlocks return EINVAL if second futex
 841                  * exists at this time.
 842                  *
 843                  * Glibc fall back to FUTEX_WAKE in case of any error
 844                  * returned by FUTEX_CMP_REQUEUE.
 845                  */
 846                 error = futex_get(args->uaddr2, NULL, &f2,
 847                     flags | FUTEX_DONTEXISTS);
 848                 if (error) {
 849                         futex_put(f, NULL);
 850
 851                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 852                         return (error);
 853                 }
 854                 error = copyin(args->uaddr, &val, sizeof(val));
 855                 if (error) {
 856                         LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
 857                             error);
 858                         LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
 859                             error);
 860                         futex_put(f2, NULL);
 861                         futex_put(f, NULL);
 862
 863                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 864                         return (error);
 865                 }
 866                 if (val != args->val3) {
 867                         LIN_SDT_PROBE2(futex, linux_sys_futex,
 868                             debug_cmp_requeue_value_neq, args->val, val);
 869                         LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
 870                             args->val, val);
 871                         futex_put(f2, NULL);
 872                         futex_put(f, NULL);
 873
 874                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
 875                         return (EAGAIN);
 876                 }
 877
 878                 nrwake = (int)(unsigned long)args->timeout;
 879                 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
 880                 futex_put(f2, NULL);
 881                 futex_put(f, NULL);
 882                 break;
 883
 884         case LINUX_FUTEX_WAKE_OP:
 885                 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
 886                     args->uaddr, args->op, args->val, args->uaddr2, args->val3);
 887                 LINUX_CTR5(sys_futex, "WAKE_OP "
 888                     "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
 889                     args->uaddr, args->val, args->uaddr2, args->val3,
 890                     args->timeout);
 891
 892                 error = futex_get(args->uaddr, NULL, &f, flags);
 893                 if (error) {
 894                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 895                         return (error);
 896                 }
 897
 898                 if (args->uaddr != args->uaddr2)
 899                         error = futex_get(args->uaddr2, NULL, &f2, flags);
 900                 if (error) {
 901                         futex_put(f, NULL);
 902
 903                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
 904                         return (error);
 905                 }
 906
 907                 /*
 908                  * This function returns positive number as results and
 909                  * negative as errors
 910                  */
 911                 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
 912
 913                 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
 914                     args->uaddr, op_ret);
 915
 916                 if (op_ret < 0) {
 917                         /* XXX: We don't handle the EFAULT yet. */
 918                         if (op_ret != -EFAULT) {
 919                                 if (f2 != NULL)
 920                                         futex_put(f2, NULL);
 921                                 futex_put(f, NULL);
 922
 923                                 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
 924                                     -op_ret);
 925                                 return (-op_ret);
 926                         } else {
 927                                 LIN_SDT_PROBE0(futex, linux_sys_futex,
 928                                     unhandled_efault);
 929                         }
 930                         if (f2 != NULL)
 931                                 futex_put(f2, NULL);
 932                         futex_put(f, NULL);
 933
 934                         LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT);
 935                         return (EFAULT);
 936                 }
 937
 938                 ret = futex_wake(f, args->val, args->val3);
 939
 940                 if (op_ret > 0) {
 941                         op_ret = 0;
 942                         nrwake = (int)(unsigned long)args->timeout;
 943
 944                         if (f2 != NULL)
 945                                 op_ret += futex_wake(f2, nrwake, args->val3);
 946                         else
 947                                 op_ret += futex_wake(f, nrwake, args->val3);
 948                         ret += op_ret;
 949
 950                 }
 951                 if (f2 != NULL)
 952                         futex_put(f2, NULL);
 953                 futex_put(f, NULL);
 954                 td->td_retval[0] = ret;
 955                 break;
 956
 957         case LINUX_FUTEX_LOCK_PI:
 958                 /* not yet implemented */
 959                 pem = pem_find(td->td_proc);
 960                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 961                         linux_msg(td,
 962                                   "linux_sys_futex: "
 963                                   "unsupported futex_pi op\n");
 964                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 965                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 966                             unimplemented_lock_pi);
 967                 }
 968                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 969                 return (ENOSYS);
 970
 971         case LINUX_FUTEX_UNLOCK_PI:
 972                 /* not yet implemented */
 973                 pem = pem_find(td->td_proc);
 974                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 975                         linux_msg(td,
 976                                   "linux_sys_futex: "
 977                                   "unsupported futex_pi op\n");
 978                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 979                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 980                             unimplemented_unlock_pi);
 981                 }
 982                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 983                 return (ENOSYS);
 984
 985         case LINUX_FUTEX_TRYLOCK_PI:
 986                 /* not yet implemented */
 987                 pem = pem_find(td->td_proc);
 988                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
 989                         linux_msg(td,
 990                                   "linux_sys_futex: "
 991                                   "unsupported futex_pi op\n");
 992                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
 993                         LIN_SDT_PROBE0(futex, linux_sys_futex,
 994                             unimplemented_trylock_pi);
 995                 }
 996                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
 997                 return (ENOSYS);
 998
 999         case LINUX_FUTEX_REQUEUE:
1000
1001                 /*
1002                  * Glibc does not use this operation since version 2.3.3,
1003                  * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
1004                  * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
1005                  * FUTEX_REQUEUE returned EINVAL.
1006                  */
1007                 pem = pem_find(td->td_proc);
1008                 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
1009                         linux_msg(td,
1010                                   "linux_sys_futex: "
1011                                   "unsupported futex_requeue op\n");
1012                         pem->flags |= LINUX_XDEPR_REQUEUEOP;
1013                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1014                             deprecated_requeue);
1015                 }
1016
1017                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
1018                 return (EINVAL);
1019
1020         case LINUX_FUTEX_WAIT_REQUEUE_PI:
1021                 /* not yet implemented */
1022                 pem = pem_find(td->td_proc);
1023                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1024                         linux_msg(td,
1025                                   "linux_sys_futex: "
1026                                   "unsupported futex_pi op\n");
1027                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1028                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1029                             unimplemented_wait_requeue_pi);
1030                 }
1031                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1032                 return (ENOSYS);
1033
1034         case LINUX_FUTEX_CMP_REQUEUE_PI:
1035                 /* not yet implemented */
1036                 pem = pem_find(td->td_proc);
1037                 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1038                         linux_msg(td,
1039                                   "linux_sys_futex: "
1040                                   "unsupported futex_pi op\n");
1041                         pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1042                         LIN_SDT_PROBE0(futex, linux_sys_futex,
1043                             unimplemented_cmp_requeue_pi);
1044                 }
1045                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1046                 return (ENOSYS);
1047
1048         default:
1049                 linux_msg(td,
1050                           "linux_sys_futex: unknown op %d\n", args->op);
1051                 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1052                     args->op);
1053                 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1054                 return (ENOSYS);
1055         }
1056
1057         LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1058         return (error);
1059 }
1060
1061 int
1062 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1063 {
1064         struct linux_emuldata *em;
1065
1066         LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1067
1068         if (args->len != sizeof(struct linux_robust_list_head)) {
1069                 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1070                 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1071                 return (EINVAL);
1072         }
1073
1074         em = em_find(td);
1075         em->robust_futexes = args->head;
1076
1077         LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1078         return (0);
1079 }
1080
1081 int
1082 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1083 {
1084         struct linux_emuldata *em;
1085         struct linux_robust_list_head *head;
1086         l_size_t len = sizeof(struct linux_robust_list_head);
1087         struct thread *td2;
1088         int error = 0;
1089
1090         LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1091
1092         if (!args->pid) {
1093                 em = em_find(td);
1094                 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1095                 head = em->robust_futexes;
1096         } else {
1097                 td2 = tdfind(args->pid, -1);
1098                 if (td2 == NULL) {
1099                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1100                             ESRCH);
1101                         return (ESRCH);
1102                 }
1103                 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) {
1104                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1105                             EPERM);
1106                         PROC_UNLOCK(td2->td_proc);
1107                         return (EPERM);
1108                 }
1109
1110                 em = em_find(td2);
1111                 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1112                 /* XXX: ptrace? */
1113                 if (priv_check(td, PRIV_CRED_SETUID) ||
1114                     priv_check(td, PRIV_CRED_SETEUID) ||
1115                     p_candebug(td, td2->td_proc)) {
1116                         PROC_UNLOCK(td2->td_proc);
1117
1118                         LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1119                             EPERM);
1120                         return (EPERM);
1121                 }
1122                 head = em->robust_futexes;
1123
1124                 PROC_UNLOCK(td2->td_proc);
1125         }
1126
1127         error = copyout(&len, args->len, sizeof(l_size_t));
1128         if (error) {
1129                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1130                     error);
1131                 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1132                 return (EFAULT);
1133         }
1134
1135         error = copyout(&head, args->head, sizeof(head));
1136         if (error) {
1137                 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1138                     error);
1139         }
1140
1141         LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1142         return (error);
1143 }
1144
1145 static int
1146 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
1147     unsigned int pi)
1148 {
1149         uint32_t uval, nval, mval;
1150         struct futex *f;
1151         int error;
1152
1153         LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi);
1154
1155 retry:
1156         error = copyin(uaddr, &uval, 4);
1157         if (error) {
1158                 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1159                 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1160                 return (EFAULT);
1161         }
1162         if ((uval & FUTEX_TID_MASK) == em->em_tid) {
1163                 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1164                 nval = casuword32(uaddr, uval, mval);
1165
1166                 if (nval == -1) {
1167                         LIN_SDT_PROBE1(futex, handle_futex_death, return,
1168                             EFAULT);
1169                         return (EFAULT);
1170                 }
1171
1172                 if (nval != uval)
1173                         goto retry;
1174
1175                 if (!pi && (uval & FUTEX_WAITERS)) {
1176                         error = futex_get(uaddr, NULL, &f,
1177                             FUTEX_DONTCREATE | FUTEX_SHARED);
1178                         if (error) {
1179                                 LIN_SDT_PROBE1(futex, handle_futex_death,
1180                                     return, error);
1181                                 return (error);
1182                         }
1183                         if (f != NULL) {
1184                                 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1185                                 futex_put(f, NULL);
1186                         }
1187                 }
1188         }
1189
1190         LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1191         return (0);
1192 }
1193
1194 static int
1195 fetch_robust_entry(struct linux_robust_list **entry,
1196     struct linux_robust_list **head, unsigned int *pi)
1197 {
1198         l_ulong uentry;
1199         int error;
1200
1201         LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1202
1203         error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1204         if (error) {
1205                 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1206                 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1207                 return (EFAULT);
1208         }
1209
1210         *entry = (void *)(uentry & ~1UL);
1211         *pi = uentry & 1;
1212
1213         LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1214         return (0);
1215 }
1216
1217 /* This walks the list of robust futexes releasing them. */
1218 void
1219 release_futexes(struct thread *td, struct linux_emuldata *em)
1220 {
1221         struct linux_robust_list_head *head = NULL;
1222         struct linux_robust_list *entry, *next_entry, *pending;
1223         unsigned int limit = 2048, pi, next_pi, pip;
1224         l_long futex_offset;
1225         int rc, error;
1226
1227         LIN_SDT_PROBE2(futex, release_futexes, entry, td, em);
1228
1229         head = em->robust_futexes;
1230
1231         if (head == NULL) {
1232                 LIN_SDT_PROBE0(futex, release_futexes, return);
1233                 return;
1234         }
1235
1236         if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1237                 LIN_SDT_PROBE0(futex, release_futexes, return);
1238                 return;
1239         }
1240
1241         error = copyin(&head->futex_offset, &futex_offset,
1242             sizeof(futex_offset));
1243         if (error) {
1244                 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1245                 LIN_SDT_PROBE0(futex, release_futexes, return);
1246                 return;
1247         }
1248
1249         if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1250                 LIN_SDT_PROBE0(futex, release_futexes, return);
1251                 return;
1252         }
1253
1254         while (entry != &head->list) {
1255                 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1256
1257                 if (entry != pending)
1258                         if (handle_futex_death(em,
1259                             (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1260                                 LIN_SDT_PROBE0(futex, release_futexes, return);
1261                                 return;
1262                         }
1263                 if (rc) {
1264                         LIN_SDT_PROBE0(futex, release_futexes, return);
1265                         return;
1266                 }
1267
1268                 entry = next_entry;
1269                 pi = next_pi;
1270
1271                 if (!--limit)
1272                         break;
1273
1274                 sched_relinquish(curthread);
1275         }
1276
1277         if (pending)
1278                 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1279
1280         LIN_SDT_PROBE0(futex, release_futexes, return);
1281 }