commit ac6c54657cb221f94e76df350a152914f4f1319b
Author: Torvald Riegel <triegel@redhat.com>
Date: Thu Dec 4 14:12:23 2014 +0100
Add and use new glibc-internal futex API.
This adds new functions for futex operations, starting with wait,
abstimed_wait, reltimed_wait, wake. They add documentation and error
checking according to the current draft of the Linux kernel futex manpage.
Waiting with absolute or relative timeouts is split into separate functions.
This allows for removing a few cases of code duplication in pthreads code,
which uses absolute timeouts; also, it allows us to put platform-specific
code to go from an absolute to a relative timeout into the platform-specific
futex abstractions. The latter is done by adding lll_futex_abstimed_wait.
I expect that we will refactor this later on, depending on how we do the
lll_ parts.
Futex operations that can be canceled are also split out into separate
functions suffixed by "_cancelable".
@@ -29,6 +29,7 @@
#include <tls.h>
#include <list.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <kernel-features.h>
#include <stack-aliasing.h>
@@ -987,7 +988,8 @@ setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
if (t->setxid_futex == -1
&& ! atomic_compare_and_exchange_bool_acq (&t->setxid_futex, -2, -1))
do
- lll_futex_wait (&t->setxid_futex, -2, LLL_PRIVATE);
+ futex_wait_simple ((unsigned int *) &t->setxid_futex, -2,
+ FUTEX_PRIVATE);
while (t->setxid_futex == -2);
/* Don't let the thread exit before the setxid handler runs. */
@@ -1005,7 +1007,7 @@ setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
if ((ch & SETXID_BITMASK) == 0)
{
t->setxid_futex = 1;
- lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &t->setxid_futex, 1, FUTEX_PRIVATE);
}
return;
}
@@ -1032,7 +1034,7 @@ setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t)
/* Release the futex just in case. */
t->setxid_futex = 1;
- lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &t->setxid_futex, 1, FUTEX_PRIVATE);
}
@@ -1141,7 +1143,8 @@ __nptl_setxid (struct xid_command *cmdp)
int cur = cmdp->cntr;
while (cur != 0)
{
- lll_futex_wait (&cmdp->cntr, cur, LLL_PRIVATE);
+ futex_wait_simple ((unsigned int *) &cmdp->cntr, cur,
+ FUTEX_PRIVATE);
cur = cmdp->cntr;
}
}
@@ -1251,7 +1254,8 @@ __wait_lookup_done (void)
continue;
do
- lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE);
+ futex_wait_simple ((unsigned int *) gscope_flagp,
+ THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
}
@@ -1273,7 +1277,8 @@ __wait_lookup_done (void)
continue;
do
- lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE);
+ futex_wait_simple ((unsigned int *) gscope_flagp,
+ THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
}
@@ -19,6 +19,7 @@
#include <setjmp.h>
#include <stdlib.h>
#include "pthreadP.h"
+#include <futex-internal.h>
/* The next two functions are similar to pthread_setcanceltype() but
@@ -93,7 +94,7 @@ __pthread_disable_asynccancel (int oldtype)
while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
== CANCELING_BITMASK, 0))
{
- lll_futex_wait (&self->cancelhandling, newval, LLL_PRIVATE);
+ futex_wait_simple (&self->cancelhandling, newval, FUTEX_PRIVATE);
newval = THREAD_GETMEM (self, cancelhandling);
}
}
new file mode 100644
@@ -0,0 +1,341 @@
+/* futex operations for glibc-internal use.
+ Copyright (C) 2014-2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef FUTEX_INTERNAL_H
+#define FUTEX_INTERNAL_H
+
+#include <errno.h>
+#include <lowlevellock-futex.h>
+#include <sys/time.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <nptl/pthreadP.h>
+#include <libc-internal.h>
+
+/* This file defines futex operations used internally in glibc. A futex
+ consists of the so-called futex word in userspace, which is of type int
+ and represents an application-specific condition, and kernel state
+ associated with this particular futex word (e.g., wait queues). The futex
+ operations we provide are wrappers for the futex syscalls and add
+ glibc-specific error checking of the syscall return value. We abort on
+ error codes that are caused by bugs in glibc or in the calling application,
+ or when an error code is not known. We return error codes that can arise
+ in correct executions to the caller. Each operation calls out exactly the
+ return values that callers need to handle.
+
+ The private flag must be either FUTEX_PRIVATE or FUTEX_SHARED.
+
+ We expect callers to only use these operations if futexes are supported.
+
+ Given that waking other threads waiting on a futex involves concurrent
+ accesses to the futex word, you must use atomic operations to access the
+ futex word.
+
+ Due to POSIX requirements on when synchronization data structures such
+ as mutexes or semaphores can be destroyed and due to the futex design
+ having separate fast/slow paths for wake-ups, we need to consider that
+ futex_wake calls might effectively target a data structure that has been
+ destroyed and reused for another object, or unmapped; thus, some
+ errors or spurious wake-ups can happen in correct executions that would
+ not be possible in a program using just a single futex whose lifetime
+ does not end before the program terminates. For background, see:
+ https://sourceware.org/ml/libc-alpha/2014-04/msg00075.html
+ https://lkml.org/lkml/2014/11/27/472
+
+ We also expect a Linux kernel version of 2.6.22 or more recent (since this
+ version, EINTR is not returned on spurious wake-ups anymore). */
+
+#define FUTEX_PRIVATE LLL_PRIVATE
+#define FUTEX_SHARED LLL_SHARED
+
+/* Returns FUTEX_PRIVATE if pshared is zero and private futexes are supported;
+ returns FUTEX_SHARED otherwise. */
+static __always_inline int
+futex_private_if_supported (int pshared)
+{
+ if (pshared != 0)
+ return FUTEX_SHARED;
+#ifdef __ASSUME_PRIVATE_FUTEX
+ return FUTEX_PRIVATE;
+#else
+ return THREAD_GETMEM (THREAD_SELF, header.private_futex)
+ ^ FUTEX_PRIVATE_FLAG;
+#endif
+}
+
+
+/* Atomically wrt other futex operations on the same futex, this blocks iff
+ the value *FUTEX_WORD matches the expected value. This is
+ semantically equivalent to:
+ l = <get lock associated with futex> (FUTEX_WORD);
+ wait_flag = <get wait_flag associated with futex> (FUTEX_WORD);
+ lock (l);
+ val = atomic_load_relaxed (FUTEX_WORD);
+ if (val != expected) { unlock (l); return EAGAIN; }
+ atomic_store_relaxed (wait_flag, true);
+ unlock (l);
+ // Now block; can time out in futex_time_wait (see below)
+ while (atomic_load_relaxed(wait_flag) && !<spurious wake-up>);
+
+ Note that no guarantee of a happens-before relation between a woken
+ futex_wait and a futex_wake is documented; however, this does not matter
+ in practice because we have to consider spurious wake-ups (see below),
+ and thus would not be able to reliably reason about which futex_wake woke
+ us.
+
+ Returns 0 if woken by a futex operation or spuriously. (Note that due to
+ the POSIX requirements mentioned above, we need to conservatively assume
+ that unrelated futex_wake operations could wake this futex; it is easiest
+ to just be prepared for spurious wake-ups.)
+ Returns EAGAIN if the futex word did not match the expected value.
+ Returns EINTR if waiting was interrupted by a signal.
+
+ Note that some previous code in glibc assumed the underlying futex
+ operation (e.g., syscall) to start with or include the equivalent of a
+ seq_cst fence; this allows one to avoid an explicit seq_cst fence before
+ a futex_wait call when synchronizing similar to Dekker synchronization.
+ However, we make no such guarantee here.
+ */
+static __always_inline int
+futex_wait (unsigned int *futex_word, unsigned int expected, int private)
+{
+ int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ return -err;
+
+ case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Like futex_wait but does not provide any indication why we stopped waiting.
+ Thus, when this function returns, you have to always check FUTEX_WORD to
+ determine whether you need to continue waiting, and you cannot detect
+ whether the waiting was interrupted by a signal. Example use:
+ while (atomic_load_relaxed (&futex_word) == 23)
+ futex_wait_simple (&futex_word, 23, FUTEX_PRIVATE);
+ This is common enough to make providing this wrapper worthwhile. */
+static __always_inline void
+futex_wait_simple (unsigned int *futex_word, unsigned int expected,
+ int private)
+{
+ ignore_value (futex_wait (futex_word, expected, private));
+}
+
+/* Like futex_wait but cancelable. */
+static __always_inline int
+futex_wait_cancelable (unsigned int *futex_word, unsigned int expected,
+ int private)
+{
+ int oldtype;
+ oldtype = __pthread_enable_asynccancel ();
+ int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
+ __pthread_disable_asynccancel (oldtype);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ return -err;
+
+ case -ETIMEDOUT: /* Cannot have happened as we provided no timeout. */
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Like futex_wait, but will eventually time out (i.e., stop being
+ blocked) after the duration of time provided (i.e., RELTIME) has
+ passed. The caller must provide a normalized RELTIME. RELTIME can also
+ equal NULL, in which case this function behaves equivalent to futex_wait.
+
+ Returns 0 if woken by a futex operation or spuriously. (Note that due to
+ the POSIX requirements mentioned above, we need to conservatively assume
+ that unrelated futex_wake operations could wake this futex; it is easiest
+ to just be prepared for spurious wake-ups.)
+ Returns EAGAIN if the futex word did not match the expected value.
+ Returns EINTR if waiting was interrupted by a signal.
+ Returns ETIMEDOUT if the timeout expired.
+ */
+static __always_inline int
+futex_reltimed_wait (unsigned int* futex_word, unsigned int expected,
+ const struct timespec* reltime, int private)
+{
+ int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Like futex_reltimed_wait, but cancelable. */
+static __always_inline int
+futex_reltimed_wait_cancelable (unsigned int* futex_word,
+ unsigned int expected,
+ const struct timespec* reltime, int private)
+{
+ int oldtype;
+ oldtype = __pthread_enable_asynccancel ();
+ int err = lll_futex_timed_wait (futex_word, expected, reltime, private);
+ __pthread_disable_asynccancel (oldtype);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
+ absolute point in time; a call will time out after this point in time. */
+static __always_inline int
+futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
+ const struct timespec* abstime, int private)
+{
+ int err = lll_futex_abstimed_wait (futex_word, expected, abstime, private);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Like futex_reltimed_wait, but cancelable. */
+static __always_inline int
+futex_abstimed_wait_cancelable (unsigned int* futex_word,
+ unsigned int expected,
+ const struct timespec* abstime, int private)
+{
+ int oldtype;
+ oldtype = __pthread_enable_asynccancel ();
+ int err = lll_futex_abstimed_wait (futex_word, expected, abstime, private);
+ __pthread_disable_asynccancel (oldtype);
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ return -err;
+
+ case -EFAULT: /* Must have been caused by a glibc or application bug. */
+ case -EINVAL: /* Either due to wrong alignment or due to the timeout not
+ being normalized. Must have been caused by a glibc or
+ application bug. */
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+/* Atomically wrt other futex operations on the same futex, this unblocks the
+ specified number of processes, or all processes blocked on this futex if
+ there are fewer than the specified number. Semantically, this is
+ equivalent to:
+ l = <get lock associated with futex> (FUTEX_WORD);
+ lock (l);
+ for (res = 0; PROCESSES_TO_WAKE > 0; PROCESSES_TO_WAKE--, res++) {
+ if (<no process blocked on futex>) break;
+ wf = <get wait_flag of a process blocked on futex> (FUTEX_WORD);
+ // No happens-before guarantee with woken futex_wait (see above)
+ atomic_store_relaxed (wf, 0);
+ }
+ return res;
+
+ Note that we need to support futex_wake calls to past futexes whose memory
+ has potentially been reused due to POSIX' requirements on synchronization
+ object destruction (see above); therefore, we must not report or abort
+ on most errors. */
+static __always_inline void
+futex_wake (unsigned int* futex_word, int processes_to_wake, int private)
+{
+ int res = lll_futex_wake (futex_word, processes_to_wake, private);
+ /* No error. Ignore the number of woken processes. */
+ if (res >= 0)
+ return;
+ switch (res)
+ {
+ case -EFAULT: /* Could have happened due to memory reuse. */
+ case -EINVAL: /* Could be either due to incorrect alignment (a bug in
+ glibc or in the application) or due to memory being
+ reused for a PI futex. We cannot distinguish between the
+ two causes, and one of them is correct use, so we do not
+ act in this case. */
+ return;
+ case -ENOSYS: /* Must have been caused by a glibc bug. */
+ /* No other errors are documented at this time. */
+ default:
+ abort ();
+ }
+}
+
+#endif /* futex-internal.h */
@@ -34,6 +34,7 @@
#include <shlib-compat.h>
#include <smp.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <kernel-features.h>
#include <libc-internal.h>
#include <pthread-pids.h>
@@ -279,10 +280,10 @@ sighandler_setxid (int sig, siginfo_t *si, void *ctx)
/* And release the futex. */
self->setxid_futex = 1;
- lll_futex_wake (&self->setxid_futex, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &self->setxid_futex, 1, FUTEX_PRIVATE);
if (atomic_decrement_val (&__xidcmd->cntr) == 0)
- lll_futex_wake (&__xidcmd->cntr, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &__xidcmd->cntr, 1, FUTEX_PRIVATE);
}
#endif
@@ -57,6 +57,8 @@ pthread_barrier_init (barrier, attr, count)
ibarrier->init_count = count;
ibarrier->curr_event = 0;
+ /* XXX Don't use futex_private_if_supported here as long as there are still
+ assembly implementations that expect the value determined below. */
#ifdef __ASSUME_PRIVATE_FUTEX
ibarrier->private = (iattr->pshared != PTHREAD_PROCESS_PRIVATE
? 0 : FUTEX_PRIVATE_FLAG);
@@ -19,6 +19,7 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthreadP.h>
@@ -29,9 +30,12 @@ pthread_barrier_wait (barrier)
{
struct pthread_barrier *ibarrier = (struct pthread_barrier *) barrier;
int result = 0;
+ int lll_private = ibarrier->private ^ FUTEX_PRIVATE_FLAG;
+ int futex_private = (lll_private == LLL_PRIVATE)
+ ? FUTEX_PRIVATE : FUTEX_SHARED;
/* Make sure we are alone. */
- lll_lock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
+ lll_lock (ibarrier->lock, lll_private);
/* One more arrival. */
--ibarrier->left;
@@ -44,8 +48,7 @@ pthread_barrier_wait (barrier)
++ibarrier->curr_event;
/* Wake up everybody. */
- lll_futex_wake (&ibarrier->curr_event, INT_MAX,
- ibarrier->private ^ FUTEX_PRIVATE_FLAG);
+ futex_wake (&ibarrier->curr_event, INT_MAX, futex_private);
/* This is the thread which finished the serialization. */
result = PTHREAD_BARRIER_SERIAL_THREAD;
@@ -57,12 +60,11 @@ pthread_barrier_wait (barrier)
unsigned int event = ibarrier->curr_event;
/* Before suspending, make the barrier available to others. */
- lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
+ lll_unlock (ibarrier->lock, lll_private);
/* Wait for the event counter of the barrier to change. */
do
- lll_futex_wait (&ibarrier->curr_event, event,
- ibarrier->private ^ FUTEX_PRIVATE_FLAG);
+ futex_wait_simple (&ibarrier->curr_event, event, futex_private);
while (event == ibarrier->curr_event);
}
@@ -72,7 +74,7 @@ pthread_barrier_wait (barrier)
/* If this was the last woken thread, unlock. */
if (atomic_increment_val (&ibarrier->left) == init_count)
/* We are done. */
- lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
+ lll_unlock (ibarrier->lock, lll_private);
return result;
}
@@ -31,6 +31,7 @@
#include <kernel-features.h>
#include <exit-thread.h>
#include <default-sched.h>
+#include <futex-internal.h>
#include <shlib-compat.h>
@@ -269,7 +270,7 @@ START_THREAD_DEFN
/* Allow setxid from now onwards. */
if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2))
- lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &pd->setxid_futex, 1, FUTEX_PRIVATE);
#ifdef __NR_set_robust_list
# ifndef __ASSUME_SET_ROBUST_LIST
@@ -414,7 +415,7 @@ START_THREAD_DEFN
this->__list.__next = NULL;
atomic_or (&this->__lock, FUTEX_OWNER_DIED);
- lll_futex_wake (&this->__lock, 1, /* XYZ */ LLL_SHARED);
+ futex_wake (&this->__lock, 1, /* XYZ */ FUTEX_SHARED);
}
while (robust != (void *) &pd->robust_head);
}
@@ -442,7 +443,12 @@ START_THREAD_DEFN
/* Some other thread might call any of the setXid functions and expect
us to reply. In this case wait until we did that. */
do
- lll_futex_wait (&pd->setxid_futex, 0, LLL_PRIVATE);
+ /* XXX This differs from the typical futex_wait_simple pattern in that
+ the futex_wait condition (setxid_futex) is different from the
+ condition used in the surrounding loop (cancelhandling). We need
+ to check and document why this is correct. */
+ futex_wait_simple ((unsigned int *) &pd->setxid_futex, 0,
+ FUTEX_PRIVATE);
while (pd->cancelhandling & SETXID_BITMASK);
/* Reset the value so that the stack can be reused. */
@@ -683,7 +689,7 @@ __pthread_create_2_1 (newthread, attr, start_routine, arg)
stillborn thread. */
if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0)
== -2))
- lll_futex_wake (&pd->setxid_futex, 1, LLL_PRIVATE);
+ futex_wake ((unsigned int *) &pd->setxid_futex, 1, FUTEX_PRIVATE);
/* Free the resources. */
__deallocate_stack (pd);
@@ -17,7 +17,7 @@
<http://www.gnu.org/licenses/>. */
#include "pthreadP.h"
-#include <lowlevellock.h>
+#include <futex-internal.h>
#include <atomic.h>
@@ -35,7 +35,7 @@ clear_once_control (void *arg)
get interrupted (see __pthread_once), so all we need to relay to other
threads is the state being reset again. */
atomic_store_relaxed (once_control, 0);
- lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
+ futex_wake ((unsigned int *) once_control, INT_MAX, FUTEX_PRIVATE);
}
@@ -100,8 +100,10 @@ __pthread_once_slow (pthread_once_t *once_control, void (*init_routine) (void))
is set and __PTHREAD_ONCE_DONE is not. */
if (val == newval)
{
- /* Same generation, some other thread was faster. Wait. */
- lll_futex_wait (once_control, newval, LLL_PRIVATE);
+ /* Same generation, some other thread was faster. Wait and
+ retry. */
+ futex_wait_simple ((unsigned int *)once_control,
+ (unsigned int) newval, FUTEX_PRIVATE);
continue;
}
}
@@ -122,7 +124,7 @@ __pthread_once_slow (pthread_once_t *once_control, void (*init_routine) (void))
atomic_store_release (once_control, __PTHREAD_ONCE_DONE);
/* Wake up all other threads. */
- lll_futex_wake (once_control, INT_MAX, LLL_PRIVATE);
+ futex_wake ((unsigned int *) once_control, INT_MAX, FUTEX_PRIVATE);
break;
}
@@ -19,6 +19,7 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <stap-probe.h>
@@ -32,6 +33,8 @@ __pthread_rwlock_rdlock_slow (pthread_rwlock_t *rwlock)
{
int result = 0;
bool wake = false;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
/* Lock is taken in caller. */
@@ -60,9 +63,10 @@ __pthread_rwlock_rdlock_slow (pthread_rwlock_t *rwlock)
/* Free the lock. */
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- /* Wait for the writer to finish. */
- lll_futex_wait (&rwlock->__data.__readers_wakeup, waitval,
- rwlock->__data.__shared);
+ /* Wait for the writer to finish. We do not check the return value
+ because we decide how to continue based on the state of the rwlock. */
+ futex_wait_simple (&rwlock->__data.__readers_wakeup, waitval,
+ futex_shared);
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
@@ -103,8 +107,7 @@ __pthread_rwlock_rdlock_slow (pthread_rwlock_t *rwlock)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
if (wake)
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX, futex_shared);
return result;
}
@@ -117,6 +120,8 @@ __pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
{
int result = 0;
bool wake = false;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
LIBC_PROBE (rdlock_entry, 1, rwlock);
@@ -164,8 +169,7 @@ __pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
if (wake)
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX, futex_shared);
return result;
}
@@ -19,10 +19,10 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <sys/time.h>
-#include <kernel-features.h>
#include <stdbool.h>
@@ -34,6 +34,8 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
{
int result = 0;
bool wake = false;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
/* Make sure we are alone. */
lll_lock(rwlock->__data.__lock, rwlock->__data.__shared);
@@ -91,38 +93,6 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
break;
}
- /* Work around the fact that the kernel rejects negative timeout values
- despite them being valid. */
- if (__glibc_unlikely (abstime->tv_sec < 0))
- {
- result = ETIMEDOUT;
- break;
- }
-
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
- /* Get the current time. So far we support only one clock. */
- struct timeval tv;
- (void) __gettimeofday (&tv, NULL);
-
- /* Convert the absolute timeout value to a relative timeout. */
- struct timespec rt;
- rt.tv_sec = abstime->tv_sec - tv.tv_sec;
- rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
- if (rt.tv_nsec < 0)
- {
- rt.tv_nsec += 1000000000;
- --rt.tv_sec;
- }
- /* Did we already time out? */
- if (rt.tv_sec < 0)
- {
- /* Yep, return with an appropriate error. */
- result = ETIMEDOUT;
- break;
- }
-#endif
-
/* Remember that we are a reader. */
if (++rwlock->__data.__nr_readers_queued == 0)
{
@@ -137,17 +107,11 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
/* Free the lock. */
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- /* Wait for the writer to finish. */
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
- err = lll_futex_timed_wait (&rwlock->__data.__readers_wakeup,
- waitval, &rt, rwlock->__data.__shared);
-#else
- err = lll_futex_timed_wait_bitset (&rwlock->__data.__readers_wakeup,
- waitval, abstime,
- FUTEX_CLOCK_REALTIME,
- rwlock->__data.__shared);
-#endif
+ /* Wait for the writer to finish. We handle ETIMEDOUT below; on other
+ return values, we decide how to continue based on the state of the
+ rwlock. */
+ err = futex_abstimed_wait (&rwlock->__data.__readers_wakeup, waitval,
+ abstime, futex_shared);
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
@@ -155,7 +119,7 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
--rwlock->__data.__nr_readers_queued;
/* Did the futex call time out? */
- if (err == -ETIMEDOUT)
+ if (err == ETIMEDOUT)
{
/* Yep, report it. */
result = ETIMEDOUT;
@@ -167,8 +131,7 @@ pthread_rwlock_timedrdlock (rwlock, abstime)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
if (wake)
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX, futex_shared);
return result;
}
@@ -19,10 +19,10 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <sys/time.h>
-#include <kernel-features.h>
#include <stdbool.h>
@@ -34,6 +34,8 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
{
int result = 0;
bool wake_readers = false;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
/* Make sure we are alone. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
@@ -71,37 +73,6 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
break;
}
- /* Work around the fact that the kernel rejects negative timeout values
- despite them being valid. */
- if (__glibc_unlikely (abstime->tv_sec < 0))
- {
- result = ETIMEDOUT;
- break;
- }
-
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
- /* Get the current time. So far we support only one clock. */
- struct timeval tv;
- (void) __gettimeofday (&tv, NULL);
-
- /* Convert the absolute timeout value to a relative timeout. */
- struct timespec rt;
- rt.tv_sec = abstime->tv_sec - tv.tv_sec;
- rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
- if (rt.tv_nsec < 0)
- {
- rt.tv_nsec += 1000000000;
- --rt.tv_sec;
- }
- /* Did we already time out? */
- if (rt.tv_sec < 0)
- {
- result = ETIMEDOUT;
- break;
- }
-#endif
-
/* Remember that we are a writer. */
if (++rwlock->__data.__nr_writers_queued == 0)
{
@@ -116,17 +87,11 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
/* Free the lock. */
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- /* Wait for the writer or reader(s) to finish. */
-#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
- err = lll_futex_timed_wait (&rwlock->__data.__writer_wakeup,
- waitval, &rt, rwlock->__data.__shared);
-#else
- err = lll_futex_timed_wait_bitset (&rwlock->__data.__writer_wakeup,
- waitval, abstime,
- FUTEX_CLOCK_REALTIME,
- rwlock->__data.__shared);
-#endif
+ /* Wait for the writer or reader(s) to finish. We handle ETIMEDOUT
+ below; on other return values, we decide how to continue based on
+ the state of the rwlock. */
+ err = futex_abstimed_wait (&rwlock->__data.__writer_wakeup, waitval,
+ abstime, futex_shared);
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
@@ -135,7 +100,7 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
--rwlock->__data.__nr_writers_queued;
/* Did the futex call time out? */
- if (err == -ETIMEDOUT)
+ if (err == ETIMEDOUT)
{
result = ETIMEDOUT;
/* If we prefer writers, it can have happened that readers blocked
@@ -166,8 +131,7 @@ pthread_rwlock_timedwrlock (rwlock, abstime)
/* Might be required after timeouts. */
if (wake_readers)
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX, futex_shared);
return result;
}
@@ -19,6 +19,7 @@
#include <errno.h>
#include "pthreadP.h"
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <elide.h>
#include <stdbool.h>
@@ -28,6 +29,8 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
{
int result = EBUSY;
bool wake = false;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
if (ELIDE_TRYLOCK (rwlock->__data.__rwelision,
rwlock->__data.__lock == 0
@@ -63,8 +66,7 @@ __pthread_rwlock_tryrdlock (pthread_rwlock_t *rwlock)
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
if (wake)
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX, futex_shared);
return result;
}
@@ -19,6 +19,7 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <stap-probe.h>
@@ -29,6 +30,9 @@
int
__pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
{
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
+
LIBC_PROBE (rwlock_unlock, 1, rwlock);
if (ELIDE_UNLOCK (rwlock->__data.__writer == 0
@@ -51,16 +55,15 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
{
++rwlock->__data.__writer_wakeup;
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- lll_futex_wake (&rwlock->__data.__writer_wakeup, 1,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__writer_wakeup, 1, futex_shared);
return 0;
}
else if (rwlock->__data.__nr_readers_queued)
{
++rwlock->__data.__readers_wakeup;
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- lll_futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
- rwlock->__data.__shared);
+ futex_wake (&rwlock->__data.__readers_wakeup, INT_MAX,
+ futex_shared);
return 0;
}
}
@@ -19,6 +19,7 @@
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <stap-probe.h>
@@ -30,6 +31,8 @@ static int __attribute__((noinline))
__pthread_rwlock_wrlock_slow (pthread_rwlock_t *rwlock)
{
int result = 0;
+ int futex_shared =
+ (rwlock->__data.__shared == LLL_PRIVATE) ? FUTEX_PRIVATE : FUTEX_SHARED;
/* Caller has taken the lock. */
@@ -58,9 +61,11 @@ __pthread_rwlock_wrlock_slow (pthread_rwlock_t *rwlock)
/* Free the lock. */
lll_unlock (rwlock->__data.__lock, rwlock->__data.__shared);
- /* Wait for the writer or reader(s) to finish. */
- lll_futex_wait (&rwlock->__data.__writer_wakeup, waitval,
- rwlock->__data.__shared);
+ /* Wait for the writer or reader(s) to finish. We do not check the
+ return value because we decide how to continue based on the state of
+ the rwlock. */
+ futex_wait_simple (&rwlock->__data.__writer_wakeup, waitval,
+ futex_shared);
/* Get the lock. */
lll_lock (rwlock->__data.__lock, rwlock->__data.__shared);
@@ -21,22 +21,7 @@
#include <shlib-compat.h>
#include "semaphoreP.h"
#include <kernel-features.h>
-
-/* Returns FUTEX_PRIVATE if pshared is zero and private futexes are supported;
- returns FUTEX_SHARED otherwise.
- TODO Remove when cleaning up the futex API throughout glibc. */
-static __always_inline int
-futex_private_if_supported (int pshared)
-{
- if (pshared != 0)
- return LLL_SHARED;
-#ifdef __ASSUME_PRIVATE_FUTEX
- return LLL_PRIVATE;
-#else
- return THREAD_GETMEM (THREAD_SELF, header.private_futex)
- ^ FUTEX_PRIVATE_FLAG;
-#endif
-}
+#include <futex-internal.h>
int
@@ -30,6 +30,7 @@
#include <sys/stat.h>
#include "semaphoreP.h"
#include <shm-directory.h>
+#include <futex-internal.h>
/* Comparison function for search of existing mapping. */
@@ -200,7 +201,7 @@ sem_open (const char *name, int oflag, ...)
sem.newsem.nwaiters = 0;
#endif
/* This always is a shared semaphore. */
- sem.newsem.private = LLL_SHARED;
+ sem.newsem.private = FUTEX_SHARED;
/* Initialize the remaining bytes as well. */
memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0',
@@ -20,37 +20,13 @@
#include <atomic.h>
#include <errno.h>
#include <sysdep.h>
-#include <lowlevellock.h>
+#include <lowlevellock.h> /* lll_futex* used by the old code. */
+#include <futex-internal.h>
#include <internaltypes.h>
#include <semaphore.h>
#include <shlib-compat.h>
-/* Wrapper for lll_futex_wake, with error checking.
- TODO Remove when cleaning up the futex API throughout glibc. */
-static __always_inline void
-futex_wake (unsigned int* futex, int processes_to_wake, int private)
-{
- int res = lll_futex_wake (futex, processes_to_wake, private);
- /* No error. Ignore the number of woken processes. */
- if (res >= 0)
- return;
- switch (res)
- {
- case -EFAULT: /* Could have happened due to memory reuse. */
- case -EINVAL: /* Could be either due to incorrect alignment (a bug in
- glibc or in the application) or due to memory being
- reused for a PI futex. We cannot distinguish between the
- two causes, and one of them is correct use, so we do not
- act in this case. */
- return;
- case -ENOSYS: /* Must have been caused by a glibc bug. */
- /* No other errors are documented at this time. */
- default:
- abort ();
- }
-}
-
/* See sem_wait for an explanation of the algorithm. */
int
@@ -17,6 +17,7 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#include <lowlevellock.h> /* lll_futex* used by the old code. */
#include "sem_waitcommon.c"
int
@@ -20,7 +20,7 @@
#include <kernel-features.h>
#include <errno.h>
#include <sysdep.h>
-#include <lowlevellock.h>
+#include <futex-internal.h>
#include <internaltypes.h>
#include <semaphore.h>
#include <sys/time.h>
@@ -29,110 +29,6 @@
#include <shlib-compat.h>
#include <atomic.h>
-/* Wrapper for lll_futex_wait with absolute timeout and error checking.
- TODO Remove when cleaning up the futex API throughout glibc. */
-static __always_inline int
-futex_abstimed_wait (unsigned int* futex, unsigned int expected,
- const struct timespec* abstime, int private, bool cancel)
-{
- int err, oldtype;
- if (abstime == NULL)
- {
- if (cancel)
- oldtype = __pthread_enable_asynccancel ();
- err = lll_futex_wait (futex, expected, private);
- if (cancel)
- __pthread_disable_asynccancel (oldtype);
- }
- else
- {
-#if (defined __ASSUME_FUTEX_CLOCK_REALTIME \
- && defined lll_futex_timed_wait_bitset)
- /* The Linux kernel returns EINVAL for this, but in userspace
- such a value is valid. */
- if (abstime->tv_sec < 0)
- return ETIMEDOUT;
-#else
- struct timeval tv;
- struct timespec rt;
- int sec, nsec;
-
- /* Get the current time. */
- __gettimeofday (&tv, NULL);
-
- /* Compute relative timeout. */
- sec = abstime->tv_sec - tv.tv_sec;
- nsec = abstime->tv_nsec - tv.tv_usec * 1000;
- if (nsec < 0)
- {
- nsec += 1000000000;
- --sec;
- }
-
- /* Already timed out? */
- if (sec < 0)
- return ETIMEDOUT;
-
- /* Do wait. */
- rt.tv_sec = sec;
- rt.tv_nsec = nsec;
-#endif
- if (cancel)
- oldtype = __pthread_enable_asynccancel ();
-#if (defined __ASSUME_FUTEX_CLOCK_REALTIME \
- && defined lll_futex_timed_wait_bitset)
- err = lll_futex_timed_wait_bitset (futex, expected, abstime,
- FUTEX_CLOCK_REALTIME, private);
-#else
- err = lll_futex_timed_wait (futex, expected, &rt, private);
-#endif
- if (cancel)
- __pthread_disable_asynccancel (oldtype);
- }
- switch (err)
- {
- case 0:
- case -EAGAIN:
- case -EINTR:
- case -ETIMEDOUT:
- return -err;
-
- case -EFAULT: /* Must have been caused by a glibc or application bug. */
- case -EINVAL: /* Either due to wrong alignment or due to the timeout not
- being normalized. Must have been caused by a glibc or
- application bug. */
- case -ENOSYS: /* Must have been caused by a glibc bug. */
- /* No other errors are documented at this time. */
- default:
- abort ();
- }
-}
-
-/* Wrapper for lll_futex_wake, with error checking.
- TODO Remove when cleaning up the futex API throughout glibc. */
-static __always_inline void
-futex_wake (unsigned int* futex, int processes_to_wake, int private)
-{
- int res = lll_futex_wake (futex, processes_to_wake, private);
- /* No error. Ignore the number of woken processes. */
- if (res >= 0)
- return;
- switch (res)
- {
- case -EFAULT: /* Could have happened due to memory reuse. */
- case -EINVAL: /* Could be either due to incorrect alignment (a bug in
- glibc or in the application) or due to memory being
- reused for a PI futex. We cannot distinguish between the
- two causes, and one of them is correct use, so we do not
- act in this case. */
- return;
- case -ENOSYS: /* Must have been caused by a glibc bug. */
- /* No other errors are documented at this time. */
- default:
- abort ();
- }
-}
-
/* The semaphore provides two main operations: sem_post adds a token to the
semaphore; sem_wait grabs a token from the semaphore, potentially waiting
@@ -220,11 +116,12 @@ do_futex_wait (struct new_sem *sem, const struct timespec *abstime)
int err;
#if __HAVE_64B_ATOMICS
- err = futex_abstimed_wait ((unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0,
- abstime, sem->private, true);
+ err = futex_abstimed_wait_cancelable (
+ (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0, abstime,
+ sem->private);
#else
- err = futex_abstimed_wait (&sem->value, SEM_NWAITERS_MASK, abstime,
- sem->private, true);
+ err = futex_abstimed_wait_cancelable (&sem->value, SEM_NWAITERS_MASK,
+ abstime, sem->private);
#endif
return err;
@@ -20,6 +20,7 @@
#include <stdlib.h>
#include <fork.h>
#include <atomic.h>
+#include <futex-internal.h>
void
@@ -114,7 +115,7 @@ __unregister_atfork (dso_handle)
atomic_decrement (&deleted->handler->refcntr);
unsigned int val;
while ((val = deleted->handler->refcntr) != 0)
- lll_futex_wait (&deleted->handler->refcntr, val, LLL_PRIVATE);
+ futex_wait_simple (&deleted->handler->refcntr, val, FUTEX_PRIVATE);
deleted = deleted->next;
}
@@ -18,7 +18,7 @@
#include <assert.h>
#include <atomic.h>
-#include <lowlevellock.h>
+#include <futex-internal.h>
#include <nacl-interfaces.h>
#include <nptl/pthreadP.h>
@@ -64,7 +64,7 @@ __exit_thread (void)
assert (NACL_EXITING_TID > 0);
atomic_store_relaxed (&pd->tid, NACL_EXITING_TID);
- lll_futex_wake (&pd->tid, 1, LLL_PRIVATE);
+ futex_wake (&pd->tid, 1, FUTEX_PRIVATE);
}
/* This clears PD->tid some time after the thread stack can never
@@ -63,6 +63,11 @@
-_err; \
})
+/* Wait until a lll_futex_wake call on FUTEXP, or time ABSTIME has passed. */
+#define lll_futex_abstimed_wait(futexp, val, timeout, private) \
+ (- __nacl_irt_futex.futex_wait_abs ((volatile int *) (futexp), \
+ val, (abstime)));
+
/* Wake up up to NR waiters on FUTEXP. */
#define lll_futex_wake(futexp, nr, private) \
({ \
@@ -22,14 +22,14 @@
#include <assert.h>
#include <nptl/pthreadP.h>
-#include <lowlevellock.h>
+#include <nptl/futex-internal.h>
#define DONT_NEED_AIO_MISC_COND 1
#define AIO_MISC_NOTIFY(waitlist) \
do { \
if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \
- lll_futex_wake (waitlist->counterp, 1, LLL_PRIVATE); \
+ futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \
} while (0)
#define AIO_MISC_WAIT(result, futex, timeout, cancel) \
@@ -48,9 +48,9 @@
int status; \
do \
{ \
- status = lll_futex_timed_wait (futexaddr, oldval, timeout, \
- LLL_PRIVATE); \
- if (status != -EWOULDBLOCK) \
+ status = futex_reltimed_wait ((unsigned int *) futexaddr, \
+ oldval, timeout, FUTEX_PRIVATE); \
+ if (status != EAGAIN) \
break; \
\
oldval = *futexaddr; \
@@ -60,12 +60,12 @@
if (cancel) \
LIBC_CANCEL_RESET (oldtype); \
\
- if (status == -EINTR) \
+ if (status == EINTR) \
result = EINTR; \
- else if (status == -ETIMEDOUT) \
+ else if (status == ETIMEDOUT) \
result = EAGAIN; \
else \
- assert (status == 0 || status == -EWOULDBLOCK); \
+ assert (status == 0 || status == EAGAIN); \
\
pthread_mutex_lock (&__aio_requests_mutex); \
} \
@@ -30,6 +30,7 @@
#include <nptl/pthreadP.h>
#include <fork.h>
#include <arch-fork.h>
+#include <nptl/futex-internal.h>
static void
@@ -219,7 +220,7 @@ __libc_fork (void)
if (atomic_decrement_and_test (&allp->handler->refcntr)
&& allp->handler->need_signal)
- lll_futex_wake (&allp->handler->refcntr, 1, LLL_PRIVATE);
+ futex_wake (&allp->handler->refcntr, 1, FUTEX_PRIVATE);
allp = allp->next;
}
@@ -23,14 +23,14 @@
#include <assert.h>
#include <signal.h>
#include <nptl/pthreadP.h>
-#include <lowlevellock.h>
+#include <nptl/futex-internal.h>
#define DONT_NEED_GAI_MISC_COND 1
#define GAI_MISC_NOTIFY(waitlist) \
do { \
if (*waitlist->counterp > 0 && --*waitlist->counterp == 0) \
- lll_futex_wake (waitlist->counterp, 1, LLL_PRIVATE); \
+ futex_wake ((unsigned int *) waitlist->counterp, 1, FUTEX_PRIVATE); \
} while (0)
#define GAI_MISC_WAIT(result, futex, timeout, cancel) \
@@ -49,9 +49,9 @@
int status; \
do \
{ \
- status = lll_futex_timed_wait (futexaddr, oldval, timeout, \
- LLL_PRIVATE); \
- if (status != -EWOULDBLOCK) \
+ status = futex_reltimed_wait ((unsigned int *)futexaddr, \
+ oldval, timeout, FUTEX_PRIVATE); \
+ if (status != EAGAIN) \
break; \
\
oldval = *futexaddr; \
@@ -61,12 +61,12 @@
if (cancel) \
LIBC_CANCEL_RESET (oldtype); \
\
- if (status == -EINTR) \
+ if (status == EINTR) \
result = EINTR; \
- else if (status == -ETIMEDOUT) \
+ else if (status == ETIMEDOUT) \
result = EAGAIN; \
else \
- assert (status == 0 || status == -EWOULDBLOCK); \
+ assert (status == 0 || status == EAGAIN); \
\
pthread_mutex_lock (&__gai_requests_mutex); \
} \
@@ -43,6 +43,11 @@
#define lll_futex_timed_wait(futexp, val, timeout, private) \
-ENOSYS
+/* Wait until a lll_futex_wake call on FUTEXP, or ABSTIME, a point in time
+ counted by CLOCK_REALTIME, has passed. ABSTIME must be normalized. */
+#define lll_futex_abstimed_wait(futexp, val, abstime, private) \
+ -ENOSYS
+
/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
@@ -22,6 +22,7 @@
#ifndef __ASSEMBLER__
#include <sysdep.h>
#include <tls.h>
+#include <sys/time.h>
#include <kernel-features.h>
#endif
@@ -92,6 +93,19 @@
__lll_private_flag (FUTEX_WAIT, private), \
val, timeout)
+#define lll_futex_abstimed_wait(futexp, val, abstime, private) \
+ ({ \
+ /* Work around the fact that the kernel rejects negative timeout values \
+ despite them being valid. */ \
+ int ret; \
+ if (__glibc_unlikely (((abstime) != NULL) && ((abstime)->tv_sec < 0))) \
+ ret = -ETIMEDOUT; \
+ else \
+ ret = lll_futex_timed_wait_bitset (futexp, val, abstime, \
+ FUTEX_CLOCK_REALTIME, private); \
+ ret; \
+ })
+
#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
lll_futex_syscall (6, futexp, \
__lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \