Patch
ce7eb0e90315 ("nptl: Cleanup cancellation macros") changed the
join sequence for internal common __pthread_timedjoin_ex to use the
new macro lll_wait_tid. The idea was this macro would issue the
cancellable futex operation depending whether the timeout is used or
not. However if a timeout is used, __lll_timedwait_tid is called and
it is not a cancellable entrypoint.
This patch fixes it by simplifying the code in various ways:
- Instead of adding the cancellation handling on __lll_timedwait_tid,
it moves the generic implementation to pthread_join_common.c (called
now timedwait_tid with some fixes to use the correct type for pid).
- The llvm_wait_tid macro is removed, along with its replication on
x86_64, i686, and sparc arch-specific lowlevellock.h.
- sparc32 __lll_timedwait_tid is also removed, since the code is similar
to generic one.
- x86_64 and i386 provides arch-specific __lll_timedwait_tid which is
also removed since they are similar in functionality to generic C code
and there is no indication it is better than compiler generated code.
New tests, tst-join8 and tst-join9, are provided to check if
pthread_timedjoin_np acts as a cancellation point.
Checked on x86_64-linux-gnu, i686-linux-gnu, sparcv9-linux-gnu, and
aarch64-linux-gnu.
[BZ #24215]
* nptl/Makefile (lpthread-routines): Remove lll_timedwait_tid.
(tests): Add tst-join8 tst-join9.
* nptl/lll_timedwait_tid.c: Remove file.
* sysdeps/sparc/sparc32/lll_timedwait_tid.c: Likewise.
* sysdeps/unix/sysv/linux/i386/lll_timedwait_tid.c: Likewise.
* sysdeps/sysv/linux/x86_64/lll_timedwait_tid.c: Likewise.
* nptl/pthread_join_common.c (timedwait_tid): New function.
(__pthread_timedjoin_ex): Act as cancellation entrypoint is block
is set.
* nptl/tst-join5.c (thread_join): New function.
(tf1, tf2, do_test): Use libsupport and add pthread_timedjoin_np
check.
* nptl/tst-join8.c: New file.
* nptl/tst-join9.c: Likewise.
* sysdeps/nptl/lowlevellock-futex.h (lll_futex_wait_cancel,
lll_futex_timed_wait_cancel): Add generic macros.
* sysdeps/nptl/lowlevellock.h (__lll_timedwait_tid, lll_wait_tid):
Remove definitions.
* sysdeps/unix/sysv/linux/i386/lowlevellock.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/lowlevellock.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Likewise.
* sysdeps/sparc/sparc32/lowlevellock.c (__lll_timedwait_tid):
Remove function.
* sysdeps/unix/sysv/linux/i386/lowlevellock.S (__lll_timedwait_tid):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
* sysdeps/unix/sysv/linux/lowlevellock-futex.h
(lll_futex_timed_wait_cancel): New macro.
+2019-02-14 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ [BZ #2421]
+ * nptl/Makefile (lpthread-routines): Remove lll_timedwait_tid.
+ (tests): Add tst-join8 tst-join9.
+ * nptl/lll_timedwait_tid.c: Remove file.
+ * sysdeps/sparc/sparc32/lll_timedwait_tid.c: Likewise.
+ * sysdeps/unix/sysv/linux/i386/lll_timedwait_tid.c: Likewise.
+ * sysdeps/sysv/linux/x86_64/lll_timedwait_tid.c: Likewise.
+ * nptl/pthread_join_common.c (timedwait_tid): New function.
+ (__pthread_timedjoin_ex): Act as cancellation entrypoint is block
+ is set.
+ * nptl/tst-join5.c (thread_join): New function.
+ (tf1, tf2, do_test): Use libsupport and add pthread_timedjoin_np
+ check.
+ * nptl/tst-join8.c: New file.
+ * nptl/tst-join9.c: Likewise.
+ * sysdeps/nptl/lowlevellock-futex.h (lll_futex_wait_cancel,
+ lll_futex_timed_wait_cancel): Add generic macros.
+ * sysdeps/nptl/lowlevellock.h (__lll_timedwait_tid, lll_wait_tid):
+ Remove definitions.
+ * sysdeps/unix/sysv/linux/i386/lowlevellock.h: Likewise.
+ * sysdeps/unix/sysv/linux/sparc/lowlevellock.h: Likewise.
+ * sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Likewise.
+ * sysdeps/sparc/sparc32/lowlevellock.c (__lll_timedwait_tid):
+ Remove function.
+ * sysdeps/unix/sysv/linux/i386/lowlevellock.S (__lll_timedwait_tid):
+ Likewise.
+ * sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
+ * sysdeps/unix/sysv/linux/lowlevellock-futex.h
+ (lll_futex_timed_wait_cancel): New macro.
+
2019-02-14 Wilco Dijkstra <wdijkstr@arm.com>
* benchtests/Makefile: Add malloc-simple benchmark.
pt-longjmp pt-cleanup\
cancellation \
lowlevellock \
- lll_timedlock_wait lll_timedwait_tid \
+ lll_timedlock_wait \
pt-fork pt-vfork pt-fcntl \
$(pthread-compat-wrappers) \
pt-raise pt-system \
tst-kill1 tst-kill2 tst-kill3 tst-kill4 tst-kill5 tst-kill6 \
tst-raise1 \
tst-join1 tst-join2 tst-join3 tst-join4 tst-join5 tst-join6 tst-join7 \
+ tst-join8 tst-join9 \
tst-detach1 \
tst-eintr1 tst-eintr2 tst-eintr3 tst-eintr4 tst-eintr5 \
tst-tsd1 tst-tsd2 tst-tsd3 tst-tsd4 tst-tsd5 tst-tsd6 \
+++ /dev/null
-/* Timed waiting for thread death. Generic futex-using version.
- Copyright (C) 2003-2019 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
-
- 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/>. */
-
-#include <atomic.h>
-#include <errno.h>
-#include <lowlevellock.h>
-#include <sys/time.h>
-
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
- wake-up when the clone terminates. The memory location contains the
- thread ID while the clone is running and is reset to zero by the kernel
- afterwards. The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates. */
-int
-__lll_timedwait_tid (int *tidp, const struct timespec *abstime)
-{
- int tid;
-
- if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
- return EINVAL;
-
- /* Repeat until thread terminated. */
- while ((tid = *tidp) != 0)
- {
- struct timeval tv;
- struct timespec rt;
-
- /* Get the current time. */
- (void) __gettimeofday (&tv, NULL);
-
- /* Compute relative timeout. */
- 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;
- }
-
- /* Already timed out? */
- if (rt.tv_sec < 0)
- return ETIMEDOUT;
-
- /* If *tidp == tid, wait until thread terminates or the wait times out.
- The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates.
- */
- if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
- return ETIMEDOUT;
- }
-
- return 0;
-}
atomic_compare_exchange_weak_acquire (&arg, &self, NULL);
}
+/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
+ wake-up when the clone terminates. The memory location contains the
+ thread ID while the clone is running and is reset to zero by the kernel
+ afterwards. The kernel up to version 3.16.3 does not use the private futex
+ operations for futex wake-up when the clone terminates. */
+static int
+timedwait_tid (pid_t *tidp, const struct timespec *abstime)
+{
+ pid_t tid;
+
+ if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
+ return EINVAL;
+
+ /* Repeat until thread terminated. */
+ while ((tid = *tidp) != 0)
+ {
+ struct timeval tv;
+ struct timespec rt;
+
+ /* Get the current time. */
+ __gettimeofday (&tv, NULL);
+
+ /* Compute relative timeout. */
+ 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;
+ }
+
+ /* Already timed out? */
+ if (rt.tv_sec < 0)
+ return ETIMEDOUT;
+
+ /* If *tidp == tid, wait until thread terminates or the wait times out.
+ The kernel up to version 3.16.3 does not use the private futex
+ operations for futex wake-up when the clone terminates. */
+ if (lll_futex_timed_wait_cancel (tidp, tid, &rt, LLL_SHARED)
+ == -ETIMEDOUT)
+ return ETIMEDOUT;
+ }
+
+ return 0;
+}
+
int
__pthread_timedjoin_ex (pthread_t threadid, void **thread_return,
const struct timespec *abstime, bool block)
/* There is already somebody waiting for the thread. */
return EINVAL;
+ /* BLOCK waits either indefinitely or based on an absolute time. POSIX also
+ states a cancellation point shall occur for pthread_join, and we use the
+ same rationale for posix_timedjoin_np. Both timedwait_tid and the futex
+ call use the cancellable variant. */
if (block)
{
/* During the wait we change to asynchronous cancellation. If we
un-wait-ed for again. */
pthread_cleanup_push (cleanup, &pd->joinid);
- result = lll_wait_tid (pd->tid, abstime);
+ if (abstime != NULL)
+ result = timedwait_tid (&pd->tid, abstime);
+ else
+ {
+ pid_t tid;
+ /* We need acquire MO here so that we synchronize with the
+ kernel's store to 0 when the clone terminates. (see above) */
+ while ((tid = atomic_load_acquire (&pd->tid)) != 0)
+ lll_futex_wait_cancel (&pd->tid, tid, LLL_SHARED);
+ }
pthread_cleanup_pop (0);
}
#include <time.h>
#include <unistd.h>
+#include <support/check.h>
+#include <support/xthread.h>
static void
wait_code (void)
static pthread_barrier_t b;
#endif
+static int
+thread_join (pthread_t thread, void **retval)
+{
+#ifdef USE_PTHREAD_TIMEDJOIN_NP
+ struct timespec tv;
+ TEST_COMPARE (clock_gettime (CLOCK_REALTIME, &tv), 0);
+ /* Arbitrary large timeout to make it act as pthread_join. */
+ tv.tv_sec += 1000;
+ return pthread_timedjoin_np ((pthread_t) thread, retval, &tv);
+#else
+ return pthread_join ((pthread_t) thread, retval);
+#endif
+}
+
static void *
tf1 (void *arg)
{
#ifdef WAIT_IN_CHILD
- int e = pthread_barrier_wait (&b);
- if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
- {
- printf ("%s: barrier_wait failed\n", __func__);
- exit (1);
- }
+ xpthread_barrier_wait (&b);
wait_code ();
#endif
- pthread_join ((pthread_t) arg, NULL);
+ thread_join ((pthread_t) arg, NULL);
exit (42);
}
tf2 (void *arg)
{
#ifdef WAIT_IN_CHILD
- int e = pthread_barrier_wait (&b);
- if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
- {
- printf ("%s: barrier_wait failed\n", __func__);
- exit (1);
- }
+ xpthread_barrier_wait (&b);
wait_code ();
#endif
- pthread_join ((pthread_t) arg, NULL);
+
+ thread_join ((pthread_t) arg, NULL);
exit (43);
}
do_test (void)
{
#ifdef WAIT_IN_CHILD
- if (pthread_barrier_init (&b, NULL, 2) != 0)
- {
- puts ("barrier_init failed");
- return 1;
- }
+ xpthread_barrier_init (&b, NULL, 2);
#endif
pthread_t th;
- int err = pthread_join (pthread_self (), NULL);
+ int err = thread_join (pthread_self (), NULL);
if (err == 0)
{
puts ("1st circular join succeeded");
return 1;
}
- if (pthread_create (&th, NULL, tf1, (void *) pthread_self ()) != 0)
- {
- puts ("1st create failed");
- return 1;
- }
+ th = xpthread_create (NULL, tf1, (void *) pthread_self ());
#ifndef WAIT_IN_CHILD
wait_code ();
#endif
- if (pthread_cancel (th) != 0)
- {
- puts ("cannot cancel 1st thread");
- return 1;
- }
+ xpthread_cancel (th);
#ifdef WAIT_IN_CHILD
- int e = pthread_barrier_wait (&b);
- if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
- {
- printf ("%s: barrier_wait failed\n", __func__);
- return 1;
- }
+ xpthread_barrier_wait (&b);
#endif
void *r;
- err = pthread_join (th, &r);
+ err = thread_join (th, &r);
if (err != 0)
{
printf ("cannot join 1st thread: %d\n", err);
return 1;
}
- err = pthread_join (pthread_self (), NULL);
+ err = thread_join (pthread_self (), NULL);
if (err == 0)
{
puts ("2nd circular join succeeded");
return 1;
}
- if (pthread_create (&th, NULL, tf2, (void *) pthread_self ()) != 0)
- {
- puts ("2nd create failed");
- return 1;
- }
+ th = xpthread_create (NULL, tf2, (void *) pthread_self ());
#ifndef WAIT_IN_CHILD
wait_code ();
#endif
- if (pthread_cancel (th) != 0)
- {
- puts ("cannot cancel 2nd thread");
- return 1;
- }
+ xpthread_cancel (th);
#ifdef WAIT_IN_CHILD
- e = pthread_barrier_wait (&b);
- if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
- {
- printf ("%s: barrier_wait failed\n", __func__);
- return 1;
- }
+ xpthread_barrier_wait (&b);
#endif
- if (pthread_join (th, &r) != 0)
+ if (thread_join (th, &r) != 0)
{
puts ("cannot join 2nd thread");
return 1;
return 1;
}
- err = pthread_join (pthread_self (), NULL);
+ err = thread_join (pthread_self (), NULL);
if (err == 0)
{
puts ("3rd circular join succeeded");
return 0;
}
-#define TEST_FUNCTION do_test ()
-#include "../test-skeleton.c"
+#include <support/test-driver.c>
--- /dev/null
+/* Check if pthread_timedjoin_np is a cancellation entrypoint.
+ Copyright (C) 2019 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/>. */
+
+#define USE_PTHREAD_TIMEDJOIN_NP 1
+#include <nptl/tst-join5.c>
--- /dev/null
+/* Check if pthread_timedjoin_np is a cancellation entrypoint.
+ Copyright (C) 2019 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/>. */
+
+#define USE_PTHREAD_TIMEDJOIN_NP 1
+#define WAIT_IN_CHILD 1
+#include <nptl/tst-join5.c>
val, private) \
-ENOSYS
+/* Like lll_futex_wait, but acting as a cancellable entrypoint. */
+#define lll_futex_wait_cancel(futexp, val, private) \
+ -ENOSYS
+
+/* Like lll_futex_timed_wait, but acting as a cancellable entrypoint. */
+#define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
+ -ENOSYS
#endif /* lowlevellock-futex.h */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
-extern int __lll_timedwait_tid (int *, const struct timespec *)
- attribute_hidden;
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
- wake-up when the clone terminates. The memory location contains the
- thread ID while the clone is running and is reset to zero by the kernel
- afterwards. The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates.
- If ABSTIME is not NULL, is used a timeout for futex call. If the timeout
- occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL.
- The futex operation are issues with cancellable versions. */
-#define lll_wait_tid(tid, abstime) \
- ({ \
- int __res = 0; \
- __typeof (tid) __tid; \
- if (abstime != NULL) \
- __res = __lll_timedwait_tid (&(tid), (abstime)); \
- else \
- /* We need acquire MO here so that we synchronize with the \
- kernel's store to 0 when the clone terminates. (see above) */ \
- while ((__tid = atomic_load_acquire (&(tid))) != 0) \
- lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED); \
- __res; \
- })
-
-
#endif /* lowlevellock.h */
+++ /dev/null
-/* __lll_timedwait_tid is in lowlevellock.c. */
return 0;
}
-
-
-int
-__lll_timedwait_tid (int *tidp, const struct timespec *abstime)
-{
- int tid;
-
- if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
- return EINVAL;
-
- /* Repeat until thread terminated. */
- while ((tid = *tidp) != 0)
- {
- struct timeval tv;
- struct timespec rt;
-
- /* Get the current time. */
- (void) __gettimeofday (&tv, NULL);
-
- /* Compute relative timeout. */
- 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;
- }
-
- /* Already timed out? */
- if (rt.tv_sec < 0)
- return ETIMEDOUT;
-
- /* Wait until thread terminates. The kernel so far does not use
- the private futex operations for this. */
- if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
- return ETIMEDOUT;
- }
-
- return 0;
-}
#endif
+++ /dev/null
-/* __lll_timedwait_tid is in lowlevellock.S. */
ret
cfi_endproc
.size __lll_unlock_wake,.-__lll_unlock_wake
-
- .globl __lll_timedwait_tid
- .type __lll_timedwait_tid,@function
- .hidden __lll_timedwait_tid
- .align 16
-__lll_timedwait_tid:
- pushl %edi
- pushl %esi
- pushl %ebx
- pushl %ebp
-
- movl %eax, %ebp
- movl %edx, %edi
- subl $8, %esp
-
- /* Get current time. */
-2: movl %esp, %ebx
- xorl %ecx, %ecx
- movl $__NR_gettimeofday, %eax
- ENTER_KERNEL
-
- /* Compute relative timeout. */
- movl 4(%esp), %eax
- movl $1000, %edx
- mul %edx /* Milli seconds to nano seconds. */
- movl (%edi), %ecx
- movl 4(%edi), %edx
- subl (%esp), %ecx
- subl %eax, %edx
- jns 5f
- addl $1000000000, %edx
- subl $1, %ecx
-5: testl %ecx, %ecx
- js 6f /* Time is already up. */
-
- movl %ecx, (%esp) /* Store relative timeout. */
- movl %edx, 4(%esp)
-
- movl (%ebp), %edx
- testl %edx, %edx
- jz 4f
-
- movl %esp, %esi
- /* XXX The kernel so far uses global futex for the wakeup at
- all times. */
- xorl %ecx, %ecx /* movl $FUTEX_WAIT, %ecx */
- movl %ebp, %ebx
- movl $SYS_futex, %eax
- ENTER_KERNEL
-
- cmpl $0, (%ebx)
- jne 1f
-4: xorl %eax, %eax
-
-3: addl $8, %esp
- popl %ebp
- popl %ebx
- popl %esi
- popl %edi
- ret
-
-1: cmpl $-ETIMEDOUT, %eax
- jne 2b
-6: movl $ETIMEDOUT, %eax
- jmp 3b
- .size __lll_timedwait_tid,.-__lll_timedwait_tid
#endif
#define lll_islocked(futex) \
(futex != LLL_LOCK_INITIALIZER)
-extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
- __attribute__ ((regparm (2))) attribute_hidden;
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
- wake-up when the clone terminates. The memory location contains the
- thread ID while the clone is running and is reset to zero by the kernel
- afterwards. The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates.
- If ABSTIME is not NULL, is used a timeout for futex call. If the timeout
- occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL.
- The futex operation are issues with cancellable versions. */
-#define lll_wait_tid(tid, abstime) \
- ({ \
- int __res = 0; \
- __typeof (tid) __tid; \
- if (abstime != NULL) \
- __res = __lll_timedwait_tid (&(tid), (abstime)); \
- else \
- /* We need acquire MO here so that we synchronize with the \
- kernel's store to 0 when the clone terminates. (see above) */ \
- while ((__tid = atomic_load_acquire (&(tid))) != 0) \
- lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED); \
- __res; \
- })
-
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;
__err; \
})
+#define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
+ ({ \
+ int __oldtype = CANCEL_ASYNC (); \
+ long int __err = lll_futex_timed_wait (futexp, val, timeout, private); \
+ CANCEL_RESET (__oldtype); \
+ __err; \
+ })
#endif /* !__ASSEMBLER__ */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
-extern int __lll_timedwait_tid (int *, const struct timespec *)
- attribute_hidden;
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
- wake-up when the clone terminates. The memory location contains the
- thread ID while the clone is running and is reset to zero by the kernel
- afterwards. The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates.
- If ABSTIME is not NULL, is used a timeout for futex call. If the timeout
- occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL.
- The futex operation are issues with cancellable versions. */
-#define lll_wait_tid(tid, abstime) \
- ({ \
- int __res = 0; \
- __typeof (tid) __tid; \
- if (abstime != NULL) \
- __res = __lll_timedwait_tid (&(tid), (abstime)); \
- else \
- /* We need acquire MO here so that we synchronize with the \
- kernel's store to 0 when the clone terminates. (see above) */ \
- while ((__tid = atomic_load_acquire (&(tid))) != 0) \
- lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED); \
- __res; \
- })
-
#endif /* lowlevellock.h */
+++ /dev/null
-/* __lll_timedwait_tid is in lowlevellock.S. */
retq
cfi_endproc
.size __lll_unlock_wake,.-__lll_unlock_wake
-
- .globl __lll_timedwait_tid
- .type __lll_timedwait_tid,@function
- .hidden __lll_timedwait_tid
- .align 16
-__lll_timedwait_tid:
- cfi_startproc
- pushq %r12
- cfi_adjust_cfa_offset(8)
- pushq %r13
- cfi_adjust_cfa_offset(8)
- cfi_offset(%r12, -16)
- cfi_offset(%r13, -24)
-
- movq %rdi, %r12
- movq %rsi, %r13
-
- /* Align stack to 16 bytes when calling __gettimeofday. */
- subq $24, %rsp
- cfi_adjust_cfa_offset(24)
-
- /* Get current time. */
-2: movq %rsp, %rdi
- xorl %esi, %esi
- /* This call works because we directly jump to a system call entry
- which preserves all the registers. */
- call JUMPTARGET(__gettimeofday)
-
- /* Compute relative timeout. */
- movq 8(%rsp), %rax
- movl $1000, %edi
- mul %rdi /* Milli seconds to nano seconds. */
- movq (%r13), %rdi
- movq 8(%r13), %rsi
- subq (%rsp), %rdi
- subq %rax, %rsi
- jns 5f
- addq $1000000000, %rsi
- decq %rdi
-5: testq %rdi, %rdi
- js 6f /* Time is already up. */
-
- movq %rdi, (%rsp) /* Store relative timeout. */
- movq %rsi, 8(%rsp)
-
- movl (%r12), %edx
- testl %edx, %edx
- jz 4f
-
- movq %rsp, %r10
- /* XXX The kernel so far uses global futex for the wakeup at
- all times. */
-#if FUTEX_WAIT == 0
- xorl %esi, %esi
-#else
- movl $FUTEX_WAIT, %esi
-#endif
- movq %r12, %rdi
- movl $SYS_futex, %eax
- syscall
-
- cmpl $0, (%rdi)
- jne 1f
-4: xorl %eax, %eax
-
-8: addq $24, %rsp
- cfi_adjust_cfa_offset(-24)
- popq %r13
- cfi_adjust_cfa_offset(-8)
- cfi_restore(%r13)
- popq %r12
- cfi_adjust_cfa_offset(-8)
- cfi_restore(%r12)
- retq
-
- cfi_adjust_cfa_offset(32)
-1: cmpq $-ETIMEDOUT, %rax
- jne 2b
-
-6: movl $ETIMEDOUT, %eax
- jmp 8b
- cfi_endproc
- .size __lll_timedwait_tid,.-__lll_timedwait_tid
#endif
#define lll_islocked(futex) \
(futex != LLL_LOCK_INITIALIZER)
-extern int __lll_timedwait_tid (int *, const struct timespec *)
- attribute_hidden;
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
- wake-up when the clone terminates. The memory location contains the
- thread ID while the clone is running and is reset to zero by the kernel
- afterwards. The kernel up to version 3.16.3 does not use the private futex
- operations for futex wake-up when the clone terminates.
- If ABSTIME is not NULL, is used a timeout for futex call. If the timeout
- occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL.
- The futex operation are issues with cancellable versions. */
-#define lll_wait_tid(tid, abstime) \
- ({ \
- int __res = 0; \
- __typeof (tid) __tid; \
- if (abstime != NULL) \
- __res = __lll_timedwait_tid (&(tid), (abstime)); \
- else \
- /* We need acquire MO here so that we synchronize with the \
- kernel's store to 0 when the clone terminates. (see above) */ \
- while ((__tid = atomic_load_acquire (&(tid))) != 0) \
- lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED); \
- __res; \
- })
-
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;