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/* Copyright (C) 2002-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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 <sysdep.h>
#include <shlib-compat.h>
#include <lowlevellock.h>
#include <lowlevelcond.h>
#include <pthread-pi-defines.h>
#include <kernel-features.h>
#include <pthread-errnos.h>
#include <stap-probe.h>
.text
ENTRY(__pthread_cond_signal)
LIBC_PROBE (cond_signal, 1, %rdi)
/* Get internal lock. */
movq %rdi, %r8
movl $1, %esi
xorl %eax, %eax
LOCK
#if cond_lock == 0
cmpxchgl %esi, (%rdi)
#else
cmpxchgl %esi, cond_lock(%rdi)
#endif
jnz 1f
2: addq $cond_futex, %rdi
movq total_seq(%r8), %rcx
cmpq wakeup_seq(%r8), %rcx
jbe 4f
/* Bump the wakeup number. */
addq $1, wakeup_seq(%r8)
addl $1, (%rdi)
/* Wake up one thread. */
LP_OP(cmp) $-1, dep_mutex(%r8)
movl $FUTEX_WAKE_OP, %esi
movl $1, %edx
movl $SYS_futex, %eax
je 8f
/* Get the address of the mutex used. */
mov dep_mutex(%r8), %RCX_LP
movl MUTEX_KIND(%rcx), %r11d
andl $(ROBUST_BIT|PI_BIT), %r11d
cmpl $PI_BIT, %r11d
je 9f
#ifdef __ASSUME_PRIVATE_FUTEX
movl $(FUTEX_WAKE_OP|FUTEX_PRIVATE_FLAG), %esi
#else
orl %fs:PRIVATE_FUTEX, %esi
#endif
8: movl $1, %r10d
#if cond_lock != 0
addq $cond_lock, %r8
#endif
movl $FUTEX_OP_CLEAR_WAKE_IF_GT_ONE, %r9d
syscall
#if cond_lock != 0
subq $cond_lock, %r8
#endif
/* For any kind of error, we try again with WAKE.
The general test also covers running on old kernels. */
cmpq $-4095, %rax
jae 7f
xorl %eax, %eax
retq
/* Wake up one thread and requeue none in the PI Mutex case. */
9: movl $(FUTEX_CMP_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %esi
movq %rcx, %r8
xorq %r10, %r10
movl (%rdi), %r9d // XXX Can this be right?
syscall
leaq -cond_futex(%rdi), %r8
/* For any kind of error, we try again with WAKE.
The general test also covers running on old kernels. */
cmpq $-4095, %rax
jb 4f
7:
#ifdef __ASSUME_PRIVATE_FUTEX
andl $FUTEX_PRIVATE_FLAG, %esi
#else
andl %fs:PRIVATE_FUTEX, %esi
#endif
orl $FUTEX_WAKE, %esi
movl $SYS_futex, %eax
/* %rdx should be 1 already from $FUTEX_WAKE_OP syscall.
movl $1, %edx */
syscall
/* Unlock. */
4: LOCK
#if cond_lock == 0
decl (%r8)
#else
decl cond_lock(%r8)
#endif
jne 5f
6: xorl %eax, %eax
retq
/* Initial locking failed. */
1:
#if cond_lock != 0
addq $cond_lock, %rdi
#endif
LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
movl $LLL_PRIVATE, %eax
movl $LLL_SHARED, %esi
cmovne %eax, %esi
callq __lll_lock_wait
#if cond_lock != 0
subq $cond_lock, %rdi
#endif
jmp 2b
/* Unlock in loop requires wakeup. */
5:
movq %r8, %rdi
#if cond_lock != 0
addq $cond_lock, %rdi
#endif
LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
movl $LLL_PRIVATE, %eax
movl $LLL_SHARED, %esi
cmovne %eax, %esi
callq __lll_unlock_wake
jmp 6b
END(__pthread_cond_signal)
versioned_symbol (libpthread, __pthread_cond_signal, pthread_cond_signal,
GLIBC_2_3_2)
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