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2002-12-04 Ulrich Drepper <drepper@redhat.com> * sysdeps/unix/sysv/linux/i386/lowlevellock.h: Mark asms as volatile and add memory clobbers to lock operations.
266 lines
8.3 KiB
C
266 lines
8.3 KiB
C
/* Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#ifndef _LOWLEVELLOCK_H
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#define _LOWLEVELLOCK_H 1
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#include <time.h>
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#include <bits/pthreadtypes.h>
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#ifndef LOCK_INSTR
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# ifdef UP
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# define LOCK_INSTR /* nothing */
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# else
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# define LOCK_INSTR "lock;"
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# endif
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#endif
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#define SYS_futex 240
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#define FUTEX_WAIT 0
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#define FUTEX_WAKE 1
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/* Initializer for compatibility lock. */
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#define LLL_MUTEX_LOCK_INITIALIZER (0)
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/* Does not preserve %eax and %ecx. */
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extern int __lll_mutex_lock_wait (int val, int *__futex)
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__attribute ((regparm (2))) attribute_hidden;
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/* Does not preserver %eax, %ecx, and %edx. */
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extern int __lll_mutex_timedlock_wait (int val, int *__futex,
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const struct timespec *abstime)
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__attribute ((regparm (3))) attribute_hidden;
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/* Preserves all registers but %eax. */
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extern int __lll_mutex_unlock_wait (int *__futex)
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__attribute ((regparm (1))) attribute_hidden;
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#define lll_mutex_trylock(futex) \
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({ unsigned char ret; \
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__asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0" \
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: "=a" (ret), "=m" (futex) \
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: "r" (1), "1" (futex), "0" (0) \
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: "memory"); \
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ret; })
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#define lll_mutex_lock(futex) \
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(void) ({ int ignore1, ignore2; \
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__asm __volatile (LOCK_INSTR "xaddl %0, %2\n\t" \
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"testl %0, %0\n\t" \
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"jne 1f\n\t" \
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".subsection 1\n" \
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"1:\tleal %2, %%ecx\n\t" \
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"call __lll_mutex_lock_wait\n\t" \
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"jmp 2f\n\t" \
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".previous\n" \
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"2:" \
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: "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
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: "0" (1), "2" (futex) \
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: "memory"); })
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#define lll_mutex_timedlock(futex, timeout) \
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({ int result, ignore1, ignore2; \
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__asm __volatile (LOCK_INSTR "xaddl %0, %3\n\t" \
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"testl %0, %0\n\t" \
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"jne 1f\n\t" \
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".subsection 1\n" \
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"1:\tleal %3, %%ecx\n\t" \
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"movl %6, %%edx\n\t" \
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"call __lll_mutex_timedlock_wait\n\t" \
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"jmp 2f\n\t" \
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".previous\n" \
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"2:" \
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: "=a" (result), "=&c" (ignore1), "=&d" (ignore2), \
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"=m" (futex) \
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: "0" (1), "3" (futex), "m" (timeout) \
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: "memory"); \
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result; })
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#define lll_mutex_unlock(futex) \
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(void) ({ int ignore; \
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__asm __volatile (LOCK_INSTR "decl %0\n\t" \
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"jne 1f\n\t" \
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".subsection 1\n" \
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"1:\tleal %0, %%eax\n\t" \
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"call __lll_mutex_unlock_wake\n\t" \
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"jmp 2f\n\t" \
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".previous\n" \
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"2:" \
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: "=m" (futex), "=&a" (ignore) \
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: "0" (futex) \
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: "memory"); })
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#define lll_mutex_islocked(futex) \
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(futex != 0)
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/* We have a separate internal lock implementation which is not tied
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to binary compatibility. */
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/* Type for lock object. */
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typedef int lll_lock_t;
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/* Initializers for lock. */
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#define LLL_LOCK_INITIALIZER (1)
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#define LLL_LOCK_INITIALIZER_LOCKED (0)
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extern int __lll_lock_wait (int val, int *__futex)
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__attribute ((regparm (2))) attribute_hidden;
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extern int __lll_unlock_wake (int *__futex)
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__attribute ((regparm (1))) attribute_hidden;
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extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
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/* The states of a lock are:
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1 - untaken
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0 - taken by one user
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<0 - taken by more users */
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#define lll_trylock(futex) \
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({ unsigned char ret; \
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__asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0" \
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: "=a" (ret), "=m" (futex) \
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: "r" (0), "1" (futex), "0" (1) \
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: "memory"); \
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ret; })
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#define lll_lock(futex) \
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(void) ({ int ignore1, ignore2; \
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__asm __volatile (LOCK_INSTR "xaddl %0, %2\n\t" \
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"jne 1f\n\t" \
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".subsection 1\n" \
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"1:\tleal %2, %%ecx\n\t" \
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"call __lll_lock_wait\n\t" \
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"jmp 2f\n\t" \
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".previous\n" \
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"2:" \
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: "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
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: "0" (-1), "2" (futex) \
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: "memory"); })
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#define lll_unlock(futex) \
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(void) ({ int ignore; \
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__asm __volatile (LOCK_INSTR "incl %0\n\t" \
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"jng 1f\n\t" \
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".subsection 1\n" \
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"1:\tleal %0, %%eax\n\t" \
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"call __lll_unlock_wake\n\t" \
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"jmp 2f\n\t" \
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".previous\n" \
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"2:" \
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: "=m" (futex), "=&a" (ignore) \
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: "0" (futex) \
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: "memory"); })
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#define lll_islocked(futex) \
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(futex != 0)
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/* The kernel notifies a process with uses CLONE_CLEARTID via futex
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wakeup when the clone terminates. The memory location contains the
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thread ID while the clone is running and is reset to zero
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afterwards.
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The macro parameter must not have any side effect. */
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#ifdef PIC
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# define LLL_TID_EBX_LOAD "xchgl %2, %%ebx\n"
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# define LLL_TID_EBX_REG "D"
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#else
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# define LLL_TID_EBX_LOAD
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# define LLL_TID_EBX_REG "b"
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#endif
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#define lll_wait_tid(tid) \
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do { \
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int __ignore; \
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register __typeof (tid) _tid asm ("edx") = (tid); \
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if (_tid != 0) \
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__asm __volatile (LLL_TID_EBX_LOAD \
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"1:\tmovl %1, %%eax\n\t" \
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"int $0x80\n\t" \
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"cmpl $0, (%%ebx)\n\t" \
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"jne,pn 1b\n\t" \
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LLL_TID_EBX_LOAD \
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: "=&a" (__ignore) \
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: "i" (SYS_futex), LLL_TID_EBX_REG (&tid), "S" (0), \
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"c" (FUTEX_WAIT), "d" (_tid)); \
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} while (0)
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extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
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__attribute__ ((regparm (2))) attribute_hidden;
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#define lll_timedwait_tid(tid, abstime) \
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({ \
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int __result = 0; \
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if (tid != 0) \
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{ \
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if (abstime == NULL || abstime->tv_nsec >= 1000000000) \
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__result = EINVAL; \
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else \
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__result = __lll_timedwait_tid (&tid, abstime); \
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} \
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__result; })
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#define lll_wake_tid(tid) \
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do { \
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int __ignore; \
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(tid) = 0; \
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__asm __volatile (LLL_TID_EBX_LOAD \
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"\tint $0x80\n\t" \
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LLL_TID_EBX_LOAD \
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: "=a" (__ignore) \
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: "0" (SYS_futex), LLL_TID_EBX_REG (&(tid)), "S" (0), \
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"c" (FUTEX_WAKE), "d" (0x7fffffff)); \
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} while (0)
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/* Conditional variable handling. */
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extern void __lll_cond_wait (pthread_cond_t *cond)
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__attribute ((regparm (1))) attribute_hidden;
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extern int __lll_cond_timedwait (pthread_cond_t *cond,
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const struct timespec *abstime)
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__attribute ((regparm (2))) attribute_hidden;
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extern void __lll_cond_wake (pthread_cond_t *cond)
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__attribute ((regparm (1))) attribute_hidden;
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extern void __lll_cond_broadcast (pthread_cond_t *cond)
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__attribute ((regparm (1))) attribute_hidden;
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#define lll_cond_wait(cond) \
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__lll_cond_wait (cond)
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#define lll_cond_timedwait(cond, abstime) \
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__lll_cond_timedwait (cond, abstime)
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#define lll_cond_wake(cond) \
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__lll_cond_wake (cond)
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#define lll_cond_broadcast(cond) \
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__lll_cond_broadcast (cond)
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#endif /* lowlevellock.h */
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