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+/* Copyright (C) 2002 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _LOWLEVELLOCK_H
+#define _LOWLEVELLOCK_H 1
+
+#include <time.h>
+#include <bits/pthreadtypes.h>
+
+#ifndef LOCK_INSTR
+# ifdef UP
+# define LOCK_INSTR /* nothing */
+# else
+# define LOCK_INSTR "lock;"
+# endif
+#endif
+
+#define SYS_futex 240
+#define FUTEX_WAIT 0
+#define FUTEX_WAKE 1
+
+
+/* Initializer for compatibility lock. */
+#define LLL_MUTEX_LOCK_INITIALIZER (0)
+
+
+/* Does not preserve %eax and %ecx. */
+extern int __lll_mutex_lock_wait (int val, int *__futex)
+ __attribute ((regparm (2))) attribute_hidden;
+/* Does not preserver %eax, %ecx, and %edx. */
+extern int __lll_mutex_timedlock_wait (int val, int *__futex,
+ const struct timespec *abstime)
+ __attribute ((regparm (3))) attribute_hidden;
+/* Preserves all registers but %eax. */
+extern int __lll_mutex_unlock_wait (int *__futex)
+ __attribute ((regparm (1))) attribute_hidden;
+
+
+#define lll_mutex_trylock(futex) \
+ ({ unsigned char ret; \
+ __asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0" \
+ : "=a" (ret), "=m" (futex) \
+ : "r" (1), "1" (futex), "0" (0)); \
+ ret; })
+
+
+#define lll_mutex_lock(futex) \
+ (void) ({ int ignore1, ignore2; \
+ __asm (LOCK_INSTR "xaddl %0, %2\n\t" \
+ "testl %0, %0\n\t" \
+ "jne 1f\n\t" \
+ ".subsection 1\n" \
+ "1:\tleal %2, %%ecx\n\t" \
+ "call __lll_mutex_lock_wait\n\t" \
+ "jmp 2f\n\t" \
+ ".previous\n" \
+ "2:" \
+ : "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
+ : "0" (1), "2" (futex)); })
+
+
+#define lll_mutex_timedlock(futex, timeout) \
+ ({ int result, ignore1, ignore2; \
+ __asm (LOCK_INSTR "xaddl %0, %3\n\t" \
+ "testl %0, %0\n\t" \
+ "jne 1f\n\t" \
+ ".subsection 1\n" \
+ "1:\tleal %3, %%ecx\n\t" \
+ "movl %6, %%edx\n\t" \
+ "call __lll_mutex_timedlock_wait\n\t" \
+ "jmp 2f\n\t" \
+ ".previous\n" \
+ "2:" \
+ : "=a" (result), "=&c" (ignore1), "=&d" (ignore2), "=m" (futex) \
+ : "0" (1), "3" (futex), "m" (timeout)); \
+ result; })
+
+
+#define lll_mutex_unlock(futex) \
+ (void) ({ int ignore; \
+ __asm (LOCK_INSTR "decl %0\n\t" \
+ "jne 1f\n\t" \
+ ".subsection 1\n" \
+ "1:\tleal %0, %%eax\n\t" \
+ "call __lll_mutex_unlock_wake\n\t" \
+ "jmp 2f\n\t" \
+ ".previous\n" \
+ "2:" \
+ : "=m" (futex), "=&a" (ignore) \
+ : "0" (futex)); })
+
+
+#define lll_mutex_islocked(futex) \
+ (futex != 0)
+
+
+/* We have a separate internal lock implementation which is not tied
+ to binary compatibility. */
+
+/* Type for lock object. */
+typedef int lll_lock_t;
+
+/* Initializers for lock. */
+#define LLL_LOCK_INITIALIZER (1)
+#define LLL_LOCK_INITIALIZER_LOCKED (0)
+
+
+extern int __lll_lock_wait (int val, int *__futex)
+ __attribute ((regparm (2))) attribute_hidden;
+extern int __lll_unlock_wake (int *__futex)
+ __attribute ((regparm (1))) attribute_hidden;
+extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
+
+
+/* The states of a lock are:
+ 1 - untaken
+ 0 - taken by one user
+ <0 - taken by more users */
+
+
+#define lll_trylock(futex) \
+ ({ unsigned char ret; \
+ __asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0" \
+ : "=a" (ret), "=m" (futex) \
+ : "r" (0), "1" (futex), "0" (1)); \
+ ret; })
+
+
+#define lll_lock(futex) \
+ (void) ({ int ignore1, ignore2; \
+ __asm (LOCK_INSTR "xaddl %0, %2\n\t" \
+ "jne 1f\n\t" \
+ ".subsection 1\n" \
+ "1:\tleal %2, %%ecx\n\t" \
+ "call __lll_lock_wait\n\t" \
+ "jmp 2f\n\t" \
+ ".previous\n" \
+ "2:" \
+ : "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
+ : "0" (-1), "2" (futex)); })
+
+
+#define lll_unlock(futex) \
+ (void) ({ int ignore; \
+ __asm (LOCK_INSTR "incl %0\n\t" \
+ "jng 1f\n\t" \
+ ".subsection 1\n" \
+ "1:\tleal %0, %%eax\n\t" \
+ "call __lll_unlock_wake\n\t" \
+ "jmp 2f\n\t" \
+ ".previous\n" \
+ "2:" \
+ : "=m" (futex), "=&a" (ignore) \
+ : "0" (futex)); })
+
+
+#define lll_islocked(futex) \
+ (futex != 0)
+
+
+/* The kernel notifies a process with uses CLONE_CLEARTID via futex
+ wakeup when the clone terminates. The memory location contains the
+ thread ID while the clone is running and is reset to zero
+ afterwards.
+
+ The macro parameter must not have any side effect. */
+#ifdef PIC
+# define LLL_TID_EBX_LOAD "xchgl %2, %%ebx\n"
+# define LLL_TID_EBX_REG "D"
+#else
+# define LLL_TID_EBX_LOAD
+# define LLL_TID_EBX_REG "b"
+#endif
+#define lll_wait_tid(tid) \
+ do { \
+ int __ignore; \
+ register __typeof (tid) _tid asm ("edx") = (tid); \
+ if (_tid != 0) \
+ __asm __volatile (LLL_TID_EBX_LOAD \
+ "1:\tmovl %1, %%eax\n\t" \
+ "int $0x80\n\t" \
+ "cmpl $0, (%%ebx)\n\t" \
+ "jne,pn 1b\n\t" \
+ LLL_TID_EBX_LOAD \
+ : "=&a" (__ignore) \
+ : "i" (SYS_futex), LLL_TID_EBX_REG (&tid), "S" (0), \
+ "c" (FUTEX_WAIT), "d" (_tid)); \
+ } while (0)
+
+extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
+ __attribute__ ((regparm (2))) attribute_hidden;
+#define lll_timedwait_tid(tid, abstime) \
+ ({ \
+ int __result = 0; \
+ if (tid != 0) \
+ { \
+ if (abstime == NULL || abstime->tv_nsec >= 1000000000) \
+ __result = EINVAL; \
+ else \
+ __result = __lll_timedwait_tid (&tid, abstime); \
+ } \
+ __result; })
+
+
+#define lll_wake_tid(tid) \
+ do { \
+ int __ignore; \
+ (tid) = 0; \
+ __asm __volatile (LLL_TID_EBX_LOAD \
+ "\tint $0x80\n\t" \
+ LLL_TID_EBX_LOAD \
+ : "=a" (__ignore) \
+ : "0" (SYS_futex), LLL_TID_EBX_REG (&(tid)), "S" (0), \
+ "c" (FUTEX_WAKE), "d" (0x7fffffff)); \
+ } while (0)
+
+
+/* Conditional variable handling. */
+
+extern void __lll_cond_wait (pthread_cond_t *cond)
+ __attribute ((regparm (1))) attribute_hidden;
+extern int __lll_cond_timedwait (pthread_cond_t *cond,
+ const struct timespec *abstime)
+ __attribute ((regparm (2))) attribute_hidden;
+extern void __lll_cond_wake (pthread_cond_t *cond)
+ __attribute ((regparm (1))) attribute_hidden;
+extern void __lll_cond_broadcast (pthread_cond_t *cond)
+ __attribute ((regparm (1))) attribute_hidden;
+
+
+#define lll_cond_wait(cond) \
+ __lll_cond_wait (cond)
+#define lll_cond_timedwait(cond, abstime) \
+ __lll_cond_timedwait (cond, abstime)
+#define lll_cond_wake(cond) \
+ __lll_cond_wake (cond)
+#define lll_cond_broadcast(cond) \
+ __lll_cond_broadcast (cond)
+
+
+#endif /* lowlevellock.h */
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