/* Copyright (C) 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Paul Mackerras , 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 Libr \ary; 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 #include #include #define __NR_futex 221 #define FUTEX_WAIT 0 #define FUTEX_WAKE 1 /* Initializer for compatibility lock. */ #define LLL_MUTEX_LOCK_INITIALIZER (0) #define lll_futex_wait(futexp, val) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 4, \ (futexp), FUTEX_WAIT, (val), 0); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \ }) #define lll_futex_timed_wait(futexp, val, timespec) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 4, \ (futexp), FUTEX_WAIT, (val), (timespec)); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \ }) #define lll_futex_wake(futexp, nr) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 4, \ (futexp), FUTEX_WAKE, (nr), 0); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \ }) #ifdef UP # define __lll_acq_instr "" # define __lll_rel_instr "" #else # define __lll_acq_instr "isync" # define __lll_rel_instr "sync" #endif /* Set *futex to 1 if it is 0, atomically. Returns the old value */ #define __lll_trylock(futex) \ ({ int __val; \ __asm __volatile ("1: lwarx %0,0,%2\n" \ " cmpwi 0,%0,0\n" \ " bne 2f\n" \ " stwcx. %3,0,%2\n" \ " bne- 1b\n" \ "2: " __lll_acq_instr \ : "=&r" (__val), "=m" (*futex) \ : "r" (futex), "r" (1), "1" (*futex) \ : "cr0", "memory"); \ __val; \ }) #define lll_mutex_trylock(lock) __lll_trylock(&(lock)) /* Add inc to *futex atomically and return the old value. */ #define __lll_add(futex, inc) \ ({ int __val, __tmp; \ __asm __volatile ("1: lwarx %0,0,%3\n" \ " addi %1,%0,%4\n" \ " stwcx. %1,0,%3\n" \ " bne- 1b" \ : "=&b" (__val), "=&r" (__tmp), "=m" (*futex) \ : "r" (futex), "I" (inc), "2" (*futex) \ : "cr0"); \ __val; \ }) /* Atomically store newval and return the old value. */ #define __lll_test_and_set(futex, newval) \ ({ int __val; \ __asm __volatile (__lll_rel_instr "\n" \ "1: lwarx %0,0,%2\n" \ " stwcx. %3,0,%2\n" \ " bne- 1b" \ : "=&r" (__val), "=m" (*futex) \ : "r" (futex), "r" (newval), "1" (*futex) \ : "cr0", "memory"); \ __val; }) extern void __lll_lock_wait (int *futex, int val) attribute_hidden; #define lll_mutex_lock(lock) \ (void) ({ \ int *__futex = &(lock); \ int __val = __lll_add (__futex, 1); \ __asm __volatile (__lll_acq_instr ::: "memory"); \ if (__builtin_expect (__val != 0, 0)) \ __lll_lock_wait (__futex, __val); \ }) extern int __lll_timedlock_wait (int *futex, int val, const struct timespec *) attribute_hidden; #define lll_mutex_timedlock(lock, abstime) \ ({ int *__futex = &(lock); \ int __val = __lll_add (__futex, 1); \ __asm __volatile (__lll_acq_instr ::: "memory"); \ if (__builtin_expect (__val != 0, 0)) \ __val = __lll_timedlock_wait (__futex, __val, (abstime)); \ __val; \ }) #define lll_mutex_unlock(lock) \ ((void) ({ \ int *__futex = &(lock); \ int __val = __lll_test_and_set (__futex, 0); \ if (__builtin_expect (__val > 1, 0)) \ lll_futex_wake (__futex, 1); \ })) #define lll_mutex_islocked(futex) \ (futex != 0) /* Our internal lock implementation is identical to the binary-compatible mutex implementation. */ /* Type for lock object. */ typedef int lll_lock_t; /* Initializers for lock. */ #define LLL_LOCK_INITIALIZER (0) #define LLL_LOCK_INITIALIZER_LOCKED (1) extern int lll_unlock_wake_cb (int *__futex) attribute_hidden; /* The states of a lock are: 0 - untaken 1 - taken by one user >1 - taken by more users */ #define lll_trylock(lock) lll_mutex_trylock (lock) #define lll_lock(lock) lll_mutex_lock (lock) #define lll_unlock(lock) lll_mutex_unlock (lock) #define lll_islocked(lock) lll_mutex_islocked (lock) /* The kernel notifies a process which 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. */ #define lll_wait_tid(tid) \ do { \ __typeof (tid) __tid; \ while ((__tid = (tid)) != 0) \ lll_futex_wait (&(tid), __tid); \ } while (0) extern int __lll_timedwait_tid (int *, const struct timespec *) attribute_hidden; #define lll_timedwait_tid(tid, abstime) \ ({ \ int __res = 0; \ if ((tid) != 0) \ __res = __lll_timedwait_tid (&(tid), (abstime)); \ __res; \ }) /* Decrement *futex if it is > 0, and return the old value */ #define __lll_dec_if_positive(futex) \ ({ int __val, __tmp; \ __asm __volatile ("1: lwarx %0,0,%3\n" \ " cmpwi 0,%0,0\n" \ " addi %1,%0,-1\n" \ " ble 2f\n" \ " stwcx. %1,0,%3\n" \ " bne- 1b\n" \ "2: " __lll_acq_instr \ : "=&b" (__val), "=&r" (__tmp), "=m" (*futex) \ : "r" (futex), "2" (*futex) \ : "cr0"); \ __val; \ }) /* Conditional variable handling. */ extern void __lll_cond_wait (pthread_cond_t *cond) attribute_hidden; extern int __lll_cond_timedwait (pthread_cond_t *cond, const struct timespec *abstime) attribute_hidden; extern void __lll_cond_wake (pthread_cond_t *cond) attribute_hidden; extern void __lll_cond_broadcast (pthread_cond_t *cond) 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 */