/* Copyright (C) 2003-2015 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Martin Schwidefsky , 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 . */ #ifndef _LOWLEVELLOCK_H #define _LOWLEVELLOCK_H 1 #include #include #include #include #include #define SYS_futex 238 #define FUTEX_WAIT 0 #define FUTEX_WAKE 1 #define FUTEX_REQUEUE 3 #define FUTEX_CMP_REQUEUE 4 #define FUTEX_WAKE_OP 5 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1) #define FUTEX_LOCK_PI 6 #define FUTEX_UNLOCK_PI 7 #define FUTEX_TRYLOCK_PI 8 #define FUTEX_WAIT_BITSET 9 #define FUTEX_WAKE_BITSET 10 #define FUTEX_WAIT_REQUEUE_PI 11 #define FUTEX_CMP_REQUEUE_PI 12 #define FUTEX_PRIVATE_FLAG 128 #define FUTEX_CLOCK_REALTIME 256 #define FUTEX_BITSET_MATCH_ANY 0xffffffff /* Values for 'private' parameter of locking macros. Yes, the definition seems to be backwards. But it is not. The bit will be reversed before passing to the system call. */ #define LLL_PRIVATE 0 #define LLL_SHARED FUTEX_PRIVATE_FLAG #if IS_IN (libc) || IS_IN (rtld) /* In libc.so or ld.so all futexes are private. */ # ifdef __ASSUME_PRIVATE_FUTEX # define __lll_private_flag(fl, private) \ ((fl) | FUTEX_PRIVATE_FLAG) # else # define __lll_private_flag(fl, private) \ ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) # endif #else # ifdef __ASSUME_PRIVATE_FUTEX # define __lll_private_flag(fl, private) \ (((fl) | FUTEX_PRIVATE_FLAG) ^ (private)) # else # define __lll_private_flag(fl, private) \ (__builtin_constant_p (private) \ ? ((private) == 0 \ ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \ : (fl)) \ : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \ & THREAD_GETMEM (THREAD_SELF, header.private_futex)))) # endif #endif #define lll_futex_wait(futex, val, private) \ lll_futex_timed_wait (futex, val, NULL, private) #define lll_futex_timed_wait(futexp, val, timespec, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ \ INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ __lll_private_flag (FUTEX_WAIT, private), \ (val), (timespec)); \ }) #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ int __op = FUTEX_WAIT_BITSET | clockbit; \ \ INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (__op, private), \ (val), (timespec), NULL /* Unused. */, \ FUTEX_BITSET_MATCH_ANY); \ }) #define lll_futex_wake(futexp, nr, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ \ INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ __lll_private_flag (FUTEX_WAKE, private), \ (nr), 0); \ }) /* Returns non-zero if error happened, zero if success. */ #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (FUTEX_CMP_REQUEUE, private),\ (nr_wake), (nr_move), (mutex), (val)); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ }) /* Returns non-zero if error happened, zero if success. */ #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (FUTEX_WAKE_OP, private), \ (nr_wake), (nr_wake2), (futexp2), \ FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ }) /* Priority Inheritance support. */ #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \ lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private) #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \ mutex, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \ \ INTERNAL_SYSCALL (futex, __err, 5, (futexp), \ __lll_private_flag (__op, private), \ (val), (timespec), mutex); \ }) #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ \ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\ (nr_wake), (nr_move), (mutex), (val)); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err); \ }) #define lll_compare_and_swap(futex, oldval, newval, operation) \ do { \ __typeof (futex) __futex = (futex); \ __asm __volatile (" l %1,%0\n" \ "0: " operation "\n" \ " cs %1,%2,%0\n" \ " jl 0b\n" \ "1:" \ : "=Q" (*__futex), "=&d" (oldval), "=&d" (newval) \ : "m" (*__futex) : "cc", "memory" ); \ } while (0) static inline int __attribute__ ((always_inline)) __lll_trylock (int *futex) { unsigned int old; __asm __volatile ("cs %0,%3,%1" : "=d" (old), "=Q" (*futex) : "0" (0), "d" (1), "m" (*futex) : "cc", "memory" ); return old != 0; } #define lll_trylock(futex) __lll_trylock (&(futex)) static inline int __attribute__ ((always_inline)) __lll_cond_trylock (int *futex) { unsigned int old; __asm __volatile ("cs %0,%3,%1" : "=d" (old), "=Q" (*futex) : "0" (0), "d" (2), "m" (*futex) : "cc", "memory" ); return old != 0; } #define lll_cond_trylock(futex) __lll_cond_trylock (&(futex)) extern void __lll_lock_wait_private (int *futex) attribute_hidden; extern void __lll_lock_wait (int *futex, int private) attribute_hidden; extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden; static inline void __attribute__ ((always_inline)) __lll_lock (int *futex, int private) { if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0))) { if (__builtin_constant_p (private) && private == LLL_PRIVATE) __lll_lock_wait_private (futex); else __lll_lock_wait (futex, private); } } #define lll_lock(futex, private) __lll_lock (&(futex), private) static inline int __attribute__ ((always_inline)) __lll_robust_lock (int *futex, int id, int private) { int result = 0; if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0), 0)) result = __lll_robust_lock_wait (futex, private); return result; } #define lll_robust_lock(futex, id, private) \ __lll_robust_lock (&(futex), id, private) static inline void __attribute__ ((always_inline)) __lll_cond_lock (int *futex, int private) { if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 2, 0))) __lll_lock_wait (futex, private); } #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private) #define lll_robust_cond_lock(futex, id, private) \ __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private) extern int __lll_timedlock_wait (int *futex, const struct timespec *, int private) attribute_hidden; extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *, int private) attribute_hidden; static inline int __attribute__ ((always_inline)) __lll_timedlock (int *futex, const struct timespec *abstime, int private) { int result = 0; if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0))) result = __lll_timedlock_wait (futex, abstime, private); return result; } #define lll_timedlock(futex, abstime, private) \ __lll_timedlock (&(futex), abstime, private) #ifdef ENABLE_LOCK_ELISION extern int __lll_timedlock_elision (int *futex, short *adapt_count, const struct timespec *timeout, int private) attribute_hidden; # define lll_timedlock_elision(futex, adapt_count, timeout, private) \ __lll_timedlock_elision(&(futex), &(adapt_count), timeout, private) #endif static inline int __attribute__ ((always_inline)) __lll_robust_timedlock (int *futex, const struct timespec *abstime, int id, int private) { int result = 0; if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0), 0)) result = __lll_robust_timedlock_wait (futex, abstime, private); return result; } #define lll_robust_timedlock(futex, abstime, id, private) \ __lll_robust_timedlock (&(futex), abstime, id, private) #define __lll_unlock(futex, private) \ (void) \ ({ int __oldval; \ int __newval = 0; \ int *__futexp = (futex); \ \ lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2"); \ if (__glibc_unlikely (__oldval > 1)) \ lll_futex_wake (__futexp, 1, private); \ }) #define lll_unlock(futex, private) __lll_unlock(&(futex), private) #define __lll_robust_unlock(futex, private) \ (void) \ ({ int __oldval; \ int __newval = 0; \ int *__futexp = (futex); \ \ lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2"); \ if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \ lll_futex_wake (__futexp, 1, private); \ }) #define lll_robust_unlock(futex, private) \ __lll_robust_unlock(&(futex), private) #define lll_islocked(futex) \ (futex != 0) /* Initializers for lock. */ #define LLL_LOCK_INITIALIZER (0) #define LLL_LOCK_INITIALIZER_LOCKED (1) /* The kernel notifies a process which uses CLONE_CHILD_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(ptid) \ do \ { \ int __tid; \ \ while ((__tid = *ptid) != 0) \ lll_futex_wait (ptid, __tid, LLL_SHARED); \ } \ while (0) #define lll_wait_tid(tid) __lll_wait_tid(&(tid)) 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; \ }) #ifdef ENABLE_LOCK_ELISION extern int __lll_lock_elision (int *futex, short *adapt_count, int private) attribute_hidden; extern int __lll_unlock_elision(int *futex, int private) attribute_hidden; extern int __lll_trylock_elision(int *futex, short *adapt_count) attribute_hidden; # define lll_lock_elision(futex, adapt_count, private) \ __lll_lock_elision (&(futex), &(adapt_count), private) # define lll_unlock_elision(futex, private) \ __lll_unlock_elision (&(futex), private) # define lll_trylock_elision(futex, adapt_count) \ __lll_trylock_elision(&(futex), &(adapt_count)) #endif #endif /* lowlevellock.h */