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Diffstat (limited to 'sysdeps/unix/sysv/linux/mips/lowlevellock.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/mips/lowlevellock.h | 371 |
1 files changed, 371 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/mips/lowlevellock.h b/sysdeps/unix/sysv/linux/mips/lowlevellock.h new file mode 100644 index 0000000000..07467f3790 --- /dev/null +++ b/sysdeps/unix/sysv/linux/mips/lowlevellock.h @@ -0,0 +1,371 @@ +/* Copyright (C) 2003-2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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/>. */ + +#ifndef _LOWLEVELLOCK_H +#define _LOWLEVELLOCK_H 1 + +#include <time.h> +#include <sys/param.h> +#include <bits/pthreadtypes.h> +#include <atomic.h> +#include <sysdep.h> +#include <kernel-features.h> + +#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 !defined NOT_IN_libc || defined 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(futexp, val, private) \ + lll_futex_timed_wait(futexp, val, NULL, private) + +#define lll_futex_timed_wait(futexp, val, timespec, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \ + __lll_private_flag (FUTEX_WAIT, private), \ + (val), (timespec)); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \ + }) + +#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + int __op = FUTEX_WAIT_BITSET | clockbit; \ + __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \ + __lll_private_flag (__op, private), \ + (val), (timespec), NULL /* Unused. */, \ + FUTEX_BITSET_MATCH_ANY); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \ + }) + +#define lll_futex_wake(futexp, nr, private) \ + ({ \ + INTERNAL_SYSCALL_DECL (__err); \ + long int __ret; \ + __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \ + __lll_private_flag (FUTEX_WAKE, private), \ + (nr), 0); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \ + }) + +#define lll_robust_dead(futexv, private) \ + do \ + { \ + int *__futexp = &(futexv); \ + atomic_or (__futexp, FUTEX_OWNER_DIED); \ + lll_futex_wake (__futexp, 1, private); \ + } \ + while (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, (long) (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); \ + long int __ret; \ + int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \ + \ + __ret = INTERNAL_SYSCALL (futex, __err, 5, (futexp), \ + __lll_private_flag (__op, private), \ + (val), (timespec), mutex); \ + INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \ + }) + +#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); \ + }) + +static inline int __attribute__((always_inline)) +__lll_trylock(int *futex) +{ + return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0; +} +#define lll_trylock(lock) __lll_trylock (&(lock)) + + +static inline int __attribute__((always_inline)) +__lll_cond_trylock(int *futex) +{ + return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0; +} +#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock)) + + +static inline int __attribute__((always_inline)) +__lll_robust_trylock(int *futex, int id) +{ + return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0; +} +#define lll_robust_trylock(lock, id) \ + __lll_robust_trylock (&(lock), id) + +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; + +#define __lll_lock(futex, private) \ + ((void) ({ \ + int *__futex = (futex); \ + if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, \ + 1, 0), 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) + + +#define __lll_robust_lock(futex, id, private) \ + ({ \ + int *__futex = (futex); \ + int __val = 0; \ + \ + if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \ + 0), 0)) \ + __val = __lll_robust_lock_wait (__futex, private); \ + __val; \ + }) +#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 (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 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 (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0) + result = __lll_timedlock_wait (futex, abstime, private); + return result; +} +#define lll_timedlock(futex, abstime, private) \ + __lll_timedlock (&(futex), abstime, private) + + +static inline int __attribute__ ((always_inline)) +__lll_robust_timedlock (int *futex, const struct timespec *abstime, + int id, int private) +{ + int result = 0; + if (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 *__futex = (futex); \ + int __val = atomic_exchange_rel (__futex, 0); \ + \ + if (__builtin_expect (__val > 1, 0)) \ + lll_futex_wake (__futex, 1, private); \ + })) +#define lll_unlock(futex, private) __lll_unlock(&(futex), private) + + +#define __lll_robust_unlock(futex, private) \ + ((void) ({ \ + int *__futex = (futex); \ + int __val = atomic_exchange_rel (__futex, 0); \ + \ + if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \ + lll_futex_wake (__futex, 1, private); \ + })) +#define lll_robust_unlock(futex, private) \ + __lll_robust_unlock(&(futex), private) + + +#define lll_islocked(futex) \ + (futex != 0) + + +/* Our internal lock implementation is identical to the binary-compatible + mutex implementation. */ + +/* Initializers for lock. */ +#define LLL_LOCK_INITIALIZER (0) +#define LLL_LOCK_INITIALIZER_LOCKED (1) + +/* The states of a lock are: + 0 - untaken + 1 - taken by one user + >1 - taken by more users */ + +/* 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(tid) \ + do { \ + __typeof (tid) __tid; \ + while ((__tid = (tid)) != 0) \ + lll_futex_wait (&(tid), __tid, LLL_SHARED); \ + } 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; \ + }) + +/* Implement __libc_lock_lock using exchange_and_add, which expands into + a single instruction on XLP processors. We enable this for all MIPS + processors as atomic_exchange_and_add_acq and + atomic_compare_and_exchange_acq take the same time to execute. + This is a simplified expansion of ({ lll_lock (NAME, LLL_PRIVATE); 0; }). + + Note: __lll_lock_wait_private() resets lock value to '2', which prevents + unbounded increase of the lock value and [with billions of threads] + overflow. */ +#define __libc_lock_lock(NAME) \ + ({ \ + int *__futex = &(NAME); \ + if (__builtin_expect (atomic_exchange_and_add_acq (__futex, 1), 0)) \ + __lll_lock_wait_private (__futex); \ + 0; \ + }) + +#ifdef _MIPS_ARCH_XLP +/* The generic version using a single atomic_compare_and_exchange_acq takes + less time for non-XLP processors, so we use below for XLP only. */ +# define __libc_lock_trylock(NAME) \ + ({ \ + int *__futex = &(NAME); \ + int __result = atomic_exchange_and_add_acq (__futex, 1); \ + /* If __result == 0, we succeeded in acquiring the lock. \ + If __result == 1, we switched the lock to 'contended' state, which \ + will cause a [possibly unnecessary] call to lll_futex_wait. This is \ + unlikely, so we accept the possible inefficiency. \ + If __result >= 2, we need to set the lock to 'contended' state to avoid \ + unbounded increase from subsequent trylocks. */ \ + if (__result >= 2) \ + __result = atomic_exchange_acq (__futex, 2); \ + __result; \ + }) +#endif + +#endif /* lowlevellock.h */ |