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[PATCH 1/9][BZ 16892] Add linux-generic lowlevellock.h
- From: Bernard Ogden <bernie dot ogden at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 9 Jun 2014 21:24:46 +0100
- Subject: [PATCH 1/9][BZ 16892] Add linux-generic lowlevellock.h
- Authentication-results: sourceware.org; auth=none
Add linux-generic lowlevellock.h
Based on tile's implementation, with a few changes:
Use INTERNAL_SYSCALL_ERRNO to guarantee that error codes are
positive, then negate it and return. Only applied to the three
functions that actually inspect the error code beyond
compare-to-zero.
Prefer __glibc_unlikely to __builtin_expect, and
atomic_compare_and_exchange_bool_acq to ..._val_acq where
appropriate.
Regards,
Bernie
2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
[BZ #16892]
* sysdeps/unix/sysv/linux/lowlevellock.h: New file.
diff --git a/sysdeps/unix/sysv/linux/lowlevellock.h b/sysdeps/unix/sysv/linux/lowlevellock.h
new file mode 100644
index 0000000..32f249d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/lowlevellock.h
@@ -0,0 +1,335 @@
+/* Copyright (C) 2011-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
+
+ 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, (futexp), \
+ __lll_private_flag (FUTEX_WAIT, private), \
+ (val), (timespec)); \
+ if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
+ __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \
+ __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, (futexp), \
+ __lll_private_flag (__op, private), \
+ (val), (timespec), NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY); \
+ if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
+ __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \
+ __ret; \
+ })
+
+#define lll_futex_wake(futexp, nr, private) \
+ ({ \
+ INTERNAL_SYSCALL_DECL (__err); \
+ long int __ret; \
+ __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
+ __lll_private_flag (FUTEX_WAKE, private), \
+ (nr), 0); \
+ if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
+ __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \
+ __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, (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); \
+ })
+
+#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_bool_acq (futex, 1, 0);
+}
+#define lll_trylock(lock) __lll_trylock (&(lock))
+
+
+static inline int __attribute__ ((always_inline))
+__lll_cond_trylock (int *futex)
+{
+ return atomic_compare_and_exchange_bool_acq (futex, 2, 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_bool_acq (futex, id, 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;
+
+static inline void __attribute__ ((always_inline))
+__lll_lock (int *futex, int private)
+{
+ if (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)
+
+
+static inline int __attribute__ ((always_inline))
+__lll_robust_lock (int *futex, int id, int private)
+{
+ int result = 0;
+ if (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 (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 __oldval = atomic_exchange_rel (__futex, 0); \
+ if (__glibc_unlikely (__oldval > 1)) \
+ 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 __oldval = atomic_exchange_rel (__futex, 0); \
+ if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \
+ lll_futex_wake (__futex, 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 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; \
+ })
+
+#endif /* lowlevellock.h */