2014-07-15 Roland McGrath <roland@hack.frob.com>
+ * sysdeps/nptl/lowlevellock.h: New file.
+ * sysdeps/unix/sysv/linux/lowlevellock-futex.h: New file.
+ * sysdeps/nptl/lowlevellock-futex.h: New file.
+
* nptl/pthreadP.h (__current_sigrtmin, __current_sigrtmax):
Remove dead declarations.
--- /dev/null
+/* Low-level locking access to futex facilities. Stub version.
+ Copyright (C) 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_FUTEX_H
+#define _LOWLEVELLOCK_FUTEX_H 1
+
+#include <errno.h>
+
+
+/* Values for 'private' parameter of locking macros. Note pthreadP.h
+ optimizes for these exact values, though they are not required. */
+#define LLL_PRIVATE 0
+#define LLL_SHARED 128
+
+
+/* For most of these macros, the return value is never really used.
+ Nevertheless, the protocol is that each one returns a negated errno
+ code for failure or zero for success. (Note that the corresponding
+ Linux system calls can sometimes return positive values for success
+ cases too. We never use those values.) */
+
+
+/* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP. */
+#define lll_futex_wait(futexp, val, private) \
+ lll_futex_timed_wait (futexp, val, NULL, private)
+
+/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses. */
+#define lll_futex_timed_wait(futexp, val, timeout, private) \
+ -ENOSYS
+
+/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
+ If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
+ If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
+ TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC. */
+#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
+ -ENOSYS
+
+/* Wake up up to NR waiters on FUTEXP. */
+#define lll_futex_wake(futexp, nr, private) \
+ -ENOSYS
+
+/* Wake up up to NR_WAKE waiters on FUTEXP. Move up to NR_MOVE of the
+ rest from waiting on FUTEXP to waiting on MUTEX (a different futex). */
+#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
+ -ENOSYS
+
+/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2. */
+#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
+ -ENOSYS
+
+
+/* Like lll_futex_wait (FUTEXP, VAL, PRIVATE) but with the expectation
+ that lll_futex_cmp_requeue_pi (FUTEXP, _, _, MUTEX, _, PRIVATE) will
+ be used to do the wakeup. Confers priority-inheritance behavior on
+ the waiter. */
+#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
+ lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
+
+/* Like lll_futex_wait_requeue_pi, but with a timeout. */
+#define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \
+ mutex, private) \
+ -ENOSYS
+
+/* Like lll_futex_requeue, but pairs with lll_futex_wait_requeue_pi
+ and inherits priority from the waiter. */
+#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, \
+ val, private) \
+ -ENOSYS
+
+
+#endif /* lowlevellock-futex.h */
--- /dev/null
+/* Low-level lock implementation. Generic futex-based version.
+ Copyright (C) 2005-2014 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 <atomic.h>
+#include <lowlevellock-futex.h>
+
+#define lll_trylock(lock) \
+ atomic_compare_and_exchange_bool_acq (&(lock), 1, 0)
+
+#define lll_cond_trylock(lock) \
+ atomic_compare_and_exchange_bool_acq (&(lock), 2, 0)
+
+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;
+
+/* This is an expression rather than a statement even though its value is
+ void, so that it can be used in a comma expression or as an expression
+ that's cast to void. */
+#define __lll_lock(futex, private) \
+ ((void) \
+ ({ \
+ int *__futex = (futex); \
+ 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)
+
+
+#define __lll_robust_lock(futex, id, private) \
+ ({ \
+ int *__futex = (futex); \
+ int __val = 0; \
+ \
+ if (__glibc_unlikely \
+ (atomic_compare_and_exchange_bool_acq (__futex, id, 0))) \
+ __val = __lll_robust_lock_wait (__futex, private); \
+ __val; \
+ })
+#define lll_robust_lock(futex, id, private) \
+ __lll_robust_lock (&(futex), id, private)
+
+
+/* This is an expression rather than a statement even though its value is
+ void, so that it can be used in a comma expression or as an expression
+ that's cast to void. */
+#define __lll_cond_lock(futex, private) \
+ ((void) \
+ ({ \
+ int *__futex = (futex); \
+ if (__glibc_unlikely (atomic_exchange_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;
+
+#define __lll_timedlock(futex, abstime, private) \
+ ({ \
+ int *__futex = (futex); \
+ int __val = 0; \
+ \
+ if (__glibc_unlikely (atomic_exchange_acq (__futex, 1))) \
+ __val = __lll_timedlock_wait (__futex, abstime, private); \
+ __val; \
+ })
+#define lll_timedlock(futex, abstime, private) \
+ __lll_timedlock (&(futex), abstime, private)
+
+
+#define __lll_robust_timedlock(futex, abstime, id, private) \
+ ({ \
+ int *__futex = (futex); \
+ int __val = 0; \
+ \
+ if (__glibc_unlikely \
+ (atomic_compare_and_exchange_bool_acq (__futex, id, 0))) \
+ __val = __lll_robust_timedlock_wait (__futex, abstime, private); \
+ __val; \
+ })
+#define lll_robust_timedlock(futex, abstime, id, private) \
+ __lll_robust_timedlock (&(futex), abstime, id, private)
+
+
+/* This is an expression rather than a statement even though its value is
+ void, so that it can be used in a comma expression or as an expression
+ that's cast to void. */
+#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)
+
+
+/* This is an expression rather than a statement even though its value is
+ void, so that it can be used in a comma expression or as an expression
+ that's cast to void. */
+#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) != LLL_LOCK_INITIALIZER)
+
+
+/* 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; \
+ })
+
+
+#endif /* lowlevellock.h */
--- /dev/null
+/* Low-level locking access to futex facilities. Linux version.
+ Copyright (C) 2005-2014 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_FUTEX_H
+#define _LOWLEVELLOCK_FUTEX_H 1
+
+#include <sysdep.h>
+#include <tls.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_syscall(nargs, futexp, op, ...) \
+ ({ \
+ INTERNAL_SYSCALL_DECL (__err); \
+ long int __ret = INTERNAL_SYSCALL (futex, __err, nargs, futexp, op, \
+ __VA_ARGS__); \
+ (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
+ ? -INTERNAL_SYSCALL_ERRNO (__ret, __err) : 0); \
+ })
+
+#define lll_futex_wait(futexp, val, private) \
+ lll_futex_timed_wait (futexp, val, NULL, private)
+
+#define lll_futex_timed_wait(futexp, val, timeout, private) \
+ lll_futex_syscall (4, futexp, \
+ __lll_private_flag (FUTEX_WAIT, private), \
+ val, timeout)
+
+#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
+ lll_futex_syscall (6, futexp, \
+ __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
+ private), \
+ val, timeout, NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY)
+
+#define lll_futex_wake(futexp, nr, private) \
+ lll_futex_syscall (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) \
+ lll_futex_syscall (6, futexp, \
+ __lll_private_flag (FUTEX_CMP_REQUEUE, private), \
+ nr_wake, nr_move, mutex, val)
+
+/* Returns non-zero if error happened, zero if success. */
+#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
+ lll_futex_syscall (6, futexp, \
+ __lll_private_flag (FUTEX_WAKE_OP, private), \
+ nr_wake, nr_wake2, futexp2, \
+ FUTEX_OP_CLEAR_WAKE_IF_GT_ONE)
+
+/* 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, timeout, clockbit, \
+ mutex, private) \
+ lll_futex_syscall (5, futexp, \
+ __lll_private_flag (FUTEX_WAIT_REQUEUE_PI \
+ | (clockbit), private), \
+ val, timeout, mutex)
+
+
+#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, \
+ val, private) \
+ lll_futex_syscall (6, futexp, \
+ __lll_private_flag (FUTEX_CMP_REQUEUE_PI, \
+ private), \
+ nr_wake, nr_move, mutex, val)
+
+
+#endif /* lowlevellock-futex.h */
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