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Separate Linuxisms from lowlevellock.h, make a generic one

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Roland McGrath 2014-07-15 15:23:06 -07:00
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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.

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sysdeps/nptl/lowlevellock-futex.h Normal file
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/* 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 */

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/* 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 */

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/* 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 */