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NPTL: Conditionalize direct futex syscall uses.

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This commit is contained in:
Roland McGrath 2014-10-17 14:30:16 -07:00
parent 327ae25707
commit 184ee94010
7 changed files with 62 additions and 22 deletions
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12
ChangeLog
View file

@ -1,5 +1,17 @@
2014-10-17 Roland McGrath <roland@hack.frob.com>
* nptl/nptl-init.c (__pthread_initialize_minimal_internal):
Conditionalize FUTEX_PRIVATE_FLAG and FUTEX_CLOCK_REALTIME probes
on [__NR_futex].
* nptl/pthread_mutex_init.c (prio_inherit_missing): New function,
broken out of ...
(__pthread_mutex_init): ... here. Call it.
* nptl/pthread_mutex_lock.c (__pthread_mutex_lock_full):
Conditionalize PI cases on [__NR_futex].
* nptl/pthread_mutex_timedlock.c (pthread_mutex_timedlock): Likewise.
* nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock): Likewise.
* nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_full): Likewise.
* nptl/nptl-init.c (sighandler_setxid, __xidcmd): Make definitions
conditional on [SIGSETXID].
(sigcancel_handler): Make definition conditional on [SIGCANCEL].

8
nptl/nptl-init.c
View file

@ -329,7 +329,8 @@ __pthread_initialize_minimal_internal (void)
#endif
set_robust_list_not_avail ();
#ifndef __ASSUME_PRIVATE_FUTEX
#ifdef __NR_futex
# ifndef __ASSUME_PRIVATE_FUTEX
/* Private futexes are always used (at least internally) so that
doing the test once this early is beneficial. */
{
@ -345,8 +346,8 @@ __pthread_initialize_minimal_internal (void)
know the former are not supported. This also means we know the
kernel will return ENOSYS for unknown operations. */
if (THREAD_GETMEM (pd, header.private_futex) != 0)
#endif
#ifndef __ASSUME_FUTEX_CLOCK_REALTIME
# endif
# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
{
int word = 0;
/* NB: the syscall actually takes six parameters. The last is the
@ -361,6 +362,7 @@ __pthread_initialize_minimal_internal (void)
if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS)
__set_futex_clock_realtime ();
}
# endif
#endif
/* Set initial thread's stack block from 0 up to __libc_stack_end.

36
nptl/pthread_mutex_init.c
View file

@ -18,6 +18,7 @@
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <string.h>
#include <kernel-features.h>
#include "pthreadP.h"
@ -31,10 +32,26 @@ static const struct pthread_mutexattr default_mutexattr =
};
#ifndef __ASSUME_FUTEX_LOCK_PI
static int tpi_supported;
static bool
prio_inherit_missing (void)
{
#ifdef __NR_futex
# ifndef __ASSUME_FUTEX_LOCK_PI
static int tpi_supported;
if (__glibc_unlikely (tpi_supported == 0))
{
int lock = 0;
INTERNAL_SYSCALL_DECL (err);
int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI, 0, 0);
assert (INTERNAL_SYSCALL_ERROR_P (ret, err));
tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1;
}
return __glibc_unlikely (tpi_supported < 0);
# endif
return false;
#endif
return true;
}
int
__pthread_mutex_init (mutex, mutexattr)
@ -58,19 +75,8 @@ __pthread_mutex_init (mutex, mutexattr)
break;
case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
#ifndef __ASSUME_FUTEX_LOCK_PI
if (__glibc_unlikely (tpi_supported == 0))
{
int lock = 0;
INTERNAL_SYSCALL_DECL (err);
int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI,
0, 0);
assert (INTERNAL_SYSCALL_ERROR_P (ret, err));
tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1;
}
if (__glibc_unlikely (tpi_supported < 0))
if (__glibc_unlikely (prio_inherit_missing ()))
return ENOTSUP;
#endif
break;
default:

13
nptl/pthread_mutex_lock.c
View file

@ -276,6 +276,10 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
/* The PI support requires the Linux futex system call. If that's not
available, pthread_mutex_init should never have allowed the type to
be set. So it will get the default case for an invalid type. */
#ifdef __NR_futex
case PTHREAD_MUTEX_PI_RECURSIVE_NP:
case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
case PTHREAD_MUTEX_PI_NORMAL_NP:
@ -321,9 +325,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
}
int newval = id;
#ifdef NO_INCR
# ifdef NO_INCR
newval |= FUTEX_WAITERS;
#endif
# endif
oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
newval, 0);
@ -377,9 +381,9 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
incremented which is not correct because the old owner
has to be discounted. If we are not supposed to
increment __nusers we actually have to decrement it here. */
#ifdef NO_INCR
# ifdef NO_INCR
--mutex->__data.__nusers;
#endif
# endif
return EOWNERDEAD;
}
@ -409,6 +413,7 @@ __pthread_mutex_lock_full (pthread_mutex_t *mutex)
}
}
break;
#endif /* __NR_futex. */
case PTHREAD_MUTEX_PP_RECURSIVE_NP:
case PTHREAD_MUTEX_PP_ERRORCHECK_NP:

5
nptl/pthread_mutex_timedlock.c
View file

@ -230,6 +230,10 @@ pthread_mutex_timedlock (mutex, abstime)
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
/* The PI support requires the Linux futex system call. If that's not
available, pthread_mutex_init should never have allowed the type to
be set. So it will get the default case for an invalid type. */
#ifdef __NR_futex
case PTHREAD_MUTEX_PI_RECURSIVE_NP:
case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
case PTHREAD_MUTEX_PI_NORMAL_NP:
@ -382,6 +386,7 @@ pthread_mutex_timedlock (mutex, abstime)
}
}
break;
#endif /* __NR_futex. */
case PTHREAD_MUTEX_PP_RECURSIVE_NP:
case PTHREAD_MUTEX_PP_ERRORCHECK_NP:

5
nptl/pthread_mutex_trylock.c
View file

@ -191,6 +191,10 @@ __pthread_mutex_trylock (mutex)
return 0;
/* The PI support requires the Linux futex system call. If that's not
available, pthread_mutex_init should never have allowed the type to
be set. So it will get the default case for an invalid type. */
#ifdef __NR_futex
case PTHREAD_MUTEX_PI_RECURSIVE_NP:
case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
case PTHREAD_MUTEX_PI_NORMAL_NP:
@ -319,6 +323,7 @@ __pthread_mutex_trylock (mutex)
return 0;
}
#endif /* __NR_futex. */
case PTHREAD_MUTEX_PP_RECURSIVE_NP:
case PTHREAD_MUTEX_PP_ERRORCHECK_NP:

5
nptl/pthread_mutex_unlock.c
View file

@ -158,6 +158,10 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
/* The PI support requires the Linux futex system call. If that's not
available, pthread_mutex_init should never have allowed the type to
be set. So it will get the default case for an invalid type. */
#ifdef __NR_futex
case PTHREAD_MUTEX_PI_RECURSIVE_NP:
/* Recursive mutex. */
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
@ -245,6 +249,7 @@ __pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
#endif /* __NR_futex. */
case PTHREAD_MUTEX_PP_RECURSIVE_NP:
/* Recursive mutex. */