-/* Copyright (C) 2002 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
#include <string.h>
+#include <kernel-features.h>
#include "pthreadP.h"
+#include <atomic.h>
+#include <stap-probe.h>
-static const struct pthread_mutexattr default_attr =
+static const struct pthread_mutexattr default_mutexattr =
{
/* Default is a normal mutex, not shared between processes. */
.mutexkind = PTHREAD_MUTEX_NORMAL
};
+static bool
+prio_inherit_missing (void)
+{
+#ifdef __NR_futex
+ 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 true;
+}
+
int
-__pthread_mutex_init (mutex, mutexattr)
- pthread_mutex_t *mutex;
- const pthread_mutexattr_t *mutexattr;
+__pthread_mutex_init (pthread_mutex_t *mutex,
+ const pthread_mutexattr_t *mutexattr)
{
const struct pthread_mutexattr *imutexattr;
assert (sizeof (pthread_mutex_t) <= __SIZEOF_PTHREAD_MUTEX_T);
- imutexattr = (const struct pthread_mutexattr *) mutexattr ?: &default_attr;
+ imutexattr = ((const struct pthread_mutexattr *) mutexattr
+ ?: &default_mutexattr);
+
+ /* Sanity checks. */
+ switch (__builtin_expect (imutexattr->mutexkind
+ & PTHREAD_MUTEXATTR_PROTOCOL_MASK,
+ PTHREAD_PRIO_NONE
+ << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT))
+ {
+ case PTHREAD_PRIO_NONE << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
+ break;
+
+ case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
+ if (__glibc_unlikely (prio_inherit_missing ()))
+ return ENOTSUP;
+ break;
+
+ default:
+ /* XXX: For now we don't support robust priority protected mutexes. */
+ if (imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST)
+ return ENOTSUP;
+ break;
+ }
/* Clear the whole variable. */
memset (mutex, '\0', __SIZEOF_PTHREAD_MUTEX_T);
/* Copy the values from the attribute. */
- mutex->__data.__kind = imutexattr->mutexkind & ~0x80000000;
+ mutex->__data.__kind = imutexattr->mutexkind & ~PTHREAD_MUTEXATTR_FLAG_BITS;
+
+ if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0)
+ {
+#ifndef __ASSUME_SET_ROBUST_LIST
+ if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0
+ && __set_robust_list_avail < 0)
+ return ENOTSUP;
+#endif
+
+ mutex->__data.__kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP;
+ }
+
+ switch (imutexattr->mutexkind & PTHREAD_MUTEXATTR_PROTOCOL_MASK)
+ {
+ case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
+ mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_INHERIT_NP;
+ break;
+
+ case PTHREAD_PRIO_PROTECT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
+ mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_PROTECT_NP;
+
+ int ceiling = (imutexattr->mutexkind
+ & PTHREAD_MUTEXATTR_PRIO_CEILING_MASK)
+ >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT;
+ if (! ceiling)
+ {
+ /* See __init_sched_fifo_prio. */
+ if (atomic_load_relaxed (&__sched_fifo_min_prio) == -1)
+ __init_sched_fifo_prio ();
+ if (ceiling < atomic_load_relaxed (&__sched_fifo_min_prio))
+ ceiling = atomic_load_relaxed (&__sched_fifo_min_prio);
+ }
+ mutex->__data.__lock = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
+ break;
+
+ default:
+ break;
+ }
+
+ /* The kernel when waking robust mutexes on exit never uses
+ FUTEX_PRIVATE_FLAG FUTEX_WAKE. */
+ if ((imutexattr->mutexkind & (PTHREAD_MUTEXATTR_FLAG_PSHARED
+ | PTHREAD_MUTEXATTR_FLAG_ROBUST)) != 0)
+ mutex->__data.__kind |= PTHREAD_MUTEX_PSHARED_BIT;
/* Default values: mutex not used yet. */
// mutex->__count = 0; already done by memset
- // mutex->__owner = NULL; already done by memset
+ // mutex->__owner = 0; already done by memset
+ // mutex->__nusers = 0; already done by memset
+ // mutex->__spins = 0; already done by memset
+ // mutex->__next = NULL; already done by memset
+
+ LIBC_PROBE (mutex_init, 1, mutex);
return 0;
}
-strong_alias (__pthread_mutex_init, pthread_mutex_init)
+weak_alias (__pthread_mutex_init, pthread_mutex_init)
+hidden_def (__pthread_mutex_init)