1 /* Copyright (C) 2002-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
23 #include <kernel-features.h>
26 #include <stap-probe.h>
28 static const struct pthread_mutexattr default_mutexattr
=
30 /* Default is a normal mutex, not shared between processes. */
31 .mutexkind
= PTHREAD_MUTEX_NORMAL
36 prio_inherit_missing (void)
39 # ifndef __ASSUME_FUTEX_LOCK_PI
40 static int tpi_supported
;
41 if (__glibc_unlikely (tpi_supported
== 0))
44 INTERNAL_SYSCALL_DECL (err
);
45 int ret
= INTERNAL_SYSCALL (futex
, err
, 4, &lock
, FUTEX_UNLOCK_PI
, 0, 0);
46 assert (INTERNAL_SYSCALL_ERROR_P (ret
, err
));
47 tpi_supported
= INTERNAL_SYSCALL_ERRNO (ret
, err
) == ENOSYS
? -1 : 1;
49 return __glibc_unlikely (tpi_supported
< 0);
57 __pthread_mutex_init (mutex
, mutexattr
)
58 pthread_mutex_t
*mutex
;
59 const pthread_mutexattr_t
*mutexattr
;
61 const struct pthread_mutexattr
*imutexattr
;
63 assert (sizeof (pthread_mutex_t
) <= __SIZEOF_PTHREAD_MUTEX_T
);
65 imutexattr
= ((const struct pthread_mutexattr
*) mutexattr
66 ?: &default_mutexattr
);
69 switch (__builtin_expect (imutexattr
->mutexkind
70 & PTHREAD_MUTEXATTR_PROTOCOL_MASK
,
72 << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
))
74 case PTHREAD_PRIO_NONE
<< PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
:
77 case PTHREAD_PRIO_INHERIT
<< PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
:
78 if (__glibc_unlikely (prio_inherit_missing ()))
83 /* XXX: For now we don't support robust priority protected mutexes. */
84 if (imutexattr
->mutexkind
& PTHREAD_MUTEXATTR_FLAG_ROBUST
)
89 /* Clear the whole variable. */
90 memset (mutex
, '\0', __SIZEOF_PTHREAD_MUTEX_T
);
92 /* Copy the values from the attribute. */
93 mutex
->__data
.__kind
= imutexattr
->mutexkind
& ~PTHREAD_MUTEXATTR_FLAG_BITS
;
95 if ((imutexattr
->mutexkind
& PTHREAD_MUTEXATTR_FLAG_ROBUST
) != 0)
97 #ifndef __ASSUME_SET_ROBUST_LIST
98 if ((imutexattr
->mutexkind
& PTHREAD_MUTEXATTR_FLAG_PSHARED
) != 0
99 && __set_robust_list_avail
< 0)
103 mutex
->__data
.__kind
|= PTHREAD_MUTEX_ROBUST_NORMAL_NP
;
106 switch (imutexattr
->mutexkind
& PTHREAD_MUTEXATTR_PROTOCOL_MASK
)
108 case PTHREAD_PRIO_INHERIT
<< PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
:
109 mutex
->__data
.__kind
|= PTHREAD_MUTEX_PRIO_INHERIT_NP
;
112 case PTHREAD_PRIO_PROTECT
<< PTHREAD_MUTEXATTR_PROTOCOL_SHIFT
:
113 mutex
->__data
.__kind
|= PTHREAD_MUTEX_PRIO_PROTECT_NP
;
115 int ceiling
= (imutexattr
->mutexkind
116 & PTHREAD_MUTEXATTR_PRIO_CEILING_MASK
)
117 >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT
;
120 if (__sched_fifo_min_prio
== -1)
121 __init_sched_fifo_prio ();
122 if (ceiling
< __sched_fifo_min_prio
)
123 ceiling
= __sched_fifo_min_prio
;
125 mutex
->__data
.__lock
= ceiling
<< PTHREAD_MUTEX_PRIO_CEILING_SHIFT
;
132 /* The kernel when waking robust mutexes on exit never uses
133 FUTEX_PRIVATE_FLAG FUTEX_WAKE. */
134 if ((imutexattr
->mutexkind
& (PTHREAD_MUTEXATTR_FLAG_PSHARED
135 | PTHREAD_MUTEXATTR_FLAG_ROBUST
)) != 0)
136 mutex
->__data
.__kind
|= PTHREAD_MUTEX_PSHARED_BIT
;
138 /* Default values: mutex not used yet. */
139 // mutex->__count = 0; already done by memset
140 // mutex->__owner = 0; already done by memset
141 // mutex->__nusers = 0; already done by memset
142 // mutex->__spins = 0; already done by memset
143 // mutex->__next = NULL; already done by memset
145 LIBC_PROBE (mutex_init
, 1, mutex
);
149 strong_alias (__pthread_mutex_init
, pthread_mutex_init
)
150 hidden_def (__pthread_mutex_init
)