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688903eb | 1 | /* Copyright (C) 2002-2018 Free Software Foundation, Inc. |
76a50749 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. | |
4 | ||
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. | |
9 | ||
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. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
76a50749 UD |
18 | |
19 | #include <assert.h> | |
1bcfb5a5 | 20 | #include <errno.h> |
184ee940 | 21 | #include <stdbool.h> |
76a50749 | 22 | #include <string.h> |
f8de5057 | 23 | #include <kernel-features.h> |
76a50749 | 24 | #include "pthreadP.h" |
cdcb42d7 | 25 | #include <atomic.h> |
dff91cd4 | 26 | #include <pthread-offsets.h> |
76a50749 | 27 | |
5acf7263 RM |
28 | #include <stap-probe.h> |
29 | ||
69854bb5 | 30 | static const struct pthread_mutexattr default_mutexattr = |
76a50749 UD |
31 | { |
32 | /* Default is a normal mutex, not shared between processes. */ | |
33 | .mutexkind = PTHREAD_MUTEX_NORMAL | |
34 | }; | |
35 | ||
36 | ||
184ee940 RM |
37 | static bool |
38 | prio_inherit_missing (void) | |
39 | { | |
40 | #ifdef __NR_futex | |
184ee940 RM |
41 | static int tpi_supported; |
42 | if (__glibc_unlikely (tpi_supported == 0)) | |
43 | { | |
44 | int lock = 0; | |
45 | INTERNAL_SYSCALL_DECL (err); | |
46 | int ret = INTERNAL_SYSCALL (futex, err, 4, &lock, FUTEX_UNLOCK_PI, 0, 0); | |
47 | assert (INTERNAL_SYSCALL_ERROR_P (ret, err)); | |
48 | tpi_supported = INTERNAL_SYSCALL_ERRNO (ret, err) == ENOSYS ? -1 : 1; | |
49 | } | |
50 | return __glibc_unlikely (tpi_supported < 0); | |
df47504c | 51 | #endif |
184ee940 RM |
52 | return true; |
53 | } | |
df47504c | 54 | |
76a50749 | 55 | int |
9dd346ff JM |
56 | __pthread_mutex_init (pthread_mutex_t *mutex, |
57 | const pthread_mutexattr_t *mutexattr) | |
76a50749 UD |
58 | { |
59 | const struct pthread_mutexattr *imutexattr; | |
60 | ||
72b3c6ee AZ |
61 | ASSERT_TYPE_SIZE (pthread_mutex_t, __SIZEOF_PTHREAD_MUTEX_T); |
62 | ||
dff91cd4 AZ |
63 | ASSERT_PTHREAD_INTERNAL_OFFSET (pthread_mutex_t, __data.__nusers, |
64 | __PTHREAD_MUTEX_NUSERS_OFFSET); | |
65 | ASSERT_PTHREAD_INTERNAL_OFFSET (pthread_mutex_t, __data.__kind, | |
66 | __PTHREAD_MUTEX_KIND_OFFSET); | |
67 | ASSERT_PTHREAD_INTERNAL_OFFSET (pthread_mutex_t, __data.__spins, | |
68 | __PTHREAD_MUTEX_SPINS_OFFSET); | |
69 | #if __PTHREAD_MUTEX_LOCK_ELISION | |
70 | ASSERT_PTHREAD_INTERNAL_OFFSET (pthread_mutex_t, __data.__elision, | |
71 | __PTHREAD_MUTEX_ELISION_OFFSET); | |
72 | #endif | |
73 | ASSERT_PTHREAD_INTERNAL_OFFSET (pthread_mutex_t, __data.__list, | |
74 | __PTHREAD_MUTEX_LIST_OFFSET); | |
76a50749 | 75 | |
69854bb5 SP |
76 | imutexattr = ((const struct pthread_mutexattr *) mutexattr |
77 | ?: &default_mutexattr); | |
76a50749 | 78 | |
1bcfb5a5 | 79 | /* Sanity checks. */ |
f3be81a9 UD |
80 | switch (__builtin_expect (imutexattr->mutexkind |
81 | & PTHREAD_MUTEXATTR_PROTOCOL_MASK, | |
82 | PTHREAD_PRIO_NONE | |
83 | << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT)) | |
84 | { | |
85 | case PTHREAD_PRIO_NONE << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: | |
86 | break; | |
87 | ||
df47504c | 88 | case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: |
184ee940 | 89 | if (__glibc_unlikely (prio_inherit_missing ())) |
df47504c | 90 | return ENOTSUP; |
df47504c UD |
91 | break; |
92 | ||
f3be81a9 | 93 | default: |
f17efcb4 UD |
94 | /* XXX: For now we don't support robust priority protected mutexes. */ |
95 | if (imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) | |
96 | return ENOTSUP; | |
97 | break; | |
f3be81a9 | 98 | } |
1bcfb5a5 | 99 | |
76a50749 UD |
100 | /* Clear the whole variable. */ |
101 | memset (mutex, '\0', __SIZEOF_PTHREAD_MUTEX_T); | |
102 | ||
103 | /* Copy the values from the attribute. */ | |
1bcfb5a5 | 104 | mutex->__data.__kind = imutexattr->mutexkind & ~PTHREAD_MUTEXATTR_FLAG_BITS; |
0f6699ea | 105 | |
1bcfb5a5 | 106 | if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_ROBUST) != 0) |
0f6699ea UD |
107 | { |
108 | #ifndef __ASSUME_SET_ROBUST_LIST | |
109 | if ((imutexattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_PSHARED) != 0 | |
110 | && __set_robust_list_avail < 0) | |
111 | return ENOTSUP; | |
112 | #endif | |
113 | ||
114 | mutex->__data.__kind |= PTHREAD_MUTEX_ROBUST_NORMAL_NP; | |
115 | } | |
116 | ||
f3be81a9 | 117 | switch (imutexattr->mutexkind & PTHREAD_MUTEXATTR_PROTOCOL_MASK) |
a5f2bd86 | 118 | { |
f3be81a9 | 119 | case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: |
df47504c | 120 | mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_INHERIT_NP; |
a5f2bd86 | 121 | break; |
f3be81a9 UD |
122 | |
123 | case PTHREAD_PRIO_PROTECT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT: | |
df47504c | 124 | mutex->__data.__kind |= PTHREAD_MUTEX_PRIO_PROTECT_NP; |
f17efcb4 UD |
125 | |
126 | int ceiling = (imutexattr->mutexkind | |
127 | & PTHREAD_MUTEXATTR_PRIO_CEILING_MASK) | |
128 | >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT; | |
129 | if (! ceiling) | |
130 | { | |
cdcb42d7 TR |
131 | /* See __init_sched_fifo_prio. */ |
132 | if (atomic_load_relaxed (&__sched_fifo_min_prio) == -1) | |
f17efcb4 | 133 | __init_sched_fifo_prio (); |
cdcb42d7 TR |
134 | if (ceiling < atomic_load_relaxed (&__sched_fifo_min_prio)) |
135 | ceiling = atomic_load_relaxed (&__sched_fifo_min_prio); | |
f17efcb4 UD |
136 | } |
137 | mutex->__data.__lock = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; | |
a5f2bd86 | 138 | break; |
f3be81a9 | 139 | |
a5f2bd86 RM |
140 | default: |
141 | break; | |
142 | } | |
76a50749 | 143 | |
5bd8a249 UD |
144 | /* The kernel when waking robust mutexes on exit never uses |
145 | FUTEX_PRIVATE_FLAG FUTEX_WAKE. */ | |
146 | if ((imutexattr->mutexkind & (PTHREAD_MUTEXATTR_FLAG_PSHARED | |
147 | | PTHREAD_MUTEXATTR_FLAG_ROBUST)) != 0) | |
148 | mutex->__data.__kind |= PTHREAD_MUTEX_PSHARED_BIT; | |
149 | ||
76a50749 UD |
150 | /* Default values: mutex not used yet. */ |
151 | // mutex->__count = 0; already done by memset | |
61623643 UD |
152 | // mutex->__owner = 0; already done by memset |
153 | // mutex->__nusers = 0; already done by memset | |
2c0b891a | 154 | // mutex->__spins = 0; already done by memset |
1bcfb5a5 | 155 | // mutex->__next = NULL; already done by memset |
76a50749 | 156 | |
5acf7263 RM |
157 | LIBC_PROBE (mutex_init, 1, mutex); |
158 | ||
76a50749 UD |
159 | return 0; |
160 | } | |
fa872e1b | 161 | weak_alias (__pthread_mutex_init, pthread_mutex_init) |
4d17e683 | 162 | hidden_def (__pthread_mutex_init) |