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7458026b | 1 | /* Thread library support for -fsplit-stack. */ |
8d9254fc | 2 | /* Copyright (C) 2009-2020 Free Software Foundation, Inc. |
7458026b ILT |
3 | Contributed by Ian Lance Taylor <iant@google.com>. |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 3, or (at your option) any later | |
10 | version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | Under Section 7 of GPL version 3, you are granted additional | |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
25 | ||
26 | #include "tconfig.h" | |
27 | #include "tsystem.h" | |
28 | #include "coretypes.h" | |
29 | #include "tm.h" | |
852b75ed | 30 | #include "libgcc_tm.h" |
7458026b | 31 | |
67914693 | 32 | /* If inhibit_libc is defined, we cannot compile this file. The |
7458026b ILT |
33 | effect is that people will not be able to use -fsplit-stack. That |
34 | is much better than failing the build particularly since people | |
35 | will want to define inhibit_libc while building a compiler which | |
36 | can build glibc. */ | |
37 | ||
38 | #ifndef inhibit_libc | |
39 | ||
b5204884 | 40 | #include <errno.h> |
7458026b ILT |
41 | #include <pthread.h> |
42 | ||
43 | #include "generic-morestack.h" | |
44 | ||
45 | /* We declare the pthread functions we need as weak, so that | |
46 | libgcc_s.so does not need to be linked against -lpthread. */ | |
47 | ||
48 | extern int pthread_once (pthread_once_t *, void (*) (void)) | |
49 | __attribute__ ((weak)); | |
50 | ||
51 | extern int pthread_key_create (pthread_key_t *, void (*) (void *)) | |
52 | __attribute__ ((weak)); | |
53 | ||
54 | extern int pthread_setspecific (pthread_key_t, const void *) | |
55 | __attribute__ ((weak)); | |
56 | ||
57 | /* The key for the list of stack segments to free when the thread | |
58 | exits. This is created by pthread_key_create. */ | |
59 | ||
60 | static pthread_key_t segment_list_key; | |
61 | ||
62 | /* Used to only run create_key once. */ | |
63 | ||
64 | static pthread_once_t create_key_once = PTHREAD_ONCE_INIT; | |
65 | ||
66 | /* Release all the segments for a thread. This is the destructor | |
67 | function used by pthread_key_create, and is called when a thread | |
68 | exits. */ | |
69 | ||
70 | static void | |
71 | free_segments (void* arg) | |
72 | { | |
73 | __morestack_release_segments ((struct stack_segment **) arg, 1); | |
74 | } | |
75 | ||
76 | /* Set up the key for the list of segments. This is called via | |
77 | pthread_once. */ | |
78 | ||
79 | static void | |
80 | create_key (void) | |
81 | { | |
82 | int err; | |
83 | ||
84 | err = pthread_key_create (&segment_list_key, free_segments); | |
85 | if (err != 0) | |
86 | { | |
87 | static const char msg[] = "pthread_key_create failed: errno "; | |
88 | __morestack_fail (msg, sizeof msg - 1, err); | |
89 | } | |
90 | } | |
91 | ||
92 | /* Pass information from the pthread_create wrapper to | |
93 | stack_split_initialize_thread. */ | |
94 | ||
95 | struct pthread_create_args | |
96 | { | |
97 | void *(*start_routine) (void *); | |
98 | void *arg; | |
99 | }; | |
100 | ||
101 | /* Initialize a thread. This is called via pthread_create. It calls | |
102 | a target dependent function to set up any required stack guard. */ | |
103 | ||
104 | static void* stack_split_initialize_thread (void *) | |
105 | __attribute__ ((no_split_stack)); | |
106 | ||
107 | static void * | |
108 | stack_split_initialize_thread (void *varg) | |
109 | { | |
110 | struct pthread_create_args *args = (struct pthread_create_args *) varg; | |
111 | int err; | |
112 | void *(*start_routine) (void *); | |
113 | void *arg; | |
114 | ||
115 | __stack_split_initialize (); | |
116 | ||
117 | err = pthread_setspecific (segment_list_key, (void *) &__morestack_segments); | |
118 | if (err != 0) | |
119 | { | |
120 | static const char msg[] = "pthread_setspecific failed: errno "; | |
121 | __morestack_fail (msg, sizeof msg - 1, err); | |
122 | } | |
123 | ||
124 | start_routine = args->start_routine; | |
125 | arg = args->arg; | |
126 | free (args); | |
127 | return (*start_routine) (arg); | |
128 | } | |
129 | ||
130 | /* This function wraps calls to pthread_create to make sure that the | |
131 | stack guard is initialized for new threads. FIXME: This hack will | |
132 | not be necessary if glibc supports -fsplit-stack directly. */ | |
133 | ||
134 | int __wrap_pthread_create (pthread_t *, const pthread_attr_t *, | |
135 | void *(*start_routine) (void *), void *) | |
136 | __attribute__ ((visibility ("hidden"))); | |
137 | ||
138 | extern int __real_pthread_create (pthread_t *, const pthread_attr_t *, | |
4bd18fae ILT |
139 | void *(*start_routine) (void *), void *) |
140 | __attribute__ ((weak)); | |
7458026b ILT |
141 | |
142 | int | |
143 | __wrap_pthread_create (pthread_t *tid, const pthread_attr_t *attr, | |
144 | void *(*start_routine) (void *), void *arg) | |
145 | { | |
146 | int err; | |
147 | struct pthread_create_args* args; | |
148 | ||
149 | err = pthread_once (&create_key_once, create_key); | |
150 | if (err != 0) | |
151 | { | |
152 | static const char msg[] = "pthread_once failed: errno "; | |
153 | __morestack_fail (msg, sizeof msg - 1, err); | |
154 | } | |
155 | ||
156 | args = malloc (sizeof (struct pthread_create_args)); | |
157 | if (args == NULL) | |
158 | return EAGAIN; | |
159 | args->start_routine = start_routine; | |
160 | args->arg = arg; | |
161 | return __real_pthread_create (tid, attr, stack_split_initialize_thread, args); | |
162 | } | |
163 | ||
164 | #endif /* !defined (inhibit_libc) */ |