1 /* Thread library support for -fsplit-stack. */
2 /* Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
3 Contributed by Ian Lance Taylor <iant@google.com>.
5 This file is part of GCC.
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
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
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.
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/>. */
28 #include "coretypes.h"
31 /* If inhibit_libc is defined, we can not compile this file. The
32 effect is that people will not be able to use -fsplit-stack. That
33 is much better than failing the build particularly since people
34 will want to define inhibit_libc while building a compiler which
42 #include "generic-morestack.h"
44 /* We declare the pthread functions we need as weak, so that
45 libgcc_s.so does not need to be linked against -lpthread. */
47 extern int pthread_once (pthread_once_t *, void (*) (void))
48 __attribute__ ((weak));
50 extern int pthread_key_create (pthread_key_t *, void (*) (void *))
51 __attribute__ ((weak));
53 extern int pthread_setspecific (pthread_key_t, const void *)
54 __attribute__ ((weak));
56 /* The key for the list of stack segments to free when the thread
57 exits. This is created by pthread_key_create. */
59 static pthread_key_t segment_list_key;
61 /* Used to only run create_key once. */
63 static pthread_once_t create_key_once = PTHREAD_ONCE_INIT;
65 /* Release all the segments for a thread. This is the destructor
66 function used by pthread_key_create, and is called when a thread
70 free_segments (void* arg)
72 __morestack_release_segments ((struct stack_segment **) arg, 1);
75 /* Set up the key for the list of segments. This is called via
83 err = pthread_key_create (&segment_list_key, free_segments);
86 static const char msg[] = "pthread_key_create failed: errno ";
87 __morestack_fail (msg, sizeof msg - 1, err);
91 /* Pass information from the pthread_create wrapper to
92 stack_split_initialize_thread. */
94 struct pthread_create_args
96 void *(*start_routine) (void *);
100 /* Initialize a thread. This is called via pthread_create. It calls
101 a target dependent function to set up any required stack guard. */
103 static void* stack_split_initialize_thread (void *)
104 __attribute__ ((no_split_stack));
107 stack_split_initialize_thread (void *varg)
109 struct pthread_create_args *args = (struct pthread_create_args *) varg;
111 void *(*start_routine) (void *);
114 __stack_split_initialize ();
116 err = pthread_setspecific (segment_list_key, (void *) &__morestack_segments);
119 static const char msg[] = "pthread_setspecific failed: errno ";
120 __morestack_fail (msg, sizeof msg - 1, err);
123 start_routine = args->start_routine;
126 return (*start_routine) (arg);
129 /* This function wraps calls to pthread_create to make sure that the
130 stack guard is initialized for new threads. FIXME: This hack will
131 not be necessary if glibc supports -fsplit-stack directly. */
133 int __wrap_pthread_create (pthread_t *, const pthread_attr_t *,
134 void *(*start_routine) (void *), void *)
135 __attribute__ ((visibility ("hidden")));
137 extern int __real_pthread_create (pthread_t *, const pthread_attr_t *,
138 void *(*start_routine) (void *), void *)
139 __attribute__ ((weak));
142 __wrap_pthread_create (pthread_t *tid, const pthread_attr_t *attr,
143 void *(*start_routine) (void *), void *arg)
146 struct pthread_create_args* args;
148 err = pthread_once (&create_key_once, create_key);
151 static const char msg[] = "pthread_once failed: errno ";
152 __morestack_fail (msg, sizeof msg - 1, err);
155 args = malloc (sizeof (struct pthread_create_args));
158 args->start_routine = start_routine;
160 return __real_pthread_create (tid, attr, stack_split_initialize_thread, args);
163 #endif /* !defined (inhibit_libc) */