| /* Thread library support for -fsplit-stack. */ |
| /* Copyright (C) 2009-2021 Free Software Foundation, Inc. |
| Contributed by Ian Lance Taylor <iant@google.com>. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "tconfig.h" |
| #include "tsystem.h" |
| #include "coretypes.h" |
| #include "tm.h" |
| #include "libgcc_tm.h" |
| |
| /* If inhibit_libc is defined, we cannot compile this file. The |
| effect is that people will not be able to use -fsplit-stack. That |
| is much better than failing the build particularly since people |
| will want to define inhibit_libc while building a compiler which |
| can build glibc. */ |
| |
| #ifndef inhibit_libc |
| |
| #include <errno.h> |
| #include <signal.h> |
| #include <pthread.h> |
| |
| #include "generic-morestack.h" |
| |
| /* We declare the pthread functions we need as weak, so that |
| libgcc_s.so does not need to be linked against -lpthread. */ |
| |
| extern int pthread_once (pthread_once_t *, void (*) (void)) |
| __attribute__ ((weak)); |
| |
| extern int pthread_key_create (pthread_key_t *, void (*) (void *)) |
| __attribute__ ((weak)); |
| |
| extern int pthread_setspecific (pthread_key_t, const void *) |
| __attribute__ ((weak)); |
| |
| extern int pthread_sigmask (int, const sigset_t *, sigset_t *) |
| __attribute__ ((weak)); |
| |
| /* The key for the list of stack segments to free when the thread |
| exits. This is created by pthread_key_create. */ |
| |
| static pthread_key_t segment_list_key; |
| |
| /* Used to only run create_key once. */ |
| |
| static pthread_once_t create_key_once = PTHREAD_ONCE_INIT; |
| |
| /* Release all the segments for a thread. This is the destructor |
| function used by pthread_key_create, and is called when a thread |
| exits. */ |
| |
| static void |
| free_segments (void* arg) |
| { |
| /* We must block signals in case the signal handler tries to split |
| the stack. We leave them blocked while the thread exits. */ |
| if (pthread_sigmask) |
| { |
| sigset_t mask; |
| |
| sigfillset (&mask); |
| pthread_sigmask (SIG_BLOCK, &mask, NULL); |
| } |
| |
| __morestack_release_segments ((struct stack_segment **) arg, 1); |
| } |
| |
| /* Set up the key for the list of segments. This is called via |
| pthread_once. */ |
| |
| static void |
| create_key (void) |
| { |
| int err; |
| |
| err = pthread_key_create (&segment_list_key, free_segments); |
| if (err != 0) |
| { |
| static const char msg[] = "pthread_key_create failed: errno "; |
| __morestack_fail (msg, sizeof msg - 1, err); |
| } |
| } |
| |
| /* Pass information from the pthread_create wrapper to |
| stack_split_initialize_thread. */ |
| |
| struct pthread_create_args |
| { |
| void *(*start_routine) (void *); |
| void *arg; |
| }; |
| |
| /* Initialize a thread. This is called via pthread_create. It calls |
| a target dependent function to set up any required stack guard. */ |
| |
| static void* stack_split_initialize_thread (void *) |
| __attribute__ ((no_split_stack)); |
| |
| static void * |
| stack_split_initialize_thread (void *varg) |
| { |
| struct pthread_create_args *args = (struct pthread_create_args *) varg; |
| int err; |
| void *(*start_routine) (void *); |
| void *arg; |
| |
| __stack_split_initialize (); |
| |
| err = pthread_setspecific (segment_list_key, (void *) &__morestack_segments); |
| if (err != 0) |
| { |
| static const char msg[] = "pthread_setspecific failed: errno "; |
| __morestack_fail (msg, sizeof msg - 1, err); |
| } |
| |
| start_routine = args->start_routine; |
| arg = args->arg; |
| free (args); |
| return (*start_routine) (arg); |
| } |
| |
| /* This function wraps calls to pthread_create to make sure that the |
| stack guard is initialized for new threads. FIXME: This hack will |
| not be necessary if glibc supports -fsplit-stack directly. */ |
| |
| int __wrap_pthread_create (pthread_t *, const pthread_attr_t *, |
| void *(*start_routine) (void *), void *) |
| __attribute__ ((visibility ("hidden"))); |
| |
| extern int __real_pthread_create (pthread_t *, const pthread_attr_t *, |
| void *(*start_routine) (void *), void *) |
| __attribute__ ((weak)); |
| |
| int |
| __wrap_pthread_create (pthread_t *tid, const pthread_attr_t *attr, |
| void *(*start_routine) (void *), void *arg) |
| { |
| int err; |
| struct pthread_create_args* args; |
| |
| err = pthread_once (&create_key_once, create_key); |
| if (err != 0) |
| { |
| static const char msg[] = "pthread_once failed: errno "; |
| __morestack_fail (msg, sizeof msg - 1, err); |
| } |
| |
| args = malloc (sizeof (struct pthread_create_args)); |
| if (args == NULL) |
| return EAGAIN; |
| args->start_routine = start_routine; |
| args->arg = arg; |
| return __real_pthread_create (tid, attr, stack_split_initialize_thread, args); |
| } |
| |
| #endif /* !defined (inhibit_libc) */ |