mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-09 04:11:27 +08:00
e27f41ba2b
Add <bits/indirect-return.h> and include it in <ucontext.h>. __INDIRECT_RETURN defined in <bits/indirect-return.h> indicates if swapcontext requires special compiler treatment. The default __INDIRECT_RETURN is empty. On x86, when shadow stack is enabled, __INDIRECT_RETURN is defined with indirect_return attribute, which has been added to GCC 9, to indicate that swapcontext returns via indirect branch. Otherwise __INDIRECT_RETURN is defined with returns_twice attribute. When shadow stack is enabled, remove always_inline attribute from prepare_test_buffer in string/tst-xbzero-opt.c to avoid: tst-xbzero-opt.c: In function ‘prepare_test_buffer’: tst-xbzero-opt.c:105:1: error: function ‘prepare_test_buffer’ can never be inlined because it uses setjmp prepare_test_buffer (unsigned char *buf) when indirect_return attribute isn't available. Reviewed-by: Carlos O'Donell <carlos@redhat.com> * bits/indirect-return.h: New file. * misc/sys/cdefs.h (__glibc_has_attribute): New. * sysdeps/x86/bits/indirect-return.h: Likewise. * stdlib/Makefile (headers): Add bits/indirect-return.h. * stdlib/ucontext.h: Include <bits/indirect-return.h>. (swapcontext): Add __INDIRECT_RETURN. * string/tst-xbzero-opt.c (ALWAYS_INLINE): New. (prepare_test_buffer): Use it.
57 lines
2.0 KiB
C
57 lines
2.0 KiB
C
/* Copyright (C) 1997-2018 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* System V ABI compliant user-level context switching support. */
|
|
|
|
#ifndef _UCONTEXT_H
|
|
#define _UCONTEXT_H 1
|
|
|
|
#include <features.h>
|
|
|
|
/* Get definition of __INDIRECT_RETURN. */
|
|
#include <bits/indirect-return.h>
|
|
|
|
/* Get machine dependent definition of data structures. */
|
|
#include <sys/ucontext.h>
|
|
|
|
__BEGIN_DECLS
|
|
|
|
/* Get user context and store it in variable pointed to by UCP. */
|
|
extern int getcontext (ucontext_t *__ucp) __THROWNL;
|
|
|
|
/* Set user context from information of variable pointed to by UCP. */
|
|
extern int setcontext (const ucontext_t *__ucp) __THROWNL;
|
|
|
|
/* Save current context in context variable pointed to by OUCP and set
|
|
context from variable pointed to by UCP. */
|
|
extern int swapcontext (ucontext_t *__restrict __oucp,
|
|
const ucontext_t *__restrict __ucp)
|
|
__THROWNL __INDIRECT_RETURN;
|
|
|
|
/* Manipulate user context UCP to continue with calling functions FUNC
|
|
and the ARGC-1 parameters following ARGC when the context is used
|
|
the next time in `setcontext' or `swapcontext'.
|
|
|
|
We cannot say anything about the parameters FUNC takes; `void'
|
|
is as good as any other choice. */
|
|
extern void makecontext (ucontext_t *__ucp, void (*__func) (void),
|
|
int __argc, ...) __THROW;
|
|
|
|
__END_DECLS
|
|
|
|
#endif /* ucontext.h */
|