diff options
Diffstat (limited to 'sysdeps/x86/bits')
| -rw-r--r-- | sysdeps/x86/bits/indirect-return.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/sysdeps/x86/bits/indirect-return.h b/sysdeps/x86/bits/indirect-return.h new file mode 100644 index 0000000000..d1acaca3b9 --- /dev/null +++ b/sysdeps/x86/bits/indirect-return.h @@ -0,0 +1,37 @@ +/* Definition of __INDIRECT_RETURN. x86 version. + Copyright (C) 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/>. */ + +#ifndef _UCONTEXT_H +# error "Never include <bits/indirect-return.h> directly; use <ucontext.h> instead." +#endif + +/* On x86, swapcontext returns via indirect branch when the shadow stack + is enabled. Define __INDIRECT_RETURN to indicate whether swapcontext + returns via indirect branch. */ +#if defined __CET__ && (__CET__ & 2) != 0 +# if __glibc_has_attribute (__indirect_return__) +# define __INDIRECT_RETURN __attribute__ ((__indirect_return__)) +# else +/* Newer compilers provide the indirect_return attribute, but without + it we can use returns_twice to affect the optimizer in the same + way and avoid unsafe optimizations. */ +# define __INDIRECT_RETURN __attribute__ ((__returns_twice__)) +# endif +#else +# define __INDIRECT_RETURN +#endif |