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| author | H.J. Lu <hjl.tools@gmail.com> | 2018-07-24 07:55:35 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2018-07-24 07:55:47 -0700 |
| commit | e27f41ba2b6101be1a511905bff5502ffd23828b (patch) | |
| tree | f7bd74631da12cc22e2dc5f6556a9ea2b45de5f0 /misc | |
| parent | 21526a507df8f1b2e37492193a754534d8938c0b (diff) | |
Add <bits/indirect-return.h>
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.
Diffstat (limited to 'misc')
| -rw-r--r-- | misc/sys/cdefs.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index e80a45ca68..3f6fe3cc85 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -406,6 +406,12 @@ # define __glibc_likely(cond) (cond) #endif +#ifdef __has_attribute +# define __glibc_has_attribute(attr) __has_attribute (attr) +#else +# define __glibc_has_attribute(attr) 0 +#endif + #if (!defined _Noreturn \ && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \ && !__GNUC_PREREQ (4,7)) |