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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 /stdlib | |
| 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 'stdlib')
| -rw-r--r-- | stdlib/Makefile | 2 | ||||
| -rw-r--r-- | stdlib/ucontext.h | 6 |
2 files changed, 6 insertions, 2 deletions
diff --git a/stdlib/Makefile b/stdlib/Makefile index 808a8ceab7..b5e55b0a55 100644 --- a/stdlib/Makefile +++ b/stdlib/Makefile @@ -26,7 +26,7 @@ headers := stdlib.h bits/stdlib.h bits/stdlib-ldbl.h bits/stdlib-float.h \ monetary.h bits/monetary-ldbl.h \ inttypes.h stdint.h bits/wordsize.h \ errno.h sys/errno.h bits/errno.h bits/types/error_t.h \ - ucontext.h sys/ucontext.h \ + ucontext.h sys/ucontext.h bits/indirect-return.h \ alloca.h fmtmsg.h \ bits/stdlib-bsearch.h sys/random.h bits/stdint-intn.h \ bits/stdint-uintn.h diff --git a/stdlib/ucontext.h b/stdlib/ucontext.h index eec7611631..ec630038f6 100644 --- a/stdlib/ucontext.h +++ b/stdlib/ucontext.h @@ -22,6 +22,9 @@ #include <features.h> +/* Get definition of __INDIRECT_RETURN. */ +#include <bits/indirect-return.h> + /* Get machine dependent definition of data structures. */ #include <sys/ucontext.h> @@ -36,7 +39,8 @@ 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; + 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 |