From e27f41ba2b6101be1a511905bff5502ffd23828b Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 24 Jul 2018 07:55:35 -0700 Subject: Add MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add and include it in . __INDIRECT_RETURN defined in 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 * 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 . (swapcontext): Add __INDIRECT_RETURN. * string/tst-xbzero-opt.c (ALWAYS_INLINE): New. (prepare_test_buffer): Use it. --- misc/sys/cdefs.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'misc') 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)) -- cgit 1.4.1