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x86/asm: Make objtool unreachable macros independent from GCC version

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The ASM_UNREACHABLE macro isn't GCC version-specific, so move it outside
the GCC 4.5+ check.  Otherwise the 0-day robot will report objtool
warnings for uses of ASM_UNREACHABLE with GCC 4.4.

Also move the annotate_unreachable() macro so the related macros can
stay together.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: aa5d1b8150 ("x86/asm: Add ASM_UNREACHABLE")
Link: http://lkml.kernel.org/r/fb18337dbf230fd36450d9faf19a2b2533dbcba1.1500993873.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Josh Poimboeuf 2017-07-25 09:44:51 -05:00 committed by Ingo Molnar
parent aa5d1b8150
commit 1ee6f00d11
1 changed files with 16 additions and 16 deletions
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32
include/linux/compiler-gcc.h
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@ -128,6 +128,22 @@
#define __always_unused __attribute__((unused))
#define __mode(x) __attribute__((mode(x)))
#ifdef CONFIG_STACK_VALIDATION
#define annotate_unreachable() ({ \
asm("%c0:\n\t" \
".pushsection .discard.unreachable\n\t" \
".long %c0b - .\n\t" \
".popsection\n\t" : : "i" (__LINE__)); \
})
#define ASM_UNREACHABLE \
"999:\n\t" \
".pushsection .discard.unreachable\n\t" \
".long 999b - .\n\t" \
".popsection\n\t"
#else
#define annotate_unreachable()
#endif
/* gcc version specific checks */
#if GCC_VERSION < 30200
@ -201,22 +217,6 @@
#endif
#endif
#ifdef CONFIG_STACK_VALIDATION
#define annotate_unreachable() ({ \
asm("%c0:\n\t" \
".pushsection .discard.unreachable\n\t" \
".long %c0b - .\n\t" \
".popsection\n\t" : : "i" (__LINE__)); \
})
#define ASM_UNREACHABLE \
"999:\n\t" \
".pushsection .discard.unreachable\n\t" \
".long 999b - .\n\t" \
".popsection\n\t"
#else
#define annotate_unreachable()
#endif
/*
* Mark a position in code as unreachable. This can be used to
* suppress control flow warnings after asm blocks that transfer