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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2017-11-06 07:17:37 -0600 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-11-07 10:48:22 +0100 |
| commit | d0c2e691d1cbe43662df3a08a4933f13acc352c3 (patch) | |
| tree | 9acca2fce0d50dcac9a56cc486f101b30583e1d3 /include/linux | |
| parent | 783711f0d2458ca1bd716000e767c478cef27144 (diff) | |
| download | linux-d0c2e691d1cbe43662df3a08a4933f13acc352c3.tar.gz linux-d0c2e691d1cbe43662df3a08a4933f13acc352c3.tar.bz2 linux-d0c2e691d1cbe43662df3a08a4933f13acc352c3.zip | |
objtool: Add a comment for the unreachable annotation macros
Add a comment for the unreachable annotation macros to explain their
purpose and the '__COUNTER__' label hack.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1570e48d9f87e0fc6f0126c32e7e1de6e109cb67.1509974104.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/compiler.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 202710420d6d..f8734fca54ce 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -187,6 +187,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, /* Unreachable code */ #ifdef CONFIG_STACK_VALIDATION +/* + * These macros help objtool understand GCC code flow for unreachable code. + * The __COUNTER__ based labels are a hack to make each instance of the macros + * unique, to convince GCC not to merge duplicate inline asm statements. + */ #define annotate_reachable() ({ \ asm("%c0:\n\t" \ ".pushsection .discard.reachable\n\t" \ |