Commit-ID: d0c2e691d1cbe43662df3a08a4933f13acc352c3 Gitweb: https://git.kernel.org/tip/d0c2e691d1cbe43662df3a08a4933f13acc352c3 Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Mon, 6 Nov 2017 07:17:37 -0600 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 7 Nov 2017 10:48:22 +0100
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 <torva...@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/1570e48d9f87e0fc6f0126c32e7e1de6e109cb67.1509974104.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- include/linux/compiler.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 2027104..f8734fc 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" \
