Commit d0c2e691 authored Nov 06, 2017 by Josh Poimboeuf Committed by Ingo Molnar Nov 07, 2017

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>

parent 783711f0

include/linux/compiler.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -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" \