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>
---
include/linux/compiler.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 3672353a0acd..b863e5ad91a3 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -88,6 +88,11 @@ 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" \
--
2.13.6
