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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-26 13:11:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-26 13:11:18 -0800
commitfcbc38b1b296cd38214891fb1fc714d52937d062 (patch)
treecb10b3a1bb13fb1c6e84b743550d48eaf8bfd061 /include
parent844056fd74ebdd826bd23a7d989597e15f478acb (diff)
parenta356d2ae50790f49858ebed35da9e206336fafee (diff)
downloadlinux-fcbc38b1b296cd38214891fb1fc714d52937d062.tar.bz2
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull objtool fixes from Ingo Molnar: "A handful of objtool fixes, most of them related to making the UAPI header-syncing warnings easier to read and easier to act upon" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools/headers: Sync objtool UAPI header objtool: Fix cross-build objtool: Move kernel headers/code sync check to a script objtool: Move synced files to their original relative locations objtool: Make unreachable annotation inline asms explicitly volatile objtool: Add a comment for the unreachable annotation macros
Diffstat (limited to 'include')
-rw-r--r--include/linux/compiler.h21
1 files changed, 13 insertions, 8 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 3672353a0acd..188ed9f65517 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -88,17 +88,22 @@ 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" \
- ".long %c0b - .\n\t" \
- ".popsection\n\t" : : "i" (__COUNTER__)); \
+ asm volatile("%c0:\n\t" \
+ ".pushsection .discard.reachable\n\t" \
+ ".long %c0b - .\n\t" \
+ ".popsection\n\t" : : "i" (__COUNTER__)); \
})
#define annotate_unreachable() ({ \
- asm("%c0:\n\t" \
- ".pushsection .discard.unreachable\n\t" \
- ".long %c0b - .\n\t" \
- ".popsection\n\t" : : "i" (__COUNTER__)); \
+ asm volatile("%c0:\n\t" \
+ ".pushsection .discard.unreachable\n\t" \
+ ".long %c0b - .\n\t" \
+ ".popsection\n\t" : : "i" (__COUNTER__)); \
})
#define ASM_UNREACHABLE \
"999:\n\t" \