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| author | Vasily Gorbik <gor@linux.ibm.com> | 2021-05-19 15:03:08 +0200 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@redhat.com> | 2021-05-19 15:30:58 -0500 |
| commit | f1069a8756b9e9f6c055e709740d2d66650f0fb0 (patch) | |
| tree | a05c486f47a02a6ab0720321610420f5e9c012f1 /include/linux/compiler.h | |
| parent | 8852c552402979508fdc395ae07aa8761aa46045 (diff) | |
| download | lwn-f1069a8756b9e9f6c055e709740d2d66650f0fb0.tar.gz lwn-f1069a8756b9e9f6c055e709740d2d66650f0fb0.zip | |
compiler.h: Avoid using inline asm operand modifiers
The expansion of annotate_reachable/annotate_unreachable on s390 will
result in a compiler error if the __COUNTER__ value is high enough.
For example with "i" (154) the "%c0" operand of annotate_reachable
will be expanded to -102:
-102:
.pushsection .discard.reachable
.long -102b - .
.popsection
This is a quirk of the gcc backend for s390, it interprets the %c0
as a signed byte value. Avoid using operand modifiers in this case
by simply converting __COUNTER__ to string, with the same result,
but in an arch assembler independent way.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/patch-1.thread-1a26be.git-930d1b44844a.your-ad-here.call-01621428935-ext-2104@work.hours
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index df5b405e6305..77047904cf70 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -115,18 +115,24 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, * 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 volatile("%c0:\n\t" \ +#define __stringify_label(n) #n + +#define __annotate_reachable(c) ({ \ + asm volatile(__stringify_label(c) ":\n\t" \ ".pushsection .discard.reachable\n\t" \ - ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__COUNTER__)); \ + ".long " __stringify_label(c) "b - .\n\t" \ + ".popsection\n\t"); \ }) -#define annotate_unreachable() ({ \ - asm volatile("%c0:\n\t" \ +#define annotate_reachable() __annotate_reachable(__COUNTER__) + +#define __annotate_unreachable(c) ({ \ + asm volatile(__stringify_label(c) ":\n\t" \ ".pushsection .discard.unreachable\n\t" \ - ".long %c0b - .\n\t" \ - ".popsection\n\t" : : "i" (__COUNTER__)); \ + ".long " __stringify_label(c) "b - .\n\t" \ + ".popsection\n\t"); \ }) +#define annotate_unreachable() __annotate_unreachable(__COUNTER__) + #define ASM_UNREACHABLE \ "999:\n\t" \ ".pushsection .discard.unreachable\n\t" \ |