From f1069a8756b9e9f6c055e709740d2d66650f0fb0 Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 19 May 2021 15:03:08 +0200 Subject: [PATCH] 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 Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/patch-1.thread-1a26be.git-930d1b44844a.your-ad-here.call-01621428935-ext-2104@work.hours Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Miroslav Benes Cc: Borislav Petkov Cc: linux-kernel@vger.kernel.org --- include/linux/compiler.h | 22 ++++++++++++++-------- 1 file 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" \