diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-12-19 11:20:06 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-12-20 14:47:05 -0800 |
| commit | 4cc5373f2e749a6c96e8b9fa971931a4dd852860 (patch) | |
| tree | 60a3d2520d521268ccc7594d1b5865068aff70af | |
| parent | f67e8a5e3ead61692d24a68e30496bd2634f5b68 (diff) | |
clang: work around asm output constraint problems
Work around clang problems with "=rm" asm constraint.
clang seems to always chose the memory output, while it is almost
always the worst choice.
Add ASM_OUTPUT_RM so that we can replace "=rm" constraint
where it matters for clang, while not penalizing gcc.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/compiler-clang.h | 1 | ||||
| -rw-r--r-- | include/linux/compiler_types.h | 3 |
2 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 107ce05bd16e..7edf1a07b535 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -145,6 +145,7 @@ */ #define ASM_INPUT_G "ir" #define ASM_INPUT_RM "r" +#define ASM_OUTPUT_RM "=r" /* * Declare compiler support for __typeof_unqual__() operator. diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 1280693766b9..d3318a3c2577 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -548,11 +548,12 @@ struct ftrace_likely_data { /* * Clang has trouble with constraints with multiple - * alternative behaviors (mainly "g" and "rm"). + * alternative behaviors ("g" , "rm" and "=rm"). */ #ifndef ASM_INPUT_G #define ASM_INPUT_G "g" #define ASM_INPUT_RM "rm" + #define ASM_OUTPUT_RM "=rm" #endif #ifdef CONFIG_CC_HAS_ASM_INLINE |