From: Linus Torvalds Date: Mon, 29 Sep 2025 15:54:12 +0000 (-0700) Subject: Fix CC_HAS_ASM_GOTO_OUTPUT on non-x86 architectures X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fde0ab43b9a30d08817adc5402b69fec83a61cb8;p=thirdparty%2Fkernel%2Fstable.git Fix CC_HAS_ASM_GOTO_OUTPUT on non-x86 architectures There's a silly problem with the CC_HAS_ASM_GOTO_OUTPUT test: even with a working compiler it will fail on some architectures simply because it uses the mnemonic "jmp" for testing the inline asm. And as reported by Geert, not all architectures use that mnemonic, so the test fails spuriously on such platforms (including arm and riscv, but also several other architectures). This issue avoided any obvious test failures because the build still works thanks to falling back on the old non-asm-goto code, which just generates worse code. Just use an empty asm statement instead. Reported-and-tested-by: Geert Uytterhoeven Suggested-by: Peter Zijlstra Fixes: e2ffa15b9baa ("kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on clang < 17") Cc: Nathan Chancellor Cc: Thomas Gleixner Signed-off-by: Linus Torvalds --- diff --git a/init/Kconfig b/init/Kconfig index ecddb94db8dc..6a91ec742186 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -102,7 +102,7 @@ config CC_HAS_ASM_GOTO_OUTPUT # Detect basic support depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) # Detect clang (< v17) scoped label issues - depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto("jmp %l0"::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto("jmp %l0"::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) + depends on $(success,echo 'void b(void **);void* c(void);int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b)))=c();{asm goto(""::::l1);return 2;l1:return 3;}}' | $(CC) -x c - -c -o /dev/null) config CC_HAS_ASM_GOTO_TIED_OUTPUT depends on CC_HAS_ASM_GOTO_OUTPUT