Commit fde0ab43 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Fixes: e2ffa15b ("kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on clang < 17")
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5f0a698

init/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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