From c8b8f3c50f487b145433a6c3f95efd8790079a06 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Date: Mon, 16 Mar 2026 10:36:00 +0800 Subject: [PATCH] LoongArch: Only use SC.Q when supported by the assembler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 128-bit atomic cmpxchg implementation uses the SC.Q instruction. Older versions of GNU AS do not support that instruction, erroring out: ERROR:root:{standard input}: Assembler messages: {standard input}:4831: Error: no match insn: sc.q $t0,$t1,$r14 {standard input}:6407: Error: no match insn: sc.q $t0,$t1,$r23 {standard input}:10856: Error: no match insn: sc.q $t0,$t1,$r14 make[4]: *** [../scripts/Makefile.build:289: mm/slub.o] Error 1 (Binutils 2.41) So test support for SC.Q in Kconfig and disable the atomics if the instruction is not available. Fixes: f0e4b1b6e295 ("LoongArch: Add 128-bit atomic cmpxchg support") Closes: https://lore.kernel.org/lkml/20260216082834-edc51c46-7b7a-4295-8ea5-4d9a3ca2224f@linutronix.de/ Reviewed-by: Xi Ruoyao Acked-by: Hengqi Chen Tested-by: Hengqi Chen Signed-off-by: Thomas Weißschuh Signed-off-by: Huacai Chen --- arch/loongarch/Kconfig | 3 +++ arch/loongarch/include/asm/cmpxchg.h | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index d211c6572b0a..92068ff38685 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -304,6 +304,9 @@ config AS_HAS_LBT_EXTENSION config AS_HAS_LVZ_EXTENSION def_bool $(as-instr,hvcl 0) +config AS_HAS_SCQ_EXTENSION + def_bool $(as-instr,sc.q \$t0$(comma)\$t1$(comma)\$t2) + config CC_HAS_ANNOTATE_TABLEJUMP def_bool $(cc-option,-mannotate-tablejump) diff --git a/arch/loongarch/include/asm/cmpxchg.h b/arch/loongarch/include/asm/cmpxchg.h index 58cabab6d90d..909f9274fe71 100644 --- a/arch/loongarch/include/asm/cmpxchg.h +++ b/arch/loongarch/include/asm/cmpxchg.h @@ -238,6 +238,8 @@ __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, unsigned int arch_cmpxchg((ptr), (o), (n)); \ }) +#ifdef CONFIG_AS_HAS_SCQ_EXTENSION + union __u128_halves { u128 full; struct { @@ -290,6 +292,9 @@ union __u128_halves { BUILD_BUG_ON(sizeof(*(ptr)) != 16); \ __arch_cmpxchg128(ptr, o, n, ""); \ }) + +#endif /* CONFIG_AS_HAS_SCQ_EXTENSION */ + #else #include #define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))