From 53286632450835c49b5c177f97e4899645f15730 Mon Sep 17 00:00:00 2001 From: Uros Bizjak Date: Thu, 13 Mar 2025 11:26:55 +0100 Subject: [PATCH] x86/asm: Use CLFLUSHOPT and CLWB mnemonics in Current minimum required version of binutils is 2.25, which supports CLFLUSHOPT and CLWB instruction mnemonics. Replace the byte-wise specification of CLFLUSHOPT and CLWB with these proper mnemonics. No functional change intended. Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Brian Gerst Cc: H. Peter Anvin Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250313102715.333142-1-ubizjak@gmail.com --- arch/x86/include/asm/special_insns.h | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 21ce480658b1..9b10bd102d3d 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -176,9 +176,8 @@ static __always_inline void clflush(volatile void *__p) static inline void clflushopt(volatile void *__p) { - alternative_io(".byte 0x3e; clflush %0", - ".byte 0x66; clflush %0", - X86_FEATURE_CLFLUSHOPT, + alternative_io("ds clflush %0", + "clflushopt %0", X86_FEATURE_CLFLUSHOPT, "+m" (*(volatile char __force *)__p)); } @@ -187,13 +186,10 @@ static inline void clwb(volatile void *__p) volatile struct { char x[64]; } *p = __p; asm volatile(ALTERNATIVE_2( - ".byte 0x3e; clflush (%[pax])", - ".byte 0x66; clflush (%[pax])", /* clflushopt (%%rax) */ - X86_FEATURE_CLFLUSHOPT, - ".byte 0x66, 0x0f, 0xae, 0x30", /* clwb (%%rax) */ - X86_FEATURE_CLWB) - : [p] "+m" (*p) - : [pax] "a" (p)); + "ds clflush %0", + "clflushopt %0", X86_FEATURE_CLFLUSHOPT, + "clwb %0", X86_FEATURE_CLWB) + : "+m" (*p)); } #ifdef CONFIG_X86_USER_SHADOW_STACK