Commit 53286632 authored by Uros Bizjak's avatar Uros Bizjak Committed by Ingo Molnar
Browse files

x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h> 



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: default avatarUros Bizjak <ubizjak@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250313102715.333142-1-ubizjak@gmail.com
parent 21fe2514

arch/x86/include/asm/special_insns.h

+6 −10
Original line number Diff line number Diff line
@@ -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