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

["tip-bot2 for Uros Bizjak" <tip-bot2@linutronix.de>]

The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     cc2e9e09d1a3c59cfb138a0fc6ad6f624f3d4ac8
Gitweb:        https://git.kernel.org/tip/cc2e9e09d1a3c59cfb138a0fc6ad6f624f3d4ac8
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Thu, 13 Mar 2025 11:26:55 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 13 Mar 2025 11:50:14 +01:00

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: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo 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
---
 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 03e7c2d..856d4ad 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