[PATCH] x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h>

[PATCH] x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h>

[Uros Bizjak]

Current minimum required version of binutils is 2.30,
which supports MONITORX and MWAITX instruction mnemonics.

Replace the byte-wise specification of MONITORX and
MWAITX with these proper mnemonics.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/include/asm/mwait.h | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index dd2b129b0418..d4bcbe59626d 100644
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -36,9 +36,7 @@ static __always_inline void __monitor(const void *eax, u32 ecx, u32 edx)
 
 static __always_inline void __monitorx(const void *eax, u32 ecx, u32 edx)
 {
-	/* "monitorx %eax, %ecx, %edx" */
-	asm volatile(".byte 0x0f, 0x01, 0xfa"
-		     :: "a" (eax), "c" (ecx), "d"(edx));
+	asm volatile("monitorx" :: "a" (eax), "c" (ecx), "d"(edx));
 }
 
 static __always_inline void __mwait(u32 eax, u32 ecx)
@@ -82,9 +80,7 @@ static __always_inline void __mwaitx(u32 eax, u32 ebx, u32 ecx)
 {
 	/* No MDS buffer clear as this is AMD/HYGON only */
 
-	/* "mwaitx %eax, %ebx, %ecx" */
-	asm volatile(".byte 0x0f, 0x01, 0xfb"
-		     :: "a" (eax), "b" (ebx), "c" (ecx));
+	asm volatile("mwaitx" :: "a" (eax), "b" (ebx), "c" (ecx));
 }
 
 /*
-- 
2.49.0

[tip: x86/cleanups] x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h>

[tip-bot2 for Uros Bizjak]

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

Commit-ID:     d20a5d96eddb95b4faa33247ec653a580c48fdfa
Gitweb:        https://git.kernel.org/tip/d20a5d96eddb95b4faa33247ec653a580c48fdfa
Author:        Uros Bizjak <ubizjak@gmail.com>
AuthorDate:    Mon, 16 Jun 2025 10:30:41 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Fri, 22 Aug 2025 13:52:21 +02:00

x86/idle: Use MONITORX and MWAITX mnemonics in <asm/mwait.h>

Current minimum required version of binutils is 2.30, which supports MONITORX
and MWAITX instruction mnemonics.

Replace the byte-wise specification of MONITORX and MWAITX with these proper
mnemonics.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250616083056.157460-1-ubizjak@gmail.com
---
 arch/x86/include/asm/mwait.h | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
index 6ca6516..e4815e1 100644
--- a/arch/x86/include/asm/mwait.h
+++ b/arch/x86/include/asm/mwait.h
@@ -36,9 +36,7 @@ static __always_inline void __monitor(const void *eax, u32 ecx, u32 edx)
 
 static __always_inline void __monitorx(const void *eax, u32 ecx, u32 edx)
 {
-	/* "monitorx %eax, %ecx, %edx" */
-	asm volatile(".byte 0x0f, 0x01, 0xfa"
-		     :: "a" (eax), "c" (ecx), "d"(edx));
+	asm volatile("monitorx" :: "a" (eax), "c" (ecx), "d"(edx));
 }
 
 static __always_inline void __mwait(u32 eax, u32 ecx)
@@ -80,9 +78,7 @@ static __always_inline void __mwaitx(u32 eax, u32 ebx, u32 ecx)
 {
 	/* No need for TSA buffer clearing on AMD */
 
-	/* "mwaitx %eax, %ebx, %ecx" */
-	asm volatile(".byte 0x0f, 0x01, 0xfb"
-		     :: "a" (eax), "b" (ebx), "c" (ecx));
+	asm volatile("mwaitx" :: "a" (eax), "b" (ebx), "c" (ecx));
 }
 
 /*