linux-kernel - [PATCH 02/20] x86/apic: Use named asm operands in native_apic_mem

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Message-ID: <397c12e48369bc6aa30094fbc8f795c642cee214.1741988314.git.jpoimboe@kernel.org>
Date: Fri, 14 Mar 2025 14:41:15 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Uros Bizjak <ubizjak@...il.com>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 02/20] x86/apic: Use named asm operands in native_apic_mem_write()

Use named operands in preparation for removing the operand numbering
restrictions in alternative_io().

Note this includes removing the "0" input constraint and converting its
corresponding output constraint from "=r" to "+r".  While at it, do the
same for the memory constraint.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/include/asm/apic.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index c903d358405d..ecf1b229f09b 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -98,9 +98,9 @@ static inline void native_apic_mem_write(u32 reg, u32 v)
 {
 	volatile u32 *addr = (volatile u32 *)(APIC_BASE + reg);
 
-	alternative_io("movl %0, %1", "xchgl %0, %1", X86_BUG_11AP,
-		       ASM_OUTPUT("=r" (v), "=m" (*addr)),
-		       ASM_INPUT("0" (v), "m" (*addr)));
+	alternative_io("movl %[val], %[mem]",
+		       "xchgl %[val], %[mem]", X86_BUG_11AP,
+		       ASM_OUTPUT([val] "+r" (v), [mem] "+m" (*addr)));
 }
 
 static inline u32 native_apic_mem_read(u32 reg)
-- 
2.48.1