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From: Uros Bizjak <ubizjak@gmail.com>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Uros Bizjak <ubizjak@gmail.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>
Subject: [PATCH RESEND v4 3/4] x86/segment: Use ASM_INPUT_RM in __loadsegment_fs()
Date: Mon, 30 Mar 2026 07:57:44 +0200	[thread overview]
Message-ID: <20260330055823.5793-3-ubizjak@gmail.com> (raw)
In-Reply-To: <20260330055823.5793-1-ubizjak@gmail.com>

Use the ASM_INPUT_RM macro in __loadsegment_fs() to work around clang
problems with "rm" asm constraint. clang seems to always chose the
memory input, while it is almost always the worst choice.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Cc: Thomas Gleixner <tglx@kernel.org>
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>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
---
 arch/x86/include/asm/segment.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 3fe3a310844c..0f4283dcd0c4 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -335,7 +335,7 @@ static inline void __loadsegment_fs(unsigned short value)
 
 		     _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_CLEAR_FS)
 
-		     : : "rm" (value) : "memory");
+		     : : ASM_INPUT_RM (value) : "memory");
 }
 
 /* __loadsegment_gs is intentionally undefined.  Use load_gs_index instead. */
-- 
2.53.0


  parent reply	other threads:[~2026-03-30  5:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-30  5:57 [PATCH RESEND v4 1/4] x86/fsgsbase: Remove unnecessary "memory" clobbers from FS/GS base accessors Uros Bizjak
2026-03-30  5:57 ` [PATCH RESEND v4 2/4] x86/segment: Remove unnecessary memory clobber from savesegment() Uros Bizjak
2026-03-30  7:17   ` [tip: x86/asm] x86/asm/segment: Remove unnecessary "memory" " tip-bot2 for Uros Bizjak
2026-03-30  5:57 ` Uros Bizjak [this message]
2026-03-30  7:16   ` [tip: x86/asm] x86/asm/segment: Use ASM_INPUT_RM in __loadsegment_fs() tip-bot2 for Uros Bizjak
2026-03-30  5:57 ` [PATCH RESEND v4 4/4] x86/segment: Implement loadsegment()/savesegment() macros with static inline helpers Uros Bizjak
2026-03-30  7:16   ` [tip: x86/asm] x86/asm/segment: " tip-bot2 for Uros Bizjak
2026-03-30  7:17 ` [tip: x86/asm] x86/asm/fsgsbase: Remove unnecessary "memory" clobbers from FS/GS base (read-) accessors tip-bot2 for Uros Bizjak

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