linux-kernel - x86/boot: Avoid using Intel mnemonics in AT&T syntax asm

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Message-ID: <Y71I3Ex2pvIxMpsP@hirez.programming.kicks-ass.net>
Date:   Tue, 10 Jan 2023 12:15:40 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org, linux-kernel@...r.kernel.org
Subject: x86/boot: Avoid using Intel mnemonics in AT&T syntax asm


With 'GNU assembler (GNU Binutils for Debian) 2.39.90.20221231' the
build now reports:

  arch/x86/realmode/rm/../../boot/bioscall.S: Assembler messages:
  arch/x86/realmode/rm/../../boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/realmode/rm/../../boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

  arch/x86/boot/bioscall.S: Assembler messages:
  arch/x86/boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

Which is due to:

  PR gas/29525

  Note that with the dropped CMPSD and MOVSD Intel Syntax string insn
  templates taking operands, mixed IsString/non-IsString template groups
  (with memory operands) cannot occur anymore. With that
  maybe_adjust_templates() becomes unnecessary (and is hence being
  removed).

More details: https://sourceware.org/bugzilla/show_bug.cgi?id=29525

Fixes: 7a734e7dd93b ("x86, setup: "glove box" BIOS calls -- infrastructure")
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/boot/bioscall.S |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/boot/bioscall.S
+++ b/arch/x86/boot/bioscall.S
@@ -32,7 +32,7 @@
 	movw	%dx, %si
 	movw	%sp, %di
 	movw	$11, %cx
-	rep; movsd
+	rep; movsl
 
 	/* Pop full state from the stack */
 	popal
@@ -67,7 +67,7 @@
 	jz	4f
 	movw	%sp, %si
 	movw	$11, %cx
-	rep; movsd
+	rep; movsl
 4:	addw	$44, %sp
 
 	/* Restore state and return */