From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>
Subject: Re: x86/boot: Avoid using Intel mnemonics in AT&T syntax asm
Date: Tue, 10 Jan 2023 12:35:50 +0100 [thread overview]
Message-ID: <Y71NllA2NjlNiZpX@gmail.com> (raw)
In-Reply-To: <Y71I3Ex2pvIxMpsP@hirez.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
>
> 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@infradead.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
So I think the GAS change to introduce this warning was probably
unnecessary - these instructions weren't really causing any trouble and the
syntax was basically a legacy thing that shouldn't be touched - but I guess
that argument is water down the bridge now:
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Thanks,
Ingo
next prev parent reply other threads:[~2023-01-10 11:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-10 11:15 x86/boot: Avoid using Intel mnemonics in AT&T syntax asm Peter Zijlstra
2023-01-10 11:35 ` Ingo Molnar [this message]
2023-01-11 22:59 ` H. Peter Anvin
2023-01-10 11:36 ` Borislav Petkov
2023-01-10 14:01 ` David Laight
2023-01-10 12:26 ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra
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