From: "H. Peter Anvin" <hpa@zytor.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: linux-kernel@vger.kernel.org,
"Borislav Petkov (AMD)" <bp@alien8.de>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
David Laight <david.laight.linux@gmail.com>
Subject: Re: [tip: x86/cleanups] x86/segment: Use MOVL when reading segment registers
Date: Thu, 12 Mar 2026 11:55:01 -0700 [thread overview]
Message-ID: <6b1d157d-c549-4f5a-a0d4-602bf2e86b97@zytor.com> (raw)
In-Reply-To: <CAFULd4bbEGUvz2jR7CmmAX1DVGvEuaMZfn+DANnRD8TVY8cBXw@mail.gmail.com>
On 2026-03-12 02:30, Uros Bizjak wrote:
>
> We would like to always use MOVL to avoid 0x66 operand size override
> prefix when reading to a register, but MOVL does not support memory
> operands. MOVW is required in this case.
>
Just use "mov" without any suffix.
GAS LISTING movseg.s page 1
1 .text
2
3 0000 8CD8 mov %ds,%eax
4 0002 668CD8 mov %ds,%ax
5 0005 8C1B mov %ds,(%rbx)
-hpa
next prev parent reply other threads:[~2026-03-12 19:11 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-05 9:02 [PATCH RESEND v2 1/3] x86: " Uros Bizjak
2026-01-05 9:02 ` [PATCH RESEND v2 2/3] x86/hyperv: Use savesegment() instead of inline asm() to save " Uros Bizjak
2026-01-19 16:22 ` H. Peter Anvin
2026-01-05 9:02 ` [PATCH RESEND v2 3/3] x86/hyperv: Remove ASM_CALL_CONSTRAINT with VMMCALL insn Uros Bizjak
2026-01-19 16:23 ` H. Peter Anvin
2026-01-19 16:22 ` [PATCH RESEND v2 1/3] x86: Use MOVL when reading segment registers H. Peter Anvin
2026-01-20 12:08 ` [tip: x86/cleanups] x86/segment: " tip-bot2 for Uros Bizjak
2026-01-20 12:38 ` H. Peter Anvin
2026-01-20 13:47 ` Uros Bizjak
2026-01-20 14:02 ` Uros Bizjak
2026-01-21 11:49 ` Brian Gerst
2026-01-21 14:08 ` David Laight
2026-01-21 16:16 ` Uros Bizjak
2026-01-21 18:55 ` David Laight
2026-03-12 9:30 ` Uros Bizjak
2026-03-12 18:55 ` H. Peter Anvin [this message]
2026-03-12 19:38 ` Uros Bizjak
2026-03-12 18:56 ` H. Peter Anvin
2026-03-12 19:11 ` H. Peter Anvin
2026-03-12 19:50 ` Uros Bizjak
2026-03-12 22:01 ` Uros Bizjak
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