linux-kernel - Re: [PATCH -tip 2/4] x86/idle: Use MONITOR and MWAIT mnemonics in <asm/mwait.h>

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Message-ID: <Z-6poX1TFKLKn4mB@black.fi.intel.com>
Date: Thu, 3 Apr 2025 18:30:41 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Uros Bizjak <ubizjak@...il.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH -tip 2/4] x86/idle: Use MONITOR and MWAIT mnemonics in
 <asm/mwait.h>

On Thu, Apr 03, 2025 at 06:28:13PM +0300, Andy Shevchenko wrote:
> On Wed, Apr 02, 2025 at 08:08:06PM +0200, Uros Bizjak wrote:
> > Current minimum required version of binutils is 2.25,
> > which supports MONITOR and MWAIT instruction mnemonics.
> > 
> > Replace the byte-wise specification of MONITOR and
> > MWAIT with these proper mnemonics.
> > 
> > No functional change intended.
> 
> Hmm... Is it only me who gets these, please?
> 
> In file included from acpi/cstate.c:18:
> asm/mwait.h:30:15: error: invalid operand for instruction
>    30 |         asm volatile("monitor %0, %1, %2" :: "a" (eax), "c" (ecx), "d" (edx));
>       |                      ^
> <inline asm>:1:16: note: instantiated into assembly here
>     1 |         monitor %rax, %ecx, %edx
>       |                       ^~~~~
> In file included from acpi/cstate.c:18:
> asm/mwait.h:95:15: error: instruction requires: Not 64-bit mode
>    95 |         asm volatile("sti; mwait %0, %1" :: "a" (eax), "c" (ecx));
>       |                      ^
> <inline asm>:1:7: note: instantiated into assembly here
>     1 |         sti; mwait %eax, %ecx
>       |              ^

FWIW, revert fixes the issue.

-- 
With Best Regards,
Andy Shevchenko