linux-kernel - Re: [PATCH 04/20] x86/cpu: Use named asm operands in clflushopt()

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Message-ID: <gor6hi6lzohdo6hfcffmxdzc4fiqdn2itncxatw4zkhouzmm6l@obz43xcfcl2i>
Date: Fri, 14 Mar 2025 17:07:00 -0700
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, 
	Peter Zijlstra <peterz@...radead.org>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, 
	Uros Bizjak <ubizjak@...il.com>, Andrew Cooper <andrew.cooper3@...rix.com>, 
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH 04/20] x86/cpu: Use named asm operands in clflushopt()

On Fri, Mar 14, 2025 at 01:46:00PM -1000, Linus Torvalds wrote:
> On Fri, 14 Mar 2025 at 11:42, Josh Poimboeuf <jpoimboe@...nel.org> wrote:
> >
> > +       alternative_io(".byte 0x3e; clflush %[val]",
> > +                      ".byte 0x66; clflush %[val]", X86_FEATURE_CLFLUSHOPT,
> > +                      [val] "+m" (*(volatile char __force *)__p));
> 
> Hmm. I think we could just use 'clflushopt', it looks like it exists
> in binutils-2.25, which is our minimal version requirement.
> 
> But maybe that's a separate cleanup.

You appear to be correct, I'll add a patch for that.

-- 
Josh