linux-kernel - Re: [PATCH 0/8] objtool, x86/alternative: Convert objtool annotations and x86 alternatives to assembler macros

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Message-ID: <vgmcvvmyhnkwzmleulyuystjhwez2o3ysfkofzbjphzn2miuow@q5w55bn3ljye>
Date: Wed, 10 Dec 2025 21:27:41 -0800
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Borislav Petkov <bp@...en8.de>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org, 
	Linus Torvalds <torvalds@...ux-foundation.org>, Ingo Molnar <mingo@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 0/8] objtool, x86/alternative: Convert objtool
 annotations and x86 alternatives to assembler macros

On Thu, Dec 11, 2025 at 02:06:06AM +0100, Borislav Petkov wrote:
> On Sat, Dec 06, 2025 at 01:41:07PM -0800, Josh Poimboeuf wrote:
> >   # ./arch/x86/include/asm/smap.h:47: 	alternative("", "stac", X86_FEATURE_SMAP);
> >   # 47 "./arch/x86/include/asm/smap.h" 1
> > 	ALTERNATIVE "", "stac", "( 9*32+20)"
> 
> Well, that's "readable" but one still needs to go see that ALTERNATIVE
> macro definition now, right?
> 
> So you move the gory details somewhere else.
> 
> Sorry, I fail to see why we're doing this...

Partially because Linus complains every time I mess up the code gen ;-)
But I like this change too.

Anybody reading the .s file should already know how alternatives work.
If not... go read alternatives.h!

-- 
Josh