linux-kernel - Re: [PATCH 02/14] x86/alternatives: Add nested alternatives macros

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Date: Fri, 31 May 2024 16:32:44 +0200
From: Borislav Petkov <bp@...en8.de>
To: Uros Bizjak <ubizjak@...il.com>
Cc: Borislav Petkov <bp@...nel.org>, X86 ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 02/14] x86/alternatives: Add nested alternatives macros

On Fri, May 31, 2024 at 04:30:31PM +0200, Uros Bizjak wrote:
> Please don't resurrect the %P modifier, use %c instead.
> 
> > +
> >   /*
> >    * Like alternative_call, but there are two features and respective functions.
> >    * If CPU has feature2, function2 is used.
> > @@ -307,6 +376,15 @@ static inline int alternatives_text_reserved(void *start, void *end)
> >   		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		\
> >   		  [new2] "i" (newfunc2), ## input)
> > +#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,   \
> > +			   output, input...)				      \
> > +	asm_inline volatile (N_ALTERNATIVE_2("call %P[old]", "call %P[new1]", ft_flags1,\
> > +		"call %P[new2]", ft_flags2)				      \
> > +		: output, ASM_CALL_CONSTRAINT				      \
> > +		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
> > +		  [new2] "i" (newfunc2), ## input)
> 
> Here too, %P should be avoided in favor of %c.

Yeah, will do.

We probably should update our patch checking scripts to catch such
things in the future.

/me adds to todo.

Thx.


-- 
Regards/Gruss,
    Boris.

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