[PATCH v3 2/2] arm64: Unconditionally override SYM_FUNC macros

[Mark Brown]

On Tue, Dec 14, 2021 at 03:31:07PM +0100, Ard Biesheuvel wrote:
> On Tue, 14 Dec 2021 at 15:28, Mark Brown <broonie at kernel.org> wrote:

> > > I already pointed out computed gotos, which are admittedly rare, but
> > > there are other reasons why adhering to WYSIWYG is strongly preferred
> > > for asm code IMO.

> > The use case for this macro is for SYM_FUNC_START() which is going to be
> > emitting the BTI without it really appearing directly in the code so I'm
> > not sure how much I buy that TBH.  I think you're pushing back on uses
> > of the macro outside of linkage.h more than on what linkage.h is doing,
> > that does make more sense to me.

> Fair point, but we don't really have any control over where else BTI_C
> may end up being used, no?

It's also a macro, which should put people off, and there's precious
little arm64 asm outside of arch/arm64 so I'm not sure how worried I am
about that.

> In any case, I don't think it's worth it blowing up the validation
> matrix over this, so if we can emit the same code for all
> configurations, we should IMO

We could have been doing that since the BTI kernel support was
originally merged...  TBH I'm just really surprised everyone's pushing
to generate worse code here, feels not the direction people usually go
in.
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