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

On Tue, 14 Dec 2021 at 15:28, Mark Brown [off-list ref] wrote:

On Tue, Dec 14, 2021 at 03:12:01PM +0100, Ard Biesheuvel wrote:

quoted

On Tue, 14 Dec 2021 at 15:10, Will Deacon [off-list ref] wrote:

quoted

quoted

I don't have a strong opinion here, so whatever you like. I just tend to
think that most people will have BTI enabled and there's something to be
said for having an instruction always emitted when you have a token in
assembly code.

quoted

+1

quoted

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?

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

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