Re: [PATCH v3 29/39] arm64: mte: Switch GCR_EL1 in kernel entry and exit

Catalin Marinas
2020-09-25T12:38:18Z

On Fri, Sep 25, 2020 at 12:50:23PM +0100, Vincenzo Frascino wrote:
> On 9/25/20 12:34 PM, Catalin Marinas wrote:
> > On Fri, Sep 25, 2020 at 12:50:36AM +0200, Andrey Konovalov wrote:
> >> + /*
> >> + * Calculate and set the exclude mask preserving
> >> + * the RRND (bit[16]) setting.
> >> + */
> >> + mrs_s \tmp2, SYS_GCR_EL1
> >> + bfi \tmp2, \tmp, #0, #16
> >> + msr_s SYS_GCR_EL1, \tmp2
> >> + isb
> >> +1:
> >> +#endif
> >> + .endm
> >> +
> >> + .macro mte_set_kernel_gcr, tsk, tmp, tmp2
> >
> > What's the point of a 'tsk' argument here?
>
> It is unused. I kept the interface same in between kernel and user.
> I can either add a comment or remove it. Which one do you prefer?

Please remove it. Having the same interface is more confusing since you
have a single kernel gcr_excl but multiple user gcr_excl.

--
Catalin