Re: [PATCH v7 05/12] arm64/boot: Factor out a macro to check SPE version

[James Clark <james.clark@xxxxxxxxxx>]

On 01/09/2025 11:05 am, Leo Yan wrote:
> On Thu, Aug 14, 2025 at 10:25:27AM +0100, James Clark wrote:
> > We check the version of SPE twice, and we'll add one more check in the
> > next commit so factor out a macro to do this. Change the #3 magic number
> > to the actual SPE version define (V1p2) to make it more readable.
> >
> > No functional changes intended.
> >
> > Tested-by: Leo Yan <leo.yan@xxxxxxx>
> > Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
> > ---
> >   arch/arm64/include/asm/el2_setup.h | 17 +++++++++++------
> >   1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
> > index 46033027510c..3a4ca7f9acfb 100644
> > --- a/arch/arm64/include/asm/el2_setup.h
> > +++ b/arch/arm64/include/asm/el2_setup.h
> > @@ -103,8 +103,7 @@
> >   	csel	x2, xzr, x0, eq			// all PMU counters from EL1
> >   
> >   	/* Statistical profiling */
> > -	ubfx	x0, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4
> > -	cbz	x0, .Lskip_spe_\@		// Skip if SPE not present
> > +	__spe_vers_imp .Lskip_spe_\@, ID_AA64DFR0_EL1_PMSVer_IMP, x0 // Skip if SPE not present
> >   
> >   	mrs_s	x0, SYS_PMBIDR_EL1              // If SPE available at EL2,
> >   	and	x0, x0, #(1 << PMBIDR_EL1_P_SHIFT)
> > @@ -255,6 +254,14 @@
> >   .Lskip_brbe_\@:
> >   .endm
> >   
> > +/* Branch to skip_label if SPE version is less than given version */
> > +.macro __spe_vers_imp skip_label, version, tmp
> > +    mrs    \tmp, id_aa64dfr0_el1
> > +    ubfx   \tmp, \tmp, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4
> > +    cmp    \tmp, \version
> > +    b.lt   \skip_label
> > +.endm
> > +
>
> Just wondering if we need to move the macro to the beginning of the
> file, so that we can define it first and call it afterwards.
>
> Otherwise, LGTM:
>
> Reviewed-by: Leo Yan <leo.yan@xxxxxxx>

It's not required, but all the other macros are defined before use and 
it looks a bit weird to not do it, so I can move it.

> >   /* Disable any fine grained traps */
> >   .macro __init_el2_fgt
> >   	mrs	x1, id_aa64mmfr0_el1
> > @@ -263,10 +270,8 @@
> >   
> >   	mov	x0, xzr
> >   	mov	x2, xzr
> > -	mrs	x1, id_aa64dfr0_el1
> > -	ubfx	x1, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4
> > -	cmp	x1, #3
> > -	b.lt	.Lskip_spe_fgt_\@
> > +	/* If SPEv1p2 is implemented, */
> > +	__spe_vers_imp .Lskip_spe_fgt_\@, #ID_AA64DFR0_EL1_PMSVer_V1P2, x1
> >   	/* Disable PMSNEVFR_EL1 read and write traps */
> >   	orr	x0, x0, #HDFGRTR_EL2_nPMSNEVFR_EL1_MASK
> >   	orr	x2, x2, #HDFGWTR_EL2_nPMSNEVFR_EL1_MASK
> >
> > --
> > 2.34.1