Re: [PATCH 3/9] arm64: alternatives: proton-pack: prepare for cap changes

Mark Rutland
2022-09-05T10:19:08Z

On Fri, Sep 02, 2022 at 05:19:32PM +0100, Joey Gouly wrote:
> Hi Mark,
>
> On Thu, Sep 01, 2022 at 04:13:57PM +0100, Mark Rutland wrote:
> > The spectre patching callbacks use cpus_have_final_cap() internally within
> > has_vhe(), and subsequent patches will make it invalid to call
>
> Remove the 'internally within has_vhe()', a copy paste error from the previous
> commit.

Whoops; removed.

> Otherwise:
>
> Reviewed-by: Joey Gouly <joey.gouly@arm.com>

Thanks!

Mark.

>
> > cpus_have_final_cap() before alternatives patching has completed.
> >
> > In preparation for said change, this patch modifies the spectre patching
> > callbacks use cpus_have_cap(). This is not subject to patching, and will
> > dynamically check the cpu_hwcaps array, which is functionally equivalent
> > to the existing behaviour.
> >
> > There should be no functional change as a result of this patch.
> >
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > Cc: Ard Biesheuvel <ardb@kernel.org>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: James Morse <james.morse@arm.com>
> > Cc: Joey Gouly <joey.gouly@arm.com>
> > Cc: Marc Zyngier <maz@kernel.org>
> > Cc: Will Deacon <will@kernel.org>
> > ---
> > arch/arm64/kernel/proton-pack.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c
> > index 40be3a7c2c531..8010b2e573fac 100644
> > --- a/arch/arm64/kernel/proton-pack.c
> > +++ b/arch/arm64/kernel/proton-pack.c
> > @@ -586,7 +586,7 @@ void __init spectre_v4_patch_fw_mitigation_enable(struct alt_instr *alt,
> > if (spectre_v4_mitigations_off())
> > return;
> >
> > - if (cpus_have_final_cap(ARM64_SSBS))
> > + if (cpus_have_cap(ARM64_SSBS))
> > return;
> >
> > if (spectre_v4_mitigations_dynamic())
> > --
> > 2.30.2
> >
> >
> > _______________________________________________
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