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SubjectRe: [PATCH 0/3] arm64: cpufeature: Add filter function to control
Hi Srinivas,

On 2021-01-09 00:29, Srinivas Ramana wrote:
> This patchset adds a control function for cpufeature framework
> so that the feature can be controlled at runtime.
>
> Defer PAC on boot core and use the filter function added to disable
> PAC from command line. This will help toggling the feature on systems
> that do not support PAC or where PAC needs to be disabled at runtime,
> without modifying the core kernel.
>
> The idea of adding the filter function for cpufeature is taken from
> https://lore.kernel.org/linux-arm-kernel/20200515171612.1020-25-catalin.marinas@arm.com/
> https://lore.kernel.org/linux-arm-kernel/20200515171612.1020-24-catalin.marinas@arm.com/
>
> Srinivas Ramana (3):
> arm64: Defer enabling pointer authentication on boot core
> arm64: cpufeature: Add a filter function to cpufeature
> arm64: Enable control of pointer authentication using early param
>
> Documentation/admin-guide/kernel-parameters.txt | 6 +++
> arch/arm64/include/asm/cpufeature.h | 8 +++-
> arch/arm64/include/asm/pointer_auth.h | 10 +++++
> arch/arm64/include/asm/stackprotector.h | 1 +
> arch/arm64/kernel/cpufeature.c | 53
> +++++++++++++++++++------
> arch/arm64/kernel/head.S | 4 --
> 6 files changed, 64 insertions(+), 18 deletions(-)

I've been working for some time on a similar series to allow a feature
set to be disabled during the early boot phase, initially to prevent
booting a kernel with VHE, but the mechanism is generic enough to
deal with most architectural features.

I took the liberty to lift your first patch and to add it to my
series[1],
further allowing PAuth to be disabled at boot time on top of BTI and
VHE.

I'd appreciate your comments on this.

Thanks,

M.

[1] https://lore.kernel.org/r/20210111132811.2455113-1-maz@kernel.org
--
Jazz is not dead. It just smells funny...

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