Re: [PATCH 04/11] arm64/cpufeature: add ARMv8.3 id_aa64isar1 bits

Suzuki K Poulose
2017-07-24T10:54:58Z

On 19/07/17 17:01, Mark Rutland wrote:
> From ARMv8.3 onwards, ID_AA64ISAR1 is no longer entirely RES0, and now
> has four fields describing the presence of pointer authentication
> functionality:
>
> * APA - address authentication present, using an architected algorithm
> * API - address authentication present, using an IMP DEF algorithm
> * GPA - generic authentication present, using an architected algorithm
> * GPI - generic authentication present, using an IMP DEF algoithm
>
> This patch adds the requisite definitions so that we can identify the
> presence of this functionality. For the timebeing, the features are
> hidden from userspace.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
> arch/arm64/kernel/cpufeature.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 9f9e0064..b23ad83 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -120,7 +120,11 @@ static int __init register_cpu_hwcaps_dumper(void)
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_FCMA_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0),
> - ARM64_FTR_END,
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_GPI_SHIFT, 4, 0),
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_GPA_SHIFT, 4, 0),
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_API_SHIFT, 4, 0),
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_APA_SHIFT, 4, 0),
> + ARM64_FTR_END
> };

minor nit: Could we keep the fields in the order of their positions in the register ?

With that,

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>