linux-kernel - Re: [PATCH 5/6] arm64/cpufeature: Drop TraceFilt feature exposure from ID

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Date:   Fri, 20 Mar 2020 18:19:21 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     anshuman.khandual@....com, linux-arm-kernel@...ts.infradead.org
Cc:     catalin.marinas@....com, will@...nel.org, james.morse@....com,
        maz@...nel.org, mark.rutland@....com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] arm64/cpufeature: Drop TraceFilt feature exposure
 from ID_DFR0 register

On 01/28/2020 12:39 PM, Anshuman Khandual wrote:
> ID_DFR0 based TraceFilt feature should not be exposed.

... to guests.

  Hence lets drop it.

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

> 
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Will Deacon <will@...nel.org>
> Cc: James Morse <james.morse@....com>
> Cc: Suzuki K Poulose <suzuki.poulose@....com>
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
>   arch/arm64/kernel/cpufeature.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 2726bd6441da..a8ded1f0eeaf 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -374,7 +374,6 @@ static const struct arm64_ftr_bits ftr_id_pfr2[] = {
>   };
>   
>   static const struct arm64_ftr_bits ftr_id_dfr0[] = {
> -	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
>   	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
>   	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
>   	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),
>