linux-kernel - Re: [PATCH v3 2/9] arm64: cpufeature: remove explicit RAZ fields

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Message-ID: <20170105170931.GD29765@e104818-lin.cambridge.arm.com>
Date:   Thu, 5 Jan 2017 17:09:31 +0000
From:   Catalin Marinas <catalin.marinas@....com>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, mark.rutland@....com,
        ryan.arnold@...aro.org, sid@...erved-bit.com, aph@...hat.com,
        will.deacon@....com, linux-kernel@...r.kernel.org,
        adhemerval.zanella@...aro.org, dave.martin@....com
Subject: Re: [PATCH v3 2/9] arm64: cpufeature: remove explicit RAZ fields

On Wed, Jan 04, 2017 at 05:49:00PM +0000, Suzuki K. Poulose wrote:
> From: Mark Rutland <mark.rutland@....com>
> 
> We currently have some RAZ fields described explicitly in our
> arm64_ftr_bits arrays. These are inconsistently commented, grouped,
> and/or applied, and maintaining these is error-prone.
> 
> Luckily, we don't need these at all. We'll never need to inspect RAZ
> fields to determine feature support, and init_cpu_ftr_reg() will ensure
> that any bits without a corresponding arm64_ftr_bits entry are treated
> as RES0 with strict matching requirements. In check_update_ftr_reg()
> we'll then compare these bits from the relevant cpuinfo_arm64
> structures, and need not store them in a arm64_ftr_reg.
> 
> This patch removes the unnecessary arm64_ftr_bits entries for RES0 bits.
> 
> Signed-off-by: Mark Rutland <mark.rutland@....com>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Will Deacon <will.deacon@....com>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>

Reviewed-by: Catalin Marinas <catalin.marinas@....com>