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

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Message-ID: <42122aa6-9cce-c45e-d67f-f672badce675@arm.com>
Date:   Mon, 13 Apr 2020 09:09:52 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Will Deacon <will@...nel.org>,
        Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, catalin.marinas@....com,
        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 04/09/2020 06:23 PM, Will Deacon wrote:
> On Fri, Mar 20, 2020 at 06:19:21PM +0000, Suzuki K Poulose wrote:
>> 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>
> 
> Hmm, doesn't dropping cause it to become NONSTRICT? In general, I'd prefer
> that we list all fields in these tables, rather than have implicit behaviour
> in their absence.

Just trying to understand, so we should just leave it unchanged.

ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0)

> 
> Will
>