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From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc: Mark Rutland <mark.rutland@arm.com>,
	MSM <linux-arm-msm@vger.kernel.org>,
	"Suzuki K. Poulose" <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	linux-arm-kernel <linux-arm-kernel-bounces@lists.infradead.org>
Subject: Re: Relax CPU features sanity checking on heterogeneous architectures
Date: Fri, 11 Oct 2019 19:03:58 +0530	[thread overview]
Message-ID: <8fb6dce8dcda42a14c1347295a812a0f@codeaurora.org> (raw)
In-Reply-To: <a86e9be2-fc82-afea-5e94-b15d7eef1b84@free.fr>

On 2019-10-11 16:39, Marc Gonzalez wrote:
> On 11/10/2019 12:50, Mark Rutland wrote:
> 
>> Before we make any changes, we need to check whether we do actually
>> handle this variation in a safe way, and we need to consider what this
>> means w.r.t. late CPU hotplug.
>> 
>> Even if we can handle variation at boot time, once we've determined 
>> the
>> set of system-wide features we cannot allow those to regress, and I
>> believe we'll need new code to enforce that. I don't think it's
>> sufficient to mark these as NONSTRICT, though we might do that with
>> other changes.
>> 
>> We shouldn't look at the part number at all here. We care about
>> variation across CPUs regardless of whether this is big.LITTLE or some
>> variation in tie-offs, etc.
> 
> See also the "Unexpected variation in SYS_ID_AA64MMFR0_EL1" thread
> from a year ago: (that was on msm8998)
> 
> 	https://www.spinics.net/lists/arm-kernel/msg691242.html
> 

I think, it was fixed by commit: 5717fe5ab38f ("arm64: cpufeature: Don't 
treat granule sizes as strict")

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation

WARNING: multiple messages have this Message-ID (diff)
From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	MSM <linux-arm-msm@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel-bounces@lists.infradead.org>,
	"Suzuki K. Poulose" <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: Relax CPU features sanity checking on heterogeneous architectures
Date: Fri, 11 Oct 2019 19:03:58 +0530	[thread overview]
Message-ID: <8fb6dce8dcda42a14c1347295a812a0f@codeaurora.org> (raw)
In-Reply-To: <a86e9be2-fc82-afea-5e94-b15d7eef1b84@free.fr>

On 2019-10-11 16:39, Marc Gonzalez wrote:
> On 11/10/2019 12:50, Mark Rutland wrote:
> 
>> Before we make any changes, we need to check whether we do actually
>> handle this variation in a safe way, and we need to consider what this
>> means w.r.t. late CPU hotplug.
>> 
>> Even if we can handle variation at boot time, once we've determined 
>> the
>> set of system-wide features we cannot allow those to regress, and I
>> believe we'll need new code to enforce that. I don't think it's
>> sufficient to mark these as NONSTRICT, though we might do that with
>> other changes.
>> 
>> We shouldn't look at the part number at all here. We care about
>> variation across CPUs regardless of whether this is big.LITTLE or some
>> variation in tie-offs, etc.
> 
> See also the "Unexpected variation in SYS_ID_AA64MMFR0_EL1" thread
> from a year ago: (that was on msm8998)
> 
> 	https://www.spinics.net/lists/arm-kernel/msg691242.html
> 

I think, it was fixed by commit: 5717fe5ab38f ("arm64: cpufeature: Don't 
treat granule sizes as strict")

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-10-11 13:34 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-11  5:49 Relax CPU features sanity checking on heterogeneous architectures Sai Prakash Ranjan
2019-10-11  5:49 ` Sai Prakash Ranjan
2019-10-11  9:19 ` Marc Gonzalez
2019-10-11  9:19   ` Marc Gonzalez
2019-10-11  9:57   ` Sai Prakash Ranjan
2019-10-11  9:57     ` Sai Prakash Ranjan
2019-10-11 10:50 ` Mark Rutland
2019-10-11 10:50   ` Mark Rutland
2019-10-11 11:09   ` Marc Gonzalez
2019-10-11 11:09     ` Marc Gonzalez
2019-10-11 13:33     ` Sai Prakash Ranjan [this message]
2019-10-11 13:33       ` Sai Prakash Ranjan
2019-10-11 13:17   ` Sai Prakash Ranjan
2019-10-11 13:17     ` Sai Prakash Ranjan
2019-10-11 13:34     ` Marc Zyngier
2019-10-11 13:34       ` Marc Zyngier
2019-10-11 13:40       ` Sai Prakash Ranjan
2019-10-11 13:40         ` Sai Prakash Ranjan
2019-10-17 20:00         ` Stephen Boyd
2019-10-17 20:00           ` Stephen Boyd
2019-10-18  7:20           ` Marc Zyngier
2019-10-18  7:20             ` Marc Zyngier
2019-10-18 14:33             ` Stephen Boyd
2019-10-18 14:33               ` Stephen Boyd
2019-10-18 16:40               ` Marc Zyngier
2019-10-18 16:40                 ` Marc Zyngier
2019-10-18 10:18           ` Sai Prakash Ranjan
2019-10-18 10:18             ` Sai Prakash Ranjan
2019-10-11 13:33   ` Marc Zyngier
2019-10-11 13:33     ` Marc Zyngier
2019-10-11 13:54     ` Mark Rutland
2019-10-11 13:54       ` Mark Rutland
2019-10-11 14:06       ` Marc Zyngier
2019-10-11 14:06         ` Marc Zyngier
2019-10-17 21:39       ` Jeremy Linton
2019-10-17 21:39         ` Jeremy Linton
2019-10-18  9:01         ` Catalin Marinas
2019-10-18  9:01           ` Catalin Marinas
2020-01-20  2:47       ` Sai Prakash Ranjan
2020-01-20  2:47         ` Sai Prakash Ranjan

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