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From: Suzuki.Poulose@arm.com (Suzuki K. Poulose)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 07/22] arm64: Keep track of CPU feature registers
Date: Mon, 12 Oct 2015 18:01:25 +0100	[thread overview]
Message-ID: <561BE765.1080409@arm.com> (raw)
In-Reply-To: <20151008150346.GK17192@e104818-lin.cambridge.arm.com>

On 08/10/15 16:03, Catalin Marinas wrote:
> On Thu, Oct 08, 2015 at 10:55:11AM +0100, Suzuki K. Poulose wrote:

...
>
> So we have three types of fields in these registers:
>
> a) features defined but not something we care about in Linux
> b) reserved fields
> c) features important to Linux
>
> I guess for (a), Linux may not even care if they don't match (though we
> need to be careful which fields we ignore). As for (b), even if they
> differ, since we don't know the meaning at this point, I think we should
> just ignore them. If, for example, they add a feature that Linux doesn't
> care about, they practically fall under the (a) category.
>
> Regarding exposing reserved CPUID fields to user, I assume we would
> always return 0.

Mark,

Do you have any comments on this ? The list I have here is what you came
up with in SANITY checks.

Thanks
Suzuki

WARNING: multiple messages have this Message-ID (diff)
From: "Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
To: mark.rutland@arm.com
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Vladimir.Murzin@arm.com, steve.capper@linaro.org,
	ard.biesheuvel@linaro.org, marc.zyngier@arm.com,
	andre.przywara@arm.com, will.deacon@arm.com,
	linux-kernel@vger.kernel.org, edward.nevill@linaro.org,
	aph@redhat.com, james.morse@arm.com, dave.martin@arm.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 07/22] arm64: Keep track of CPU feature registers
Date: Mon, 12 Oct 2015 18:01:25 +0100	[thread overview]
Message-ID: <561BE765.1080409@arm.com> (raw)
In-Reply-To: <20151008150346.GK17192@e104818-lin.cambridge.arm.com>

On 08/10/15 16:03, Catalin Marinas wrote:
> On Thu, Oct 08, 2015 at 10:55:11AM +0100, Suzuki K. Poulose wrote:

...
>
> So we have three types of fields in these registers:
>
> a) features defined but not something we care about in Linux
> b) reserved fields
> c) features important to Linux
>
> I guess for (a), Linux may not even care if they don't match (though we
> need to be careful which fields we ignore). As for (b), even if they
> differ, since we don't know the meaning at this point, I think we should
> just ignore them. If, for example, they add a feature that Linux doesn't
> care about, they practically fall under the (a) category.
>
> Regarding exposing reserved CPUID fields to user, I assume we would
> always return 0.

Mark,

Do you have any comments on this ? The list I have here is what you came
up with in SANITY checks.

Thanks
Suzuki


  parent reply	other threads:[~2015-10-12 17:01 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-05 17:01 [PATCH v2 00/22] arm64: Consolidate CPU feature handling Suzuki K. Poulose
2015-10-05 17:01 ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 01/22] arm64: Make the CPU information more clear Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 02/22] arm64: Delay ELF HWCAP initialisation until all CPUs are up Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 03/22] arm64: Move cpu feature detection code Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 04/22] arm64: Move mixed endian support detection Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 05/22] arm64: Move /proc/cpuinfo handling code Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 06/22] arm64: sys_reg: Define System register encoding Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-07 16:36   ` Catalin Marinas
2015-10-07 16:36     ` Catalin Marinas
2015-10-07 17:03     ` Suzuki K. Poulose
2015-10-07 17:03       ` Suzuki K. Poulose
2015-10-08 14:43       ` Catalin Marinas
2015-10-08 14:43         ` Catalin Marinas
2015-10-08 16:13         ` Suzuki K. Poulose
2015-10-08 16:13           ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 07/22] arm64: Keep track of CPU feature registers Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-07 17:16   ` Catalin Marinas
2015-10-07 17:16     ` Catalin Marinas
2015-10-08  9:55     ` Suzuki K. Poulose
2015-10-08  9:55       ` Suzuki K. Poulose
2015-10-08 15:03       ` Catalin Marinas
2015-10-08 15:03         ` Catalin Marinas
2015-10-09 13:00         ` Suzuki K. Poulose
2015-10-09 13:00           ` Suzuki K. Poulose
2015-10-12 17:01         ` Suzuki K. Poulose [this message]
2015-10-12 17:01           ` Suzuki K. Poulose
2015-10-12 17:21           ` Mark Rutland
2015-10-12 17:21             ` Mark Rutland
2015-10-13  9:40             ` Catalin Marinas
2015-10-13  9:40               ` Catalin Marinas
2015-10-09 10:56       ` Suzuki K. Poulose
2015-10-09 10:56         ` Suzuki K. Poulose
2015-10-09 14:16         ` Catalin Marinas
2015-10-09 14:16           ` Catalin Marinas
2015-10-05 17:01 ` [PATCH v2 08/22] arm64: Consolidate CPU Sanity check to CPU Feature infrastructure Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 09/22] arm64: Read system wide CPUID value Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:01 ` [PATCH v2 10/22] arm64: Cleanup mixed endian support detection Suzuki K. Poulose
2015-10-05 17:01   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 11/22] arm64: Populate cpuinfo after notify_cpu_starting Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-08 10:15   ` Catalin Marinas
2015-10-08 10:15     ` Catalin Marinas
2015-10-08 10:46     ` Suzuki K. Poulose
2015-10-08 10:46       ` Suzuki K. Poulose
2015-10-09 15:01       ` Suzuki K. Poulose
2015-10-09 15:01         ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 12/22] arm64: Delay cpu feature checks Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-06  4:41   ` kbuild test robot
2015-10-06  4:41     ` kbuild test robot
2015-10-06 11:09     ` Suzuki K. Poulose
2015-10-06 11:09       ` Suzuki K. Poulose
2015-10-08 11:08   ` Catalin Marinas
2015-10-08 11:08     ` Catalin Marinas
2015-10-13 10:12     ` Suzuki K. Poulose
2015-10-13 10:12       ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 13/22] arm64: Make use of system wide capability checks Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 14/22] arm64: Cleanup HWCAP handling Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-08 11:10   ` Catalin Marinas
2015-10-08 11:10     ` Catalin Marinas
2015-10-08 11:17     ` Russell King - ARM Linux
2015-10-08 11:17       ` Russell King - ARM Linux
2015-10-08 13:00       ` Catalin Marinas
2015-10-08 13:00         ` Catalin Marinas
2015-10-08 14:54         ` Edward Nevill
2015-10-08 14:54           ` Edward Nevill
2015-10-05 17:02 ` [PATCH v2 15/22] arm64: Move FP/ASIMD hwcap handling to common code Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 16/22] arm64/debug: Make use of the system wide safe value Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-08 11:11   ` Catalin Marinas
2015-10-08 11:11     ` Catalin Marinas
2015-10-08 11:56     ` Suzuki K. Poulose
2015-10-08 11:56       ` Suzuki K. Poulose
2015-10-08 15:08       ` Catalin Marinas
2015-10-08 15:08         ` Catalin Marinas
2015-10-08 15:57         ` Suzuki K. Poulose
2015-10-08 15:57           ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 17/22] arm64/kvm: Make use of the system wide safe values Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-10 15:17   ` Christoffer Dall
2015-10-10 15:17     ` Christoffer Dall
2015-10-10 15:17     ` Christoffer Dall
2015-10-05 17:02 ` [PATCH v2 18/22] arm64: Add helper to decode register from instruction Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 19/22] arm64: cpufeature: Track the user visible fields Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 20/22] arm64: Expose feature registers by emulating MRS Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-05 17:02 ` [PATCH v2 21/22] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose
2015-10-06  9:09   ` Russell King - ARM Linux
2015-10-06  9:09     ` Russell King - ARM Linux
2015-10-06 10:18     ` Steve Capper
2015-10-06 10:18       ` Steve Capper
2015-10-06 10:25       ` Mark Rutland
2015-10-06 10:25         ` Mark Rutland
2015-10-06 10:29         ` Steve Capper
2015-10-06 10:29           ` Steve Capper
2015-10-06 19:16       ` Russell King - ARM Linux
2015-10-06 19:16         ` Russell King - ARM Linux
2015-10-05 17:02 ` [PATCH v2 22/22] arm64: feature registers: Documentation Suzuki K. Poulose
2015-10-05 17:02   ` Suzuki K. Poulose

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