Re: [PATCH 9/9] arm64: Documentation - Expose CPU feature registers

From	Siddhesh Poyarekar <sid@reserved-bit.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 9/9] arm64: Documentation - Expose CPU feature registers
Date	2016-11-30 12:50 +0100
Message-ID	<sJboZ-5v2-5@gated-at.bofh.it> (permalink)
References	<sH2zv-3q2-3@gated-at.bofh.it> <sH2zw-3q2-23@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thursday 24 November 2016 07:10 PM, Suzuki K Poulose wrote:
> + d) CPU Identification :
> +    MIDR_EL1 is exposed to help identify the processor. On a
> +    heterogeneous system, this could be racy (just like getcpu()). The
> +    process could be migrated to another CPU by the time it uses the
> +    register value, unless the CPU affinity is set. Hence, there is no
> +    guarantee that the value reflects the processor that it is
> +    currently executing on. The REVIDR is not exposed due to this
> +    constraint, as REVIDR makes sense only in conjunction with the
> +    MIDR. Alternately, MIDR_EL1 and REVIDR_EL1 are exposed via sysfs
> +    at:
> +
> +	/sys/devices/system/cpu/cpu$ID/regs/identification/
> +	                                              \- midr
> +	                                              \- revidr
> +

This doesn't seem to be implemented in this patchset.

Siddhesh

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Re: [PATCH 9/9] arm64: Documentation - Expose CPU feature registers Siddhesh Poyarekar <sid@reserved-bit.com> - 2016-11-30 12:50 +0100

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