Messages in this thread | | | Date | Tue, 28 Jun 2016 12:06:22 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v6] arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs |
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On Tue, Jun 21, 2016 at 12:12:36PM +0100, Suzuki K Poulose wrote: > From: Steve Capper <steve.capper@linaro.org> > > It can be useful for JIT software to be aware of MIDR_EL1 and > REVIDR_EL1 to ascertain the presence of any core errata that could > affect code generation. > > This patch exposes these registers through sysfs: > > /sys/devices/system/cpu/cpu$ID/identification/midr > /sys/devices/system/cpu/cpu$ID/identification/revidr > > where $ID is the cpu number. For big.LITTLE systems, one can have a > mixture of cores (e.g. Cortex A53 and Cortex A57), thus all CPUs need > to be enumerated. > > If the kernel does not have valid information to populate these entries > with, an empty string is returned to userspace. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Signed-off-by: Steve Capper <steve.capper@linaro.org> > [ ABI documentation updates, hotplug notifiers ] > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Looks good to me, but one minor comment below.
> +static struct attribute_group cpuregs_attr_group = { > + .attrs = cpuregs_attrs, > + .name = "identification" > +};
This makes sense because MIDR/REVIDR belong to the "Identification" functional group of registers, however I wonder if we should put this under a directory called "regs" or similar, so that we don't have a confusing top-level directory where "identification" lives alongside things like "hotplug" and "cpuidle".
Either way:
Reviewed-by: Will Deacon <will.deacon@arm.com>
Will
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