On Tue, Jun 21, 2016 at 12:12:36PM +0100, Suzuki K Poulose wrote:
> From: Steve Capper <steve.cap...@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.mari...@arm.com>
> Cc: Will Deacon <will.dea...@arm.com>
> Cc: Mark Rutland <mark.rutl...@arm.com>
> Signed-off-by: Steve Capper <steve.cap...@linaro.org>
> [ ABI documentation updates, hotplug notifiers ]
> Signed-off-by: Suzuki K Poulose <suzuki.poul...@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.dea...@arm.com>
Will
