• Steve Capper's avatar
    arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs · f8d9f924
    Steve Capper authored
    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$ID/regs/identification/midr_el1
    /sys/devices/system/cpu/cpu$ID/regs/identification/revidr_el1
    
    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: Mark Rutland <mark.rutland@arm.com>
    Reviewed-by: default avatarWill Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
    [suzuki.poulose@arm.com: ABI documentation updates, hotplug notifiers, kobject changes]
    Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    f8d9f924
cpuinfo.c 9.83 KB