From f8d9f924526ad3c983569437f60e3833d6c55578 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Fri, 8 Jul 2016 16:01:13 +0100 Subject: arm64: cpuinfo: Expose MIDR_EL1 and REVIDR_EL1 to sysfs 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 Reviewed-by: Will Deacon Signed-off-by: Steve Capper [suzuki.poulose@arm.com: ABI documentation updates, hotplug notifiers, kobject changes] Signed-off-by: Suzuki K Poulose Signed-off-by: Catalin Marinas --- Documentation/ABI/testing/sysfs-devices-system-cpu | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 16501334b99f..498741737055 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -340,3 +340,13 @@ Description: POWERNV CPUFreq driver's frequency throttle stats directory and 'policyX/throttle_stats' directory and all the attributes are same as the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and attributes which give the frequency throttle information of the chip. + +What: /sys/devices/system/cpu/cpuX/regs/ + /sys/devices/system/cpu/cpuX/regs/identification/ + /sys/devices/system/cpu/cpuX/regs/identification/midr_el1 + /sys/devices/system/cpu/cpuX/regs/identification/revidr_el1 +Date: June 2016 +Contact: Linux ARM Kernel Mailing list +Description: AArch64 CPU registers + 'identification' directory exposes the CPU ID registers for + identifying model and revision of the CPU. -- cgit v1.2.3-58-ga151