cpuinfo

A /proc/cpuinfo parser for ARM devices. Will translate the ARM information (CPU implementer, part, revision, and variant) from ID to a string.

1. Introduction

ARM devices have a base register (CPUID) that includes information about each processor core. CPUID is a 32-bit register with the following structure:

   3                   2                   1                   0
 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  implementer  |variant|  0xf  |           part          | rev |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Where:

• implementer: implementer id
• variant: procesor revision (ordinal)
• part: part number
• rev: revision (path release)

The part field is defined by each implementer.

Some databases containing information about the implementer and part IDs are:

• util-linux lscpu-arm.c
• llvm Host.cpp

2. Operation

$ adb shell cat /proc/cpuinfo | ./cpuid.py - -
...
processor : 7
BogoMIPS  : 38.00
Features  : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm lrcpc dcpop asimddp
CPU implementer : 0x51 (Qualcomm)
CPU architecture: 8
CPU variant : 0xf
CPU part  : 0x804 (cortex-a76 (Kryo 4xx Gold))
CPU revision  : 14