Making sense of /proc/cpuinfo on ARM

Ever stared at output of /proc/cpuinfo and wondered what the CPU is?

...
processor       : 7
BogoMIPS        : 2.40
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 3

Or maybe like:

$ cat /proc/cpuinfo
processor       : 0
model name      : ARMv7 Processor rev 2 (v7l)
BogoMIPS        : 50.00
Features        : half thumb fastmult vfp edsp thumbee vfpv3 tls idiva idivt vfpd32 lpae
CPU implementer : 0x56
CPU architecture: 7
CPU variant     : 0x2
CPU part        : 0x584
CPU revision    : 2
...

The bits "CPU implementer" and "CPU part" could be mapped to human understandable strings. But the Kernel developers are heavily against the idea. Therefor, to the next idea: Parse in userspace. Turns out, there is a common tool almost everyone has installed does similar stuff. lscpu(1) from util-linux. So I proposed a patch to do ID mapping on arm/arm64 to util-linux, and it was accepted! So using lscpu from util-linux 2.32 (hopefully to be released soon) the above two systems look like:

Architecture:        aarch64
Byte Order:          Little Endian
CPU(s):              8
On-line CPU(s) list: 0-7
Thread(s) per core:  1
Core(s) per socket:  4
Socket(s):           2
NUMA node(s):        1
Vendor ID:           ARM
Model:               3
Model name:          Cortex-A53
Stepping:            r0p3
CPU max MHz:         1200.0000
CPU min MHz:         208.0000
BogoMIPS:            2.40
L1d cache:           unknown size
L1i cache:           unknown size
L2 cache:            unknown size
NUMA node0 CPU(s):   0-7
Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid

And

$ lscpu
Architecture:        armv7l
Byte Order:          Little Endian
CPU(s):              4
On-line CPU(s) list: 0-3
Thread(s) per core:  1
Core(s) per socket:  4
Socket(s):           1
Vendor ID:           Marvell
Model:               2
Model name:          PJ4B-MP
Stepping:            0x2
CPU max MHz:         1333.0000
CPU min MHz:         666.5000
BogoMIPS:            50.00
Flags:               half thumb fastmult vfp edsp thumbee vfpv3 tls idiva idivt vfpd32 lpae

As we can see, lscpu is quite versatile and can show more information than just what is available in cpuinfo.