arm64: cpuinfo: make /proc/cpuinfo more human-readable

As ARMv8 servers get deployed, I keep getting the same set of questions from end-users of those systems: what do all the hex numbers mean in /proc/cpuinfo and could you make them so I don't have to carry a cheat sheet with me all the time?

These patches respond to those questions. For good or ill, some of the automation used to manage systems in data centers (as well as many of the humans involved) need to have text; this helps them simply slide into place and become usable quickly.

Patch 1/2 provides the MPIDR as basic topology info in /proc/cpuinfo when using ACPI, perhaps until such time as the more robust ACPI implementation is available [0]; this is helpful in automating the selection of multi-CPU systems when many choices are available (for example, in automated testing systems). While it is yet another hex value, it does provide some topology information without interfering with what [0] will ultimately provide, and is helpful in sorting out ACPI table issues that use the MPIDR for identifying CPUs.

Patches 2/3 and 3/3 are similar in that they provide a more human- readable version of the info already available; this allows admin tools to provide proper strings to display in inventory systems, for example, or when a human is using a CI system and needs to be provided a list of possible systems to test on.

In all of the patches, I have avoided replacing or interfering with any existing output so as not to affect systems already in use.

Tested on AMD Seattle, APM Mustang and Cavium ThunderX systems.

[0] https://marc.info/?l=linux-pm&m=150584702021552&w=2

Al Stone (3):
arm64: cpuinfo: add MPIDR value to /proc/cpuinfo
arm64: cpuinfo: add human readable CPU names to /proc/cpuinfo
arm64: cpuinfo: display product info in /proc/cpuinfo

 arch/arm64/include/asm/cpu.h |   1 +
 arch/arm64/kernel/cpuinfo.c  | 225 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 226 insertions(+)

2.13.5