Fix ARM CPUID printing

[bennoleslie]

The existing print_cpuid function displays the incorrect value
for Cortex-A35. (See issue #43).

This change makes CPUID determination an explicit switch statement
rather than attempting to automatically determine it through
masking certain bits.

Note: At some level this will be a regression as it now only
prints the textual id for Cortex-A35 and no other CPU.

Improvements to list other CPUID mappings is welcome, unfortunately
the only platform I have access to for testing is Cortex-A35.

[axel-h]

This patch fixes A35, but breaks a lot of the rest. There is a list in last column of the table at http://en.wikipedia.org/wiki/Comparison_of_ARMv8-A_cores that needs to be worked in here.

[bennoleslie]

This patch fixes A35, but breaks a lot of the rest. There is a list in last column of the table at http://en.wikipedia.org/wiki/Comparison_of_ARMv8-A_cores that needs to be worked in here.

Added, but obviously untested. I think they are reasonably clear so can be merged without testing all cases.

[axel-h]

Thanks, to merge there are two things that should be addressed:

• All these ID are only valid if CPUID_IMPL(cpuid) == CPUID_IMPL_ARM. Otherwise we should just print the raw value.
• This still lacks all the ARMv7 cores
  • 0xc05: "Cortex-A5"
  • 0xc07: "Cortex-A7"
  • 0xc08: "Cortex-A8"
  • 0xc09: "Cortex-A9"
  • 0xc0d: "Cortex-A12"
  • 0xc0f: "Cortex-A15"
  • 0xc0e: "Cortex-A17"

These things are nice to have:

• There are also a few ARMv8 cores out there that we may want to add:
  • 0xd42: "Cortex-A78AE"
  • 0xd4b: "Cortex-A78C"
• This seems to be the list for the brand new ones:
  • 0xd0c, "Neoverse N1"
  • 0xd40: "Neoverse V1"
  • 0xd46: "Cortex-A510"
  • 0xd47: "Cortex-A710"
  • 0xd48: "Cortex-X2"
  • 0xd49: "Neoverse N2"
  • 0xd4a: "Neoverse E1"

[bennoleslie]

Thanks, to merge there are two things that should be addressed:

• All these ID are only valid if CPUID_IMPL(cpuid) == CPUID_IMPL_ARM. Otherwise we should just print the raw value.

I don't think this needs to be addressed to merge. This is a bug (that was preexisting). I think we should create a bug in the issue tracker and address this separately.

Doing that properly would be a refactor of the part lookup into a cpuid_get_arm_part_str(...) function. Which is a good idea. I'd just like to keep the PRs separate.

[axel-h]

Look good please add the missing DCO and consider squashing the commits.

[bennoleslie]

Look good please add the missing DCO and consider squashing the commits.

Done.