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Ensure the boot CPU is CPU 0 on arm64
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Authored by andrew on Dec 7 2020, 1:05 PM.

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Summary

We assume the boot CPU is always CPU 0 on arm64. To allow for this reserve
cpuid 0 for the boot CPU in the ACPI and FDT cases but otherwise start the
CPU as normal. We then check for the boot CPU in start_cpu and return as if
it was started.

While here extract the FDT CPU init code into a new function to simplify
cpu_mp_start and return FALSE from start_cpu when the CPU fails to start.

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rS FreeBSD src repository - subversion
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Event Timeline

andrew requested review of this revision.Dec 7 2020, 1:05 PM

Simplify by only iterating once with CPU 0 being reserved

  • Use the correct ID in cpu_init_fdt
  • Copy a comment explaining why we don't increment the CPU ID to teh FDT code
  • Fix a typo in said comment
mmel added a subscriber: mmel.

Works for me and it's much better than my initial proposal.

This revision is now accepted and ready to land.Dec 7 2020, 4:37 PM
This revision was automatically updated to reflect the committed changes.