arm64: Rearrange CPU errata workaround checks
authorSuzuki K Poulose <suzuki.poulose@arm.com>
Fri, 9 Sep 2016 13:07:10 +0000 (14:07 +0100)
committerWill Deacon <will.deacon@arm.com>
Fri, 9 Sep 2016 14:03:28 +0000 (15:03 +0100)
commitc47a1900ad710fd2c97127e2ba19da1df79cf733
tree280ee1f75639c56aca3f82abd3065f94b740c68f
parent89ba26458b72422e0a1d85eb729a15220b204458
arm64: Rearrange CPU errata workaround checks

Right now we run through the work around checks on a CPU
from __cpuinfo_store_cpu. There are some problems with that:

1) We initialise the system wide CPU feature registers only after the
Boot CPU updates its cpuinfo. Now, if a work around depends on the
variance of a CPU ID feature (e.g, check for Cache Line size mismatch),
we have no way of performing it cleanly for the boot CPU.

2) It is out of place, invoked from __cpuinfo_store_cpu() in cpuinfo.c. It
is not an obvious place for that.

This patch rearranges the CPU specific capability(aka work around) checks.

1) At the moment we use verify_local_cpu_capabilities() to check if a new
CPU has all the system advertised features. Use this for the secondary CPUs
to perform the work around check. For that we rename
  verify_local_cpu_capabilities() => check_local_cpu_capabilities()
which:

   If the system wide capabilities haven't been initialised (i.e, the CPU
   is activated at the boot), update the system wide detected work arounds.

   Otherwise (i.e a CPU hotplugged in later) verify that this CPU conforms to the
   system wide capabilities.

2) Boot CPU updates the work arounds from smp_prepare_boot_cpu() after we have
initialised the system wide CPU feature values.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/include/asm/cpufeature.h
arch/arm64/kernel/cpufeature.c
arch/arm64/kernel/cpuinfo.c
arch/arm64/kernel/smp.c