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arm64: Rearrange CPU errata workaround checks

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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>
This commit is contained in:
Suzuki K Poulose
2016-09-09 14:07:10 +01:00
committed by Will Deacon
parent 89ba26458b
commit c47a1900ad
4 changed files with 30 additions and 16 deletions
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8
arch/arm64/kernel/smp.c
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@@ -239,7 +239,7 @@ asmlinkage void secondary_start_kernel(void)
* this CPU ticks all of those. If it doesn't, the CPU will
* fail to come online.
*/
verify_local_cpu_capabilities();
check_local_cpu_capabilities();
if (cpu_ops[cpu]->cpu_postboot)
cpu_ops[cpu]->cpu_postboot();
@@ -444,6 +444,12 @@ void __init smp_prepare_boot_cpu(void)
jump_label_init();
cpuinfo_store_boot_cpu();
save_boot_cpu_run_el();
/*
* Run the errata work around checks on the boot CPU, once we have
* initialised the cpu feature infrastructure from
* cpuinfo_store_boot_cpu() above.
*/
update_cpu_errata_workarounds();
}
static u64 __init of_get_cpu_mpidr(struct device_node *dn)