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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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32
arch/arm64/kernel/cpufeature.c
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@@ -1009,18 +1009,8 @@ verify_local_cpu_features(const struct arm64_cpu_capabilities *caps)
* cannot do anything to fix it up and could cause unexpected failures. So
* we park the CPU.
*/
void verify_local_cpu_capabilities(void)
static void verify_local_cpu_capabilities(void)
{
check_early_cpu_features();
/*
* If we haven't computed the system capabilities, there is nothing
* to verify.
*/
if (!sys_caps_initialised)
return;
verify_local_cpu_errata_workarounds();
verify_local_cpu_features(arm64_features);
verify_local_elf_hwcaps(arm64_elf_hwcaps);
@@ -1028,6 +1018,26 @@ void verify_local_cpu_capabilities(void)
verify_local_elf_hwcaps(compat_elf_hwcaps);
}
void check_local_cpu_capabilities(void)
{
/*
* All secondary CPUs should conform to the early CPU features
* in use by the kernel based on boot CPU.
*/
check_early_cpu_features();
/*
* If we haven't finalised the system capabilities, this CPU gets
* a chance to update the errata work arounds.
* Otherwise, this CPU should verify that it has all the system
* advertised capabilities.
*/
if (!sys_caps_initialised)
update_cpu_errata_workarounds();
else
verify_local_cpu_capabilities();
}
static void __init setup_feature_capabilities(void)
{
update_cpu_capabilities(arm64_features, "detected feature:");