4.9-stable review patch. If anyone has any objections, please let me know.
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From: Mark Rutland mark.rutland@arm.com
From: Suzuki K Poulose suzuki.poulose@arm.com
commit 55b35d070c2534dfb714b883f3c3ae05d02032da upstream.
When a CPU is brought up after we have finalised the system wide capabilities (i.e, features and errata), we make sure the new CPU doesn't need a new errata work around which has not been detected already. However we don't run enable() method on the new CPU for the errata work arounds already detected. This could cause the new CPU running without potential work arounds. It is upto the "enable()" method to decide if this CPU should do something about the errata.
Fixes: commit 6a6efbb45b7d95c84 ("arm64: Verify CPU errata work arounds on hotplugged CPU") Cc: Will Deacon will.deacon@arm.com Cc: Mark Rutland mark.rutland@arm.com Cc: Andre Przywara andre.przywara@arm.com Cc: Dave Martin dave.martin@arm.com Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Mark Rutland mark.rutland@arm.com [v4.9 backport] Tested-by: Greg Hackmann ghackmann@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/cpu_errata.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -143,15 +143,18 @@ void verify_local_cpu_errata_workarounds { const struct arm64_cpu_capabilities *caps = arm64_errata;
- for (; caps->matches; caps++) - if (!cpus_have_cap(caps->capability) && - caps->matches(caps, SCOPE_LOCAL_CPU)) { + for (; caps->matches; caps++) { + if (cpus_have_cap(caps->capability)) { + if (caps->enable) + caps->enable((void *)caps); + } else if (caps->matches(caps, SCOPE_LOCAL_CPU)) { pr_crit("CPU%d: Requires work around for %s, not detected" " at boot time\n", smp_processor_id(), caps->desc ? : "an erratum"); cpu_die_early(); } + } }
void update_cpu_errata_workarounds(void)