diff options
| author | Will Deacon <will@kernel.org> | 2020-11-06 11:14:26 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-11-10 13:09:39 +0000 |
| commit | f969f03888b9438fdb227b6460d99ede5737326d (patch) | |
| tree | d537cff035f4204a6078cc962bd794de9d13689d /arch | |
| parent | 108aa503657ee2fe8aa071dc620d96372c252ecd (diff) | |
| download | linux-f969f03888b9438fdb227b6460d99ede5737326d.tar.bz2 | |
arm64: errata: Fix handling of 1418040 with late CPU onlining
In a surprising turn of events, it transpires that CPU capabilities
configured as ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE are never set as the
result of late-onlining. Therefore our handling of erratum 1418040 does
not get activated if it is not required by any of the boot CPUs, even
though we allow late-onlining of an affected CPU.
In order to get things working again, replace the cpus_have_const_cap()
invocation with an explicit check for the current CPU using
this_cpu_has_cap().
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201106114952.10032-1-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/process.c | 5 |
2 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f7e7144af174..c59c16a6ea8b 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -268,6 +268,8 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; /* * CPU feature detected at boot time based on feature of one or more CPUs. * All possible conflicts for a late CPU are ignored. + * NOTE: this means that a late CPU with the feature will *not* cause the + * capability to be advertised by cpus_have_*cap()! */ #define ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE \ (ARM64_CPUCAP_SCOPE_LOCAL_CPU | \ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 4784011cecac..a47a40ec6ad9 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -522,14 +522,13 @@ static void erratum_1418040_thread_switch(struct task_struct *prev, bool prev32, next32; u64 val; - if (!(IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) && - cpus_have_const_cap(ARM64_WORKAROUND_1418040))) + if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040)) return; prev32 = is_compat_thread(task_thread_info(prev)); next32 = is_compat_thread(task_thread_info(next)); - if (prev32 == next32) + if (prev32 == next32 || !this_cpu_has_cap(ARM64_WORKAROUND_1418040)) return; val = read_sysreg(cntkctl_el1); |