CPU Errata work arounds are detected and applied to the kernel code at boot time and the data is then freed up. If a new hotplugged CPU requires a work around which was not applied at boot time, there is nothing we can do but simply fail the booting.
Cc: Will Deacon <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Andre Przywara <[email protected]> Cc: Catalin Marinas <[email protected]> Signed-off-by: Suzuki K Poulose <[email protected]> --- arch/arm64/include/asm/cpufeature.h | 2 +- arch/arm64/kernel/cpu_errata.c | 22 ++++++++++++++++++++++ arch/arm64/kernel/cpufeature.c | 1 + 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 733b016..d5b7386 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -191,7 +191,7 @@ void __init setup_cpu_features(void); void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps, const char *info); void check_local_cpu_errata(void); - +void verify_local_cpu_errata(void); void verify_local_cpu_capabilities(void); u64 read_system_reg(u32 id); diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 2fd5780..d35b398 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -101,6 +101,28 @@ const struct arm64_cpu_capabilities arm64_errata[] = { } }; +/* + * The CPU Errata work arounds are detected and applied at boot time + * and the related information is freed soon after. If the new CPU requires + * an errata not detected at boot, fail this CPU. + */ +void verify_local_cpu_errata(void) +{ + const struct arm64_cpu_capabilities *caps = arm64_errata; + + for (; caps->matches; caps++) + if (!cpus_have_cap(caps->capability) && + caps->matches(caps, SCOPE_CPU)) { + int cpu = smp_processor_id(); + + if (caps->desc) + pr_crit("CPU%d: Detected - %s\n", cpu, caps->desc); + pr_crit("CPU%d: Requires an errata work around not detected" + " at boot time\n", cpu); + cpu_die_early(); + } +} + void check_local_cpu_errata(void) { update_cpu_capabilities(arm64_errata, "enabling workaround for"); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 3ace45f..2f6ce1d 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -983,6 +983,7 @@ void verify_local_cpu_capabilities(void) if (!sys_caps_initialised) return; + verify_local_cpu_errata(); verify_local_cpu_features(arm64_features); verify_local_elf_hwcaps(arm64_elf_hwcaps); if (system_supports_32bit_el0()) -- 1.7.9.5
