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    Subject[PATCH v5 06/22] arm64: capabilities: Unify the verification
    Date
    Now that each capability describes how to treat the conflicts
    of CPU cap state vs System wide cap state, we can unify the
    verification logic to a single place.

    Reviewed-by: Dave Martin <dave.martin@arm.com>
    Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
    ---
    arch/arm64/kernel/cpufeature.c | 91 +++++++++++++++++++++++++++---------------
    1 file changed, 58 insertions(+), 33 deletions(-)

    diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
    index 0b8e6b9..1fda957 100644
    --- a/arch/arm64/kernel/cpufeature.c
    +++ b/arch/arm64/kernel/cpufeature.c
    @@ -1306,6 +1306,58 @@ enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
    }

    /*
    + * Run through the list of capabilities to check for conflicts.
    + * If the system has already detected a capability, take necessary
    + * action on this CPU.
    + *
    + * Returns "false" on conflicts.
    + */
    +static bool
    +__verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list)
    +{
    + bool cpu_has_cap, system_has_cap;
    + const struct arm64_cpu_capabilities *caps;
    +
    + for (caps = caps_list; caps->matches; caps++) {
    + cpu_has_cap = __this_cpu_has_cap(caps_list, caps->capability);
    + system_has_cap = cpus_have_cap(caps->capability);
    +
    + if (system_has_cap) {
    + /*
    + * Check if the new CPU misses an advertised feature,
    + * which is not safe to miss.
    + */
    + if (!cpu_has_cap && !cpucap_late_cpu_optional(caps))
    + break;
    + /*
    + * We have to issue cpu_enable() irrespective of
    + * whether the CPU has it or not, as it is enabeld
    + * system wide. It is upto the call back to take
    + * appropriate action on this CPU.
    + */
    + if (caps->cpu_enable)
    + caps->cpu_enable(caps);
    + } else {
    + /*
    + * Check if the CPU has this capability if it isn't
    + * safe to have when the system doesn't.
    + */
    + if (cpu_has_cap && !cpucap_late_cpu_permitted(caps))
    + break;
    + }
    + }
    +
    + if (caps->matches) {
    + pr_crit("CPU%d: Detected conflict for capability %d (%s), System: %d, CPU: %d\n",
    + smp_processor_id(), caps->capability,
    + caps->desc, system_has_cap, cpu_has_cap);
    + return false;
    + }
    +
    + return true;
    +}
    +
    +/*
    * Check for CPU features that are used in early boot
    * based on the Boot CPU value.
    */
    @@ -1327,25 +1379,10 @@ verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
    }
    }

    -static void
    -verify_local_cpu_features(const struct arm64_cpu_capabilities *caps_list)
    +static void verify_local_cpu_features(void)
    {
    - const struct arm64_cpu_capabilities *caps = caps_list;
    - for (; caps->matches; caps++) {
    - if (!cpus_have_cap(caps->capability))
    - continue;
    - /*
    - * If the new CPU misses an advertised feature, we cannot proceed
    - * further, park the cpu.
    - */
    - if (!__this_cpu_has_cap(caps_list, caps->capability)) {
    - pr_crit("CPU%d: missing feature: %s\n",
    - smp_processor_id(), caps->desc);
    - cpu_die_early();
    - }
    - if (caps->cpu_enable)
    - caps->cpu_enable(caps);
    - }
    + if (!__verify_local_cpu_caps(arm64_features))
    + cpu_die_early();
    }

    static void verify_sve_features(void)
    @@ -1372,20 +1409,8 @@ static void verify_sve_features(void)
    */
    static void verify_local_cpu_errata_workarounds(void)
    {
    - const struct arm64_cpu_capabilities *caps = arm64_errata;
    -
    - for (; caps->matches; caps++) {
    - if (cpus_have_cap(caps->capability)) {
    - if (caps->cpu_enable)
    - caps->cpu_enable(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();
    - }
    - }
    + if (!__verify_local_cpu_caps(arm64_errata))
    + cpu_die_early();
    }

    static void update_cpu_errata_workarounds(void)
    @@ -1409,7 +1434,7 @@ static void __init enable_errata_workarounds(void)
    static void verify_local_cpu_capabilities(void)
    {
    verify_local_cpu_errata_workarounds();
    - verify_local_cpu_features(arm64_features);
    + verify_local_cpu_features();
    verify_local_elf_hwcaps(arm64_elf_hwcaps);

    if (system_supports_32bit_el0())
    --
    2.7.4
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