diff options
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 33 |
1 files changed, 8 insertions, 25 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 2dd695fc3472..b7b67bac0e60 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1848,6 +1848,8 @@ static int __init parse_kpti(char *str) early_param("kpti", parse_kpti); #ifdef CONFIG_ARM64_HW_AFDBM +static struct cpumask dbm_cpus __read_mostly; + static inline void __cpu_enable_hw_dbm(void) { u64 tcr = read_sysreg(tcr_el1) | TCR_HD; @@ -1883,35 +1885,22 @@ static bool cpu_can_use_dbm(const struct arm64_cpu_capabilities *cap) static void cpu_enable_hw_dbm(struct arm64_cpu_capabilities const *cap) { - if (cpu_can_use_dbm(cap)) + if (cpu_can_use_dbm(cap)) { __cpu_enable_hw_dbm(); + cpumask_set_cpu(smp_processor_id(), &dbm_cpus); + } } static bool has_hw_dbm(const struct arm64_cpu_capabilities *cap, int __unused) { - static bool detected = false; /* * DBM is a non-conflicting feature. i.e, the kernel can safely * run a mix of CPUs with and without the feature. So, we * unconditionally enable the capability to allow any late CPU * to use the feature. We only enable the control bits on the - * CPU, if it actually supports. - * - * We have to make sure we print the "feature" detection only - * when at least one CPU actually uses it. So check if this CPU - * can actually use it and print the message exactly once. - * - * This is safe as all CPUs (including secondary CPUs - due to the - * LOCAL_CPU scope - and the hotplugged CPUs - via verification) - * goes through the "matches" check exactly once. Also if a CPU - * matches the criteria, it is guaranteed that the CPU will turn - * the DBM on, as the capability is unconditionally enabled. + * CPU, if it is supported. */ - if (!detected && cpu_can_use_dbm(cap)) { - detected = true; - pr_info("detected: Hardware dirty bit management\n"); - } return true; } @@ -2448,18 +2437,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { }, #ifdef CONFIG_ARM64_HW_AFDBM { - /* - * Since we turn this on always, we don't want the user to - * think that the feature is available when it may not be. - * So hide the description. - * - * .desc = "Hardware pagetable Dirty Bit Management", - * - */ + .desc = "Hardware dirty bit management", .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE, .capability = ARM64_HW_DBM, .matches = has_hw_dbm, .cpu_enable = cpu_enable_hw_dbm, + .cpus = &dbm_cpus, ARM64_CPUID_FIELDS(ID_AA64MMFR1_EL1, HAFDBS, DBM) }, #endif |