@@ -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
Now that we have the ability to display the list of cores with a feature when its selectivly enabled, lets convert DBM to use that as well. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- arch/arm64/kernel/cpufeature.c | 33 ++++++++------------------------- 1 file changed, 8 insertions(+), 25 deletions(-)