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arm64: cpufeature: Change DBM to display enabled cores

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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>
Link: https://lore.kernel.org/r/20231017052322.1211099-3-jeremy.linton@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Jeremy Linton 2023-10-17 00:23:21 -05:00 committed by Catalin Marinas
parent 23b727dc20
commit 04d402a453
1 changed files with 8 additions and 25 deletions
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33
arch/arm64/kernel/cpufeature.c
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@ -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