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Subject[PATCH v3 15/24] arm64: Make use of system wide capability checks
Date
Now that we can reliably read the system wide safe value for a
feature register, use that to compute the system capability.
This patch also replaces the 'feature-register-specific'
methods with a generic routine to check the capability.

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
---
arch/arm64/include/asm/cpufeature.h | 1 +
arch/arm64/kernel/cpufeature.c | 79 ++++++++++++++++++++++++++---------
2 files changed, 60 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 4a02a18..bf71a8e 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -78,6 +78,7 @@ struct arm64_cpu_capabilities {
};

struct { /* Feature register checking */
+ u32 sys_reg;
int field_pos;
int min_field_value;
};
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 4360637..dd58c32 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -561,34 +561,31 @@ feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry)
return val >= entry->min_field_value;
}

-#define __ID_FEAT_CHK(reg) \
-static bool __maybe_unused \
-has_##reg##_feature(const struct arm64_cpu_capabilities *entry) \
-{ \
- u64 val; \
- \
- val = read_cpuid(reg##_el1); \
- return feature_matches(val, entry); \
-}
+static bool
+has_cpuid_feature(const struct arm64_cpu_capabilities *entry)
+{
+ u64 val;

-__ID_FEAT_CHK(id_aa64pfr0);
-__ID_FEAT_CHK(id_aa64mmfr1);
-__ID_FEAT_CHK(id_aa64isar0);
+ val = read_system_reg(entry->sys_reg);
+ return feature_matches(val, entry);
+}

static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "GIC system register CPU interface",
.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
- .matches = has_id_aa64pfr0_feature,
- .field_pos = 24,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64PFR0_EL1,
+ .field_pos = ID_AA64PFR0_GIC_SHIFT,
.min_field_value = 1,
},
#ifdef CONFIG_ARM64_PAN
{
.desc = "Privileged Access Never",
.capability = ARM64_HAS_PAN,
- .matches = has_id_aa64mmfr1_feature,
- .field_pos = 20,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64MMFR1_EL1,
+ .field_pos = ID_AA64MMFR1_PAN_SHIFT,
.min_field_value = 1,
.enable = cpu_enable_pan,
},
@@ -597,8 +594,9 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
{
.desc = "LSE atomic instructions",
.capability = ARM64_HAS_LSE_ATOMICS,
- .matches = has_id_aa64isar0_feature,
- .field_pos = 20,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64ISAR0_EL1,
+ .field_pos = ID_AA64ISAR0_ATOMICS_SHIFT,
.min_field_value = 2,
},
#endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
@@ -628,6 +626,47 @@ void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
}

/*
+ * __raw_read_system_reg() - Used by a STARTING cpu before cpuinfo is populated.
+ */
+static u64 __raw_read_system_reg(u32 sys_id)
+{
+ switch(sys_id) {
+ case SYS_ID_PFR0_EL1: return (u64)read_cpuid(ID_PFR0_EL1);
+ case SYS_ID_PFR1_EL1: return (u64)read_cpuid(ID_PFR1_EL1);
+ case SYS_ID_DFR0_EL1: return (u64)read_cpuid(ID_DFR0_EL1);
+ case SYS_ID_MMFR0_EL1: return (u64)read_cpuid(ID_MMFR0_EL1);
+ case SYS_ID_MMFR1_EL1: return (u64)read_cpuid(ID_MMFR1_EL1);
+ case SYS_ID_MMFR2_EL1: return (u64)read_cpuid(ID_MMFR2_EL1);
+ case SYS_ID_MMFR3_EL1: return (u64)read_cpuid(ID_MMFR3_EL1);
+ case SYS_ID_ISAR0_EL1: return (u64)read_cpuid(ID_ISAR0_EL1);
+ case SYS_ID_ISAR1_EL1: return (u64)read_cpuid(ID_ISAR1_EL1);
+ case SYS_ID_ISAR2_EL1: return (u64)read_cpuid(ID_ISAR2_EL1);
+ case SYS_ID_ISAR3_EL1: return (u64)read_cpuid(ID_ISAR3_EL1);
+ case SYS_ID_ISAR4_EL1: return (u64)read_cpuid(ID_ISAR4_EL1);
+ case SYS_ID_ISAR5_EL1: return (u64)read_cpuid(ID_ISAR4_EL1);
+ case SYS_MVFR0_EL1: return (u64)read_cpuid(MVFR0_EL1);
+ case SYS_MVFR1_EL1: return (u64)read_cpuid(MVFR1_EL1);
+ case SYS_MVFR2_EL1: return (u64)read_cpuid(MVFR2_EL1);
+
+ case SYS_ID_AA64PFR0_EL1: return (u64)read_cpuid(ID_AA64PFR0_EL1);
+ case SYS_ID_AA64PFR1_EL1: return (u64)read_cpuid(ID_AA64PFR0_EL1);
+ case SYS_ID_AA64DFR0_EL1: return (u64)read_cpuid(ID_AA64DFR0_EL1);
+ case SYS_ID_AA64DFR1_EL1: return (u64)read_cpuid(ID_AA64DFR0_EL1);
+ case SYS_ID_AA64MMFR0_EL1: return (u64)read_cpuid(ID_AA64MMFR0_EL1);
+ case SYS_ID_AA64MMFR1_EL1: return (u64)read_cpuid(ID_AA64MMFR1_EL1);
+ case SYS_ID_AA64ISAR0_EL1: return (u64)read_cpuid(ID_AA64ISAR0_EL1);
+ case SYS_ID_AA64ISAR1_EL1: return (u64)read_cpuid(ID_AA64ISAR1_EL1);
+
+ case SYS_CNTFRQ_EL0: return (u64)read_cpuid(CNTFRQ_EL0);
+ case SYS_CTR_EL0: return (u64)read_cpuid(CTR_EL0);
+ case SYS_DCZID_EL0: return (u64)read_cpuid(DCZID_EL0);
+ default:
+ BUG();
+ return 0;
+ }
+}
+
+/*
* Park the CPU which doesn't have the capability as advertised
* by the system.
*/
@@ -664,13 +703,13 @@ void cpu_enable_features(void)
const struct arm64_cpu_capabilities *caps = arm64_features;

for(i = 0; caps[i].desc; i++) {
- if(!cpus_have_cap(caps[i].capability))
+ if(!cpus_have_cap(caps[i].capability) || !caps[i].sys_reg)
continue;
/*
* If the new CPU misses an advertised feature, we cannot proceed
* further, park the cpu.
*/
- if (!caps[i].matches(&caps[i]))
+ if (!feature_matches(__raw_read_system_reg(caps[i].sys_reg) , &caps[i]))
fail_incapable_cpu("arm64_features", &caps[i]);
if (caps[i].enable)
caps[i].enable(NULL);
--
1.7.9.5


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