[PATCH v3 5/7] arm64: cpufeature: Track 32bit EL0 support

From: Suzuki K Poulose
Date: Thu Mar 31 2016 - 13:28:11 EST


Add cpu_hwcap bit for keeping track of the support for 32bit EL0.

Tested-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
arch/arm64/include/asm/cpufeature.h | 8 +++++++-
arch/arm64/kernel/cpufeature.c | 9 +++++++++
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 7f64285..ca8fb4b 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -35,8 +35,9 @@
#define ARM64_ALT_PAN_NOT_UAO 10
#define ARM64_HAS_VIRT_HOST_EXTN 11
#define ARM64_WORKAROUND_CAVIUM_27456 12
+#define ARM64_HAS_32BIT_EL0 13

-#define ARM64_NCAPS 13
+#define ARM64_NCAPS 14

#ifndef __ASSEMBLY__

@@ -192,6 +193,11 @@ static inline bool cpu_supports_mixed_endian_el0(void)
return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
}

+static inline bool system_supports_32bit_el0(void)
+{
+ return cpus_have_cap(ARM64_HAS_32BIT_EL0);
+}
+
static inline bool system_supports_mixed_endian_el0(void)
{
return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index cfc0cfd..739314b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -733,6 +733,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.capability = ARM64_HAS_VIRT_HOST_EXTN,
.matches = runs_at_el2,
},
+ {
+ .desc = "32bit EL0 Support",
+ .capability = ARM64_HAS_32BIT_EL0,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64PFR0_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64PFR0_EL0_SHIFT,
+ .min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
+ },
{},
};

--
1.7.9.5