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

[Suzuki K Poulose]

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

Tested-by: Yury Norov <yno...@caviumnetworks.com>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
---
 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