[PATCH v2 3/8] arm64: Add helpers for detecting AArch32 support at EL0

From: Suzuki K Poulose
Date: Thu Feb 25 2016 - 04:54:56 EST


Adds a helper to extract the support for AArch32 at EL0

Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
arch/arm64/include/asm/cpufeature.h | 7 +++++++
arch/arm64/include/asm/sysreg.h | 1 +
2 files changed, 8 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 5444a77..98f83d7 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -165,6 +165,13 @@ static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0)
cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_BIGENDEL0_SHIFT) == 0x1;
}

+static inline bool id_aa64pfr0_32bit_el0(u64 pfr0)
+{
+ u32 val = cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_EL0_SHIFT);
+
+ return val == ID_AA64PFR0_EL0_32BIT_64BIT;
+}
+
void __init setup_cpu_features(void);

void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 4aeebec..76d2f3e 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -111,6 +111,7 @@
#define ID_AA64PFR0_ASIMD_SUPPORTED 0x0
#define ID_AA64PFR0_EL1_64BIT_ONLY 0x1
#define ID_AA64PFR0_EL0_64BIT_ONLY 0x1
+#define ID_AA64PFR0_EL0_32BIT_64BIT 0x2

/* id_aa64mmfr0 */
#define ID_AA64MMFR0_TGRAN4_SHIFT 28
--
1.7.9.5