From: "Suzuki K. Poulose" <suzuki.poul...@arm.com> This patch keeps track of the mixed endian EL0 support across the system and provides helper functions to export it. The status is a boolean indicating whether all the CPUs on the system supports mixed endian at EL0.
Signed-off-by: Suzuki K. Poulose <suzuki.poul...@arm.com> --- arch/arm64/include/asm/cpufeature.h | 10 ++++++++++ arch/arm64/kernel/cpuinfo.c | 22 ++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 07547cc..c7f68d1 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -26,6 +26,9 @@ #define ARM64_NCAPS 2 +#define ID_AA64MMFR0_EL1_BigEndEL0 (0x1UL << 16) +#define ID_AA64MMFR0_EL1_BigEnd (0x1UL << 8) + #ifndef __ASSEMBLY__ extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); @@ -51,7 +54,14 @@ static inline void cpus_set_cap(unsigned int num) __set_bit(num, cpu_hwcaps); } +static inline bool id_aa64mmfr0_mixed_endian_el0(unsigned long mmfr0) +{ + return !!(mmfr0 & (ID_AA64MMFR0_EL1_BigEndEL0 | ID_AA64MMFR0_EL1_BigEnd)); +} + void check_local_cpu_errata(void); +bool system_supports_mixed_endian_el0(void); +bool cpu_supports_mixed_endian_el0(void); #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 07d435c..b6d1135 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -35,6 +35,7 @@ */ DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data); static struct cpuinfo_arm64 boot_cpu_data; +static bool mixed_endian_el0 = true; static char *icache_policy_str[] = { [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN", @@ -68,6 +69,26 @@ static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info) pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu); } +bool cpu_supports_mixed_endian_el0(void) +{ + return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1)); +} + +bool system_supports_mixed_endian_el0(void) +{ + return mixed_endian_el0; +} + +static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info) +{ + mixed_endian_el0 &= id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0); +} + +static void update_cpu_features(struct cpuinfo_arm64 *info) +{ + update_mixed_endian_el0_support(info); +} + static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu) { if ((boot & mask) == (cur & mask)) @@ -215,6 +236,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) cpuinfo_detect_icache_policy(info); check_local_cpu_errata(); + update_cpu_features(info); } void cpuinfo_store_cpu(void) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/