From b3f1537893b54d0f42f52e0f4cde5e17e21f564c Mon Sep 17 00:00:00 2001 From: "Suzuki K. Poulose" Date: Mon, 19 Oct 2015 14:24:47 +0100 Subject: [PATCH] arm64: Read system wide CPUID value Add an API for reading the safe CPUID value across the system from the new infrastructure. Signed-off-by: Suzuki K. Poulose Tested-by: Dave Martin Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/cpufeature.h | 2 ++ arch/arm64/kernel/cpufeature.c | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 01bb5cf995af..81217220eb92 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -144,6 +144,8 @@ void check_local_cpu_features(void); bool cpu_supports_mixed_endian_el0(void); bool system_supports_mixed_endian_el0(void); +u64 read_system_reg(u32 id); + #endif /* __ASSEMBLY__ */ #endif diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index aae181760e1f..b4656cabf87f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -590,6 +590,15 @@ void update_cpu_features(int cpu, update_mixed_endian_el0_support(info); } +u64 read_system_reg(u32 id) +{ + struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id); + + /* We shouldn't get a request for an unsupported register */ + BUG_ON(!regp); + return regp->sys_val; +} + static bool feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry) { -- 2.20.1