From: "Suzuki K. Poulose" <suzuki.poul...@arm.com>
Add an API for reading the safe CPUID value across the
system from the new infrastructure.
Signed-off-by: Suzuki K. Poulose <suzuki.poul...@arm.com>
---
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 7927ac2..f59e90a 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -149,6 +149,8 @@ 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 960a62f..a736c13 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -593,6 +593,15 @@ 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_sys_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)
{
--
1.7.9.5
--
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