In order to support the kpkeys_hardened_pgtables feature, we will need to decide how to allocate early page tables, before boot CPU features have been detected. To that end, add a new helper to check that the boot CPU supports POE (meaning POE will eventually be enabled).
Signed-off-by: Kevin Brodsky <[email protected]> --- arch/arm64/include/asm/cpufeature.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 4de51f8d92cb..8722e9e62702 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -1078,6 +1078,18 @@ static inline bool cpu_has_lpa2(void) #endif } +static inline bool cpu_has_poe(void) +{ + u64 mmfr3; + + if (!IS_ENABLED(CONFIG_ARM64_POE)) + return false; + + mmfr3 = read_sysreg_s(SYS_ID_AA64MMFR3_EL1); + return cpuid_feature_extract_unsigned_field(mmfr3, + ID_AA64MMFR3_EL1_S1POE_SHIFT); +} + #endif /* __ASSEMBLER__ */ #endif -- 2.51.2
