diff options
| author | Vladimir Murzin <vladimir.murzin@arm.com> | 2021-03-12 17:38:10 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-03-26 09:37:23 +0000 |
| commit | 18107f8a2df6bf1c6cac8d0713f757f866d5af51 (patch) | |
| tree | 0411230b8d6c259233a6aadcd0c0aaf261b86c2a /arch/arm64/kernel/cpufeature.c | |
| parent | 1e28eed17697bcf343c6743f0028cc3b5dd88bf0 (diff) | |
arm64: Support execute-only permissions with Enhanced PAN
Enhanced Privileged Access Never (EPAN) allows Privileged Access Never
to be used with Execute-only mappings.
Absence of such support was a reason for 24cecc377463 ("arm64: Revert
support for execute-only user mappings"). Thus now it can be revisited
and re-enabled.
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210312173811.58284-2-vladimir.murzin@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 066030717a4c..2ab04967dca7 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1821,6 +1821,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_enable_pan, }, #endif /* CONFIG_ARM64_PAN */ +#ifdef CONFIG_ARM64_EPAN + { + .desc = "Enhanced Privileged Access Never", + .capability = ARM64_HAS_EPAN, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_cpuid_feature, + .sys_reg = SYS_ID_AA64MMFR1_EL1, + .field_pos = ID_AA64MMFR1_PAN_SHIFT, + .sign = FTR_UNSIGNED, + .min_field_value = 3, + }, +#endif /* CONFIG_ARM64_EPAN */ #ifdef CONFIG_ARM64_LSE_ATOMICS { .desc = "LSE atomic instructions", |