Re: [PATCH v3 03/25] arm64: cpufeature: add Permission Overlay Extension cpucap

On Fri, Nov 24, 2023 at 04:34:48PM +0000, Joey Gouly wrote:

--- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2078,6 +2078,22 @@ config ARM64_EPAN if the cpu does not implement the feature. endmenu # "ARMv8.7 architectural features" +menu "ARMv8.9 architectural features" +config ARM64_POE

• prompt "Permission Overlay Extension"
• def_bool y
• help

•  The Permission Overlay Extension is used to implement Memory
  

•  Protection Keys. Memory Protection Keys provides a mechanism for
  

•  enforcing page-based protections, but without requiring modification
  

•  of the page tables when an application changes protection domains.
  

•  For details, see Documentation/core-api/protection-keys.rst
  

•  If unsure, say y.
  

+endmenu # "ARMv8.9 architectural features"

I agree with Mark, we typically leave the Kconfig option towards the end of the series.

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 646591c67e7a..00b6d516ed3f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2731,6 +2731,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, EVT, IMP) }, +#ifdef CONFIG_ARM64_POE

• {

• .desc = "Stage-1 Permission Overlay Extension (S1POE)",
  

• .capability = ARM64_HAS_S1POE,
  

• .type = ARM64_CPUCAP_BOOT_CPU_FEATURE,
  

• .matches = has_cpuid_feature,
  

• ARM64_CPUID_FIELDS(ID_AA64MMFR3_EL1, S1POE, IMP)
  

• },

+#endif

Keeping the #ifdef here is ok, it won't be defined at this point.