arm64: Use register field helper in kaslr_requires_kpti() (a569f5f3) · Commits · 戴 / test

Rather than open-code the extraction of the E0PD field from the MMFR2 register, we can use the cpuid_feature_extract_unsigned_field() helper instead. Acked-by:

Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by:

Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:

Will Deacon <will@kernel.org>

arch/arm64/kernel/cpufeature.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -980,7 +980,6 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
		*/
		bool kaslr_requires_kpti(void)
		{
		u64 ftr;
		if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
		return false;

		@@ -989,8 +988,9 @@ bool kaslr_requires_kpti(void)
		* where available.
		*/
		if (IS_ENABLED(CONFIG_ARM64_E0PD)) {
		ftr = read_sysreg_s(SYS_ID_AA64MMFR2_EL1);
		if ((ftr >> ID_AA64MMFR2_E0PD_SHIFT) & 0xf)
		u64 mmfr2 = read_sysreg_s(SYS_ID_AA64MMFR2_EL1);
		if (cpuid_feature_extract_unsigned_field(mmfr2,
		ID_AA64MMFR2_E0PD_SHIFT))
		return false;
		}

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