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Commit d2118271 authored by Suzuki K. Poulose's avatar Suzuki K. Poulose Committed by Catalin Marinas
Browse files

arm64: cpufeature: Add helpers for extracting unsigned values 



The cpuid_feature_extract_field() extracts the feature value
as a signed integer. This could be problematic for features
whose values are unsigned. e.g, ID_AA64DFR0_EL1:BRPs. Add
an unsigned variant for the unsigned fields.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: default avatarSuzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 667c2759

arch/arm64/include/asm/cpufeature.h

+12 −0
Original line number Diff line number Diff line
@@ -123,6 +123,18 @@ cpuid_feature_extract_field(u64 features, int field) 
	return cpuid_feature_extract_field_width(features, field, 4);

}



static inline unsigned int __attribute_const__

cpuid_feature_extract_unsigned_field_width(u64 features, int field, int width)

{

	return (u64)(features << (64 - width - field)) >> (64 - width);

}



static inline unsigned int __attribute_const__

cpuid_feature_extract_unsigned_field(u64 features, int field)

{

	return cpuid_feature_extract_unsigned_field_width(features, field, 4);

}



static inline u64 arm64_ftr_mask(struct arm64_ftr_bits *ftrp)

{

	return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);