Messages in this thread Patch in this message | | | From | "Suzuki K. Poulose" <> | Subject | [PATCH 1/5] arm64: cpufeature: Add helpers for extracting unsigned values | Date | Wed, 18 Nov 2015 17:08:56 +0000 |
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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: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com> --- 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 11d5bb0f..7a16102 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -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); -- 1.7.9.5
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