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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: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Suzuki K. Poulose 2015-11-18 17:08:56 +00:00 committed by Catalin Marinas
parent 667c27597c
commit d211827184
1 changed files with 12 additions and 0 deletions
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12
arch/arm64/include/asm/cpufeature.h
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@ -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);