diff options
| author |   Suzuki K. Poulose <suzuki.poulose@arm.com> | 2015-11-18 17:08:56 +0000 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2015-11-26 18:02:42 +0000 |
| commit | d21182718400f51f0729ae8268d94bd820ec8b71 (patch) | |
| tree | 39225ba3b0e4be910d3bedef54a8236d0f0bd02e /arch | |
| parent | Revert "arm64: Mark kernel page ranges contiguous" (diff) | |
| download | linux-dev-d21182718400f51f0729ae8268d94bd820ec8b71.tar.xz linux-dev-d21182718400f51f0729ae8268d94bd820ec8b71.zip | |
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 11d5bb0fdd54..7a161027ee12 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); |