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authorSuzuki K. Poulose <suzuki.poulose@arm.com>2015-11-18 17:08:56 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2015-11-26 18:02:42 +0000
commitd21182718400f51f0729ae8268d94bd820ec8b71 (patch)
tree39225ba3b0e4be910d3bedef54a8236d0f0bd02e /arch/arm64
parent667c27597ca823f20c524bbd486c6709f905673b (diff)
downloadop-kernel-dev-d21182718400f51f0729ae8268d94bd820ec8b71.zip
op-kernel-dev-d21182718400f51f0729ae8268d94bd820ec8b71.tar.gz
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/arm64')
-rw-r--r--arch/arm64/include/asm/cpufeature.h12
1 files changed, 12 insertions, 0 deletions
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);
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