From: James Morse james.morse@arm.com
commit 79b0e09a3c9bd74ee54582efdb351179d7c00351 upstream.
Based on arch/arm/include/asm/cputype.h, this function does the shifting and sign extension necessary when accessing cpu feature fields.
Signed-off-by: James Morse james.morse@arm.com Suggested-by: Russell King linux@arm.linux.org.uk Acked-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: David Brown david.brown@linaro.org --- arch/arm64/include/asm/cpufeature.h | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index ad54dbf..674cadd 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -70,6 +70,13 @@ static inline void cpus_set_cap(unsigned int num) __set_bit(num, cpu_hwcaps); }
+static inline int __attribute_const__ cpuid_feature_extract_field(u64 features, + int field) +{ + return (s64)(features << (64 - 4 - field)) >> (64 - 4); +} + + void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps, const char *info); void check_local_cpu_errata(void);