Commit 79b0e09a authored Jul 21, 2015 by James Morse Committed by Will Deacon Jul 27, 2015

arm64: kernel: Add cpuid_feature_extract_field() for 4bit sign extension



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>

parent ae2fb7ec

arch/arm64/include/asm/cpufeature.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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);