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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-08-27 14:02:43 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2018-09-10 18:10:09 +0300
commit86d0dd34eafffbc76a81aba6ae2d71927d3835a8 (patch)
treeb083d6e8636d919c268a8b6fef9d0311e77f50dd /arch
parent9784d82db3eb3de7851e5a3f4a2481607de2452c (diff)
downloadlinux-86d0dd34eafffbc76a81aba6ae2d71927d3835a8.tar.xz
arm64: cpufeature: add feature for CRC32 instructions
Add a CRC32 feature bit and wire it up to the CPU id register so we will be able to use alternatives patching for CRC32 operations. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/cpucaps.h3
-rw-r--r--arch/arm64/kernel/cpufeature.c9
2 files changed, 11 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index ae1f70450fb2..9932aca9704b 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -51,7 +51,8 @@
#define ARM64_SSBD 30
#define ARM64_MISMATCHED_CACHE_TYPE 31
#define ARM64_HAS_STAGE2_FWB 32
+#define ARM64_HAS_CRC32 33
-#define ARM64_NCAPS 33
+#define ARM64_NCAPS 34
#endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e238b7932096..7626b80128f5 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1222,6 +1222,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.cpu_enable = cpu_enable_hw_dbm,
},
#endif
+ {
+ .desc = "CRC32 instructions",
+ .capability = ARM64_HAS_CRC32,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .matches = has_cpuid_feature,
+ .sys_reg = SYS_ID_AA64ISAR0_EL1,
+ .field_pos = ID_AA64ISAR0_CRC32_SHIFT,
+ .min_field_value = 1,
+ },
{},
};