The accelerated CRC32 module for ARM may use either the scalar CRC32 instructions, the NEON 64x64 to 128 bit polynomial multiplication (vmull.p64) instruction, or both, depending on what the current CPU supports. However, this also requires support in binutils, and as it turns out, versions of binutils exist that support the vmull.p64 instruction but not the crc32 instructions. So refactor the Makefile logic so that this module only gets built if binutils has support for both. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> --- arch/arm/crypto/Makefile | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm/crypto/Makefile b/arch/arm/crypto/Makefile index 1822c4697278..f2215fbeed13 100644 --- a/arch/arm/crypto/Makefile +++ b/arch/arm/crypto/Makefile @@ -15,7 +15,17 @@ ce-obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o ce-obj-$(CONFIG_CRYPTO_SHA2_ARM_CE) += sha2-arm-ce.o ce-obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o ce-obj-$(CONFIG_CRYPTO_CRCT10DIF_ARM_CE) += crct10dif-arm-ce.o -ce-obj-$(CONFIG_CRYPTO_CRC32_ARM_CE) += crc32-arm-ce.o +crc-obj-$(CONFIG_CRYPTO_CRC32_ARM_CE) += crc32-arm-ce.o + +ifneq ($(crc-obj-y)$(crc-obj-m),) +ifeq ($(call as-instr,.arch armv8-a\n.arch_extension crc,y,n),y) +ce-obj-y += $(crc-obj-y) +ce-obj-m += $(crc-obj-m) +else +$(warning These CRC Extensions modules need binutils 2.23 or higher) +$(warning $(crc-obj-y) $(crc-obj-m)) +endif +endif ifneq ($(ce-obj-y)$(ce-obj-m),) ifeq ($(call as-instr,.fpu crypto-neon-fp-armv8,y,n),y) -- 2.7.4
