crypto: arm - use Kconfig based compiler checks for crypto opcodes

Instead of allowing the Crypto Extensions algorithms to be selected when
using a toolchain that does not support them, and complain about it at
build time, use the information we have about the compiler to prevent
them from being selected in the first place. Users that are stuck with
a GCC version <4.8 are unlikely to care about these routines anyway, and
it cleans up the Makefile considerably.

While at it, add explicit 'armv8-a' CPU specifiers to the code that uses
the 'crypto-neon-fp-armv8' FPU specifier so we don't regress Clang, which
will complain about this in version 10 and later.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/crypto/Kconfig

@@ -30,7 +30,7 @@ config CRYPTO_SHA1_ARM_NEON
 
 config CRYPTO_SHA1_ARM_CE
 	tristate "SHA1 digest algorithm (ARM v8 Crypto Extensions)"
-	depends on KERNEL_MODE_NEON
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
 	select CRYPTO_SHA1_ARM
 	select CRYPTO_HASH
 	help
@@ -39,7 +39,7 @@ config CRYPTO_SHA1_ARM_CE
 
 config CRYPTO_SHA2_ARM_CE
 	tristate "SHA-224/256 digest algorithm (ARM v8 Crypto Extensions)"
-	depends on KERNEL_MODE_NEON
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
 	select CRYPTO_SHA256_ARM
 	select CRYPTO_HASH
 	help
@@ -96,7 +96,7 @@ config CRYPTO_AES_ARM_BS
 
 config CRYPTO_AES_ARM_CE
 	tristate "Accelerated AES using ARMv8 Crypto Extensions"
-	depends on KERNEL_MODE_NEON
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_SIMD
 	help
@@ -105,7 +105,7 @@ config CRYPTO_AES_ARM_CE
 
 config CRYPTO_GHASH_ARM_CE
 	tristate "PMULL-accelerated GHASH using NEON/ARMv8 Crypto Extensions"
-	depends on KERNEL_MODE_NEON
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
 	select CRYPTO_HASH
 	select CRYPTO_CRYPTD
 	select CRYPTO_GF128MUL
@@ -117,12 +117,14 @@ config CRYPTO_GHASH_ARM_CE
 
 config CRYPTO_CRCT10DIF_ARM_CE
 	tristate "CRCT10DIF digest algorithm using PMULL instructions"
-	depends on KERNEL_MODE_NEON && CRC_T10DIF
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on CRC_T10DIF
 	select CRYPTO_HASH
 
 config CRYPTO_CRC32_ARM_CE
 	tristate "CRC32(C) digest algorithm using CRC and/or PMULL instructions"
-	depends on KERNEL_MODE_NEON && CRC32
+	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on CRC32
 	select CRYPTO_HASH
 
 config CRYPTO_CHACHA20_NEON

arch/arm/crypto/Makefile

@@ -12,32 +12,12 @@ obj-$(CONFIG_CRYPTO_SHA512_ARM) += sha512-arm.o
 obj-$(CONFIG_CRYPTO_CHACHA20_NEON) += chacha-neon.o
 obj-$(CONFIG_CRYPTO_NHPOLY1305_NEON) += nhpoly1305-neon.o
 
-ce-obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
-ce-obj-$(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-$(CONFIG_CRYPTO_CRCT10DIF_ARM_CE) += crct10dif-arm-ce.o
-crc-obj-$(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)
-obj-y += $(ce-obj-y)
-obj-m += $(ce-obj-m)
-else
-$(warning These ARMv8 Crypto Extensions modules need binutils 2.23 or higher)
-$(warning $(ce-obj-y) $(ce-obj-m))
-endif
-endif
+obj-$(CONFIG_CRYPTO_AES_ARM_CE) += aes-arm-ce.o
+obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
+obj-$(CONFIG_CRYPTO_SHA2_ARM_CE) += sha2-arm-ce.o
+obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o
+obj-$(CONFIG_CRYPTO_CRCT10DIF_ARM_CE) += crct10dif-arm-ce.o
+obj-$(CONFIG_CRYPTO_CRC32_ARM_CE) += crc32-arm-ce.o
 
 aes-arm-y	:= aes-cipher-core.o aes-cipher-glue.o
 aes-arm-bs-y	:= aes-neonbs-core.o aes-neonbs-glue.o

arch/arm/crypto/aes-ce-core.S

@@ -9,6 +9,7 @@
 #include <asm/assembler.h>
 
 	.text
+	.arch		armv8-a
 	.fpu		crypto-neon-fp-armv8
 	.align		3
 

arch/arm/crypto/crct10dif-ce-core.S

@@ -72,7 +72,7 @@
 #endif
 
 	.text
-	.arch		armv7-a
+	.arch		armv8-a
 	.fpu		crypto-neon-fp-armv8
 
 	init_crc	.req	r0

arch/arm/crypto/ghash-ce-core.S

@@ -88,6 +88,7 @@
 	T3_H		.req	d17
 
 	.text
+	.arch		armv8-a
 	.fpu		crypto-neon-fp-armv8
 
 	.macro		__pmull_p64, rd, rn, rm, b1, b2, b3, b4

arch/arm/crypto/sha1-ce-core.S

@@ -10,6 +10,7 @@
 #include <asm/assembler.h>
 
 	.text
+	.arch		armv8-a
 	.fpu		crypto-neon-fp-armv8
 
 	k0		.req	q0

arch/arm/crypto/sha2-ce-core.S

@@ -10,6 +10,7 @@
 #include <asm/assembler.h>
 
 	.text
+	.arch		armv8-a
 	.fpu		crypto-neon-fp-armv8
 
 	k0		.req	q7