[PATCH v3 4/4] arm64: add Crypto Extensions based synchronous core AES cipher
Ard Biesheuvel
ard.biesheuvel at linaro.org
Mon Feb 24 09:26:30 EST 2014
This implements the core AES cipher using the ARMv8 Crypto Extensions,
using only NEON registers q0 - q3.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
arch/arm64/Makefile | 1 +
arch/arm64/crypto/Makefile | 13 ++++
arch/arm64/crypto/aes-ce-cipher.c | 149 ++++++++++++++++++++++++++++++++++++++
crypto/Kconfig | 6 ++
4 files changed, 169 insertions(+)
create mode 100644 arch/arm64/crypto/Makefile
create mode 100644 arch/arm64/crypto/aes-ce-cipher.c
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 2fceb71ac3b7..8185a913c5ed 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -45,6 +45,7 @@ export TEXT_OFFSET GZFLAGS
core-y += arch/arm64/kernel/ arch/arm64/mm/
core-$(CONFIG_KVM) += arch/arm64/kvm/
core-$(CONFIG_XEN) += arch/arm64/xen/
+core-$(CONFIG_CRYPTO) += arch/arm64/crypto/
libs-y := arch/arm64/lib/ $(libs-y)
libs-y += $(LIBGCC)
diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile
new file mode 100644
index 000000000000..ac58945c50b3
--- /dev/null
+++ b/arch/arm64/crypto/Makefile
@@ -0,0 +1,13 @@
+#
+# linux/arch/arm64/crypto/Makefile
+#
+# Copyright (C) 2013 Linaro Ltd <ard.biesheuvel at linaro.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+
+obj-$(CONFIG_CRYPTO_AES_ARM64_CE) += aes-ce-cipher.o
+
+CFLAGS_aes-ce-cipher.o += -march=armv8-a+crypto
diff --git a/arch/arm64/crypto/aes-ce-cipher.c b/arch/arm64/crypto/aes-ce-cipher.c
new file mode 100644
index 000000000000..24436dbcae3e
--- /dev/null
+++ b/arch/arm64/crypto/aes-ce-cipher.c
@@ -0,0 +1,149 @@
+/*
+ * linux/arch/arm64/crypto/aes-ce-cipher.c
+ *
+ * Copyright (C) 2014 Linaro Ltd <ard.biesheuvel at linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <asm/hwcap.h>
+#include <asm/neon.h>
+#include <crypto/aes.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel at linaro.org>");
+MODULE_LICENSE("GPL");
+
+struct aes_block {
+ u8 b[AES_BLOCK_SIZE];
+};
+
+static int num_rounds(struct crypto_aes_ctx *ctx)
+{
+ /*
+ * # of rounds specified by AES:
+ * 128 bit key 10 rounds
+ * 192 bit key 12 rounds
+ * 256 bit key 14 rounds
+ * => n byte key => 6 + (n/4) rounds
+ */
+ return 6 + ctx->key_length / 4;
+}
+
+static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct aes_block *out = (struct aes_block *)dst;
+ struct aes_block const *in = (struct aes_block *)src;
+
+ kernel_neon_begin_partial(4);
+
+ __asm__(" ld1 {v0.16b}, %[in] ;"
+ " ld1 {v1.2d}, [%[key]], #16 ;"
+ " cmp %[rounds], #10 ;"
+ " bmi 0f ;"
+ " bne 3f ;"
+ " mov v3.16b, v1.16b ;"
+ " b 2f ;"
+ "0: mov v2.16b, v1.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ "1: aese v0.16b, v2.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ "2: ld1 {v1.2d}, [%[key]], #16 ;"
+ " aese v0.16b, v3.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ "3: ld1 {v2.2d}, [%[key]], #16 ;"
+ " subs %[rounds], %[rounds], #3 ;"
+ " aese v0.16b, v1.16b ;"
+ " aesmc v0.16b, v0.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ " bpl 1b ;"
+ " aese v0.16b, v2.16b ;"
+ " eor v0.16b, v0.16b, v3.16b ;"
+ " st1 {v0.16b}, %[out] ;"
+
+ : [out] "=Q"(*out)
+ : [in] "Q"(*in),
+ [rounds] "r"(num_rounds(ctx) - 2),
+ [key] "r"(ctx->key_enc)
+ : "cc");
+
+ kernel_neon_end();
+}
+
+static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct aes_block *out = (struct aes_block *)dst;
+ struct aes_block const *in = (struct aes_block *)src;
+
+ kernel_neon_begin_partial(4);
+
+ __asm__(" ld1 {v0.16b}, %[in] ;"
+ " ld1 {v1.2d}, [%[key]], #16 ;"
+ " cmp %[rounds], #10 ;"
+ " bmi 0f ;"
+ " bne 3f ;"
+ " mov v3.16b, v1.16b ;"
+ " b 2f ;"
+ "0: mov v2.16b, v1.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ "1: aesd v0.16b, v2.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ "2: ld1 {v1.2d}, [%[key]], #16 ;"
+ " aesd v0.16b, v3.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ "3: ld1 {v2.2d}, [%[key]], #16 ;"
+ " subs %[rounds], %[rounds], #3 ;"
+ " aesd v0.16b, v1.16b ;"
+ " aesimc v0.16b, v0.16b ;"
+ " ld1 {v3.2d}, [%[key]], #16 ;"
+ " bpl 1b ;"
+ " aese v0.16b, v2.16b ;"
+ " eor v0.16b, v0.16b, v3.16b ;"
+ " st1 {v0.16b}, %[out] ;"
+
+ : [out] "=Q"(*out)
+ : [in] "Q"(*in),
+ [rounds] "r"(num_rounds(ctx) - 2),
+ [key] "r"(ctx->key_dec)
+ : "cc");
+
+ kernel_neon_end();
+}
+
+static struct crypto_alg aes_alg = {
+ .cra_name = "aes",
+ .cra_driver_name = "aes-ce",
+ .cra_priority = 300,
+ .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
+ .cra_blocksize = AES_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct crypto_aes_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_cipher = {
+ .cia_min_keysize = AES_MIN_KEY_SIZE,
+ .cia_max_keysize = AES_MAX_KEY_SIZE,
+ .cia_setkey = crypto_aes_set_key,
+ .cia_encrypt = aes_cipher_encrypt,
+ .cia_decrypt = aes_cipher_decrypt
+ }
+};
+
+static int __init aes_mod_init(void)
+{
+ if (!(elf_hwcap & HWCAP_AES))
+ return -ENODEV;
+ return crypto_register_alg(&aes_alg);
+}
+
+static void __exit aes_mod_exit(void)
+{
+ crypto_unregister_alg(&aes_alg);
+}
+
+module_init(aes_mod_init);
+module_exit(aes_mod_exit);
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 7bcb70d216e1..f1d98bc346b6 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -791,6 +791,12 @@ config CRYPTO_AES_ARM_BS
This implementation does not rely on any lookup tables so it is
believed to be invulnerable to cache timing attacks.
+config CRYPTO_AES_ARM64_CE
+ tristate "Synchronous AES cipher using ARMv8 Crypto Extensions"
+ depends on ARM64 && KERNEL_MODE_NEON
+ select CRYPTO_ALGAPI
+ select CRYPTO_AES
+
config CRYPTO_ANUBIS
tristate "Anubis cipher algorithm"
select CRYPTO_ALGAPI
--
1.8.3.2
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