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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-01-11 16:41:52 +0000
committerHerbert Xu <herbert@gondor.apana.org.au>2017-01-13 00:26:49 +0800
commitbed593c0e852f5c1efd3ca4e984fd744c51cf6ee (patch)
treec3ef5fd3b1f202288c63d037f1b0bf62ea26fd4f /arch/arm64/crypto/aes-cipher-glue.c
parent293614ce3eda94a3c9b38d5c18fdc06eb1397221 (diff)
crypto: arm64/aes - add scalar implementation
This adds a scalar implementation of AES, based on the precomputed tables that are exposed by the generic AES code. Since rotates are cheap on arm64, this implementation only uses the 4 core tables (of 1 KB each), and avoids the prerotated ones, reducing the D-cache footprint by 75%. On Cortex-A57, this code manages 13.0 cycles per byte, which is ~34% faster than the generic C code. (Note that this is still >13x slower than the code that uses the optional ARMv8 Crypto Extensions, which manages <1 cycles per byte.) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/arm64/crypto/aes-cipher-glue.c')
-rw-r--r--arch/arm64/crypto/aes-cipher-glue.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/arch/arm64/crypto/aes-cipher-glue.c b/arch/arm64/crypto/aes-cipher-glue.c
new file mode 100644
index 000000000000..7288e7cbebff
--- /dev/null
+++ b/arch/arm64/crypto/aes-cipher-glue.c
@@ -0,0 +1,69 @@
+/*
+ * Scalar AES core transform
+ *
+ * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@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 <crypto/aes.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
+EXPORT_SYMBOL(__aes_arm64_encrypt);
+
+asmlinkage void __aes_arm64_decrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
+EXPORT_SYMBOL(__aes_arm64_decrypt);
+
+static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ int rounds = 6 + ctx->key_length / 4;
+
+ __aes_arm64_encrypt(ctx->key_enc, out, in, rounds);
+}
+
+static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ int rounds = 6 + ctx->key_length / 4;
+
+ __aes_arm64_decrypt(ctx->key_dec, out, in, rounds);
+}
+
+static struct crypto_alg aes_alg = {
+ .cra_name = "aes",
+ .cra_driver_name = "aes-arm64",
+ .cra_priority = 200,
+ .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,
+ .cra_cipher.cia_max_keysize = AES_MAX_KEY_SIZE,
+ .cra_cipher.cia_setkey = crypto_aes_set_key,
+ .cra_cipher.cia_encrypt = aes_encrypt,
+ .cra_cipher.cia_decrypt = aes_decrypt
+};
+
+static int __init aes_init(void)
+{
+ return crypto_register_alg(&aes_alg);
+}
+
+static void __exit aes_fini(void)
+{
+ crypto_unregister_alg(&aes_alg);
+}
+
+module_init(aes_init);
+module_exit(aes_fini);
+
+MODULE_DESCRIPTION("Scalar AES cipher for arm64");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_CRYPTO("aes");