317f2f750d
This patch adds support for the AES symmetric encryption algorithm for CPUs that have support for the AES part of the ARM v8 Crypto Extensions. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
156 lines
3.8 KiB
C
156 lines
3.8 KiB
C
/*
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* aes-ce-cipher.c - core AES cipher using ARMv8 Crypto Extensions
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*
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* Copyright (C) 2013 - 2014 Linaro Ltd <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <asm/neon.h>
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#include <crypto/aes.h>
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#include <linux/cpufeature.h>
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#include <linux/crypto.h>
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#include <linux/module.h>
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MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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struct aes_block {
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u8 b[AES_BLOCK_SIZE];
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};
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static int num_rounds(struct crypto_aes_ctx *ctx)
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{
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/*
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* # of rounds specified by AES:
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* 128 bit key 10 rounds
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* 192 bit key 12 rounds
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* 256 bit key 14 rounds
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* => n byte key => 6 + (n/4) rounds
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*/
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return 6 + ctx->key_length / 4;
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}
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static void aes_cipher_encrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
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{
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struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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struct aes_block *out = (struct aes_block *)dst;
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struct aes_block const *in = (struct aes_block *)src;
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void *dummy0;
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int dummy1;
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kernel_neon_begin_partial(4);
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__asm__(" ld1 {v0.16b}, %[in] ;"
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" ld1 {v1.2d}, [%[key]], #16 ;"
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" cmp %w[rounds], #10 ;"
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" bmi 0f ;"
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" bne 3f ;"
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" mov v3.16b, v1.16b ;"
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" b 2f ;"
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"0: mov v2.16b, v1.16b ;"
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" ld1 {v3.2d}, [%[key]], #16 ;"
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"1: aese v0.16b, v2.16b ;"
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" aesmc v0.16b, v0.16b ;"
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"2: ld1 {v1.2d}, [%[key]], #16 ;"
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" aese v0.16b, v3.16b ;"
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" aesmc v0.16b, v0.16b ;"
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"3: ld1 {v2.2d}, [%[key]], #16 ;"
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" subs %w[rounds], %w[rounds], #3 ;"
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" aese v0.16b, v1.16b ;"
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" aesmc v0.16b, v0.16b ;"
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" ld1 {v3.2d}, [%[key]], #16 ;"
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" bpl 1b ;"
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" aese v0.16b, v2.16b ;"
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" eor v0.16b, v0.16b, v3.16b ;"
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" st1 {v0.16b}, %[out] ;"
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: [out] "=Q"(*out),
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[key] "=r"(dummy0),
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[rounds] "=r"(dummy1)
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: [in] "Q"(*in),
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"1"(ctx->key_enc),
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"2"(num_rounds(ctx) - 2)
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: "cc");
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kernel_neon_end();
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}
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static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
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{
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struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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struct aes_block *out = (struct aes_block *)dst;
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struct aes_block const *in = (struct aes_block *)src;
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void *dummy0;
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int dummy1;
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kernel_neon_begin_partial(4);
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__asm__(" ld1 {v0.16b}, %[in] ;"
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" ld1 {v1.2d}, [%[key]], #16 ;"
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" cmp %w[rounds], #10 ;"
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" bmi 0f ;"
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" bne 3f ;"
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" mov v3.16b, v1.16b ;"
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" b 2f ;"
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"0: mov v2.16b, v1.16b ;"
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" ld1 {v3.2d}, [%[key]], #16 ;"
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"1: aesd v0.16b, v2.16b ;"
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" aesimc v0.16b, v0.16b ;"
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"2: ld1 {v1.2d}, [%[key]], #16 ;"
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" aesd v0.16b, v3.16b ;"
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" aesimc v0.16b, v0.16b ;"
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"3: ld1 {v2.2d}, [%[key]], #16 ;"
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" subs %w[rounds], %w[rounds], #3 ;"
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" aesd v0.16b, v1.16b ;"
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" aesimc v0.16b, v0.16b ;"
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" ld1 {v3.2d}, [%[key]], #16 ;"
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" bpl 1b ;"
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" aesd v0.16b, v2.16b ;"
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" eor v0.16b, v0.16b, v3.16b ;"
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" st1 {v0.16b}, %[out] ;"
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: [out] "=Q"(*out),
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[key] "=r"(dummy0),
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[rounds] "=r"(dummy1)
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: [in] "Q"(*in),
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"1"(ctx->key_dec),
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"2"(num_rounds(ctx) - 2)
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: "cc");
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kernel_neon_end();
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}
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static struct crypto_alg aes_alg = {
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.cra_name = "aes",
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.cra_driver_name = "aes-ce",
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.cra_priority = 300,
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = AES_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct crypto_aes_ctx),
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.cra_module = THIS_MODULE,
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.cra_cipher = {
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.cia_min_keysize = AES_MIN_KEY_SIZE,
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.cia_max_keysize = AES_MAX_KEY_SIZE,
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.cia_setkey = crypto_aes_set_key,
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.cia_encrypt = aes_cipher_encrypt,
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.cia_decrypt = aes_cipher_decrypt
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}
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};
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static int __init aes_mod_init(void)
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{
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return crypto_register_alg(&aes_alg);
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}
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static void __exit aes_mod_exit(void)
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{
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crypto_unregister_alg(&aes_alg);
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}
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module_cpu_feature_match(AES, aes_mod_init);
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module_exit(aes_mod_exit);
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