08c6781cfa
The asynchronous, merged implementations of AES in CBC, CTR and XTS modes are preferred when available (i.e., when instantiating ablkciphers explicitly). However, the synchronous core AES cipher combined with the generic CBC mode implementation will produce a 'cbc(aes)' blkcipher that is callable asynchronously as well. To prevent this implementation from being used when the accelerated asynchronous implemenation is also available, lower its priority to 250 (i.e., below the asynchronous module's priority of 300). Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
266 lines
6.3 KiB
C
266 lines
6.3 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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#include "aes-ce-setkey.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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/*
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* aes_sub() - use the aese instruction to perform the AES sbox substitution
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* on each byte in 'input'
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*/
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static u32 aes_sub(u32 input)
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{
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u32 ret;
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__asm__("dup v1.4s, %w[in] ;"
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"movi v0.16b, #0 ;"
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"aese v0.16b, v1.16b ;"
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"umov %w[out], v0.4s[0] ;"
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: [out] "=r"(ret)
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: [in] "r"(input)
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: "v0","v1");
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return ret;
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}
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int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
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unsigned int key_len)
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{
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/*
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* The AES key schedule round constants
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*/
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static u8 const rcon[] = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
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};
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u32 kwords = key_len / sizeof(u32);
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struct aes_block *key_enc, *key_dec;
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int i, j;
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if (key_len != AES_KEYSIZE_128 &&
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key_len != AES_KEYSIZE_192 &&
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key_len != AES_KEYSIZE_256)
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return -EINVAL;
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memcpy(ctx->key_enc, in_key, key_len);
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ctx->key_length = key_len;
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kernel_neon_begin_partial(2);
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for (i = 0; i < sizeof(rcon); i++) {
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u32 *rki = ctx->key_enc + (i * kwords);
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u32 *rko = rki + kwords;
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rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
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rko[1] = rko[0] ^ rki[1];
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rko[2] = rko[1] ^ rki[2];
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rko[3] = rko[2] ^ rki[3];
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if (key_len == AES_KEYSIZE_192) {
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if (i >= 7)
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break;
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rko[4] = rko[3] ^ rki[4];
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rko[5] = rko[4] ^ rki[5];
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} else if (key_len == AES_KEYSIZE_256) {
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if (i >= 6)
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break;
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rko[4] = aes_sub(rko[3]) ^ rki[4];
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rko[5] = rko[4] ^ rki[5];
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rko[6] = rko[5] ^ rki[6];
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rko[7] = rko[6] ^ rki[7];
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}
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}
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/*
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* Generate the decryption keys for the Equivalent Inverse Cipher.
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* This involves reversing the order of the round keys, and applying
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* the Inverse Mix Columns transformation on all but the first and
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* the last one.
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*/
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key_enc = (struct aes_block *)ctx->key_enc;
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key_dec = (struct aes_block *)ctx->key_dec;
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j = num_rounds(ctx);
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key_dec[0] = key_enc[j];
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for (i = 1, j--; j > 0; i++, j--)
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__asm__("ld1 {v0.16b}, %[in] ;"
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"aesimc v1.16b, v0.16b ;"
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"st1 {v1.16b}, %[out] ;"
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: [out] "=Q"(key_dec[i])
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: [in] "Q"(key_enc[j])
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: "v0","v1");
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key_dec[i] = key_enc[0];
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kernel_neon_end();
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return 0;
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}
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EXPORT_SYMBOL(ce_aes_expandkey);
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int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
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unsigned int key_len)
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{
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struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
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int ret;
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ret = ce_aes_expandkey(ctx, in_key, key_len);
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if (!ret)
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return 0;
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tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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EXPORT_SYMBOL(ce_aes_setkey);
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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 = 250,
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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 = ce_aes_setkey,
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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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