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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