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e211506979
To accommodate systems that may disallow use of the NEON in kernel mode in some circumstances, introduce a C fallback for synchronous AES in CTR mode, and use it if may_use_simd() returns false. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
54 lines
1.3 KiB
C
54 lines
1.3 KiB
C
/*
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* Fallback for sync aes(ctr) in contexts where kernel mode NEON
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* is not allowed
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*
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* Copyright (C) 2017 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 <crypto/aes.h>
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#include <crypto/internal/skcipher.h>
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asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
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static inline int aes_ctr_encrypt_fallback(struct crypto_aes_ctx *ctx,
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struct skcipher_request *req)
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{
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struct skcipher_walk walk;
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u8 buf[AES_BLOCK_SIZE];
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int err;
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err = skcipher_walk_virt(&walk, req, true);
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while (walk.nbytes > 0) {
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u8 *dst = walk.dst.virt.addr;
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u8 *src = walk.src.virt.addr;
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int nbytes = walk.nbytes;
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int tail = 0;
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if (nbytes < walk.total) {
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nbytes = round_down(nbytes, AES_BLOCK_SIZE);
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tail = walk.nbytes % AES_BLOCK_SIZE;
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}
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do {
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int bsize = min(nbytes, AES_BLOCK_SIZE);
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__aes_arm64_encrypt(ctx->key_enc, buf, walk.iv,
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6 + ctx->key_length / 4);
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crypto_xor_cpy(dst, src, buf, bsize);
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crypto_inc(walk.iv, AES_BLOCK_SIZE);
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dst += AES_BLOCK_SIZE;
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src += AES_BLOCK_SIZE;
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nbytes -= AES_BLOCK_SIZE;
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} while (nbytes > 0);
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err = skcipher_walk_done(&walk, tail);
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}
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return err;
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}
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