289 lines
8.1 KiB
C
289 lines
8.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* NEON-accelerated implementation of Speck128-XTS and Speck64-XTS
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*
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* Copyright (c) 2018 Google, Inc
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*
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* Note: the NIST recommendation for XTS only specifies a 128-bit block size,
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* but a 64-bit version (needed for Speck64) is fairly straightforward; the math
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* is just done in GF(2^64) instead of GF(2^128), with the reducing polynomial
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* x^64 + x^4 + x^3 + x + 1 from the original XEX paper (Rogaway, 2004:
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* "Efficient Instantiations of Tweakable Blockciphers and Refinements to Modes
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* OCB and PMAC"), represented as 0x1B.
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*/
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#include <asm/hwcap.h>
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#include <asm/neon.h>
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#include <asm/simd.h>
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#include <crypto/algapi.h>
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#include <crypto/gf128mul.h>
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#include <crypto/internal/skcipher.h>
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#include <crypto/speck.h>
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#include <crypto/xts.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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/* The assembly functions only handle multiples of 128 bytes */
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#define SPECK_NEON_CHUNK_SIZE 128
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/* Speck128 */
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struct speck128_xts_tfm_ctx {
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struct speck128_tfm_ctx main_key;
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struct speck128_tfm_ctx tweak_key;
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};
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asmlinkage void speck128_xts_encrypt_neon(const u64 *round_keys, int nrounds,
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void *dst, const void *src,
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unsigned int nbytes, void *tweak);
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asmlinkage void speck128_xts_decrypt_neon(const u64 *round_keys, int nrounds,
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void *dst, const void *src,
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unsigned int nbytes, void *tweak);
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typedef void (*speck128_crypt_one_t)(const struct speck128_tfm_ctx *,
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u8 *, const u8 *);
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typedef void (*speck128_xts_crypt_many_t)(const u64 *, int, void *,
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const void *, unsigned int, void *);
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static __always_inline int
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__speck128_xts_crypt(struct skcipher_request *req,
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speck128_crypt_one_t crypt_one,
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speck128_xts_crypt_many_t crypt_many)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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const struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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le128 tweak;
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int err;
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err = skcipher_walk_virt(&walk, req, true);
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crypto_speck128_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv);
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while (walk.nbytes > 0) {
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unsigned int nbytes = walk.nbytes;
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u8 *dst = walk.dst.virt.addr;
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const u8 *src = walk.src.virt.addr;
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if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) {
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unsigned int count;
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count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE);
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kernel_neon_begin();
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(*crypt_many)(ctx->main_key.round_keys,
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ctx->main_key.nrounds,
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dst, src, count, &tweak);
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kernel_neon_end();
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dst += count;
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src += count;
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nbytes -= count;
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}
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/* Handle any remainder with generic code */
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while (nbytes >= sizeof(tweak)) {
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le128_xor((le128 *)dst, (const le128 *)src, &tweak);
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(*crypt_one)(&ctx->main_key, dst, dst);
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le128_xor((le128 *)dst, (const le128 *)dst, &tweak);
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gf128mul_x_ble(&tweak, &tweak);
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dst += sizeof(tweak);
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src += sizeof(tweak);
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nbytes -= sizeof(tweak);
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}
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err = skcipher_walk_done(&walk, nbytes);
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}
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return err;
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}
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static int speck128_xts_encrypt(struct skcipher_request *req)
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{
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return __speck128_xts_crypt(req, crypto_speck128_encrypt,
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speck128_xts_encrypt_neon);
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}
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static int speck128_xts_decrypt(struct skcipher_request *req)
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{
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return __speck128_xts_crypt(req, crypto_speck128_decrypt,
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speck128_xts_decrypt_neon);
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}
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static int speck128_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
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int err;
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err = xts_verify_key(tfm, key, keylen);
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if (err)
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return err;
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keylen /= 2;
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err = crypto_speck128_setkey(&ctx->main_key, key, keylen);
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if (err)
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return err;
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return crypto_speck128_setkey(&ctx->tweak_key, key + keylen, keylen);
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}
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/* Speck64 */
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struct speck64_xts_tfm_ctx {
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struct speck64_tfm_ctx main_key;
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struct speck64_tfm_ctx tweak_key;
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};
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asmlinkage void speck64_xts_encrypt_neon(const u32 *round_keys, int nrounds,
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void *dst, const void *src,
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unsigned int nbytes, void *tweak);
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asmlinkage void speck64_xts_decrypt_neon(const u32 *round_keys, int nrounds,
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void *dst, const void *src,
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unsigned int nbytes, void *tweak);
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typedef void (*speck64_crypt_one_t)(const struct speck64_tfm_ctx *,
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u8 *, const u8 *);
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typedef void (*speck64_xts_crypt_many_t)(const u32 *, int, void *,
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const void *, unsigned int, void *);
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static __always_inline int
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__speck64_xts_crypt(struct skcipher_request *req, speck64_crypt_one_t crypt_one,
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speck64_xts_crypt_many_t crypt_many)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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const struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct skcipher_walk walk;
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__le64 tweak;
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int err;
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err = skcipher_walk_virt(&walk, req, true);
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crypto_speck64_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv);
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while (walk.nbytes > 0) {
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unsigned int nbytes = walk.nbytes;
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u8 *dst = walk.dst.virt.addr;
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const u8 *src = walk.src.virt.addr;
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if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) {
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unsigned int count;
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count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE);
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kernel_neon_begin();
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(*crypt_many)(ctx->main_key.round_keys,
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ctx->main_key.nrounds,
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dst, src, count, &tweak);
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kernel_neon_end();
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dst += count;
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src += count;
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nbytes -= count;
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}
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/* Handle any remainder with generic code */
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while (nbytes >= sizeof(tweak)) {
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*(__le64 *)dst = *(__le64 *)src ^ tweak;
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(*crypt_one)(&ctx->main_key, dst, dst);
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*(__le64 *)dst ^= tweak;
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tweak = cpu_to_le64((le64_to_cpu(tweak) << 1) ^
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((tweak & cpu_to_le64(1ULL << 63)) ?
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0x1B : 0));
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dst += sizeof(tweak);
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src += sizeof(tweak);
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nbytes -= sizeof(tweak);
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}
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err = skcipher_walk_done(&walk, nbytes);
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}
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return err;
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}
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static int speck64_xts_encrypt(struct skcipher_request *req)
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{
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return __speck64_xts_crypt(req, crypto_speck64_encrypt,
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speck64_xts_encrypt_neon);
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}
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static int speck64_xts_decrypt(struct skcipher_request *req)
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{
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return __speck64_xts_crypt(req, crypto_speck64_decrypt,
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speck64_xts_decrypt_neon);
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}
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static int speck64_xts_setkey(struct crypto_skcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
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int err;
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err = xts_verify_key(tfm, key, keylen);
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if (err)
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return err;
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keylen /= 2;
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err = crypto_speck64_setkey(&ctx->main_key, key, keylen);
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if (err)
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return err;
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return crypto_speck64_setkey(&ctx->tweak_key, key + keylen, keylen);
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}
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static struct skcipher_alg speck_algs[] = {
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{
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.base.cra_name = "xts(speck128)",
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.base.cra_driver_name = "xts-speck128-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = SPECK128_BLOCK_SIZE,
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.base.cra_ctxsize = sizeof(struct speck128_xts_tfm_ctx),
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.base.cra_alignmask = 7,
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.base.cra_module = THIS_MODULE,
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.min_keysize = 2 * SPECK128_128_KEY_SIZE,
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.max_keysize = 2 * SPECK128_256_KEY_SIZE,
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.ivsize = SPECK128_BLOCK_SIZE,
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.walksize = SPECK_NEON_CHUNK_SIZE,
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.setkey = speck128_xts_setkey,
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.encrypt = speck128_xts_encrypt,
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.decrypt = speck128_xts_decrypt,
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}, {
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.base.cra_name = "xts(speck64)",
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.base.cra_driver_name = "xts-speck64-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = SPECK64_BLOCK_SIZE,
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.base.cra_ctxsize = sizeof(struct speck64_xts_tfm_ctx),
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.base.cra_alignmask = 7,
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.base.cra_module = THIS_MODULE,
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.min_keysize = 2 * SPECK64_96_KEY_SIZE,
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.max_keysize = 2 * SPECK64_128_KEY_SIZE,
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.ivsize = SPECK64_BLOCK_SIZE,
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.walksize = SPECK_NEON_CHUNK_SIZE,
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.setkey = speck64_xts_setkey,
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.encrypt = speck64_xts_encrypt,
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.decrypt = speck64_xts_decrypt,
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}
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};
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static int __init speck_neon_module_init(void)
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{
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if (!(elf_hwcap & HWCAP_NEON))
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return -ENODEV;
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return crypto_register_skciphers(speck_algs, ARRAY_SIZE(speck_algs));
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}
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static void __exit speck_neon_module_exit(void)
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{
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crypto_unregister_skciphers(speck_algs, ARRAY_SIZE(speck_algs));
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}
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module_init(speck_neon_module_init);
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module_exit(speck_neon_module_exit);
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MODULE_DESCRIPTION("Speck block cipher (NEON-accelerated)");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
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MODULE_ALIAS_CRYPTO("xts(speck128)");
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MODULE_ALIAS_CRYPTO("xts-speck128-neon");
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MODULE_ALIAS_CRYPTO("xts(speck64)");
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MODULE_ALIAS_CRYPTO("xts-speck64-neon");
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