diff options
Diffstat (limited to 'arch/arm/crypto/chacha20-neon-glue.c')
| -rw-r--r-- | arch/arm/crypto/chacha20-neon-glue.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/arch/arm/crypto/chacha20-neon-glue.c b/arch/arm/crypto/chacha20-neon-glue.c new file mode 100644 index 000000000..59a7be08e --- /dev/null +++ b/arch/arm/crypto/chacha20-neon-glue.c @@ -0,0 +1,127 @@ +/* + * ChaCha20 256-bit cipher algorithm, RFC7539, ARM NEON functions + * + * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Based on: + * ChaCha20 256-bit cipher algorithm, RFC7539, SIMD glue code + * + * Copyright (C) 2015 Martin Willi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <crypto/algapi.h> +#include <crypto/chacha20.h> +#include <crypto/internal/skcipher.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#include <asm/hwcap.h> +#include <asm/neon.h> +#include <asm/simd.h> + +asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src); +asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src); + +static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src, + unsigned int bytes) +{ + u8 buf[CHACHA20_BLOCK_SIZE]; + + while (bytes >= CHACHA20_BLOCK_SIZE * 4) { + chacha20_4block_xor_neon(state, dst, src); + bytes -= CHACHA20_BLOCK_SIZE * 4; + src += CHACHA20_BLOCK_SIZE * 4; + dst += CHACHA20_BLOCK_SIZE * 4; + state[12] += 4; + } + while (bytes >= CHACHA20_BLOCK_SIZE) { + chacha20_block_xor_neon(state, dst, src); + bytes -= CHACHA20_BLOCK_SIZE; + src += CHACHA20_BLOCK_SIZE; + dst += CHACHA20_BLOCK_SIZE; + state[12]++; + } + if (bytes) { + memcpy(buf, src, bytes); + chacha20_block_xor_neon(state, buf, buf); + memcpy(dst, buf, bytes); + } +} + +static int chacha20_neon(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct chacha20_ctx *ctx = crypto_skcipher_ctx(tfm); + struct skcipher_walk walk; + u32 state[16]; + int err; + + if (req->cryptlen <= CHACHA20_BLOCK_SIZE || !may_use_simd()) + return crypto_chacha20_crypt(req); + + err = skcipher_walk_virt(&walk, req, true); + + crypto_chacha20_init(state, ctx, walk.iv); + + kernel_neon_begin(); + while (walk.nbytes > 0) { + unsigned int nbytes = walk.nbytes; + + if (nbytes < walk.total) + nbytes = round_down(nbytes, walk.stride); + + chacha20_doneon(state, walk.dst.virt.addr, walk.src.virt.addr, + nbytes); + err = skcipher_walk_done(&walk, walk.nbytes - nbytes); + } + kernel_neon_end(); + + return err; +} + +static struct skcipher_alg alg = { + .base.cra_name = "chacha20", + .base.cra_driver_name = "chacha20-neon", + .base.cra_priority = 300, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct chacha20_ctx), + .base.cra_module = THIS_MODULE, + + .min_keysize = CHACHA20_KEY_SIZE, + .max_keysize = CHACHA20_KEY_SIZE, + .ivsize = CHACHA20_IV_SIZE, + .chunksize = CHACHA20_BLOCK_SIZE, + .walksize = 4 * CHACHA20_BLOCK_SIZE, + .setkey = crypto_chacha20_setkey, + .encrypt = chacha20_neon, + .decrypt = chacha20_neon, +}; + +static int __init chacha20_simd_mod_init(void) +{ + if (!(elf_hwcap & HWCAP_NEON)) + return -ENODEV; + + return crypto_register_skcipher(&alg); +} + +static void __exit chacha20_simd_mod_fini(void) +{ + crypto_unregister_skcipher(&alg); +} + +module_init(chacha20_simd_mod_init); +module_exit(chacha20_simd_mod_fini); + +MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS_CRYPTO("chacha20"); |