| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * s390 ChaCha stream cipher. |
| * |
| * Copyright IBM Corp. 2021 |
| */ |
| |
| #define KMSG_COMPONENT "chacha_s390" |
| #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
| |
| #include <crypto/internal/chacha.h> |
| #include <crypto/internal/skcipher.h> |
| #include <crypto/algapi.h> |
| #include <linux/cpufeature.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/sizes.h> |
| #include <asm/fpu/api.h> |
| #include "chacha-s390.h" |
| |
| static void chacha20_crypt_s390(u32 *state, u8 *dst, const u8 *src, |
| unsigned int nbytes, const u32 *key, |
| u32 *counter) |
| { |
| struct kernel_fpu vxstate; |
| |
| kernel_fpu_begin(&vxstate, KERNEL_VXR); |
| chacha20_vx(dst, src, nbytes, key, counter); |
| kernel_fpu_end(&vxstate, KERNEL_VXR); |
| |
| *counter += round_up(nbytes, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE; |
| } |
| |
| static int chacha20_s390(struct skcipher_request *req) |
| { |
| struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); |
| struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm); |
| u32 state[CHACHA_STATE_WORDS] __aligned(16); |
| struct skcipher_walk walk; |
| unsigned int nbytes; |
| int rc; |
| |
| rc = skcipher_walk_virt(&walk, req, false); |
| chacha_init_generic(state, ctx->key, req->iv); |
| |
| while (walk.nbytes > 0) { |
| nbytes = walk.nbytes; |
| if (nbytes < walk.total) |
| nbytes = round_down(nbytes, walk.stride); |
| |
| if (nbytes <= CHACHA_BLOCK_SIZE) { |
| chacha_crypt_generic(state, walk.dst.virt.addr, |
| walk.src.virt.addr, nbytes, |
| ctx->nrounds); |
| } else { |
| chacha20_crypt_s390(state, walk.dst.virt.addr, |
| walk.src.virt.addr, nbytes, |
| &state[4], &state[12]); |
| } |
| rc = skcipher_walk_done(&walk, walk.nbytes - nbytes); |
| } |
| return rc; |
| } |
| |
| void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds) |
| { |
| /* TODO: implement hchacha_block_arch() in assembly */ |
| hchacha_block_generic(state, stream, nrounds); |
| } |
| EXPORT_SYMBOL(hchacha_block_arch); |
| |
| void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv) |
| { |
| chacha_init_generic(state, key, iv); |
| } |
| EXPORT_SYMBOL(chacha_init_arch); |
| |
| void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, |
| unsigned int bytes, int nrounds) |
| { |
| /* s390 chacha20 implementation has 20 rounds hard-coded, |
| * it cannot handle a block of data or less, but otherwise |
| * it can handle data of arbitrary size |
| */ |
| if (bytes <= CHACHA_BLOCK_SIZE || nrounds != 20) |
| chacha_crypt_generic(state, dst, src, bytes, nrounds); |
| else |
| chacha20_crypt_s390(state, dst, src, bytes, |
| &state[4], &state[12]); |
| } |
| EXPORT_SYMBOL(chacha_crypt_arch); |
| |
| static struct skcipher_alg chacha_algs[] = { |
| { |
| .base.cra_name = "chacha20", |
| .base.cra_driver_name = "chacha20-s390", |
| .base.cra_priority = 900, |
| .base.cra_blocksize = 1, |
| .base.cra_ctxsize = sizeof(struct chacha_ctx), |
| .base.cra_module = THIS_MODULE, |
| |
| .min_keysize = CHACHA_KEY_SIZE, |
| .max_keysize = CHACHA_KEY_SIZE, |
| .ivsize = CHACHA_IV_SIZE, |
| .chunksize = CHACHA_BLOCK_SIZE, |
| .setkey = chacha20_setkey, |
| .encrypt = chacha20_s390, |
| .decrypt = chacha20_s390, |
| } |
| }; |
| |
| static int __init chacha_mod_init(void) |
| { |
| return IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER) ? |
| crypto_register_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs)) : 0; |
| } |
| |
| static void __exit chacha_mod_fini(void) |
| { |
| if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) |
| crypto_unregister_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs)); |
| } |
| |
| module_cpu_feature_match(VXRS, chacha_mod_init); |
| module_exit(chacha_mod_fini); |
| |
| MODULE_DESCRIPTION("ChaCha20 stream cipher"); |
| MODULE_LICENSE("GPL v2"); |
| |
| MODULE_ALIAS_CRYPTO("chacha20"); |