arch/riscv/crypto/chacha-riscv64-glue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ChaCha20 using the RISC-V vector crypto extensions
   4  *
   5  * Copyright (C) 2023 SiFive, Inc.
   6  * Author: Jerry Shih <jerry.shih@sifive.com>
   7  */
   8
   9 #include <asm/simd.h>
  10 #include <asm/vector.h>
  11 #include <crypto/internal/chacha.h>
  12 #include <crypto/internal/skcipher.h>
  13 #include <linux/linkage.h>
  14 #include <linux/module.h>
  15
  16 asmlinkage void chacha20_zvkb(const u32 key[8], const u8 *in, u8 *out,
  17                               size_t len, const u32 iv[4]);
  18
  19 static int riscv64_chacha20_crypt(struct skcipher_request *req)
  20 {
  21         u32 iv[CHACHA_IV_SIZE / sizeof(u32)];
  22         u8 block_buffer[CHACHA_BLOCK_SIZE];
  23         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  24         const struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
  25         struct skcipher_walk walk;
  26         unsigned int nbytes;
  27         unsigned int tail_bytes;
  28         int err;
  29
  30         iv[0] = get_unaligned_le32(req->iv);
  31         iv[1] = get_unaligned_le32(req->iv + 4);
  32         iv[2] = get_unaligned_le32(req->iv + 8);
  33         iv[3] = get_unaligned_le32(req->iv + 12);
  34
  35         err = skcipher_walk_virt(&walk, req, false);
  36         while (walk.nbytes) {
  37                 nbytes = walk.nbytes & ~(CHACHA_BLOCK_SIZE - 1);
  38                 tail_bytes = walk.nbytes & (CHACHA_BLOCK_SIZE - 1);
  39                 kernel_vector_begin();
  40                 if (nbytes) {
  41                         chacha20_zvkb(ctx->key, walk.src.virt.addr,
  42                                       walk.dst.virt.addr, nbytes, iv);
  43                         iv[0] += nbytes / CHACHA_BLOCK_SIZE;
  44                 }
  45                 if (walk.nbytes == walk.total && tail_bytes > 0) {
  46                         memcpy(block_buffer, walk.src.virt.addr + nbytes,
  47                                tail_bytes);
  48                         chacha20_zvkb(ctx->key, block_buffer, block_buffer,
  49                                       CHACHA_BLOCK_SIZE, iv);
  50                         memcpy(walk.dst.virt.addr + nbytes, block_buffer,
  51                                tail_bytes);
  52                         tail_bytes = 0;
  53                 }
  54                 kernel_vector_end();
  55
  56                 err = skcipher_walk_done(&walk, tail_bytes);
  57         }
  58
  59         return err;
  60 }
  61
  62 static struct skcipher_alg riscv64_chacha_alg = {
  63         .setkey = chacha20_setkey,
  64         .encrypt = riscv64_chacha20_crypt,
  65         .decrypt = riscv64_chacha20_crypt,
  66         .min_keysize = CHACHA_KEY_SIZE,
  67         .max_keysize = CHACHA_KEY_SIZE,
  68         .ivsize = CHACHA_IV_SIZE,
  69         .chunksize = CHACHA_BLOCK_SIZE,
  70         .walksize = 4 * CHACHA_BLOCK_SIZE,
  71         .base = {
  72                 .cra_blocksize = 1,
  73                 .cra_ctxsize = sizeof(struct chacha_ctx),
  74                 .cra_priority = 300,
  75                 .cra_name = "chacha20",
  76                 .cra_driver_name = "chacha20-riscv64-zvkb",
  77                 .cra_module = THIS_MODULE,
  78         },
  79 };
  80
  81 static int __init riscv64_chacha_mod_init(void)
  82 {
  83         if (riscv_isa_extension_available(NULL, ZVKB) &&
  84             riscv_vector_vlen() >= 128)
  85                 return crypto_register_skcipher(&riscv64_chacha_alg);
  86
  87         return -ENODEV;
  88 }
  89
  90 static void __exit riscv64_chacha_mod_exit(void)
  91 {
  92         crypto_unregister_skcipher(&riscv64_chacha_alg);
  93 }
  94
  95 module_init(riscv64_chacha_mod_init);
  96 module_exit(riscv64_chacha_mod_exit);
  97
  98 MODULE_DESCRIPTION("ChaCha20 (RISC-V accelerated)");
  99 MODULE_AUTHOR("Jerry Shih <jerry.shih@sifive.com>");
 100 MODULE_LICENSE("GPL");
 101 MODULE_ALIAS_CRYPTO("chacha20");