linux/arch/x86/crypto/twofish_glue_3way.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Glue Code for 3-way parallel assembler optimized version of Twofish
   4 *
   5 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
   6 */
   7
   8#include <crypto/algapi.h>
   9#include <crypto/twofish.h>
  10#include <linux/crypto.h>
  11#include <linux/init.h>
  12#include <linux/module.h>
  13#include <linux/types.h>
  14
  15#include "twofish.h"
  16#include "ecb_cbc_helpers.h"
  17
  18EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
  19EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
  20
  21static int twofish_setkey_skcipher(struct crypto_skcipher *tfm,
  22                                   const u8 *key, unsigned int keylen)
  23{
  24        return twofish_setkey(&tfm->base, key, keylen);
  25}
  26
  27static inline void twofish_enc_blk_3way(const void *ctx, u8 *dst, const u8 *src)
  28{
  29        __twofish_enc_blk_3way(ctx, dst, src, false);
  30}
  31
  32void twofish_dec_blk_cbc_3way(const void *ctx, u8 *dst, const u8 *src)
  33{
  34        u8 buf[2][TF_BLOCK_SIZE];
  35        const u8 *s = src;
  36
  37        if (dst == src)
  38                s = memcpy(buf, src, sizeof(buf));
  39        twofish_dec_blk_3way(ctx, dst, src);
  40        crypto_xor(dst + TF_BLOCK_SIZE, s, sizeof(buf));
  41
  42}
  43EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
  44
  45static int ecb_encrypt(struct skcipher_request *req)
  46{
  47        ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
  48        ECB_BLOCK(3, twofish_enc_blk_3way);
  49        ECB_BLOCK(1, twofish_enc_blk);
  50        ECB_WALK_END();
  51}
  52
  53static int ecb_decrypt(struct skcipher_request *req)
  54{
  55        ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
  56        ECB_BLOCK(3, twofish_dec_blk_3way);
  57        ECB_BLOCK(1, twofish_dec_blk);
  58        ECB_WALK_END();
  59}
  60
  61static int cbc_encrypt(struct skcipher_request *req)
  62{
  63        CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
  64        CBC_ENC_BLOCK(twofish_enc_blk);
  65        CBC_WALK_END();
  66}
  67
  68static int cbc_decrypt(struct skcipher_request *req)
  69{
  70        CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
  71        CBC_DEC_BLOCK(3, twofish_dec_blk_cbc_3way);
  72        CBC_DEC_BLOCK(1, twofish_dec_blk);
  73        CBC_WALK_END();
  74}
  75
  76static struct skcipher_alg tf_skciphers[] = {
  77        {
  78                .base.cra_name          = "ecb(twofish)",
  79                .base.cra_driver_name   = "ecb-twofish-3way",
  80                .base.cra_priority      = 300,
  81                .base.cra_blocksize     = TF_BLOCK_SIZE,
  82                .base.cra_ctxsize       = sizeof(struct twofish_ctx),
  83                .base.cra_module        = THIS_MODULE,
  84                .min_keysize            = TF_MIN_KEY_SIZE,
  85                .max_keysize            = TF_MAX_KEY_SIZE,
  86                .setkey                 = twofish_setkey_skcipher,
  87                .encrypt                = ecb_encrypt,
  88                .decrypt                = ecb_decrypt,
  89        }, {
  90                .base.cra_name          = "cbc(twofish)",
  91                .base.cra_driver_name   = "cbc-twofish-3way",
  92                .base.cra_priority      = 300,
  93                .base.cra_blocksize     = TF_BLOCK_SIZE,
  94                .base.cra_ctxsize       = sizeof(struct twofish_ctx),
  95                .base.cra_module        = THIS_MODULE,
  96                .min_keysize            = TF_MIN_KEY_SIZE,
  97                .max_keysize            = TF_MAX_KEY_SIZE,
  98                .ivsize                 = TF_BLOCK_SIZE,
  99                .setkey                 = twofish_setkey_skcipher,
 100                .encrypt                = cbc_encrypt,
 101                .decrypt                = cbc_decrypt,
 102        },
 103};
 104
 105static bool is_blacklisted_cpu(void)
 106{
 107        if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 108                return false;
 109
 110        if (boot_cpu_data.x86 == 0x06 &&
 111                (boot_cpu_data.x86_model == 0x1c ||
 112                 boot_cpu_data.x86_model == 0x26 ||
 113                 boot_cpu_data.x86_model == 0x36)) {
 114                /*
 115                 * On Atom, twofish-3way is slower than original assembler
 116                 * implementation. Twofish-3way trades off some performance in
 117                 * storing blocks in 64bit registers to allow three blocks to
 118                 * be processed parallel. Parallel operation then allows gaining
 119                 * more performance than was trade off, on out-of-order CPUs.
 120                 * However Atom does not benefit from this parallelism and
 121                 * should be blacklisted.
 122                 */
 123                return true;
 124        }
 125
 126        if (boot_cpu_data.x86 == 0x0f) {
 127                /*
 128                 * On Pentium 4, twofish-3way is slower than original assembler
 129                 * implementation because excessive uses of 64bit rotate and
 130                 * left-shifts (which are really slow on P4) needed to store and
 131                 * handle 128bit block in two 64bit registers.
 132                 */
 133                return true;
 134        }
 135
 136        return false;
 137}
 138
 139static int force;
 140module_param(force, int, 0);
 141MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
 142
 143static int __init init(void)
 144{
 145        if (!force && is_blacklisted_cpu()) {
 146                printk(KERN_INFO
 147                        "twofish-x86_64-3way: performance on this CPU "
 148                        "would be suboptimal: disabling "
 149                        "twofish-x86_64-3way.\n");
 150                return -ENODEV;
 151        }
 152
 153        return crypto_register_skciphers(tf_skciphers,
 154                                         ARRAY_SIZE(tf_skciphers));
 155}
 156
 157static void __exit fini(void)
 158{
 159        crypto_unregister_skciphers(tf_skciphers, ARRAY_SIZE(tf_skciphers));
 160}
 161
 162module_init(init);
 163module_exit(fini);
 164
 165MODULE_LICENSE("GPL");
 166MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
 167MODULE_ALIAS_CRYPTO("twofish");
 168MODULE_ALIAS_CRYPTO("twofish-asm");
 169