crypto/842.c

   1 /*
   2  * Cryptographic API for the 842 software compression algorithm.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * Copyright (C) IBM Corporation, 2011-2015
  15  *
  16  * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
  17  *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
  18  *
  19  * Rewrite: Dan Streetman <ddstreet@ieee.org>
  20  *
  21  * This is the software implementation of compression and decompression using
  22  * the 842 format.  This uses the software 842 library at lib/842/ which is
  23  * only a reference implementation, and is very, very slow as compared to other
  24  * software compressors.  You probably do not want to use this software
  25  * compression.  If you have access to the PowerPC 842 compression hardware, you
  26  * want to use the 842 hardware compression interface, which is at:
  27  * drivers/crypto/nx/nx-842-crypto.c
  28  */
  29
  30 #include <linux/init.h>
  31 #include <linux/module.h>
  32 #include <linux/crypto.h>
  33 #include <linux/sw842.h>
  34 #include <crypto/internal/scompress.h>
  35
  36 struct crypto842_ctx {
  37         void *wmem;     /* working memory for compress */
  38 };
  39
  40 static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
  41 {
  42         void *ctx;
  43
  44         ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
  45         if (!ctx)
  46                 return ERR_PTR(-ENOMEM);
  47
  48         return ctx;
  49 }
  50
  51 static int crypto842_init(struct crypto_tfm *tfm)
  52 {
  53         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  54
  55         ctx->wmem = crypto842_alloc_ctx(NULL);
  56         if (IS_ERR(ctx->wmem))
  57                 return -ENOMEM;
  58
  59         return 0;
  60 }
  61
  62 static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
  63 {
  64         kfree(ctx);
  65 }
  66
  67 static void crypto842_exit(struct crypto_tfm *tfm)
  68 {
  69         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  70
  71         crypto842_free_ctx(NULL, ctx->wmem);
  72 }
  73
  74 static int crypto842_compress(struct crypto_tfm *tfm,
  75                               const u8 *src, unsigned int slen,
  76                               u8 *dst, unsigned int *dlen)
  77 {
  78         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  79
  80         return sw842_compress(src, slen, dst, dlen, ctx->wmem);
  81 }
  82
  83 static int crypto842_scompress(struct crypto_scomp *tfm,
  84                                const u8 *src, unsigned int slen,
  85                                u8 *dst, unsigned int *dlen, void *ctx)
  86 {
  87         return sw842_compress(src, slen, dst, dlen, ctx);
  88 }
  89
  90 static int crypto842_decompress(struct crypto_tfm *tfm,
  91                                 const u8 *src, unsigned int slen,
  92                                 u8 *dst, unsigned int *dlen)
  93 {
  94         return sw842_decompress(src, slen, dst, dlen);
  95 }
  96
  97 static int crypto842_sdecompress(struct crypto_scomp *tfm,
  98                                  const u8 *src, unsigned int slen,
  99                                  u8 *dst, unsigned int *dlen, void *ctx)
 100 {
 101         return sw842_decompress(src, slen, dst, dlen);
 102 }
 103
 104 static struct crypto_alg alg = {
 105         .cra_name               = "842",
 106         .cra_driver_name        = "842-generic",
 107         .cra_priority           = 100,
 108         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 109         .cra_ctxsize            = sizeof(struct crypto842_ctx),
 110         .cra_module             = THIS_MODULE,
 111         .cra_init               = crypto842_init,
 112         .cra_exit               = crypto842_exit,
 113         .cra_u                  = { .compress = {
 114         .coa_compress           = crypto842_compress,
 115         .coa_decompress         = crypto842_decompress } }
 116 };
 117
 118 static struct scomp_alg scomp = {
 119         .alloc_ctx              = crypto842_alloc_ctx,
 120         .free_ctx               = crypto842_free_ctx,
 121         .compress               = crypto842_scompress,
 122         .decompress             = crypto842_sdecompress,
 123         .base                   = {
 124                 .cra_name       = "842",
 125                 .cra_driver_name = "842-scomp",
 126                 .cra_priority    = 100,
 127                 .cra_module      = THIS_MODULE,
 128         }
 129 };
 130
 131 static int __init crypto842_mod_init(void)
 132 {
 133         int ret;
 134
 135         ret = crypto_register_alg(&alg);
 136         if (ret)
 137                 return ret;
 138
 139         ret = crypto_register_scomp(&scomp);
 140         if (ret) {
 141                 crypto_unregister_alg(&alg);
 142                 return ret;
 143         }
 144
 145         return ret;
 146 }
 147 module_init(crypto842_mod_init);
 148
 149 static void __exit crypto842_mod_exit(void)
 150 {
 151         crypto_unregister_alg(&alg);
 152         crypto_unregister_scomp(&scomp);
 153 }
 154 module_exit(crypto842_mod_exit);
 155
 156 MODULE_LICENSE("GPL");
 157 MODULE_DESCRIPTION("842 Software Compression Algorithm");
 158 MODULE_ALIAS_CRYPTO("842");
 159 MODULE_ALIAS_CRYPTO("842-generic");
 160 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");