crypto/842.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Cryptographic API for the 842 software compression algorithm.
   4  *
   5  * Copyright (C) IBM Corporation, 2011-2015
   6  *
   7  * Original Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
   8  *                   Seth Jennings <sjenning@linux.vnet.ibm.com>
   9  *
  10  * Rewrite: Dan Streetman <ddstreet@ieee.org>
  11  *
  12  * This is the software implementation of compression and decompression using
  13  * the 842 format.  This uses the software 842 library at lib/842/ which is
  14  * only a reference implementation, and is very, very slow as compared to other
  15  * software compressors.  You probably do not want to use this software
  16  * compression.  If you have access to the PowerPC 842 compression hardware, you
  17  * want to use the 842 hardware compression interface, which is at:
  18  * drivers/crypto/nx/nx-842-crypto.c
  19  */
  20
  21 #include <linux/init.h>
  22 #include <linux/module.h>
  23 #include <linux/crypto.h>
  24 #include <linux/sw842.h>
  25 #include <crypto/internal/scompress.h>
  26
  27 struct crypto842_ctx {
  28         void *wmem;     /* working memory for compress */
  29 };
  30
  31 static void *crypto842_alloc_ctx(struct crypto_scomp *tfm)
  32 {
  33         void *ctx;
  34
  35         ctx = kmalloc(SW842_MEM_COMPRESS, GFP_KERNEL);
  36         if (!ctx)
  37                 return ERR_PTR(-ENOMEM);
  38
  39         return ctx;
  40 }
  41
  42 static int crypto842_init(struct crypto_tfm *tfm)
  43 {
  44         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  45
  46         ctx->wmem = crypto842_alloc_ctx(NULL);
  47         if (IS_ERR(ctx->wmem))
  48                 return -ENOMEM;
  49
  50         return 0;
  51 }
  52
  53 static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
  54 {
  55         kfree(ctx);
  56 }
  57
  58 static void crypto842_exit(struct crypto_tfm *tfm)
  59 {
  60         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  61
  62         crypto842_free_ctx(NULL, ctx->wmem);
  63 }
  64
  65 static int crypto842_compress(struct crypto_tfm *tfm,
  66                               const u8 *src, unsigned int slen,
  67                               u8 *dst, unsigned int *dlen)
  68 {
  69         struct crypto842_ctx *ctx = crypto_tfm_ctx(tfm);
  70
  71         return sw842_compress(src, slen, dst, dlen, ctx->wmem);
  72 }
  73
  74 static int crypto842_scompress(struct crypto_scomp *tfm,
  75                                const u8 *src, unsigned int slen,
  76                                u8 *dst, unsigned int *dlen, void *ctx)
  77 {
  78         return sw842_compress(src, slen, dst, dlen, ctx);
  79 }
  80
  81 static int crypto842_decompress(struct crypto_tfm *tfm,
  82                                 const u8 *src, unsigned int slen,
  83                                 u8 *dst, unsigned int *dlen)
  84 {
  85         return sw842_decompress(src, slen, dst, dlen);
  86 }
  87
  88 static int crypto842_sdecompress(struct crypto_scomp *tfm,
  89                                  const u8 *src, unsigned int slen,
  90                                  u8 *dst, unsigned int *dlen, void *ctx)
  91 {
  92         return sw842_decompress(src, slen, dst, dlen);
  93 }
  94
  95 static struct crypto_alg alg = {
  96         .cra_name               = "842",
  97         .cra_driver_name        = "842-generic",
  98         .cra_priority           = 100,
  99         .cra_flags              = CRYPTO_ALG_TYPE_COMPRESS,
 100         .cra_ctxsize            = sizeof(struct crypto842_ctx),
 101         .cra_module             = THIS_MODULE,
 102         .cra_init               = crypto842_init,
 103         .cra_exit               = crypto842_exit,
 104         .cra_u                  = { .compress = {
 105         .coa_compress           = crypto842_compress,
 106         .coa_decompress         = crypto842_decompress } }
 107 };
 108
 109 static struct scomp_alg scomp = {
 110         .alloc_ctx              = crypto842_alloc_ctx,
 111         .free_ctx               = crypto842_free_ctx,
 112         .compress               = crypto842_scompress,
 113         .decompress             = crypto842_sdecompress,
 114         .base                   = {
 115                 .cra_name       = "842",
 116                 .cra_driver_name = "842-scomp",
 117                 .cra_priority    = 100,
 118                 .cra_module      = THIS_MODULE,
 119         }
 120 };
 121
 122 static int __init crypto842_mod_init(void)
 123 {
 124         int ret;
 125
 126         ret = crypto_register_alg(&alg);
 127         if (ret)
 128                 return ret;
 129
 130         ret = crypto_register_scomp(&scomp);
 131         if (ret) {
 132                 crypto_unregister_alg(&alg);
 133                 return ret;
 134         }
 135
 136         return ret;
 137 }
 138 subsys_initcall(crypto842_mod_init);
 139
 140 static void __exit crypto842_mod_exit(void)
 141 {
 142         crypto_unregister_alg(&alg);
 143         crypto_unregister_scomp(&scomp);
 144 }
 145 module_exit(crypto842_mod_exit);
 146
 147 MODULE_LICENSE("GPL");
 148 MODULE_DESCRIPTION("842 Software Compression Algorithm");
 149 MODULE_ALIAS_CRYPTO("842");
 150 MODULE_ALIAS_CRYPTO("842-generic");
 151 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");