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 
crypto842_alloc_ctx(struct crypto_scomp * tfm)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 
crypto842_init(struct crypto_tfm * tfm)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 
crypto842_free_ctx(struct crypto_scomp * tfm,void * ctx)62 static void crypto842_free_ctx(struct crypto_scomp *tfm, void *ctx)
63 {
64 	kfree(ctx);
65 }
66 
crypto842_exit(struct crypto_tfm * tfm)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 
crypto842_compress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)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 
crypto842_scompress(struct crypto_scomp * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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 
crypto842_decompress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)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 
crypto842_sdecompress(struct crypto_scomp * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen,void * ctx)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 
crypto842_mod_init(void)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 
crypto842_mod_exit(void)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>");
161