1 /*
2 * Glue code for SHA-256 implementation for SPE instructions (PPC)
3 *
4 * Based on generic implementation. The assembler module takes care
5 * about the SPE registers so it can run from interrupt context.
6 *
7 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16 #include <crypto/internal/hash.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/mm.h>
20 #include <linux/cryptohash.h>
21 #include <linux/types.h>
22 #include <crypto/sha.h>
23 #include <asm/byteorder.h>
24 #include <asm/switch_to.h>
25 #include <linux/hardirq.h>
26
27 /*
28 * MAX_BYTES defines the number of bytes that are allowed to be processed
29 * between preempt_disable() and preempt_enable(). SHA256 takes ~2,000
30 * operations per 64 bytes. e500 cores can issue two arithmetic instructions
31 * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2).
32 * Thus 1KB of input data will need an estimated maximum of 18,000 cycles.
33 * Headroom for cache misses included. Even with the low end model clocked
34 * at 667 MHz this equals to a critical time window of less than 27us.
35 *
36 */
37 #define MAX_BYTES 1024
38
39 extern void ppc_spe_sha256_transform(u32 *state, const u8 *src, u32 blocks);
40
spe_begin(void)41 static void spe_begin(void)
42 {
43 /* We just start SPE operations and will save SPE registers later. */
44 preempt_disable();
45 enable_kernel_spe();
46 }
47
spe_end(void)48 static void spe_end(void)
49 {
50 /* reenable preemption */
51 preempt_enable();
52 }
53
ppc_sha256_clear_context(struct sha256_state * sctx)54 static inline void ppc_sha256_clear_context(struct sha256_state *sctx)
55 {
56 int count = sizeof(struct sha256_state) >> 2;
57 u32 *ptr = (u32 *)sctx;
58
59 /* make sure we can clear the fast way */
60 BUILD_BUG_ON(sizeof(struct sha256_state) % 4);
61 do { *ptr++ = 0; } while (--count);
62 }
63
ppc_spe_sha256_init(struct shash_desc * desc)64 static int ppc_spe_sha256_init(struct shash_desc *desc)
65 {
66 struct sha256_state *sctx = shash_desc_ctx(desc);
67
68 sctx->state[0] = SHA256_H0;
69 sctx->state[1] = SHA256_H1;
70 sctx->state[2] = SHA256_H2;
71 sctx->state[3] = SHA256_H3;
72 sctx->state[4] = SHA256_H4;
73 sctx->state[5] = SHA256_H5;
74 sctx->state[6] = SHA256_H6;
75 sctx->state[7] = SHA256_H7;
76 sctx->count = 0;
77
78 return 0;
79 }
80
ppc_spe_sha224_init(struct shash_desc * desc)81 static int ppc_spe_sha224_init(struct shash_desc *desc)
82 {
83 struct sha256_state *sctx = shash_desc_ctx(desc);
84
85 sctx->state[0] = SHA224_H0;
86 sctx->state[1] = SHA224_H1;
87 sctx->state[2] = SHA224_H2;
88 sctx->state[3] = SHA224_H3;
89 sctx->state[4] = SHA224_H4;
90 sctx->state[5] = SHA224_H5;
91 sctx->state[6] = SHA224_H6;
92 sctx->state[7] = SHA224_H7;
93 sctx->count = 0;
94
95 return 0;
96 }
97
ppc_spe_sha256_update(struct shash_desc * desc,const u8 * data,unsigned int len)98 static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data,
99 unsigned int len)
100 {
101 struct sha256_state *sctx = shash_desc_ctx(desc);
102 const unsigned int offset = sctx->count & 0x3f;
103 const unsigned int avail = 64 - offset;
104 unsigned int bytes;
105 const u8 *src = data;
106
107 if (avail > len) {
108 sctx->count += len;
109 memcpy((char *)sctx->buf + offset, src, len);
110 return 0;
111 }
112
113 sctx->count += len;
114
115 if (offset) {
116 memcpy((char *)sctx->buf + offset, src, avail);
117
118 spe_begin();
119 ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1);
120 spe_end();
121
122 len -= avail;
123 src += avail;
124 }
125
126 while (len > 63) {
127 /* cut input data into smaller blocks */
128 bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
129 bytes = bytes & ~0x3f;
130
131 spe_begin();
132 ppc_spe_sha256_transform(sctx->state, src, bytes >> 6);
133 spe_end();
134
135 src += bytes;
136 len -= bytes;
137 };
138
139 memcpy((char *)sctx->buf, src, len);
140 return 0;
141 }
142
ppc_spe_sha256_final(struct shash_desc * desc,u8 * out)143 static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out)
144 {
145 struct sha256_state *sctx = shash_desc_ctx(desc);
146 const unsigned int offset = sctx->count & 0x3f;
147 char *p = (char *)sctx->buf + offset;
148 int padlen;
149 __be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56);
150 __be32 *dst = (__be32 *)out;
151
152 padlen = 55 - offset;
153 *p++ = 0x80;
154
155 spe_begin();
156
157 if (padlen < 0) {
158 memset(p, 0x00, padlen + sizeof (u64));
159 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
160 p = (char *)sctx->buf;
161 padlen = 56;
162 }
163
164 memset(p, 0, padlen);
165 *pbits = cpu_to_be64(sctx->count << 3);
166 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
167
168 spe_end();
169
170 dst[0] = cpu_to_be32(sctx->state[0]);
171 dst[1] = cpu_to_be32(sctx->state[1]);
172 dst[2] = cpu_to_be32(sctx->state[2]);
173 dst[3] = cpu_to_be32(sctx->state[3]);
174 dst[4] = cpu_to_be32(sctx->state[4]);
175 dst[5] = cpu_to_be32(sctx->state[5]);
176 dst[6] = cpu_to_be32(sctx->state[6]);
177 dst[7] = cpu_to_be32(sctx->state[7]);
178
179 ppc_sha256_clear_context(sctx);
180 return 0;
181 }
182
ppc_spe_sha224_final(struct shash_desc * desc,u8 * out)183 static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out)
184 {
185 u32 D[SHA256_DIGEST_SIZE >> 2];
186 __be32 *dst = (__be32 *)out;
187
188 ppc_spe_sha256_final(desc, (u8 *)D);
189
190 /* avoid bytewise memcpy */
191 dst[0] = D[0];
192 dst[1] = D[1];
193 dst[2] = D[2];
194 dst[3] = D[3];
195 dst[4] = D[4];
196 dst[5] = D[5];
197 dst[6] = D[6];
198
199 /* clear sensitive data */
200 memzero_explicit(D, SHA256_DIGEST_SIZE);
201 return 0;
202 }
203
ppc_spe_sha256_export(struct shash_desc * desc,void * out)204 static int ppc_spe_sha256_export(struct shash_desc *desc, void *out)
205 {
206 struct sha256_state *sctx = shash_desc_ctx(desc);
207
208 memcpy(out, sctx, sizeof(*sctx));
209 return 0;
210 }
211
ppc_spe_sha256_import(struct shash_desc * desc,const void * in)212 static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in)
213 {
214 struct sha256_state *sctx = shash_desc_ctx(desc);
215
216 memcpy(sctx, in, sizeof(*sctx));
217 return 0;
218 }
219
220 static struct shash_alg algs[2] = { {
221 .digestsize = SHA256_DIGEST_SIZE,
222 .init = ppc_spe_sha256_init,
223 .update = ppc_spe_sha256_update,
224 .final = ppc_spe_sha256_final,
225 .export = ppc_spe_sha256_export,
226 .import = ppc_spe_sha256_import,
227 .descsize = sizeof(struct sha256_state),
228 .statesize = sizeof(struct sha256_state),
229 .base = {
230 .cra_name = "sha256",
231 .cra_driver_name= "sha256-ppc-spe",
232 .cra_priority = 300,
233 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
234 .cra_blocksize = SHA256_BLOCK_SIZE,
235 .cra_module = THIS_MODULE,
236 }
237 }, {
238 .digestsize = SHA224_DIGEST_SIZE,
239 .init = ppc_spe_sha224_init,
240 .update = ppc_spe_sha256_update,
241 .final = ppc_spe_sha224_final,
242 .export = ppc_spe_sha256_export,
243 .import = ppc_spe_sha256_import,
244 .descsize = sizeof(struct sha256_state),
245 .statesize = sizeof(struct sha256_state),
246 .base = {
247 .cra_name = "sha224",
248 .cra_driver_name= "sha224-ppc-spe",
249 .cra_priority = 300,
250 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
251 .cra_blocksize = SHA224_BLOCK_SIZE,
252 .cra_module = THIS_MODULE,
253 }
254 } };
255
ppc_spe_sha256_mod_init(void)256 static int __init ppc_spe_sha256_mod_init(void)
257 {
258 return crypto_register_shashes(algs, ARRAY_SIZE(algs));
259 }
260
ppc_spe_sha256_mod_fini(void)261 static void __exit ppc_spe_sha256_mod_fini(void)
262 {
263 crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
264 }
265
266 module_init(ppc_spe_sha256_mod_init);
267 module_exit(ppc_spe_sha256_mod_fini);
268
269 MODULE_LICENSE("GPL");
270 MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized");
271
272 MODULE_ALIAS_CRYPTO("sha224");
273 MODULE_ALIAS_CRYPTO("sha224-ppc-spe");
274 MODULE_ALIAS_CRYPTO("sha256");
275 MODULE_ALIAS_CRYPTO("sha256-ppc-spe");
276