1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Glue code for SHA-256 implementation for SPE instructions (PPC)
4 *
5 * Based on generic implementation. The assembler module takes care
6 * about the SPE registers so it can run from interrupt context.
7 *
8 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
9 */
10
11 #include <crypto/internal/hash.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/mm.h>
15 #include <linux/cryptohash.h>
16 #include <linux/types.h>
17 #include <crypto/sha.h>
18 #include <asm/byteorder.h>
19 #include <asm/switch_to.h>
20 #include <linux/hardirq.h>
21
22 /*
23 * MAX_BYTES defines the number of bytes that are allowed to be processed
24 * between preempt_disable() and preempt_enable(). SHA256 takes ~2,000
25 * operations per 64 bytes. e500 cores can issue two arithmetic instructions
26 * per clock cycle using one 32/64 bit unit (SU1) and one 32 bit unit (SU2).
27 * Thus 1KB of input data will need an estimated maximum of 18,000 cycles.
28 * Headroom for cache misses included. Even with the low end model clocked
29 * at 667 MHz this equals to a critical time window of less than 27us.
30 *
31 */
32 #define MAX_BYTES 1024
33
34 extern void ppc_spe_sha256_transform(u32 *state, const u8 *src, u32 blocks);
35
spe_begin(void)36 static void spe_begin(void)
37 {
38 /* We just start SPE operations and will save SPE registers later. */
39 preempt_disable();
40 enable_kernel_spe();
41 }
42
spe_end(void)43 static void spe_end(void)
44 {
45 disable_kernel_spe();
46 /* reenable preemption */
47 preempt_enable();
48 }
49
ppc_sha256_clear_context(struct sha256_state * sctx)50 static inline void ppc_sha256_clear_context(struct sha256_state *sctx)
51 {
52 int count = sizeof(struct sha256_state) >> 2;
53 u32 *ptr = (u32 *)sctx;
54
55 /* make sure we can clear the fast way */
56 BUILD_BUG_ON(sizeof(struct sha256_state) % 4);
57 do { *ptr++ = 0; } while (--count);
58 }
59
ppc_spe_sha256_init(struct shash_desc * desc)60 static int ppc_spe_sha256_init(struct shash_desc *desc)
61 {
62 struct sha256_state *sctx = shash_desc_ctx(desc);
63
64 sctx->state[0] = SHA256_H0;
65 sctx->state[1] = SHA256_H1;
66 sctx->state[2] = SHA256_H2;
67 sctx->state[3] = SHA256_H3;
68 sctx->state[4] = SHA256_H4;
69 sctx->state[5] = SHA256_H5;
70 sctx->state[6] = SHA256_H6;
71 sctx->state[7] = SHA256_H7;
72 sctx->count = 0;
73
74 return 0;
75 }
76
ppc_spe_sha224_init(struct shash_desc * desc)77 static int ppc_spe_sha224_init(struct shash_desc *desc)
78 {
79 struct sha256_state *sctx = shash_desc_ctx(desc);
80
81 sctx->state[0] = SHA224_H0;
82 sctx->state[1] = SHA224_H1;
83 sctx->state[2] = SHA224_H2;
84 sctx->state[3] = SHA224_H3;
85 sctx->state[4] = SHA224_H4;
86 sctx->state[5] = SHA224_H5;
87 sctx->state[6] = SHA224_H6;
88 sctx->state[7] = SHA224_H7;
89 sctx->count = 0;
90
91 return 0;
92 }
93
ppc_spe_sha256_update(struct shash_desc * desc,const u8 * data,unsigned int len)94 static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data,
95 unsigned int len)
96 {
97 struct sha256_state *sctx = shash_desc_ctx(desc);
98 const unsigned int offset = sctx->count & 0x3f;
99 const unsigned int avail = 64 - offset;
100 unsigned int bytes;
101 const u8 *src = data;
102
103 if (avail > len) {
104 sctx->count += len;
105 memcpy((char *)sctx->buf + offset, src, len);
106 return 0;
107 }
108
109 sctx->count += len;
110
111 if (offset) {
112 memcpy((char *)sctx->buf + offset, src, avail);
113
114 spe_begin();
115 ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1);
116 spe_end();
117
118 len -= avail;
119 src += avail;
120 }
121
122 while (len > 63) {
123 /* cut input data into smaller blocks */
124 bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
125 bytes = bytes & ~0x3f;
126
127 spe_begin();
128 ppc_spe_sha256_transform(sctx->state, src, bytes >> 6);
129 spe_end();
130
131 src += bytes;
132 len -= bytes;
133 };
134
135 memcpy((char *)sctx->buf, src, len);
136 return 0;
137 }
138
ppc_spe_sha256_final(struct shash_desc * desc,u8 * out)139 static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out)
140 {
141 struct sha256_state *sctx = shash_desc_ctx(desc);
142 const unsigned int offset = sctx->count & 0x3f;
143 char *p = (char *)sctx->buf + offset;
144 int padlen;
145 __be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56);
146 __be32 *dst = (__be32 *)out;
147
148 padlen = 55 - offset;
149 *p++ = 0x80;
150
151 spe_begin();
152
153 if (padlen < 0) {
154 memset(p, 0x00, padlen + sizeof (u64));
155 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
156 p = (char *)sctx->buf;
157 padlen = 56;
158 }
159
160 memset(p, 0, padlen);
161 *pbits = cpu_to_be64(sctx->count << 3);
162 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
163
164 spe_end();
165
166 dst[0] = cpu_to_be32(sctx->state[0]);
167 dst[1] = cpu_to_be32(sctx->state[1]);
168 dst[2] = cpu_to_be32(sctx->state[2]);
169 dst[3] = cpu_to_be32(sctx->state[3]);
170 dst[4] = cpu_to_be32(sctx->state[4]);
171 dst[5] = cpu_to_be32(sctx->state[5]);
172 dst[6] = cpu_to_be32(sctx->state[6]);
173 dst[7] = cpu_to_be32(sctx->state[7]);
174
175 ppc_sha256_clear_context(sctx);
176 return 0;
177 }
178
ppc_spe_sha224_final(struct shash_desc * desc,u8 * out)179 static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out)
180 {
181 u32 D[SHA256_DIGEST_SIZE >> 2];
182 __be32 *dst = (__be32 *)out;
183
184 ppc_spe_sha256_final(desc, (u8 *)D);
185
186 /* avoid bytewise memcpy */
187 dst[0] = D[0];
188 dst[1] = D[1];
189 dst[2] = D[2];
190 dst[3] = D[3];
191 dst[4] = D[4];
192 dst[5] = D[5];
193 dst[6] = D[6];
194
195 /* clear sensitive data */
196 memzero_explicit(D, SHA256_DIGEST_SIZE);
197 return 0;
198 }
199
ppc_spe_sha256_export(struct shash_desc * desc,void * out)200 static int ppc_spe_sha256_export(struct shash_desc *desc, void *out)
201 {
202 struct sha256_state *sctx = shash_desc_ctx(desc);
203
204 memcpy(out, sctx, sizeof(*sctx));
205 return 0;
206 }
207
ppc_spe_sha256_import(struct shash_desc * desc,const void * in)208 static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in)
209 {
210 struct sha256_state *sctx = shash_desc_ctx(desc);
211
212 memcpy(sctx, in, sizeof(*sctx));
213 return 0;
214 }
215
216 static struct shash_alg algs[2] = { {
217 .digestsize = SHA256_DIGEST_SIZE,
218 .init = ppc_spe_sha256_init,
219 .update = ppc_spe_sha256_update,
220 .final = ppc_spe_sha256_final,
221 .export = ppc_spe_sha256_export,
222 .import = ppc_spe_sha256_import,
223 .descsize = sizeof(struct sha256_state),
224 .statesize = sizeof(struct sha256_state),
225 .base = {
226 .cra_name = "sha256",
227 .cra_driver_name= "sha256-ppc-spe",
228 .cra_priority = 300,
229 .cra_blocksize = SHA256_BLOCK_SIZE,
230 .cra_module = THIS_MODULE,
231 }
232 }, {
233 .digestsize = SHA224_DIGEST_SIZE,
234 .init = ppc_spe_sha224_init,
235 .update = ppc_spe_sha256_update,
236 .final = ppc_spe_sha224_final,
237 .export = ppc_spe_sha256_export,
238 .import = ppc_spe_sha256_import,
239 .descsize = sizeof(struct sha256_state),
240 .statesize = sizeof(struct sha256_state),
241 .base = {
242 .cra_name = "sha224",
243 .cra_driver_name= "sha224-ppc-spe",
244 .cra_priority = 300,
245 .cra_blocksize = SHA224_BLOCK_SIZE,
246 .cra_module = THIS_MODULE,
247 }
248 } };
249
ppc_spe_sha256_mod_init(void)250 static int __init ppc_spe_sha256_mod_init(void)
251 {
252 return crypto_register_shashes(algs, ARRAY_SIZE(algs));
253 }
254
ppc_spe_sha256_mod_fini(void)255 static void __exit ppc_spe_sha256_mod_fini(void)
256 {
257 crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
258 }
259
260 module_init(ppc_spe_sha256_mod_init);
261 module_exit(ppc_spe_sha256_mod_fini);
262
263 MODULE_LICENSE("GPL");
264 MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized");
265
266 MODULE_ALIAS_CRYPTO("sha224");
267 MODULE_ALIAS_CRYPTO("sha224-ppc-spe");
268 MODULE_ALIAS_CRYPTO("sha256");
269 MODULE_ALIAS_CRYPTO("sha256-ppc-spe");
270