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/types.h>
16 #include <crypto/sha2.h>
17 #include <crypto/sha256_base.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
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
43 static void spe_end(void)
44 {
45 disable_kernel_spe();
46 /* reenable preemption */
47 preempt_enable();
48 }
49
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
60 static int ppc_spe_sha256_update(struct shash_desc *desc, const u8 *data,
61 unsigned int len)
62 {
63 struct sha256_state *sctx = shash_desc_ctx(desc);
64 const unsigned int offset = sctx->count & 0x3f;
65 const unsigned int avail = 64 - offset;
66 unsigned int bytes;
67 const u8 *src = data;
68
69 if (avail > len) {
70 sctx->count += len;
71 memcpy((char *)sctx->buf + offset, src, len);
72 return 0;
73 }
74
75 sctx->count += len;
76
77 if (offset) {
78 memcpy((char *)sctx->buf + offset, src, avail);
79
80 spe_begin();
81 ppc_spe_sha256_transform(sctx->state, (const u8 *)sctx->buf, 1);
82 spe_end();
83
84 len -= avail;
85 src += avail;
86 }
87
88 while (len > 63) {
89 /* cut input data into smaller blocks */
90 bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
91 bytes = bytes & ~0x3f;
92
93 spe_begin();
94 ppc_spe_sha256_transform(sctx->state, src, bytes >> 6);
95 spe_end();
96
97 src += bytes;
98 len -= bytes;
99 }
100
101 memcpy((char *)sctx->buf, src, len);
102 return 0;
103 }
104
105 static int ppc_spe_sha256_final(struct shash_desc *desc, u8 *out)
106 {
107 struct sha256_state *sctx = shash_desc_ctx(desc);
108 const unsigned int offset = sctx->count & 0x3f;
109 char *p = (char *)sctx->buf + offset;
110 int padlen;
111 __be64 *pbits = (__be64 *)(((char *)&sctx->buf) + 56);
112 __be32 *dst = (__be32 *)out;
113
114 padlen = 55 - offset;
115 *p++ = 0x80;
116
117 spe_begin();
118
119 if (padlen < 0) {
120 memset(p, 0x00, padlen + sizeof (u64));
121 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
122 p = (char *)sctx->buf;
123 padlen = 56;
124 }
125
126 memset(p, 0, padlen);
127 *pbits = cpu_to_be64(sctx->count << 3);
128 ppc_spe_sha256_transform(sctx->state, sctx->buf, 1);
129
130 spe_end();
131
132 dst[0] = cpu_to_be32(sctx->state[0]);
133 dst[1] = cpu_to_be32(sctx->state[1]);
134 dst[2] = cpu_to_be32(sctx->state[2]);
135 dst[3] = cpu_to_be32(sctx->state[3]);
136 dst[4] = cpu_to_be32(sctx->state[4]);
137 dst[5] = cpu_to_be32(sctx->state[5]);
138 dst[6] = cpu_to_be32(sctx->state[6]);
139 dst[7] = cpu_to_be32(sctx->state[7]);
140
141 ppc_sha256_clear_context(sctx);
142 return 0;
143 }
144
145 static int ppc_spe_sha224_final(struct shash_desc *desc, u8 *out)
146 {
147 __be32 D[SHA256_DIGEST_SIZE >> 2];
148 __be32 *dst = (__be32 *)out;
149
150 ppc_spe_sha256_final(desc, (u8 *)D);
151
152 /* avoid bytewise memcpy */
153 dst[0] = D[0];
154 dst[1] = D[1];
155 dst[2] = D[2];
156 dst[3] = D[3];
157 dst[4] = D[4];
158 dst[5] = D[5];
159 dst[6] = D[6];
160
161 /* clear sensitive data */
162 memzero_explicit(D, SHA256_DIGEST_SIZE);
163 return 0;
164 }
165
166 static int ppc_spe_sha256_export(struct shash_desc *desc, void *out)
167 {
168 struct sha256_state *sctx = shash_desc_ctx(desc);
169
170 memcpy(out, sctx, sizeof(*sctx));
171 return 0;
172 }
173
174 static int ppc_spe_sha256_import(struct shash_desc *desc, const void *in)
175 {
176 struct sha256_state *sctx = shash_desc_ctx(desc);
177
178 memcpy(sctx, in, sizeof(*sctx));
179 return 0;
180 }
181
182 static struct shash_alg algs[2] = { {
183 .digestsize = SHA256_DIGEST_SIZE,
184 .init = sha256_base_init,
185 .update = ppc_spe_sha256_update,
186 .final = ppc_spe_sha256_final,
187 .export = ppc_spe_sha256_export,
188 .import = ppc_spe_sha256_import,
189 .descsize = sizeof(struct sha256_state),
190 .statesize = sizeof(struct sha256_state),
191 .base = {
192 .cra_name = "sha256",
193 .cra_driver_name= "sha256-ppc-spe",
194 .cra_priority = 300,
195 .cra_blocksize = SHA256_BLOCK_SIZE,
196 .cra_module = THIS_MODULE,
197 }
198 }, {
199 .digestsize = SHA224_DIGEST_SIZE,
200 .init = sha224_base_init,
201 .update = ppc_spe_sha256_update,
202 .final = ppc_spe_sha224_final,
203 .export = ppc_spe_sha256_export,
204 .import = ppc_spe_sha256_import,
205 .descsize = sizeof(struct sha256_state),
206 .statesize = sizeof(struct sha256_state),
207 .base = {
208 .cra_name = "sha224",
209 .cra_driver_name= "sha224-ppc-spe",
210 .cra_priority = 300,
211 .cra_blocksize = SHA224_BLOCK_SIZE,
212 .cra_module = THIS_MODULE,
213 }
214 } };
215
216 static int __init ppc_spe_sha256_mod_init(void)
217 {
218 return crypto_register_shashes(algs, ARRAY_SIZE(algs));
219 }
220
221 static void __exit ppc_spe_sha256_mod_fini(void)
222 {
223 crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
224 }
225
226 module_init(ppc_spe_sha256_mod_init);
227 module_exit(ppc_spe_sha256_mod_fini);
228
229 MODULE_LICENSE("GPL");
230 MODULE_DESCRIPTION("SHA-224 and SHA-256 Secure Hash Algorithm, SPE optimized");
231
232 MODULE_ALIAS_CRYPTO("sha224");
233 MODULE_ALIAS_CRYPTO("sha224-ppc-spe");
234 MODULE_ALIAS_CRYPTO("sha256");
235 MODULE_ALIAS_CRYPTO("sha256-ppc-spe");
236
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