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