1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Glue code for SHA-1 implementation for SPE instructions (PPC)
4 *
5 * Based on generic implementation.
6 *
7 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
8 */
9
10#include <crypto/internal/hash.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/mm.h>
14#include <linux/types.h>
15#include <crypto/sha1.h>
16#include <crypto/sha1_base.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(). SHA1 takes ~1000
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 2KB 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 2048
32
33extern void ppc_spe_sha1_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_sha1_clear_context(struct sha1_state *sctx)
50{
51	int count = sizeof(struct sha1_state) >> 2;
52	u32 *ptr = (u32 *)sctx;
53
54	/* make sure we can clear the fast way */
55	BUILD_BUG_ON(sizeof(struct sha1_state) % 4);
56	do { *ptr++ = 0; } while (--count);
57}
58
59static int ppc_spe_sha1_update(struct shash_desc *desc, const u8 *data,
60			unsigned int len)
61{
62	struct sha1_state *sctx = shash_desc_ctx(desc);
63	const unsigned int offset = sctx->count & 0x3f;
64	const unsigned int avail = 64 - offset;
65	unsigned int bytes;
66	const u8 *src = data;
67
68	if (avail > len) {
69		sctx->count += len;
70		memcpy((char *)sctx->buffer + offset, src, len);
71		return 0;
72	}
73
74	sctx->count += len;
75
76	if (offset) {
77		memcpy((char *)sctx->buffer + offset, src, avail);
78
79		spe_begin();
80		ppc_spe_sha1_transform(sctx->state, (const u8 *)sctx->buffer, 1);
81		spe_end();
82
83		len -= avail;
84		src += avail;
85	}
86
87	while (len > 63) {
88		bytes = (len > MAX_BYTES) ? MAX_BYTES : len;
89		bytes = bytes & ~0x3f;
90
91		spe_begin();
92		ppc_spe_sha1_transform(sctx->state, src, bytes >> 6);
93		spe_end();
94
95		src += bytes;
96		len -= bytes;
97	}
98
99	memcpy((char *)sctx->buffer, src, len);
100	return 0;
101}
102
103static int ppc_spe_sha1_final(struct shash_desc *desc, u8 *out)
104{
105	struct sha1_state *sctx = shash_desc_ctx(desc);
106	const unsigned int offset = sctx->count & 0x3f;
107	char *p = (char *)sctx->buffer + offset;
108	int padlen;
109	__be64 *pbits = (__be64 *)(((char *)&sctx->buffer) + 56);
110	__be32 *dst = (__be32 *)out;
111
112	padlen = 55 - offset;
113	*p++ = 0x80;
114
115	spe_begin();
116
117	if (padlen < 0) {
118		memset(p, 0x00, padlen + sizeof (u64));
119		ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
120		p = (char *)sctx->buffer;
121		padlen = 56;
122	}
123
124	memset(p, 0, padlen);
125	*pbits = cpu_to_be64(sctx->count << 3);
126	ppc_spe_sha1_transform(sctx->state, sctx->buffer, 1);
127
128	spe_end();
129
130	dst[0] = cpu_to_be32(sctx->state[0]);
131	dst[1] = cpu_to_be32(sctx->state[1]);
132	dst[2] = cpu_to_be32(sctx->state[2]);
133	dst[3] = cpu_to_be32(sctx->state[3]);
134	dst[4] = cpu_to_be32(sctx->state[4]);
135
136	ppc_sha1_clear_context(sctx);
137	return 0;
138}
139
140static int ppc_spe_sha1_export(struct shash_desc *desc, void *out)
141{
142	struct sha1_state *sctx = shash_desc_ctx(desc);
143
144	memcpy(out, sctx, sizeof(*sctx));
145	return 0;
146}
147
148static int ppc_spe_sha1_import(struct shash_desc *desc, const void *in)
149{
150	struct sha1_state *sctx = shash_desc_ctx(desc);
151
152	memcpy(sctx, in, sizeof(*sctx));
153	return 0;
154}
155
156static struct shash_alg alg = {
157	.digestsize	=	SHA1_DIGEST_SIZE,
158	.init		=	sha1_base_init,
159	.update		=	ppc_spe_sha1_update,
160	.final		=	ppc_spe_sha1_final,
161	.export		=	ppc_spe_sha1_export,
162	.import		=	ppc_spe_sha1_import,
163	.descsize	=	sizeof(struct sha1_state),
164	.statesize	=	sizeof(struct sha1_state),
165	.base		=	{
166		.cra_name	=	"sha1",
167		.cra_driver_name=	"sha1-ppc-spe",
168		.cra_priority	=	300,
169		.cra_blocksize	=	SHA1_BLOCK_SIZE,
170		.cra_module	=	THIS_MODULE,
171	}
172};
173
174static int __init ppc_spe_sha1_mod_init(void)
175{
176	return crypto_register_shash(&alg);
177}
178
179static void __exit ppc_spe_sha1_mod_fini(void)
180{
181	crypto_unregister_shash(&alg);
182}
183
184module_init(ppc_spe_sha1_mod_init);
185module_exit(ppc_spe_sha1_mod_fini);
186
187MODULE_LICENSE("GPL");
188MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, SPE optimized");
189
190MODULE_ALIAS_CRYPTO("sha1");
191MODULE_ALIAS_CRYPTO("sha1-ppc-spe");
192