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 
33 extern void ppc_spe_sha1_transform(u32 *state, const u8 *src, u32 blocks);
34 
spe_begin(void)35 static 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 
spe_end(void)42 static void spe_end(void)
43 {
44 	disable_kernel_spe();
45 	/* reenable preemption */
46 	preempt_enable();
47 }
48 
ppc_sha1_clear_context(struct sha1_state * sctx)49 static 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 
ppc_spe_sha1_update(struct shash_desc * desc,const u8 * data,unsigned int len)59 static 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 
ppc_spe_sha1_final(struct shash_desc * desc,u8 * out)103 static 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 
ppc_spe_sha1_export(struct shash_desc * desc,void * out)140 static 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 
ppc_spe_sha1_import(struct shash_desc * desc,const void * in)148 static 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 
156 static 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 
ppc_spe_sha1_mod_init(void)174 static int __init ppc_spe_sha1_mod_init(void)
175 {
176 	return crypto_register_shash(&alg);
177 }
178 
ppc_spe_sha1_mod_fini(void)179 static void __exit ppc_spe_sha1_mod_fini(void)
180 {
181 	crypto_unregister_shash(&alg);
182 }
183 
184 module_init(ppc_spe_sha1_mod_init);
185 module_exit(ppc_spe_sha1_mod_fini);
186 
187 MODULE_LICENSE("GPL");
188 MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm, SPE optimized");
189 
190 MODULE_ALIAS_CRYPTO("sha1");
191 MODULE_ALIAS_CRYPTO("sha1-ppc-spe");
192