1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
4 *
5 * Copyright (C) 2015 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
6 */
7
8#include <asm/hwcap.h>
9#include <asm/neon.h>
10#include <asm/simd.h>
11#include <asm/unaligned.h>
12#include <crypto/b128ops.h>
13#include <crypto/cryptd.h>
14#include <crypto/internal/hash.h>
15#include <crypto/internal/simd.h>
16#include <crypto/gf128mul.h>
17#include <linux/cpufeature.h>
18#include <linux/crypto.h>
19#include <linux/jump_label.h>
20#include <linux/module.h>
21
22MODULE_DESCRIPTION("GHASH hash function using ARMv8 Crypto Extensions");
23MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
24MODULE_LICENSE("GPL v2");
25MODULE_ALIAS_CRYPTO("ghash");
26
27#define GHASH_BLOCK_SIZE	16
28#define GHASH_DIGEST_SIZE	16
29
30struct ghash_key {
31	be128	k;
32	u64	h[][2];
33};
34
35struct ghash_desc_ctx {
36	u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
37	u8 buf[GHASH_BLOCK_SIZE];
38	u32 count;
39};
40
41struct ghash_async_ctx {
42	struct cryptd_ahash *cryptd_tfm;
43};
44
45asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
46				       u64 const h[][2], const char *head);
47
48asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
49				      u64 const h[][2], const char *head);
50
51static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_p64);
52
53static int ghash_init(struct shash_desc *desc)
54{
55	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
56
57	*ctx = (struct ghash_desc_ctx){};
58	return 0;
59}
60
61static void ghash_do_update(int blocks, u64 dg[], const char *src,
62			    struct ghash_key *key, const char *head)
63{
64	if (likely(crypto_simd_usable())) {
65		kernel_neon_begin();
66		if (static_branch_likely(&use_p64))
67			pmull_ghash_update_p64(blocks, dg, src, key->h, head);
68		else
69			pmull_ghash_update_p8(blocks, dg, src, key->h, head);
70		kernel_neon_end();
71	} else {
72		be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
73
74		do {
75			const u8 *in = src;
76
77			if (head) {
78				in = head;
79				blocks++;
80				head = NULL;
81			} else {
82				src += GHASH_BLOCK_SIZE;
83			}
84
85			crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
86			gf128mul_lle(&dst, &key->k);
87		} while (--blocks);
88
89		dg[0] = be64_to_cpu(dst.b);
90		dg[1] = be64_to_cpu(dst.a);
91	}
92}
93
94static int ghash_update(struct shash_desc *desc, const u8 *src,
95			unsigned int len)
96{
97	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
98	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
99
100	ctx->count += len;
101
102	if ((partial + len) >= GHASH_BLOCK_SIZE) {
103		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
104		int blocks;
105
106		if (partial) {
107			int p = GHASH_BLOCK_SIZE - partial;
108
109			memcpy(ctx->buf + partial, src, p);
110			src += p;
111			len -= p;
112		}
113
114		blocks = len / GHASH_BLOCK_SIZE;
115		len %= GHASH_BLOCK_SIZE;
116
117		ghash_do_update(blocks, ctx->digest, src, key,
118				partial ? ctx->buf : NULL);
119		src += blocks * GHASH_BLOCK_SIZE;
120		partial = 0;
121	}
122	if (len)
123		memcpy(ctx->buf + partial, src, len);
124	return 0;
125}
126
127static int ghash_final(struct shash_desc *desc, u8 *dst)
128{
129	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
130	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
131
132	if (partial) {
133		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
134
135		memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
136		ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
137	}
138	put_unaligned_be64(ctx->digest[1], dst);
139	put_unaligned_be64(ctx->digest[0], dst + 8);
140
141	*ctx = (struct ghash_desc_ctx){};
142	return 0;
143}
144
145static void ghash_reflect(u64 h[], const be128 *k)
146{
147	u64 carry = be64_to_cpu(k->a) >> 63;
148
149	h[0] = (be64_to_cpu(k->b) << 1) | carry;
150	h[1] = (be64_to_cpu(k->a) << 1) | (be64_to_cpu(k->b) >> 63);
151
152	if (carry)
153		h[1] ^= 0xc200000000000000UL;
154}
155
156static int ghash_setkey(struct crypto_shash *tfm,
157			const u8 *inkey, unsigned int keylen)
158{
159	struct ghash_key *key = crypto_shash_ctx(tfm);
160
161	if (keylen != GHASH_BLOCK_SIZE)
162		return -EINVAL;
163
164	/* needed for the fallback */
165	memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
166	ghash_reflect(key->h[0], &key->k);
167
168	if (static_branch_likely(&use_p64)) {
169		be128 h = key->k;
170
171		gf128mul_lle(&h, &key->k);
172		ghash_reflect(key->h[1], &h);
173
174		gf128mul_lle(&h, &key->k);
175		ghash_reflect(key->h[2], &h);
176
177		gf128mul_lle(&h, &key->k);
178		ghash_reflect(key->h[3], &h);
179	}
180	return 0;
181}
182
183static struct shash_alg ghash_alg = {
184	.digestsize		= GHASH_DIGEST_SIZE,
185	.init			= ghash_init,
186	.update			= ghash_update,
187	.final			= ghash_final,
188	.setkey			= ghash_setkey,
189	.descsize		= sizeof(struct ghash_desc_ctx),
190
191	.base.cra_name		= "ghash",
192	.base.cra_driver_name	= "ghash-ce-sync",
193	.base.cra_priority	= 300 - 1,
194	.base.cra_blocksize	= GHASH_BLOCK_SIZE,
195	.base.cra_ctxsize	= sizeof(struct ghash_key) + sizeof(u64[2]),
196	.base.cra_module	= THIS_MODULE,
197};
198
199static int ghash_async_init(struct ahash_request *req)
200{
201	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
202	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
203	struct ahash_request *cryptd_req = ahash_request_ctx(req);
204	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
205	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
206	struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
207
208	desc->tfm = child;
209	return crypto_shash_init(desc);
210}
211
212static int ghash_async_update(struct ahash_request *req)
213{
214	struct ahash_request *cryptd_req = ahash_request_ctx(req);
215	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
216	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
217	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
218
219	if (!crypto_simd_usable() ||
220	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
221		memcpy(cryptd_req, req, sizeof(*req));
222		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
223		return crypto_ahash_update(cryptd_req);
224	} else {
225		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
226		return shash_ahash_update(req, desc);
227	}
228}
229
230static int ghash_async_final(struct ahash_request *req)
231{
232	struct ahash_request *cryptd_req = ahash_request_ctx(req);
233	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
234	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
235	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
236
237	if (!crypto_simd_usable() ||
238	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
239		memcpy(cryptd_req, req, sizeof(*req));
240		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
241		return crypto_ahash_final(cryptd_req);
242	} else {
243		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
244		return crypto_shash_final(desc, req->result);
245	}
246}
247
248static int ghash_async_digest(struct ahash_request *req)
249{
250	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
251	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
252	struct ahash_request *cryptd_req = ahash_request_ctx(req);
253	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
254
255	if (!crypto_simd_usable() ||
256	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
257		memcpy(cryptd_req, req, sizeof(*req));
258		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
259		return crypto_ahash_digest(cryptd_req);
260	} else {
261		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
262		struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
263
264		desc->tfm = child;
265		return shash_ahash_digest(req, desc);
266	}
267}
268
269static int ghash_async_import(struct ahash_request *req, const void *in)
270{
271	struct ahash_request *cryptd_req = ahash_request_ctx(req);
272	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
273	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
274	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
275
276	desc->tfm = cryptd_ahash_child(ctx->cryptd_tfm);
277
278	return crypto_shash_import(desc, in);
279}
280
281static int ghash_async_export(struct ahash_request *req, void *out)
282{
283	struct ahash_request *cryptd_req = ahash_request_ctx(req);
284	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
285
286	return crypto_shash_export(desc, out);
287}
288
289static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
290			      unsigned int keylen)
291{
292	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
293	struct crypto_ahash *child = &ctx->cryptd_tfm->base;
294
295	crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
296	crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
297			       & CRYPTO_TFM_REQ_MASK);
298	return crypto_ahash_setkey(child, key, keylen);
299}
300
301static int ghash_async_init_tfm(struct crypto_tfm *tfm)
302{
303	struct cryptd_ahash *cryptd_tfm;
304	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
305
306	cryptd_tfm = cryptd_alloc_ahash("ghash-ce-sync", 0, 0);
307	if (IS_ERR(cryptd_tfm))
308		return PTR_ERR(cryptd_tfm);
309	ctx->cryptd_tfm = cryptd_tfm;
310	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
311				 sizeof(struct ahash_request) +
312				 crypto_ahash_reqsize(&cryptd_tfm->base));
313
314	return 0;
315}
316
317static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
318{
319	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
320
321	cryptd_free_ahash(ctx->cryptd_tfm);
322}
323
324static struct ahash_alg ghash_async_alg = {
325	.init			= ghash_async_init,
326	.update			= ghash_async_update,
327	.final			= ghash_async_final,
328	.setkey			= ghash_async_setkey,
329	.digest			= ghash_async_digest,
330	.import			= ghash_async_import,
331	.export			= ghash_async_export,
332	.halg.digestsize	= GHASH_DIGEST_SIZE,
333	.halg.statesize		= sizeof(struct ghash_desc_ctx),
334	.halg.base		= {
335		.cra_name	= "ghash",
336		.cra_driver_name = "ghash-ce",
337		.cra_priority	= 300,
338		.cra_flags	= CRYPTO_ALG_ASYNC,
339		.cra_blocksize	= GHASH_BLOCK_SIZE,
340		.cra_ctxsize	= sizeof(struct ghash_async_ctx),
341		.cra_module	= THIS_MODULE,
342		.cra_init	= ghash_async_init_tfm,
343		.cra_exit	= ghash_async_exit_tfm,
344	},
345};
346
347static int __init ghash_ce_mod_init(void)
348{
349	int err;
350
351	if (!(elf_hwcap & HWCAP_NEON))
352		return -ENODEV;
353
354	if (elf_hwcap2 & HWCAP2_PMULL) {
355		ghash_alg.base.cra_ctxsize += 3 * sizeof(u64[2]);
356		static_branch_enable(&use_p64);
357	}
358
359	err = crypto_register_shash(&ghash_alg);
360	if (err)
361		return err;
362	err = crypto_register_ahash(&ghash_async_alg);
363	if (err)
364		goto err_shash;
365
366	return 0;
367
368err_shash:
369	crypto_unregister_shash(&ghash_alg);
370	return err;
371}
372
373static void __exit ghash_ce_mod_exit(void)
374{
375	crypto_unregister_ahash(&ghash_async_alg);
376	crypto_unregister_shash(&ghash_alg);
377}
378
379module_init(ghash_ce_mod_init);
380module_exit(ghash_ce_mod_exit);
381