xref: /linux/arch/arm64/crypto/aes-glue.c (revision fbf5df34a4dbcd09d433dd4f0916bf9b2ddb16de)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/arch/arm64/crypto/aes-glue.c - wrapper code for ARMv8 AES
4  *
5  * Copyright (C) 2013 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
6  */
7 
8 #include <crypto/aes.h>
9 #include <crypto/ctr.h>
10 #include <crypto/internal/skcipher.h>
11 #include <crypto/scatterwalk.h>
12 #include <crypto/sha2.h>
13 #include <crypto/utils.h>
14 #include <crypto/xts.h>
15 #include <linux/cpufeature.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/string.h>
19 
20 #include <asm/hwcap.h>
21 #include <asm/simd.h>
22 
23 #ifdef USE_V8_CRYPTO_EXTENSIONS
24 #define MODE			"ce"
25 #define PRIO			300
26 #define aes_expandkey		ce_aes_expandkey
27 #define aes_ecb_encrypt		ce_aes_ecb_encrypt
28 #define aes_ecb_decrypt		ce_aes_ecb_decrypt
29 #define aes_cbc_encrypt		ce_aes_cbc_encrypt
30 #define aes_cbc_decrypt		ce_aes_cbc_decrypt
31 #define aes_cbc_cts_encrypt	ce_aes_cbc_cts_encrypt
32 #define aes_cbc_cts_decrypt	ce_aes_cbc_cts_decrypt
33 #define aes_essiv_cbc_encrypt	ce_aes_essiv_cbc_encrypt
34 #define aes_essiv_cbc_decrypt	ce_aes_essiv_cbc_decrypt
35 #define aes_ctr_encrypt		ce_aes_ctr_encrypt
36 #define aes_xctr_encrypt	ce_aes_xctr_encrypt
37 #define aes_xts_encrypt		ce_aes_xts_encrypt
38 #define aes_xts_decrypt		ce_aes_xts_decrypt
39 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS/XCTR using ARMv8 Crypto Extensions");
40 #else
41 #define MODE			"neon"
42 #define PRIO			200
43 #define aes_ecb_encrypt		neon_aes_ecb_encrypt
44 #define aes_ecb_decrypt		neon_aes_ecb_decrypt
45 #define aes_cbc_encrypt		neon_aes_cbc_encrypt
46 #define aes_cbc_decrypt		neon_aes_cbc_decrypt
47 #define aes_cbc_cts_encrypt	neon_aes_cbc_cts_encrypt
48 #define aes_cbc_cts_decrypt	neon_aes_cbc_cts_decrypt
49 #define aes_essiv_cbc_encrypt	neon_aes_essiv_cbc_encrypt
50 #define aes_essiv_cbc_decrypt	neon_aes_essiv_cbc_decrypt
51 #define aes_ctr_encrypt		neon_aes_ctr_encrypt
52 #define aes_xctr_encrypt	neon_aes_xctr_encrypt
53 #define aes_xts_encrypt		neon_aes_xts_encrypt
54 #define aes_xts_decrypt		neon_aes_xts_decrypt
55 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS/XCTR using ARMv8 NEON");
56 #endif
57 #if defined(USE_V8_CRYPTO_EXTENSIONS) || !IS_ENABLED(CONFIG_CRYPTO_AES_ARM64_BS)
58 MODULE_ALIAS_CRYPTO("ecb(aes)");
59 MODULE_ALIAS_CRYPTO("cbc(aes)");
60 MODULE_ALIAS_CRYPTO("ctr(aes)");
61 MODULE_ALIAS_CRYPTO("xts(aes)");
62 MODULE_ALIAS_CRYPTO("xctr(aes)");
63 #endif
64 MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
65 MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)");
66 
67 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
68 MODULE_IMPORT_NS("CRYPTO_INTERNAL");
69 MODULE_LICENSE("GPL v2");
70 
71 struct crypto_aes_xts_ctx {
72 	struct crypto_aes_ctx key1;
73 	struct crypto_aes_ctx __aligned(8) key2;
74 };
75 
76 struct crypto_aes_essiv_cbc_ctx {
77 	struct crypto_aes_ctx key1;
78 	struct crypto_aes_ctx __aligned(8) key2;
79 };
80 
81 static int skcipher_aes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
82 			       unsigned int key_len)
83 {
84 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
85 
86 	return aes_expandkey(ctx, in_key, key_len);
87 }
88 
89 static int __maybe_unused xts_set_key(struct crypto_skcipher *tfm,
90 				      const u8 *in_key, unsigned int key_len)
91 {
92 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
93 	int ret;
94 
95 	ret = xts_verify_key(tfm, in_key, key_len);
96 	if (ret)
97 		return ret;
98 
99 	ret = aes_expandkey(&ctx->key1, in_key, key_len / 2);
100 	if (!ret)
101 		ret = aes_expandkey(&ctx->key2, &in_key[key_len / 2],
102 				    key_len / 2);
103 	return ret;
104 }
105 
106 static int __maybe_unused essiv_cbc_set_key(struct crypto_skcipher *tfm,
107 					    const u8 *in_key,
108 					    unsigned int key_len)
109 {
110 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
111 	u8 digest[SHA256_DIGEST_SIZE];
112 	int ret;
113 
114 	ret = aes_expandkey(&ctx->key1, in_key, key_len);
115 	if (ret)
116 		return ret;
117 
118 	sha256(in_key, key_len, digest);
119 
120 	return aes_expandkey(&ctx->key2, digest, sizeof(digest));
121 }
122 
123 static int __maybe_unused ecb_encrypt(struct skcipher_request *req)
124 {
125 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
126 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
127 	int err, rounds = 6 + ctx->key_length / 4;
128 	struct skcipher_walk walk;
129 	unsigned int blocks;
130 
131 	err = skcipher_walk_virt(&walk, req, false);
132 
133 	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
134 		scoped_ksimd()
135 			aes_ecb_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
136 					ctx->key_enc, rounds, blocks);
137 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
138 	}
139 	return err;
140 }
141 
142 static int __maybe_unused ecb_decrypt(struct skcipher_request *req)
143 {
144 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
145 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
146 	int err, rounds = 6 + ctx->key_length / 4;
147 	struct skcipher_walk walk;
148 	unsigned int blocks;
149 
150 	err = skcipher_walk_virt(&walk, req, false);
151 
152 	while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
153 		scoped_ksimd()
154 			aes_ecb_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
155 					ctx->key_dec, rounds, blocks);
156 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
157 	}
158 	return err;
159 }
160 
161 static int cbc_encrypt_walk(struct skcipher_request *req,
162 			    struct skcipher_walk *walk)
163 {
164 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
165 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
166 	int err = 0, rounds = 6 + ctx->key_length / 4;
167 	unsigned int blocks;
168 
169 	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
170 		scoped_ksimd()
171 			aes_cbc_encrypt(walk->dst.virt.addr, walk->src.virt.addr,
172 					ctx->key_enc, rounds, blocks, walk->iv);
173 		err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
174 	}
175 	return err;
176 }
177 
178 static int __maybe_unused cbc_encrypt(struct skcipher_request *req)
179 {
180 	struct skcipher_walk walk;
181 	int err;
182 
183 	err = skcipher_walk_virt(&walk, req, false);
184 	if (err)
185 		return err;
186 	return cbc_encrypt_walk(req, &walk);
187 }
188 
189 static int cbc_decrypt_walk(struct skcipher_request *req,
190 			    struct skcipher_walk *walk)
191 {
192 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
193 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
194 	int err = 0, rounds = 6 + ctx->key_length / 4;
195 	unsigned int blocks;
196 
197 	while ((blocks = (walk->nbytes / AES_BLOCK_SIZE))) {
198 		scoped_ksimd()
199 			aes_cbc_decrypt(walk->dst.virt.addr, walk->src.virt.addr,
200 					ctx->key_dec, rounds, blocks, walk->iv);
201 		err = skcipher_walk_done(walk, walk->nbytes % AES_BLOCK_SIZE);
202 	}
203 	return err;
204 }
205 
206 static int __maybe_unused cbc_decrypt(struct skcipher_request *req)
207 {
208 	struct skcipher_walk walk;
209 	int err;
210 
211 	err = skcipher_walk_virt(&walk, req, false);
212 	if (err)
213 		return err;
214 	return cbc_decrypt_walk(req, &walk);
215 }
216 
217 static int cts_cbc_encrypt(struct skcipher_request *req)
218 {
219 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
220 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
221 	int err, rounds = 6 + ctx->key_length / 4;
222 	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
223 	struct scatterlist *src = req->src, *dst = req->dst;
224 	struct scatterlist sg_src[2], sg_dst[2];
225 	struct skcipher_request subreq;
226 	struct skcipher_walk walk;
227 
228 	skcipher_request_set_tfm(&subreq, tfm);
229 	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
230 				      NULL, NULL);
231 
232 	if (req->cryptlen <= AES_BLOCK_SIZE) {
233 		if (req->cryptlen < AES_BLOCK_SIZE)
234 			return -EINVAL;
235 		cbc_blocks = 1;
236 	}
237 
238 	if (cbc_blocks > 0) {
239 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
240 					   cbc_blocks * AES_BLOCK_SIZE,
241 					   req->iv);
242 
243 		err = skcipher_walk_virt(&walk, &subreq, false) ?:
244 		      cbc_encrypt_walk(&subreq, &walk);
245 		if (err)
246 			return err;
247 
248 		if (req->cryptlen == AES_BLOCK_SIZE)
249 			return 0;
250 
251 		dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
252 		if (req->dst != req->src)
253 			dst = scatterwalk_ffwd(sg_dst, req->dst,
254 					       subreq.cryptlen);
255 	}
256 
257 	/* handle ciphertext stealing */
258 	skcipher_request_set_crypt(&subreq, src, dst,
259 				   req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
260 				   req->iv);
261 
262 	err = skcipher_walk_virt(&walk, &subreq, false);
263 	if (err)
264 		return err;
265 
266 	scoped_ksimd()
267 		aes_cbc_cts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
268 				    ctx->key_enc, rounds, walk.nbytes, walk.iv);
269 
270 	return skcipher_walk_done(&walk, 0);
271 }
272 
273 static int cts_cbc_decrypt(struct skcipher_request *req)
274 {
275 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
276 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
277 	int err, rounds = 6 + ctx->key_length / 4;
278 	int cbc_blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
279 	struct scatterlist *src = req->src, *dst = req->dst;
280 	struct scatterlist sg_src[2], sg_dst[2];
281 	struct skcipher_request subreq;
282 	struct skcipher_walk walk;
283 
284 	skcipher_request_set_tfm(&subreq, tfm);
285 	skcipher_request_set_callback(&subreq, skcipher_request_flags(req),
286 				      NULL, NULL);
287 
288 	if (req->cryptlen <= AES_BLOCK_SIZE) {
289 		if (req->cryptlen < AES_BLOCK_SIZE)
290 			return -EINVAL;
291 		cbc_blocks = 1;
292 	}
293 
294 	if (cbc_blocks > 0) {
295 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
296 					   cbc_blocks * AES_BLOCK_SIZE,
297 					   req->iv);
298 
299 		err = skcipher_walk_virt(&walk, &subreq, false) ?:
300 		      cbc_decrypt_walk(&subreq, &walk);
301 		if (err)
302 			return err;
303 
304 		if (req->cryptlen == AES_BLOCK_SIZE)
305 			return 0;
306 
307 		dst = src = scatterwalk_ffwd(sg_src, req->src, subreq.cryptlen);
308 		if (req->dst != req->src)
309 			dst = scatterwalk_ffwd(sg_dst, req->dst,
310 					       subreq.cryptlen);
311 	}
312 
313 	/* handle ciphertext stealing */
314 	skcipher_request_set_crypt(&subreq, src, dst,
315 				   req->cryptlen - cbc_blocks * AES_BLOCK_SIZE,
316 				   req->iv);
317 
318 	err = skcipher_walk_virt(&walk, &subreq, false);
319 	if (err)
320 		return err;
321 
322 	scoped_ksimd()
323 		aes_cbc_cts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
324 				    ctx->key_dec, rounds, walk.nbytes, walk.iv);
325 
326 	return skcipher_walk_done(&walk, 0);
327 }
328 
329 static int __maybe_unused essiv_cbc_encrypt(struct skcipher_request *req)
330 {
331 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
332 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
333 	int err, rounds = 6 + ctx->key1.key_length / 4;
334 	struct skcipher_walk walk;
335 	unsigned int blocks;
336 
337 	err = skcipher_walk_virt(&walk, req, false);
338 
339 	blocks = walk.nbytes / AES_BLOCK_SIZE;
340 	if (blocks) {
341 		scoped_ksimd()
342 			aes_essiv_cbc_encrypt(walk.dst.virt.addr,
343 					      walk.src.virt.addr,
344 					      ctx->key1.key_enc, rounds, blocks,
345 					      req->iv, ctx->key2.key_enc);
346 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
347 	}
348 	return err ?: cbc_encrypt_walk(req, &walk);
349 }
350 
351 static int __maybe_unused essiv_cbc_decrypt(struct skcipher_request *req)
352 {
353 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
354 	struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
355 	int err, rounds = 6 + ctx->key1.key_length / 4;
356 	struct skcipher_walk walk;
357 	unsigned int blocks;
358 
359 	err = skcipher_walk_virt(&walk, req, false);
360 
361 	blocks = walk.nbytes / AES_BLOCK_SIZE;
362 	if (blocks) {
363 		scoped_ksimd()
364 			aes_essiv_cbc_decrypt(walk.dst.virt.addr,
365 					      walk.src.virt.addr,
366 					      ctx->key1.key_dec, rounds, blocks,
367 					      req->iv, ctx->key2.key_enc);
368 		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
369 	}
370 	return err ?: cbc_decrypt_walk(req, &walk);
371 }
372 
373 static int __maybe_unused xctr_encrypt(struct skcipher_request *req)
374 {
375 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
376 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
377 	int err, rounds = 6 + ctx->key_length / 4;
378 	struct skcipher_walk walk;
379 	unsigned int byte_ctr = 0;
380 
381 	err = skcipher_walk_virt(&walk, req, false);
382 
383 	while (walk.nbytes > 0) {
384 		const u8 *src = walk.src.virt.addr;
385 		unsigned int nbytes = walk.nbytes;
386 		u8 *dst = walk.dst.virt.addr;
387 		u8 buf[AES_BLOCK_SIZE];
388 
389 		/*
390 		 * If given less than 16 bytes, we must copy the partial block
391 		 * into a temporary buffer of 16 bytes to avoid out of bounds
392 		 * reads and writes.  Furthermore, this code is somewhat unusual
393 		 * in that it expects the end of the data to be at the end of
394 		 * the temporary buffer, rather than the start of the data at
395 		 * the start of the temporary buffer.
396 		 */
397 		if (unlikely(nbytes < AES_BLOCK_SIZE))
398 			src = dst = memcpy(buf + sizeof(buf) - nbytes,
399 					   src, nbytes);
400 		else if (nbytes < walk.total)
401 			nbytes &= ~(AES_BLOCK_SIZE - 1);
402 
403 		scoped_ksimd()
404 			aes_xctr_encrypt(dst, src, ctx->key_enc, rounds, nbytes,
405 							 walk.iv, byte_ctr);
406 
407 		if (unlikely(nbytes < AES_BLOCK_SIZE))
408 			memcpy(walk.dst.virt.addr,
409 			       buf + sizeof(buf) - nbytes, nbytes);
410 		byte_ctr += nbytes;
411 
412 		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
413 	}
414 
415 	return err;
416 }
417 
418 static int __maybe_unused ctr_encrypt(struct skcipher_request *req)
419 {
420 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
421 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
422 	int err, rounds = 6 + ctx->key_length / 4;
423 	struct skcipher_walk walk;
424 
425 	err = skcipher_walk_virt(&walk, req, false);
426 
427 	while (walk.nbytes > 0) {
428 		const u8 *src = walk.src.virt.addr;
429 		unsigned int nbytes = walk.nbytes;
430 		u8 *dst = walk.dst.virt.addr;
431 		u8 buf[AES_BLOCK_SIZE];
432 
433 		/*
434 		 * If given less than 16 bytes, we must copy the partial block
435 		 * into a temporary buffer of 16 bytes to avoid out of bounds
436 		 * reads and writes.  Furthermore, this code is somewhat unusual
437 		 * in that it expects the end of the data to be at the end of
438 		 * the temporary buffer, rather than the start of the data at
439 		 * the start of the temporary buffer.
440 		 */
441 		if (unlikely(nbytes < AES_BLOCK_SIZE))
442 			src = dst = memcpy(buf + sizeof(buf) - nbytes,
443 					   src, nbytes);
444 		else if (nbytes < walk.total)
445 			nbytes &= ~(AES_BLOCK_SIZE - 1);
446 
447 		scoped_ksimd()
448 			aes_ctr_encrypt(dst, src, ctx->key_enc, rounds, nbytes,
449 					walk.iv);
450 
451 		if (unlikely(nbytes < AES_BLOCK_SIZE))
452 			memcpy(walk.dst.virt.addr,
453 			       buf + sizeof(buf) - nbytes, nbytes);
454 
455 		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
456 	}
457 
458 	return err;
459 }
460 
461 static int __maybe_unused xts_encrypt(struct skcipher_request *req)
462 {
463 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
464 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
465 	int err, first, rounds = 6 + ctx->key1.key_length / 4;
466 	int tail = req->cryptlen % AES_BLOCK_SIZE;
467 	struct scatterlist sg_src[2], sg_dst[2];
468 	struct skcipher_request subreq;
469 	struct scatterlist *src, *dst;
470 	struct skcipher_walk walk;
471 
472 	if (req->cryptlen < AES_BLOCK_SIZE)
473 		return -EINVAL;
474 
475 	err = skcipher_walk_virt(&walk, req, false);
476 
477 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
478 		int xts_blocks = DIV_ROUND_UP(req->cryptlen,
479 					      AES_BLOCK_SIZE) - 2;
480 
481 		skcipher_walk_abort(&walk);
482 
483 		skcipher_request_set_tfm(&subreq, tfm);
484 		skcipher_request_set_callback(&subreq,
485 					      skcipher_request_flags(req),
486 					      NULL, NULL);
487 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
488 					   xts_blocks * AES_BLOCK_SIZE,
489 					   req->iv);
490 		req = &subreq;
491 		err = skcipher_walk_virt(&walk, req, false);
492 	} else {
493 		tail = 0;
494 	}
495 
496 	scoped_ksimd() {
497 		for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
498 			int nbytes = walk.nbytes;
499 
500 			if (walk.nbytes < walk.total)
501 				nbytes &= ~(AES_BLOCK_SIZE - 1);
502 
503 			aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
504 					ctx->key1.key_enc, rounds, nbytes,
505 					ctx->key2.key_enc, walk.iv, first);
506 			err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
507 		}
508 
509 		if (err || likely(!tail))
510 			return err;
511 
512 		dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
513 		if (req->dst != req->src)
514 			dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
515 
516 		skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
517 					   req->iv);
518 
519 		err = skcipher_walk_virt(&walk, &subreq, false);
520 		if (err)
521 			return err;
522 
523 		aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
524 				ctx->key1.key_enc, rounds, walk.nbytes,
525 				ctx->key2.key_enc, walk.iv, first);
526 	}
527 	return skcipher_walk_done(&walk, 0);
528 }
529 
530 static int __maybe_unused xts_decrypt(struct skcipher_request *req)
531 {
532 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
533 	struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
534 	int err, first, rounds = 6 + ctx->key1.key_length / 4;
535 	int tail = req->cryptlen % AES_BLOCK_SIZE;
536 	struct scatterlist sg_src[2], sg_dst[2];
537 	struct skcipher_request subreq;
538 	struct scatterlist *src, *dst;
539 	struct skcipher_walk walk;
540 
541 	if (req->cryptlen < AES_BLOCK_SIZE)
542 		return -EINVAL;
543 
544 	err = skcipher_walk_virt(&walk, req, false);
545 
546 	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
547 		int xts_blocks = DIV_ROUND_UP(req->cryptlen,
548 					      AES_BLOCK_SIZE) - 2;
549 
550 		skcipher_walk_abort(&walk);
551 
552 		skcipher_request_set_tfm(&subreq, tfm);
553 		skcipher_request_set_callback(&subreq,
554 					      skcipher_request_flags(req),
555 					      NULL, NULL);
556 		skcipher_request_set_crypt(&subreq, req->src, req->dst,
557 					   xts_blocks * AES_BLOCK_SIZE,
558 					   req->iv);
559 		req = &subreq;
560 		err = skcipher_walk_virt(&walk, req, false);
561 	} else {
562 		tail = 0;
563 	}
564 
565 	scoped_ksimd() {
566 		for (first = 1; walk.nbytes >= AES_BLOCK_SIZE; first = 0) {
567 			int nbytes = walk.nbytes;
568 
569 			if (walk.nbytes < walk.total)
570 				nbytes &= ~(AES_BLOCK_SIZE - 1);
571 
572 			aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
573 					ctx->key1.key_dec, rounds, nbytes,
574 					ctx->key2.key_enc, walk.iv, first);
575 			err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
576 		}
577 
578 		if (err || likely(!tail))
579 			return err;
580 
581 		dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
582 		if (req->dst != req->src)
583 			dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
584 
585 		skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
586 					   req->iv);
587 
588 		err = skcipher_walk_virt(&walk, &subreq, false);
589 		if (err)
590 			return err;
591 
592 		aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
593 				ctx->key1.key_dec, rounds, walk.nbytes,
594 				ctx->key2.key_enc, walk.iv, first);
595 	}
596 	return skcipher_walk_done(&walk, 0);
597 }
598 
599 static struct skcipher_alg aes_algs[] = { {
600 #if defined(USE_V8_CRYPTO_EXTENSIONS) || !IS_ENABLED(CONFIG_CRYPTO_AES_ARM64_BS)
601 	.base = {
602 		.cra_name		= "ecb(aes)",
603 		.cra_driver_name	= "ecb-aes-" MODE,
604 		.cra_priority		= PRIO,
605 		.cra_blocksize		= AES_BLOCK_SIZE,
606 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
607 		.cra_module		= THIS_MODULE,
608 	},
609 	.min_keysize	= AES_MIN_KEY_SIZE,
610 	.max_keysize	= AES_MAX_KEY_SIZE,
611 	.setkey		= skcipher_aes_setkey,
612 	.encrypt	= ecb_encrypt,
613 	.decrypt	= ecb_decrypt,
614 }, {
615 	.base = {
616 		.cra_name		= "cbc(aes)",
617 		.cra_driver_name	= "cbc-aes-" MODE,
618 		.cra_priority		= PRIO,
619 		.cra_blocksize		= AES_BLOCK_SIZE,
620 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
621 		.cra_module		= THIS_MODULE,
622 	},
623 	.min_keysize	= AES_MIN_KEY_SIZE,
624 	.max_keysize	= AES_MAX_KEY_SIZE,
625 	.ivsize		= AES_BLOCK_SIZE,
626 	.setkey		= skcipher_aes_setkey,
627 	.encrypt	= cbc_encrypt,
628 	.decrypt	= cbc_decrypt,
629 }, {
630 	.base = {
631 		.cra_name		= "ctr(aes)",
632 		.cra_driver_name	= "ctr-aes-" MODE,
633 		.cra_priority		= PRIO,
634 		.cra_blocksize		= 1,
635 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
636 		.cra_module		= THIS_MODULE,
637 	},
638 	.min_keysize	= AES_MIN_KEY_SIZE,
639 	.max_keysize	= AES_MAX_KEY_SIZE,
640 	.ivsize		= AES_BLOCK_SIZE,
641 	.chunksize	= AES_BLOCK_SIZE,
642 	.setkey		= skcipher_aes_setkey,
643 	.encrypt	= ctr_encrypt,
644 	.decrypt	= ctr_encrypt,
645 }, {
646 	.base = {
647 		.cra_name		= "xctr(aes)",
648 		.cra_driver_name	= "xctr-aes-" MODE,
649 		.cra_priority		= PRIO,
650 		.cra_blocksize		= 1,
651 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
652 		.cra_module		= THIS_MODULE,
653 	},
654 	.min_keysize	= AES_MIN_KEY_SIZE,
655 	.max_keysize	= AES_MAX_KEY_SIZE,
656 	.ivsize		= AES_BLOCK_SIZE,
657 	.chunksize	= AES_BLOCK_SIZE,
658 	.setkey		= skcipher_aes_setkey,
659 	.encrypt	= xctr_encrypt,
660 	.decrypt	= xctr_encrypt,
661 }, {
662 	.base = {
663 		.cra_name		= "xts(aes)",
664 		.cra_driver_name	= "xts-aes-" MODE,
665 		.cra_priority		= PRIO,
666 		.cra_blocksize		= AES_BLOCK_SIZE,
667 		.cra_ctxsize		= sizeof(struct crypto_aes_xts_ctx),
668 		.cra_module		= THIS_MODULE,
669 	},
670 	.min_keysize	= 2 * AES_MIN_KEY_SIZE,
671 	.max_keysize	= 2 * AES_MAX_KEY_SIZE,
672 	.ivsize		= AES_BLOCK_SIZE,
673 	.walksize	= 2 * AES_BLOCK_SIZE,
674 	.setkey		= xts_set_key,
675 	.encrypt	= xts_encrypt,
676 	.decrypt	= xts_decrypt,
677 }, {
678 #endif
679 	.base = {
680 		.cra_name		= "cts(cbc(aes))",
681 		.cra_driver_name	= "cts-cbc-aes-" MODE,
682 		.cra_priority		= PRIO,
683 		.cra_blocksize		= AES_BLOCK_SIZE,
684 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
685 		.cra_module		= THIS_MODULE,
686 	},
687 	.min_keysize	= AES_MIN_KEY_SIZE,
688 	.max_keysize	= AES_MAX_KEY_SIZE,
689 	.ivsize		= AES_BLOCK_SIZE,
690 	.walksize	= 2 * AES_BLOCK_SIZE,
691 	.setkey		= skcipher_aes_setkey,
692 	.encrypt	= cts_cbc_encrypt,
693 	.decrypt	= cts_cbc_decrypt,
694 }, {
695 	.base = {
696 		.cra_name		= "essiv(cbc(aes),sha256)",
697 		.cra_driver_name	= "essiv-cbc-aes-sha256-" MODE,
698 		.cra_priority		= PRIO + 1,
699 		.cra_blocksize		= AES_BLOCK_SIZE,
700 		.cra_ctxsize		= sizeof(struct crypto_aes_essiv_cbc_ctx),
701 		.cra_module		= THIS_MODULE,
702 	},
703 	.min_keysize	= AES_MIN_KEY_SIZE,
704 	.max_keysize	= AES_MAX_KEY_SIZE,
705 	.ivsize		= AES_BLOCK_SIZE,
706 	.setkey		= essiv_cbc_set_key,
707 	.encrypt	= essiv_cbc_encrypt,
708 	.decrypt	= essiv_cbc_decrypt,
709 } };
710 
711 static void aes_exit(void)
712 {
713 	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
714 }
715 
716 static int __init aes_init(void)
717 {
718 	return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
719 }
720 
721 #ifdef USE_V8_CRYPTO_EXTENSIONS
722 module_cpu_feature_match(AES, aes_init);
723 #else
724 module_init(aes_init);
725 #endif
726 module_exit(aes_exit);
727