1 /*
2 * Glue code for AES implementation for SPE instructions (PPC)
3 *
4 * Based on generic implementation. The assembler module takes care
5 * about the SPE registers so it can run from interrupt context.
6 *
7 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16 #include <crypto/aes.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/types.h>
20 #include <linux/errno.h>
21 #include <linux/crypto.h>
22 #include <asm/byteorder.h>
23 #include <asm/switch_to.h>
24 #include <crypto/algapi.h>
25
26 /*
27 * MAX_BYTES defines the number of bytes that are allowed to be processed
28 * between preempt_disable() and preempt_enable(). e500 cores can issue two
29 * instructions per clock cycle using one 32/64 bit unit (SU1) and one 32
30 * bit unit (SU2). One of these can be a memory access that is executed via
31 * a single load and store unit (LSU). XTS-AES-256 takes ~780 operations per
32 * 16 byte block block or 25 cycles per byte. Thus 768 bytes of input data
33 * will need an estimated maximum of 20,000 cycles. Headroom for cache misses
34 * included. Even with the low end model clocked at 667 MHz this equals to a
35 * critical time window of less than 30us. The value has been choosen to
36 * process a 512 byte disk block in one or a large 1400 bytes IPsec network
37 * packet in two runs.
38 *
39 */
40 #define MAX_BYTES 768
41
42 struct ppc_aes_ctx {
43 u32 key_enc[AES_MAX_KEYLENGTH_U32];
44 u32 key_dec[AES_MAX_KEYLENGTH_U32];
45 u32 rounds;
46 };
47
48 struct ppc_xts_ctx {
49 u32 key_enc[AES_MAX_KEYLENGTH_U32];
50 u32 key_dec[AES_MAX_KEYLENGTH_U32];
51 u32 key_twk[AES_MAX_KEYLENGTH_U32];
52 u32 rounds;
53 };
54
55 extern void ppc_encrypt_aes(u8 *out, const u8 *in, u32 *key_enc, u32 rounds);
56 extern void ppc_decrypt_aes(u8 *out, const u8 *in, u32 *key_dec, u32 rounds);
57 extern void ppc_encrypt_ecb(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
58 u32 bytes);
59 extern void ppc_decrypt_ecb(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
60 u32 bytes);
61 extern void ppc_encrypt_cbc(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
62 u32 bytes, u8 *iv);
63 extern void ppc_decrypt_cbc(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
64 u32 bytes, u8 *iv);
65 extern void ppc_crypt_ctr (u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
66 u32 bytes, u8 *iv);
67 extern void ppc_encrypt_xts(u8 *out, const u8 *in, u32 *key_enc, u32 rounds,
68 u32 bytes, u8 *iv, u32 *key_twk);
69 extern void ppc_decrypt_xts(u8 *out, const u8 *in, u32 *key_dec, u32 rounds,
70 u32 bytes, u8 *iv, u32 *key_twk);
71
72 extern void ppc_expand_key_128(u32 *key_enc, const u8 *key);
73 extern void ppc_expand_key_192(u32 *key_enc, const u8 *key);
74 extern void ppc_expand_key_256(u32 *key_enc, const u8 *key);
75
76 extern void ppc_generate_decrypt_key(u32 *key_dec,u32 *key_enc,
77 unsigned int key_len);
78
spe_begin(void)79 static void spe_begin(void)
80 {
81 /* disable preemption and save users SPE registers if required */
82 preempt_disable();
83 enable_kernel_spe();
84 }
85
spe_end(void)86 static void spe_end(void)
87 {
88 /* reenable preemption */
89 preempt_enable();
90 }
91
ppc_aes_setkey(struct crypto_tfm * tfm,const u8 * in_key,unsigned int key_len)92 static int ppc_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
93 unsigned int key_len)
94 {
95 struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
96
97 if (key_len != AES_KEYSIZE_128 &&
98 key_len != AES_KEYSIZE_192 &&
99 key_len != AES_KEYSIZE_256) {
100 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
101 return -EINVAL;
102 }
103
104 switch (key_len) {
105 case AES_KEYSIZE_128:
106 ctx->rounds = 4;
107 ppc_expand_key_128(ctx->key_enc, in_key);
108 break;
109 case AES_KEYSIZE_192:
110 ctx->rounds = 5;
111 ppc_expand_key_192(ctx->key_enc, in_key);
112 break;
113 case AES_KEYSIZE_256:
114 ctx->rounds = 6;
115 ppc_expand_key_256(ctx->key_enc, in_key);
116 break;
117 }
118
119 ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
120
121 return 0;
122 }
123
ppc_xts_setkey(struct crypto_tfm * tfm,const u8 * in_key,unsigned int key_len)124 static int ppc_xts_setkey(struct crypto_tfm *tfm, const u8 *in_key,
125 unsigned int key_len)
126 {
127 struct ppc_xts_ctx *ctx = crypto_tfm_ctx(tfm);
128
129 key_len >>= 1;
130
131 if (key_len != AES_KEYSIZE_128 &&
132 key_len != AES_KEYSIZE_192 &&
133 key_len != AES_KEYSIZE_256) {
134 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
135 return -EINVAL;
136 }
137
138 switch (key_len) {
139 case AES_KEYSIZE_128:
140 ctx->rounds = 4;
141 ppc_expand_key_128(ctx->key_enc, in_key);
142 ppc_expand_key_128(ctx->key_twk, in_key + AES_KEYSIZE_128);
143 break;
144 case AES_KEYSIZE_192:
145 ctx->rounds = 5;
146 ppc_expand_key_192(ctx->key_enc, in_key);
147 ppc_expand_key_192(ctx->key_twk, in_key + AES_KEYSIZE_192);
148 break;
149 case AES_KEYSIZE_256:
150 ctx->rounds = 6;
151 ppc_expand_key_256(ctx->key_enc, in_key);
152 ppc_expand_key_256(ctx->key_twk, in_key + AES_KEYSIZE_256);
153 break;
154 }
155
156 ppc_generate_decrypt_key(ctx->key_dec, ctx->key_enc, key_len);
157
158 return 0;
159 }
160
ppc_aes_encrypt(struct crypto_tfm * tfm,u8 * out,const u8 * in)161 static void ppc_aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
162 {
163 struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
164
165 spe_begin();
166 ppc_encrypt_aes(out, in, ctx->key_enc, ctx->rounds);
167 spe_end();
168 }
169
ppc_aes_decrypt(struct crypto_tfm * tfm,u8 * out,const u8 * in)170 static void ppc_aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
171 {
172 struct ppc_aes_ctx *ctx = crypto_tfm_ctx(tfm);
173
174 spe_begin();
175 ppc_decrypt_aes(out, in, ctx->key_dec, ctx->rounds);
176 spe_end();
177 }
178
ppc_ecb_encrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)179 static int ppc_ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
180 struct scatterlist *src, unsigned int nbytes)
181 {
182 struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
183 struct blkcipher_walk walk;
184 unsigned int ubytes;
185 int err;
186
187 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
188 blkcipher_walk_init(&walk, dst, src, nbytes);
189 err = blkcipher_walk_virt(desc, &walk);
190
191 while ((nbytes = walk.nbytes)) {
192 ubytes = nbytes > MAX_BYTES ?
193 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
194 nbytes -= ubytes;
195
196 spe_begin();
197 ppc_encrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
198 ctx->key_enc, ctx->rounds, nbytes);
199 spe_end();
200
201 err = blkcipher_walk_done(desc, &walk, ubytes);
202 }
203
204 return err;
205 }
206
ppc_ecb_decrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)207 static int ppc_ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
208 struct scatterlist *src, unsigned int nbytes)
209 {
210 struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
211 struct blkcipher_walk walk;
212 unsigned int ubytes;
213 int err;
214
215 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
216 blkcipher_walk_init(&walk, dst, src, nbytes);
217 err = blkcipher_walk_virt(desc, &walk);
218
219 while ((nbytes = walk.nbytes)) {
220 ubytes = nbytes > MAX_BYTES ?
221 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
222 nbytes -= ubytes;
223
224 spe_begin();
225 ppc_decrypt_ecb(walk.dst.virt.addr, walk.src.virt.addr,
226 ctx->key_dec, ctx->rounds, nbytes);
227 spe_end();
228
229 err = blkcipher_walk_done(desc, &walk, ubytes);
230 }
231
232 return err;
233 }
234
ppc_cbc_encrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)235 static int ppc_cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
236 struct scatterlist *src, unsigned int nbytes)
237 {
238 struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
239 struct blkcipher_walk walk;
240 unsigned int ubytes;
241 int err;
242
243 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
244 blkcipher_walk_init(&walk, dst, src, nbytes);
245 err = blkcipher_walk_virt(desc, &walk);
246
247 while ((nbytes = walk.nbytes)) {
248 ubytes = nbytes > MAX_BYTES ?
249 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
250 nbytes -= ubytes;
251
252 spe_begin();
253 ppc_encrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
254 ctx->key_enc, ctx->rounds, nbytes, walk.iv);
255 spe_end();
256
257 err = blkcipher_walk_done(desc, &walk, ubytes);
258 }
259
260 return err;
261 }
262
ppc_cbc_decrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)263 static int ppc_cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
264 struct scatterlist *src, unsigned int nbytes)
265 {
266 struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
267 struct blkcipher_walk walk;
268 unsigned int ubytes;
269 int err;
270
271 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
272 blkcipher_walk_init(&walk, dst, src, nbytes);
273 err = blkcipher_walk_virt(desc, &walk);
274
275 while ((nbytes = walk.nbytes)) {
276 ubytes = nbytes > MAX_BYTES ?
277 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
278 nbytes -= ubytes;
279
280 spe_begin();
281 ppc_decrypt_cbc(walk.dst.virt.addr, walk.src.virt.addr,
282 ctx->key_dec, ctx->rounds, nbytes, walk.iv);
283 spe_end();
284
285 err = blkcipher_walk_done(desc, &walk, ubytes);
286 }
287
288 return err;
289 }
290
ppc_ctr_crypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)291 static int ppc_ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
292 struct scatterlist *src, unsigned int nbytes)
293 {
294 struct ppc_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
295 struct blkcipher_walk walk;
296 unsigned int pbytes, ubytes;
297 int err;
298
299 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
300 blkcipher_walk_init(&walk, dst, src, nbytes);
301 err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
302
303 while ((pbytes = walk.nbytes)) {
304 pbytes = pbytes > MAX_BYTES ? MAX_BYTES : pbytes;
305 pbytes = pbytes == nbytes ?
306 nbytes : pbytes & ~(AES_BLOCK_SIZE - 1);
307 ubytes = walk.nbytes - pbytes;
308
309 spe_begin();
310 ppc_crypt_ctr(walk.dst.virt.addr, walk.src.virt.addr,
311 ctx->key_enc, ctx->rounds, pbytes , walk.iv);
312 spe_end();
313
314 nbytes -= pbytes;
315 err = blkcipher_walk_done(desc, &walk, ubytes);
316 }
317
318 return err;
319 }
320
ppc_xts_encrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)321 static int ppc_xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
322 struct scatterlist *src, unsigned int nbytes)
323 {
324 struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
325 struct blkcipher_walk walk;
326 unsigned int ubytes;
327 int err;
328 u32 *twk;
329
330 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
331 blkcipher_walk_init(&walk, dst, src, nbytes);
332 err = blkcipher_walk_virt(desc, &walk);
333 twk = ctx->key_twk;
334
335 while ((nbytes = walk.nbytes)) {
336 ubytes = nbytes > MAX_BYTES ?
337 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
338 nbytes -= ubytes;
339
340 spe_begin();
341 ppc_encrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
342 ctx->key_enc, ctx->rounds, nbytes, walk.iv, twk);
343 spe_end();
344
345 twk = NULL;
346 err = blkcipher_walk_done(desc, &walk, ubytes);
347 }
348
349 return err;
350 }
351
ppc_xts_decrypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)352 static int ppc_xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
353 struct scatterlist *src, unsigned int nbytes)
354 {
355 struct ppc_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
356 struct blkcipher_walk walk;
357 unsigned int ubytes;
358 int err;
359 u32 *twk;
360
361 desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
362 blkcipher_walk_init(&walk, dst, src, nbytes);
363 err = blkcipher_walk_virt(desc, &walk);
364 twk = ctx->key_twk;
365
366 while ((nbytes = walk.nbytes)) {
367 ubytes = nbytes > MAX_BYTES ?
368 nbytes - MAX_BYTES : nbytes & (AES_BLOCK_SIZE - 1);
369 nbytes -= ubytes;
370
371 spe_begin();
372 ppc_decrypt_xts(walk.dst.virt.addr, walk.src.virt.addr,
373 ctx->key_dec, ctx->rounds, nbytes, walk.iv, twk);
374 spe_end();
375
376 twk = NULL;
377 err = blkcipher_walk_done(desc, &walk, ubytes);
378 }
379
380 return err;
381 }
382
383 /*
384 * Algorithm definitions. Disabling alignment (cra_alignmask=0) was chosen
385 * because the e500 platform can handle unaligned reads/writes very efficently.
386 * This improves IPsec thoughput by another few percent. Additionally we assume
387 * that AES context is always aligned to at least 8 bytes because it is created
388 * with kmalloc() in the crypto infrastructure
389 *
390 */
391 static struct crypto_alg aes_algs[] = { {
392 .cra_name = "aes",
393 .cra_driver_name = "aes-ppc-spe",
394 .cra_priority = 300,
395 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
396 .cra_blocksize = AES_BLOCK_SIZE,
397 .cra_ctxsize = sizeof(struct ppc_aes_ctx),
398 .cra_alignmask = 0,
399 .cra_module = THIS_MODULE,
400 .cra_u = {
401 .cipher = {
402 .cia_min_keysize = AES_MIN_KEY_SIZE,
403 .cia_max_keysize = AES_MAX_KEY_SIZE,
404 .cia_setkey = ppc_aes_setkey,
405 .cia_encrypt = ppc_aes_encrypt,
406 .cia_decrypt = ppc_aes_decrypt
407 }
408 }
409 }, {
410 .cra_name = "ecb(aes)",
411 .cra_driver_name = "ecb-ppc-spe",
412 .cra_priority = 300,
413 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
414 .cra_blocksize = AES_BLOCK_SIZE,
415 .cra_ctxsize = sizeof(struct ppc_aes_ctx),
416 .cra_alignmask = 0,
417 .cra_type = &crypto_blkcipher_type,
418 .cra_module = THIS_MODULE,
419 .cra_u = {
420 .blkcipher = {
421 .min_keysize = AES_MIN_KEY_SIZE,
422 .max_keysize = AES_MAX_KEY_SIZE,
423 .ivsize = AES_BLOCK_SIZE,
424 .setkey = ppc_aes_setkey,
425 .encrypt = ppc_ecb_encrypt,
426 .decrypt = ppc_ecb_decrypt,
427 }
428 }
429 }, {
430 .cra_name = "cbc(aes)",
431 .cra_driver_name = "cbc-ppc-spe",
432 .cra_priority = 300,
433 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
434 .cra_blocksize = AES_BLOCK_SIZE,
435 .cra_ctxsize = sizeof(struct ppc_aes_ctx),
436 .cra_alignmask = 0,
437 .cra_type = &crypto_blkcipher_type,
438 .cra_module = THIS_MODULE,
439 .cra_u = {
440 .blkcipher = {
441 .min_keysize = AES_MIN_KEY_SIZE,
442 .max_keysize = AES_MAX_KEY_SIZE,
443 .ivsize = AES_BLOCK_SIZE,
444 .setkey = ppc_aes_setkey,
445 .encrypt = ppc_cbc_encrypt,
446 .decrypt = ppc_cbc_decrypt,
447 }
448 }
449 }, {
450 .cra_name = "ctr(aes)",
451 .cra_driver_name = "ctr-ppc-spe",
452 .cra_priority = 300,
453 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
454 .cra_blocksize = 1,
455 .cra_ctxsize = sizeof(struct ppc_aes_ctx),
456 .cra_alignmask = 0,
457 .cra_type = &crypto_blkcipher_type,
458 .cra_module = THIS_MODULE,
459 .cra_u = {
460 .blkcipher = {
461 .min_keysize = AES_MIN_KEY_SIZE,
462 .max_keysize = AES_MAX_KEY_SIZE,
463 .ivsize = AES_BLOCK_SIZE,
464 .setkey = ppc_aes_setkey,
465 .encrypt = ppc_ctr_crypt,
466 .decrypt = ppc_ctr_crypt,
467 }
468 }
469 }, {
470 .cra_name = "xts(aes)",
471 .cra_driver_name = "xts-ppc-spe",
472 .cra_priority = 300,
473 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
474 .cra_blocksize = AES_BLOCK_SIZE,
475 .cra_ctxsize = sizeof(struct ppc_xts_ctx),
476 .cra_alignmask = 0,
477 .cra_type = &crypto_blkcipher_type,
478 .cra_module = THIS_MODULE,
479 .cra_u = {
480 .blkcipher = {
481 .min_keysize = AES_MIN_KEY_SIZE * 2,
482 .max_keysize = AES_MAX_KEY_SIZE * 2,
483 .ivsize = AES_BLOCK_SIZE,
484 .setkey = ppc_xts_setkey,
485 .encrypt = ppc_xts_encrypt,
486 .decrypt = ppc_xts_decrypt,
487 }
488 }
489 } };
490
ppc_aes_mod_init(void)491 static int __init ppc_aes_mod_init(void)
492 {
493 return crypto_register_algs(aes_algs, ARRAY_SIZE(aes_algs));
494 }
495
ppc_aes_mod_fini(void)496 static void __exit ppc_aes_mod_fini(void)
497 {
498 crypto_unregister_algs(aes_algs, ARRAY_SIZE(aes_algs));
499 }
500
501 module_init(ppc_aes_mod_init);
502 module_exit(ppc_aes_mod_fini);
503
504 MODULE_LICENSE("GPL");
505 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS, SPE optimized");
506
507 MODULE_ALIAS_CRYPTO("aes");
508 MODULE_ALIAS_CRYPTO("ecb(aes)");
509 MODULE_ALIAS_CRYPTO("cbc(aes)");
510 MODULE_ALIAS_CRYPTO("ctr(aes)");
511 MODULE_ALIAS_CRYPTO("xts(aes)");
512 MODULE_ALIAS_CRYPTO("aes-ppc-spe");
513