xref: /openbmc/linux/block/t10-pi.c (revision 6e63153d) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * t10_pi.c - Functions for generating and verifying T10 Protection
4  *	      Information.
5  */
6 
7 #include <linux/t10-pi.h>
8 #include <linux/blk-integrity.h>
9 #include <linux/crc-t10dif.h>
10 #include <linux/crc64.h>
11 #include <linux/module.h>
12 #include <net/checksum.h>
13 #include <asm/unaligned.h>
14 
15 typedef __be16 (csum_fn) (void *, unsigned int);
16 
17 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
18 {
19 	return cpu_to_be16(crc_t10dif(data, len));
20 }
21 
22 static __be16 t10_pi_ip_fn(void *data, unsigned int len)
23 {
24 	return (__force __be16)ip_compute_csum(data, len);
25 }
26 
27 /*
28  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
29  * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
30  * tag.
31  */
32 static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
33 		csum_fn *fn, enum t10_dif_type type)
34 {
35 	unsigned int i;
36 
37 	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
38 		struct t10_pi_tuple *pi = iter->prot_buf;
39 
40 		pi->guard_tag = fn(iter->data_buf, iter->interval);
41 		pi->app_tag = 0;
42 
43 		if (type == T10_PI_TYPE1_PROTECTION)
44 			pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
45 		else
46 			pi->ref_tag = 0;
47 
48 		iter->data_buf += iter->interval;
49 		iter->prot_buf += iter->tuple_size;
50 		iter->seed++;
51 	}
52 
53 	return BLK_STS_OK;
54 }
55 
56 static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
57 		csum_fn *fn, enum t10_dif_type type)
58 {
59 	unsigned int i;
60 
61 	BUG_ON(type == T10_PI_TYPE0_PROTECTION);
62 
63 	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
64 		struct t10_pi_tuple *pi = iter->prot_buf;
65 		__be16 csum;
66 
67 		if (type == T10_PI_TYPE1_PROTECTION ||
68 		    type == T10_PI_TYPE2_PROTECTION) {
69 			if (pi->app_tag == T10_PI_APP_ESCAPE)
70 				goto next;
71 
72 			if (be32_to_cpu(pi->ref_tag) !=
73 			    lower_32_bits(iter->seed)) {
74 				pr_err("%s: ref tag error at location %llu " \
75 				       "(rcvd %u)\n", iter->disk_name,
76 				       (unsigned long long)
77 				       iter->seed, be32_to_cpu(pi->ref_tag));
78 				return BLK_STS_PROTECTION;
79 			}
80 		} else if (type == T10_PI_TYPE3_PROTECTION) {
81 			if (pi->app_tag == T10_PI_APP_ESCAPE &&
82 			    pi->ref_tag == T10_PI_REF_ESCAPE)
83 				goto next;
84 		}
85 
86 		csum = fn(iter->data_buf, iter->interval);
87 
88 		if (pi->guard_tag != csum) {
89 			pr_err("%s: guard tag error at sector %llu " \
90 			       "(rcvd %04x, want %04x)\n", iter->disk_name,
91 			       (unsigned long long)iter->seed,
92 			       be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
93 			return BLK_STS_PROTECTION;
94 		}
95 
96 next:
97 		iter->data_buf += iter->interval;
98 		iter->prot_buf += iter->tuple_size;
99 		iter->seed++;
100 	}
101 
102 	return BLK_STS_OK;
103 }
104 
105 static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
106 {
107 	return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
108 }
109 
110 static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
111 {
112 	return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
113 }
114 
115 static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
116 {
117 	return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
118 }
119 
120 static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
121 {
122 	return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
123 }
124 
125 /**
126  * t10_pi_type1_prepare - prepare PI prior submitting request to device
127  * @rq:              request with PI that should be prepared
128  *
129  * For Type 1/Type 2, the virtual start sector is the one that was
130  * originally submitted by the block layer for the ref_tag usage. Due to
131  * partitioning, MD/DM cloning, etc. the actual physical start sector is
132  * likely to be different. Remap protection information to match the
133  * physical LBA.
134  */
135 static void t10_pi_type1_prepare(struct request *rq)
136 {
137 	const int tuple_sz = rq->q->integrity.tuple_size;
138 	u32 ref_tag = t10_pi_ref_tag(rq);
139 	struct bio *bio;
140 
141 	__rq_for_each_bio(bio, rq) {
142 		struct bio_integrity_payload *bip = bio_integrity(bio);
143 		u32 virt = bip_get_seed(bip) & 0xffffffff;
144 		struct bio_vec iv;
145 		struct bvec_iter iter;
146 
147 		/* Already remapped? */
148 		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
149 			break;
150 
151 		bip_for_each_vec(iv, bip, iter) {
152 			unsigned int j;
153 			void *p;
154 
155 			p = bvec_kmap_local(&iv);
156 			for (j = 0; j < iv.bv_len; j += tuple_sz) {
157 				struct t10_pi_tuple *pi = p;
158 
159 				if (be32_to_cpu(pi->ref_tag) == virt)
160 					pi->ref_tag = cpu_to_be32(ref_tag);
161 				virt++;
162 				ref_tag++;
163 				p += tuple_sz;
164 			}
165 			kunmap_local(p);
166 		}
167 
168 		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
169 	}
170 }
171 
172 /**
173  * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
174  * @rq:              request with PI that should be prepared
175  * @nr_bytes:        total bytes to prepare
176  *
177  * For Type 1/Type 2, the virtual start sector is the one that was
178  * originally submitted by the block layer for the ref_tag usage. Due to
179  * partitioning, MD/DM cloning, etc. the actual physical start sector is
180  * likely to be different. Since the physical start sector was submitted
181  * to the device, we should remap it back to virtual values expected by the
182  * block layer.
183  */
184 static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
185 {
186 	unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
187 	const int tuple_sz = rq->q->integrity.tuple_size;
188 	u32 ref_tag = t10_pi_ref_tag(rq);
189 	struct bio *bio;
190 
191 	__rq_for_each_bio(bio, rq) {
192 		struct bio_integrity_payload *bip = bio_integrity(bio);
193 		u32 virt = bip_get_seed(bip) & 0xffffffff;
194 		struct bio_vec iv;
195 		struct bvec_iter iter;
196 
197 		bip_for_each_vec(iv, bip, iter) {
198 			unsigned int j;
199 			void *p;
200 
201 			p = bvec_kmap_local(&iv);
202 			for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
203 				struct t10_pi_tuple *pi = p;
204 
205 				if (be32_to_cpu(pi->ref_tag) == ref_tag)
206 					pi->ref_tag = cpu_to_be32(virt);
207 				virt++;
208 				ref_tag++;
209 				intervals--;
210 				p += tuple_sz;
211 			}
212 			kunmap_local(p);
213 		}
214 	}
215 }
216 
217 static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
218 {
219 	return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
220 }
221 
222 static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
223 {
224 	return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
225 }
226 
227 static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
228 {
229 	return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
230 }
231 
232 static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
233 {
234 	return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
235 }
236 
237 /* Type 3 does not have a reference tag so no remapping is required. */
238 static void t10_pi_type3_prepare(struct request *rq)
239 {
240 }
241 
242 /* Type 3 does not have a reference tag so no remapping is required. */
243 static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
244 {
245 }
246 
247 const struct blk_integrity_profile t10_pi_type1_crc = {
248 	.name			= "T10-DIF-TYPE1-CRC",
249 	.generate_fn		= t10_pi_type1_generate_crc,
250 	.verify_fn		= t10_pi_type1_verify_crc,
251 	.prepare_fn		= t10_pi_type1_prepare,
252 	.complete_fn		= t10_pi_type1_complete,
253 };
254 EXPORT_SYMBOL(t10_pi_type1_crc);
255 
256 const struct blk_integrity_profile t10_pi_type1_ip = {
257 	.name			= "T10-DIF-TYPE1-IP",
258 	.generate_fn		= t10_pi_type1_generate_ip,
259 	.verify_fn		= t10_pi_type1_verify_ip,
260 	.prepare_fn		= t10_pi_type1_prepare,
261 	.complete_fn		= t10_pi_type1_complete,
262 };
263 EXPORT_SYMBOL(t10_pi_type1_ip);
264 
265 const struct blk_integrity_profile t10_pi_type3_crc = {
266 	.name			= "T10-DIF-TYPE3-CRC",
267 	.generate_fn		= t10_pi_type3_generate_crc,
268 	.verify_fn		= t10_pi_type3_verify_crc,
269 	.prepare_fn		= t10_pi_type3_prepare,
270 	.complete_fn		= t10_pi_type3_complete,
271 };
272 EXPORT_SYMBOL(t10_pi_type3_crc);
273 
274 const struct blk_integrity_profile t10_pi_type3_ip = {
275 	.name			= "T10-DIF-TYPE3-IP",
276 	.generate_fn		= t10_pi_type3_generate_ip,
277 	.verify_fn		= t10_pi_type3_verify_ip,
278 	.prepare_fn		= t10_pi_type3_prepare,
279 	.complete_fn		= t10_pi_type3_complete,
280 };
281 EXPORT_SYMBOL(t10_pi_type3_ip);
282 
283 static __be64 ext_pi_crc64(void *data, unsigned int len)
284 {
285 	return cpu_to_be64(crc64_rocksoft(data, len));
286 }
287 
288 static blk_status_t ext_pi_crc64_generate(struct blk_integrity_iter *iter,
289 					enum t10_dif_type type)
290 {
291 	unsigned int i;
292 
293 	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
294 		struct crc64_pi_tuple *pi = iter->prot_buf;
295 
296 		pi->guard_tag = ext_pi_crc64(iter->data_buf, iter->interval);
297 		pi->app_tag = 0;
298 
299 		if (type == T10_PI_TYPE1_PROTECTION)
300 			put_unaligned_be48(iter->seed, pi->ref_tag);
301 		else
302 			put_unaligned_be48(0ULL, pi->ref_tag);
303 
304 		iter->data_buf += iter->interval;
305 		iter->prot_buf += iter->tuple_size;
306 		iter->seed++;
307 	}
308 
309 	return BLK_STS_OK;
310 }
311 
312 static bool ext_pi_ref_escape(u8 *ref_tag)
313 {
314 	static u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
315 
316 	return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
317 }
318 
319 static blk_status_t ext_pi_crc64_verify(struct blk_integrity_iter *iter,
320 				      enum t10_dif_type type)
321 {
322 	unsigned int i;
323 
324 	for (i = 0; i < iter->data_size; i += iter->interval) {
325 		struct crc64_pi_tuple *pi = iter->prot_buf;
326 		u64 ref, seed;
327 		__be64 csum;
328 
329 		if (type == T10_PI_TYPE1_PROTECTION) {
330 			if (pi->app_tag == T10_PI_APP_ESCAPE)
331 				goto next;
332 
333 			ref = get_unaligned_be48(pi->ref_tag);
334 			seed = lower_48_bits(iter->seed);
335 			if (ref != seed) {
336 				pr_err("%s: ref tag error at location %llu (rcvd %llu)\n",
337 					iter->disk_name, seed, ref);
338 				return BLK_STS_PROTECTION;
339 			}
340 		} else if (type == T10_PI_TYPE3_PROTECTION) {
341 			if (pi->app_tag == T10_PI_APP_ESCAPE &&
342 			    ext_pi_ref_escape(pi->ref_tag))
343 				goto next;
344 		}
345 
346 		csum = ext_pi_crc64(iter->data_buf, iter->interval);
347 		if (pi->guard_tag != csum) {
348 			pr_err("%s: guard tag error at sector %llu " \
349 			       "(rcvd %016llx, want %016llx)\n",
350 				iter->disk_name, (unsigned long long)iter->seed,
351 				be64_to_cpu(pi->guard_tag), be64_to_cpu(csum));
352 			return BLK_STS_PROTECTION;
353 		}
354 
355 next:
356 		iter->data_buf += iter->interval;
357 		iter->prot_buf += iter->tuple_size;
358 		iter->seed++;
359 	}
360 
361 	return BLK_STS_OK;
362 }
363 
364 static blk_status_t ext_pi_type1_verify_crc64(struct blk_integrity_iter *iter)
365 {
366 	return ext_pi_crc64_verify(iter, T10_PI_TYPE1_PROTECTION);
367 }
368 
369 static blk_status_t ext_pi_type1_generate_crc64(struct blk_integrity_iter *iter)
370 {
371 	return ext_pi_crc64_generate(iter, T10_PI_TYPE1_PROTECTION);
372 }
373 
374 static void ext_pi_type1_prepare(struct request *rq)
375 {
376 	const int tuple_sz = rq->q->integrity.tuple_size;
377 	u64 ref_tag = ext_pi_ref_tag(rq);
378 	struct bio *bio;
379 
380 	__rq_for_each_bio(bio, rq) {
381 		struct bio_integrity_payload *bip = bio_integrity(bio);
382 		u64 virt = lower_48_bits(bip_get_seed(bip));
383 		struct bio_vec iv;
384 		struct bvec_iter iter;
385 
386 		/* Already remapped? */
387 		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
388 			break;
389 
390 		bip_for_each_vec(iv, bip, iter) {
391 			unsigned int j;
392 			void *p;
393 
394 			p = bvec_kmap_local(&iv);
395 			for (j = 0; j < iv.bv_len; j += tuple_sz) {
396 				struct crc64_pi_tuple *pi = p;
397 				u64 ref = get_unaligned_be48(pi->ref_tag);
398 
399 				if (ref == virt)
400 					put_unaligned_be48(ref_tag, pi->ref_tag);
401 				virt++;
402 				ref_tag++;
403 				p += tuple_sz;
404 			}
405 			kunmap_local(p);
406 		}
407 
408 		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
409 	}
410 }
411 
412 static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
413 {
414 	unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
415 	const int tuple_sz = rq->q->integrity.tuple_size;
416 	u64 ref_tag = ext_pi_ref_tag(rq);
417 	struct bio *bio;
418 
419 	__rq_for_each_bio(bio, rq) {
420 		struct bio_integrity_payload *bip = bio_integrity(bio);
421 		u64 virt = lower_48_bits(bip_get_seed(bip));
422 		struct bio_vec iv;
423 		struct bvec_iter iter;
424 
425 		bip_for_each_vec(iv, bip, iter) {
426 			unsigned int j;
427 			void *p;
428 
429 			p = bvec_kmap_local(&iv);
430 			for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
431 				struct crc64_pi_tuple *pi = p;
432 				u64 ref = get_unaligned_be48(pi->ref_tag);
433 
434 				if (ref == ref_tag)
435 					put_unaligned_be48(virt, pi->ref_tag);
436 				virt++;
437 				ref_tag++;
438 				intervals--;
439 				p += tuple_sz;
440 			}
441 			kunmap_local(p);
442 		}
443 	}
444 }
445 
446 static blk_status_t ext_pi_type3_verify_crc64(struct blk_integrity_iter *iter)
447 {
448 	return ext_pi_crc64_verify(iter, T10_PI_TYPE3_PROTECTION);
449 }
450 
451 static blk_status_t ext_pi_type3_generate_crc64(struct blk_integrity_iter *iter)
452 {
453 	return ext_pi_crc64_generate(iter, T10_PI_TYPE3_PROTECTION);
454 }
455 
456 const struct blk_integrity_profile ext_pi_type1_crc64 = {
457 	.name			= "EXT-DIF-TYPE1-CRC64",
458 	.generate_fn		= ext_pi_type1_generate_crc64,
459 	.verify_fn		= ext_pi_type1_verify_crc64,
460 	.prepare_fn		= ext_pi_type1_prepare,
461 	.complete_fn		= ext_pi_type1_complete,
462 };
463 EXPORT_SYMBOL_GPL(ext_pi_type1_crc64);
464 
465 const struct blk_integrity_profile ext_pi_type3_crc64 = {
466 	.name			= "EXT-DIF-TYPE3-CRC64",
467 	.generate_fn		= ext_pi_type3_generate_crc64,
468 	.verify_fn		= ext_pi_type3_verify_crc64,
469 	.prepare_fn		= t10_pi_type3_prepare,
470 	.complete_fn		= t10_pi_type3_complete,
471 };
472 EXPORT_SYMBOL_GPL(ext_pi_type3_crc64);
473 
474 MODULE_LICENSE("GPL");
475 MODULE_LICENSE("GPL");
476