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1/*
2 * Persistent Memory Driver
3 *
4 * Copyright (c) 2014-2015, Intel Corporation.
5 * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
6 * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 */
17
18#include <asm/cacheflush.h>
19#include <linux/blkdev.h>
20#include <linux/hdreg.h>
21#include <linux/init.h>
22#include <linux/platform_device.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/badblocks.h>
26#include <linux/memremap.h>
27#include <linux/vmalloc.h>
28#include <linux/blk-mq.h>
29#include <linux/pfn_t.h>
30#include <linux/slab.h>
31#include <linux/uio.h>
32#include <linux/dax.h>
33#include <linux/nd.h>
34#include <linux/backing-dev.h>
35#include "pmem.h"
36#include "pfn.h"
37#include "nd.h"
38#include "nd-core.h"
39
40static struct device *to_dev(struct pmem_device *pmem)
41{
42 /*
43 * nvdimm bus services need a 'dev' parameter, and we record the device
44 * at init in bb.dev.
45 */
46 return pmem->bb.dev;
47}
48
49static struct nd_region *to_region(struct pmem_device *pmem)
50{
51 return to_nd_region(to_dev(pmem)->parent);
52}
53
54static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
55 phys_addr_t offset, unsigned int len)
56{
57 struct device *dev = to_dev(pmem);
58 sector_t sector;
59 long cleared;
60 blk_status_t rc = BLK_STS_OK;
61
62 sector = (offset - pmem->data_offset) / 512;
63
64 cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
65 if (cleared < len)
66 rc = BLK_STS_IOERR;
67 if (cleared > 0 && cleared / 512) {
68 cleared /= 512;
69 dev_dbg(dev, "%#llx clear %ld sector%s\n",
70 (unsigned long long) sector, cleared,
71 cleared > 1 ? "s" : "");
72 badblocks_clear(&pmem->bb, sector, cleared);
73 if (pmem->bb_state)
74 sysfs_notify_dirent(pmem->bb_state);
75 }
76
77 arch_invalidate_pmem(pmem->virt_addr + offset, len);
78
79 return rc;
80}
81
82static void write_pmem(void *pmem_addr, struct page *page,
83 unsigned int off, unsigned int len)
84{
85 unsigned int chunk;
86 void *mem;
87
88 while (len) {
89 mem = kmap_atomic(page);
90 chunk = min_t(unsigned int, len, PAGE_SIZE);
91 memcpy_flushcache(pmem_addr, mem + off, chunk);
92 kunmap_atomic(mem);
93 len -= chunk;
94 off = 0;
95 page++;
96 pmem_addr += PAGE_SIZE;
97 }
98}
99
100static blk_status_t read_pmem(struct page *page, unsigned int off,
101 void *pmem_addr, unsigned int len)
102{
103 unsigned int chunk;
104 int rc;
105 void *mem;
106
107 while (len) {
108 mem = kmap_atomic(page);
109 chunk = min_t(unsigned int, len, PAGE_SIZE);
110 rc = memcpy_mcsafe(mem + off, pmem_addr, chunk);
111 kunmap_atomic(mem);
112 if (rc)
113 return BLK_STS_IOERR;
114 len -= chunk;
115 off = 0;
116 page++;
117 pmem_addr += PAGE_SIZE;
118 }
119 return BLK_STS_OK;
120}
121
122static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
123 unsigned int len, unsigned int off, bool is_write,
124 sector_t sector)
125{
126 blk_status_t rc = BLK_STS_OK;
127 bool bad_pmem = false;
128 phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
129 void *pmem_addr = pmem->virt_addr + pmem_off;
130
131 if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
132 bad_pmem = true;
133
134 if (!is_write) {
135 if (unlikely(bad_pmem))
136 rc = BLK_STS_IOERR;
137 else {
138 rc = read_pmem(page, off, pmem_addr, len);
139 flush_dcache_page(page);
140 }
141 } else {
142 /*
143 * Note that we write the data both before and after
144 * clearing poison. The write before clear poison
145 * handles situations where the latest written data is
146 * preserved and the clear poison operation simply marks
147 * the address range as valid without changing the data.
148 * In this case application software can assume that an
149 * interrupted write will either return the new good
150 * data or an error.
151 *
152 * However, if pmem_clear_poison() leaves the data in an
153 * indeterminate state we need to perform the write
154 * after clear poison.
155 */
156 flush_dcache_page(page);
157 write_pmem(pmem_addr, page, off, len);
158 if (unlikely(bad_pmem)) {
159 rc = pmem_clear_poison(pmem, pmem_off, len);
160 write_pmem(pmem_addr, page, off, len);
161 }
162 }
163
164 return rc;
165}
166
167/* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */
168#ifndef REQ_FLUSH
169#define REQ_FLUSH REQ_PREFLUSH
170#endif
171
172static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
173{
174 blk_status_t rc = 0;
175 bool do_acct;
176 unsigned long start;
177 struct bio_vec bvec;
178 struct bvec_iter iter;
179 struct pmem_device *pmem = q->queuedata;
180 struct nd_region *nd_region = to_region(pmem);
181
182 if (bio->bi_opf & REQ_FLUSH)
183 nvdimm_flush(nd_region);
184
185 do_acct = nd_iostat_start(bio, &start);
186 bio_for_each_segment(bvec, bio, iter) {
187 rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
188 bvec.bv_offset, op_is_write(bio_op(bio)),
189 iter.bi_sector);
190 if (rc) {
191 bio->bi_status = rc;
192 break;
193 }
194 }
195 if (do_acct)
196 nd_iostat_end(bio, start);
197
198 if (bio->bi_opf & REQ_FUA)
199 nvdimm_flush(nd_region);
200
201 bio_endio(bio);
202 return BLK_QC_T_NONE;
203}
204
205static int pmem_rw_page(struct block_device *bdev, sector_t sector,
206 struct page *page, bool is_write)
207{
208 struct pmem_device *pmem = bdev->bd_queue->queuedata;
209 blk_status_t rc;
210
211 rc = pmem_do_bvec(pmem, page, hpage_nr_pages(page) * PAGE_SIZE,
212 0, is_write, sector);
213
214 /*
215 * The ->rw_page interface is subtle and tricky. The core
216 * retries on any error, so we can only invoke page_endio() in
217 * the successful completion case. Otherwise, we'll see crashes
218 * caused by double completion.
219 */
220 if (rc == 0)
221 page_endio(page, is_write, 0);
222
223 return blk_status_to_errno(rc);
224}
225
226/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
227__weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
228 long nr_pages, void **kaddr, pfn_t *pfn)
229{
230 resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
231
232 if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
233 PFN_PHYS(nr_pages))))
234 return -EIO;
235 *kaddr = pmem->virt_addr + offset;
236 *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
237
238 /*
239 * If badblocks are present, limit known good range to the
240 * requested range.
241 */
242 if (unlikely(pmem->bb.count))
243 return nr_pages;
244 return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
245}
246
247static const struct block_device_operations pmem_fops = {
248 .owner = THIS_MODULE,
249 .rw_page = pmem_rw_page,
250 .revalidate_disk = nvdimm_revalidate_disk,
251};
252
253static long pmem_dax_direct_access(struct dax_device *dax_dev,
254 pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn)
255{
256 struct pmem_device *pmem = dax_get_private(dax_dev);
257
258 return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn);
259}
260
261static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
262 void *addr, size_t bytes, struct iov_iter *i)
263{
264 return copy_from_iter_flushcache(addr, bytes, i);
265}
266
267static const struct dax_operations pmem_dax_ops = {
268 .direct_access = pmem_dax_direct_access,
269 .copy_from_iter = pmem_copy_from_iter,
270};
271
272static const struct attribute_group *pmem_attribute_groups[] = {
273 &dax_attribute_group,
274 NULL,
275};
276
277static void pmem_release_queue(void *q)
278{
279 blk_cleanup_queue(q);
280}
281
282static void pmem_freeze_queue(void *q)
283{
284 blk_freeze_queue_start(q);
285}
286
287static void pmem_release_disk(void *__pmem)
288{
289 struct pmem_device *pmem = __pmem;
290
291 kill_dax(pmem->dax_dev);
292 put_dax(pmem->dax_dev);
293 del_gendisk(pmem->disk);
294 put_disk(pmem->disk);
295}
296
297static int pmem_attach_disk(struct device *dev,
298 struct nd_namespace_common *ndns)
299{
300 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
301 struct nd_region *nd_region = to_nd_region(dev->parent);
302 int nid = dev_to_node(dev), fua, wbc;
303 struct resource *res = &nsio->res;
304 struct resource bb_res;
305 struct nd_pfn *nd_pfn = NULL;
306 struct dax_device *dax_dev;
307 struct nd_pfn_sb *pfn_sb;
308 struct pmem_device *pmem;
309 struct request_queue *q;
310 struct device *gendev;
311 struct gendisk *disk;
312 void *addr;
313 int rc;
314
315 pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
316 if (!pmem)
317 return -ENOMEM;
318
319 /* while nsio_rw_bytes is active, parse a pfn info block if present */
320 if (is_nd_pfn(dev)) {
321 nd_pfn = to_nd_pfn(dev);
322 rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
323 if (rc)
324 return rc;
325 }
326
327 /* we're attaching a block device, disable raw namespace access */
328 devm_nsio_disable(dev, nsio);
329
330 dev_set_drvdata(dev, pmem);
331 pmem->phys_addr = res->start;
332 pmem->size = resource_size(res);
333 fua = nvdimm_has_flush(nd_region);
334 if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
335 dev_warn(dev, "unable to guarantee persistence of writes\n");
336 fua = 0;
337 }
338 wbc = nvdimm_has_cache(nd_region);
339
340 if (!devm_request_mem_region(dev, res->start, resource_size(res),
341 dev_name(&ndns->dev))) {
342 dev_warn(dev, "could not reserve region %pR\n", res);
343 return -EBUSY;
344 }
345
346 q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev), NULL);
347 if (!q)
348 return -ENOMEM;
349
350 if (devm_add_action_or_reset(dev, pmem_release_queue, q))
351 return -ENOMEM;
352
353 pmem->pfn_flags = PFN_DEV;
354 pmem->pgmap.ref = &q->q_usage_counter;
355 if (is_nd_pfn(dev)) {
356 addr = devm_memremap_pages(dev, &pmem->pgmap);
357 pfn_sb = nd_pfn->pfn_sb;
358 pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
359 pmem->pfn_pad = resource_size(res) -
360 resource_size(&pmem->pgmap.res);
361 pmem->pfn_flags |= PFN_MAP;
362 memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
363 bb_res.start += pmem->data_offset;
364 } else if (pmem_should_map_pages(dev)) {
365 memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
366 pmem->pgmap.altmap_valid = false;
367 addr = devm_memremap_pages(dev, &pmem->pgmap);
368 pmem->pfn_flags |= PFN_MAP;
369 memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
370 } else
371 addr = devm_memremap(dev, pmem->phys_addr,
372 pmem->size, ARCH_MEMREMAP_PMEM);
373
374 /*
375 * At release time the queue must be frozen before
376 * devm_memremap_pages is unwound
377 */
378 if (devm_add_action_or_reset(dev, pmem_freeze_queue, q))
379 return -ENOMEM;
380
381 if (IS_ERR(addr))
382 return PTR_ERR(addr);
383 pmem->virt_addr = addr;
384
385 blk_queue_write_cache(q, wbc, fua);
386 blk_queue_make_request(q, pmem_make_request);
387 blk_queue_physical_block_size(q, PAGE_SIZE);
388 blk_queue_logical_block_size(q, pmem_sector_size(ndns));
389 blk_queue_max_hw_sectors(q, UINT_MAX);
390 blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
391 blk_queue_flag_set(QUEUE_FLAG_DAX, q);
392 q->queuedata = pmem;
393
394 disk = alloc_disk_node(0, nid);
395 if (!disk)
396 return -ENOMEM;
397 pmem->disk = disk;
398
399 disk->fops = &pmem_fops;
400 disk->queue = q;
401 disk->flags = GENHD_FL_EXT_DEVT;
402 disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNCHRONOUS_IO;
403 nvdimm_namespace_disk_name(ndns, disk->disk_name);
404 set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
405 / 512);
406 if (devm_init_badblocks(dev, &pmem->bb))
407 return -ENOMEM;
408 nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res);
409 disk->bb = &pmem->bb;
410
411 dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
412 if (!dax_dev) {
413 put_disk(disk);
414 return -ENOMEM;
415 }
416 dax_write_cache(dax_dev, wbc);
417 pmem->dax_dev = dax_dev;
418
419 gendev = disk_to_dev(disk);
420 gendev->groups = pmem_attribute_groups;
421
422 device_add_disk(dev, disk);
423 if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
424 return -ENOMEM;
425
426 revalidate_disk(disk);
427
428 pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
429 "badblocks");
430 if (!pmem->bb_state)
431 dev_warn(dev, "'badblocks' notification disabled\n");
432
433 return 0;
434}
435
436static int nd_pmem_probe(struct device *dev)
437{
438 struct nd_namespace_common *ndns;
439
440 ndns = nvdimm_namespace_common_probe(dev);
441 if (IS_ERR(ndns))
442 return PTR_ERR(ndns);
443
444 if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
445 return -ENXIO;
446
447 if (is_nd_btt(dev))
448 return nvdimm_namespace_attach_btt(ndns);
449
450 if (is_nd_pfn(dev))
451 return pmem_attach_disk(dev, ndns);
452
453 /* if we find a valid info-block we'll come back as that personality */
454 if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
455 || nd_dax_probe(dev, ndns) == 0)
456 return -ENXIO;
457
458 /* ...otherwise we're just a raw pmem device */
459 return pmem_attach_disk(dev, ndns);
460}
461
462static int nd_pmem_remove(struct device *dev)
463{
464 struct pmem_device *pmem = dev_get_drvdata(dev);
465
466 if (is_nd_btt(dev))
467 nvdimm_namespace_detach_btt(to_nd_btt(dev));
468 else {
469 /*
470 * Note, this assumes device_lock() context to not race
471 * nd_pmem_notify()
472 */
473 sysfs_put(pmem->bb_state);
474 pmem->bb_state = NULL;
475 }
476 nvdimm_flush(to_nd_region(dev->parent));
477
478 return 0;
479}
480
481static void nd_pmem_shutdown(struct device *dev)
482{
483 nvdimm_flush(to_nd_region(dev->parent));
484}
485
486static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
487{
488 struct nd_region *nd_region;
489 resource_size_t offset = 0, end_trunc = 0;
490 struct nd_namespace_common *ndns;
491 struct nd_namespace_io *nsio;
492 struct resource res;
493 struct badblocks *bb;
494 struct kernfs_node *bb_state;
495
496 if (event != NVDIMM_REVALIDATE_POISON)
497 return;
498
499 if (is_nd_btt(dev)) {
500 struct nd_btt *nd_btt = to_nd_btt(dev);
501
502 ndns = nd_btt->ndns;
503 nd_region = to_nd_region(ndns->dev.parent);
504 nsio = to_nd_namespace_io(&ndns->dev);
505 bb = &nsio->bb;
506 bb_state = NULL;
507 } else {
508 struct pmem_device *pmem = dev_get_drvdata(dev);
509
510 nd_region = to_region(pmem);
511 bb = &pmem->bb;
512 bb_state = pmem->bb_state;
513
514 if (is_nd_pfn(dev)) {
515 struct nd_pfn *nd_pfn = to_nd_pfn(dev);
516 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
517
518 ndns = nd_pfn->ndns;
519 offset = pmem->data_offset +
520 __le32_to_cpu(pfn_sb->start_pad);
521 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
522 } else {
523 ndns = to_ndns(dev);
524 }
525
526 nsio = to_nd_namespace_io(&ndns->dev);
527 }
528
529 res.start = nsio->res.start + offset;
530 res.end = nsio->res.end - end_trunc;
531 nvdimm_badblocks_populate(nd_region, bb, &res);
532 if (bb_state)
533 sysfs_notify_dirent(bb_state);
534}
535
536MODULE_ALIAS("pmem");
537MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
538MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
539static struct nd_device_driver nd_pmem_driver = {
540 .probe = nd_pmem_probe,
541 .remove = nd_pmem_remove,
542 .notify = nd_pmem_notify,
543 .shutdown = nd_pmem_shutdown,
544 .drv = {
545 .name = "nd_pmem",
546 },
547 .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
548};
549
550module_nd_driver(nd_pmem_driver);
551
552MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
553MODULE_LICENSE("GPL v2");