drivers/nvdimm/pmem.c

   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/set_memory.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/badblocks.h>
  27 #include <linux/memremap.h>
  28 #include <linux/vmalloc.h>
  29 #include <linux/blk-mq.h>
  30 #include <linux/pfn_t.h>
  31 #include <linux/slab.h>
  32 #include <linux/uio.h>
  33 #include <linux/dax.h>
  34 #include <linux/nd.h>
  35 #include <linux/backing-dev.h>
  36 #include "pmem.h"
  37 #include "pfn.h"
  38 #include "nd.h"
  39 #include "nd-core.h"
  40
  41 static struct device *to_dev(struct pmem_device *pmem)
  42 {
  43         /*
  44          * nvdimm bus services need a 'dev' parameter, and we record the device
  45          * at init in bb.dev.
  46          */
  47         return pmem->bb.dev;
  48 }
  49
  50 static struct nd_region *to_region(struct pmem_device *pmem)
  51 {
  52         return to_nd_region(to_dev(pmem)->parent);
  53 }
  54
  55 static void hwpoison_clear(struct pmem_device *pmem,
  56                 phys_addr_t phys, unsigned int len)
  57 {
  58         unsigned long pfn_start, pfn_end, pfn;
  59
  60         /* only pmem in the linear map supports HWPoison */
  61         if (is_vmalloc_addr(pmem->virt_addr))
  62                 return;
  63
  64         pfn_start = PHYS_PFN(phys);
  65         pfn_end = pfn_start + PHYS_PFN(len);
  66         for (pfn = pfn_start; pfn < pfn_end; pfn++) {
  67                 struct page *page = pfn_to_page(pfn);
  68
  69                 /*
  70                  * Note, no need to hold a get_dev_pagemap() reference
  71                  * here since we're in the driver I/O path and
  72                  * outstanding I/O requests pin the dev_pagemap.
  73                  */
  74                 if (test_and_clear_pmem_poison(page))
  75                         clear_mce_nospec(pfn);
  76         }
  77 }
  78
  79 static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
  80                 phys_addr_t offset, unsigned int len)
  81 {
  82         struct device *dev = to_dev(pmem);
  83         sector_t sector;
  84         long cleared;
  85         blk_status_t rc = BLK_STS_OK;
  86
  87         sector = (offset - pmem->data_offset) / 512;
  88
  89         cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
  90         if (cleared < len)
  91                 rc = BLK_STS_IOERR;
  92         if (cleared > 0 && cleared / 512) {
  93                 hwpoison_clear(pmem, pmem->phys_addr + offset, cleared);
  94                 cleared /= 512;
  95                 dev_dbg(dev, "%#llx clear %ld sector%s\n",
  96                                 (unsigned long long) sector, cleared,
  97                                 cleared > 1 ? "s" : "");
  98                 badblocks_clear(&pmem->bb, sector, cleared);
  99                 if (pmem->bb_state)
 100                         sysfs_notify_dirent(pmem->bb_state);
 101         }
 102
 103         arch_invalidate_pmem(pmem->virt_addr + offset, len);
 104
 105         return rc;
 106 }
 107
 108 static void write_pmem(void *pmem_addr, struct page *page,
 109                 unsigned int off, unsigned int len)
 110 {
 111         unsigned int chunk;
 112         void *mem;
 113
 114         while (len) {
 115                 mem = kmap_atomic(page);
 116                 chunk = min_t(unsigned int, len, PAGE_SIZE);
 117                 memcpy_flushcache(pmem_addr, mem + off, chunk);
 118                 kunmap_atomic(mem);
 119                 len -= chunk;
 120                 off = 0;
 121                 page++;
 122                 pmem_addr += PAGE_SIZE;
 123         }
 124 }
 125
 126 static blk_status_t read_pmem(struct page *page, unsigned int off,
 127                 void *pmem_addr, unsigned int len)
 128 {
 129         unsigned int chunk;
 130         unsigned long rem;
 131         void *mem;
 132
 133         while (len) {
 134                 mem = kmap_atomic(page);
 135                 chunk = min_t(unsigned int, len, PAGE_SIZE);
 136                 rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
 137                 kunmap_atomic(mem);
 138                 if (rem)
 139                         return BLK_STS_IOERR;
 140                 len -= chunk;
 141                 off = 0;
 142                 page++;
 143                 pmem_addr += PAGE_SIZE;
 144         }
 145         return BLK_STS_OK;
 146 }
 147
 148 static blk_status_t pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 149                         unsigned int len, unsigned int off, unsigned int op,
 150                         sector_t sector)
 151 {
 152         blk_status_t rc = BLK_STS_OK;
 153         bool bad_pmem = false;
 154         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
 155         void *pmem_addr = pmem->virt_addr + pmem_off;
 156
 157         if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
 158                 bad_pmem = true;
 159
 160         if (!op_is_write(op)) {
 161                 if (unlikely(bad_pmem))
 162                         rc = BLK_STS_IOERR;
 163                 else {
 164                         rc = read_pmem(page, off, pmem_addr, len);
 165                         flush_dcache_page(page);
 166                 }
 167         } else {
 168                 /*
 169                  * Note that we write the data both before and after
 170                  * clearing poison.  The write before clear poison
 171                  * handles situations where the latest written data is
 172                  * preserved and the clear poison operation simply marks
 173                  * the address range as valid without changing the data.
 174                  * In this case application software can assume that an
 175                  * interrupted write will either return the new good
 176                  * data or an error.
 177                  *
 178                  * However, if pmem_clear_poison() leaves the data in an
 179                  * indeterminate state we need to perform the write
 180                  * after clear poison.
 181                  */
 182                 flush_dcache_page(page);
 183                 write_pmem(pmem_addr, page, off, len);
 184                 if (unlikely(bad_pmem)) {
 185                         rc = pmem_clear_poison(pmem, pmem_off, len);
 186                         write_pmem(pmem_addr, page, off, len);
 187                 }
 188         }
 189
 190         return rc;
 191 }
 192
 193 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
 194 {
 195         blk_status_t rc = 0;
 196         bool do_acct;
 197         unsigned long start;
 198         struct bio_vec bvec;
 199         struct bvec_iter iter;
 200         struct pmem_device *pmem = q->queuedata;
 201         struct nd_region *nd_region = to_region(pmem);
 202
 203         if (bio->bi_opf & REQ_PREFLUSH)
 204                 nvdimm_flush(nd_region);
 205
 206         do_acct = nd_iostat_start(bio, &start);
 207         bio_for_each_segment(bvec, bio, iter) {
 208                 rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
 209                                 bvec.bv_offset, bio_op(bio), iter.bi_sector);
 210                 if (rc) {
 211                         bio->bi_status = rc;
 212                         break;
 213                 }
 214         }
 215         if (do_acct)
 216                 nd_iostat_end(bio, start);
 217
 218         if (bio->bi_opf & REQ_FUA)
 219                 nvdimm_flush(nd_region);
 220
 221         bio_endio(bio);
 222         return BLK_QC_T_NONE;
 223 }
 224
 225 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 226                        struct page *page, unsigned int op)
 227 {
 228         struct pmem_device *pmem = bdev->bd_queue->queuedata;
 229         blk_status_t rc;
 230
 231         rc = pmem_do_bvec(pmem, page, hpage_nr_pages(page) * PAGE_SIZE,
 232                           0, op, sector);
 233
 234         /*
 235          * The ->rw_page interface is subtle and tricky.  The core
 236          * retries on any error, so we can only invoke page_endio() in
 237          * the successful completion case.  Otherwise, we'll see crashes
 238          * caused by double completion.
 239          */
 240         if (rc == 0)
 241                 page_endio(page, op_is_write(op), 0);
 242
 243         return blk_status_to_errno(rc);
 244 }
 245
 246 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
 247 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 248                 long nr_pages, void **kaddr, pfn_t *pfn)
 249 {
 250         resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
 251
 252         if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
 253                                         PFN_PHYS(nr_pages))))
 254                 return -EIO;
 255
 256         if (kaddr)
 257                 *kaddr = pmem->virt_addr + offset;
 258         if (pfn)
 259                 *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
 260
 261         /*
 262          * If badblocks are present, limit known good range to the
 263          * requested range.
 264          */
 265         if (unlikely(pmem->bb.count))
 266                 return nr_pages;
 267         return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
 268 }
 269
 270 static const struct block_device_operations pmem_fops = {
 271         .owner =                THIS_MODULE,
 272         .rw_page =              pmem_rw_page,
 273         .revalidate_disk =      nvdimm_revalidate_disk,
 274 };
 275
 276 static long pmem_dax_direct_access(struct dax_device *dax_dev,
 277                 pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn)
 278 {
 279         struct pmem_device *pmem = dax_get_private(dax_dev);
 280
 281         return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn);
 282 }
 283
 284 static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 285                 void *addr, size_t bytes, struct iov_iter *i)
 286 {
 287         return copy_from_iter_flushcache(addr, bytes, i);
 288 }
 289
 290 static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 291                 void *addr, size_t bytes, struct iov_iter *i)
 292 {
 293         return copy_to_iter_mcsafe(addr, bytes, i);
 294 }
 295
 296 static const struct dax_operations pmem_dax_ops = {
 297         .direct_access = pmem_dax_direct_access,
 298         .copy_from_iter = pmem_copy_from_iter,
 299         .copy_to_iter = pmem_copy_to_iter,
 300 };
 301
 302 static const struct attribute_group *pmem_attribute_groups[] = {
 303         &dax_attribute_group,
 304         NULL,
 305 };
 306
 307 static void pmem_release_queue(void *q)
 308 {
 309         blk_cleanup_queue(q);
 310 }
 311
 312 static void pmem_freeze_queue(void *q)
 313 {
 314         blk_freeze_queue_start(q);
 315 }
 316
 317 static void pmem_release_disk(void *__pmem)
 318 {
 319         struct pmem_device *pmem = __pmem;
 320
 321         kill_dax(pmem->dax_dev);
 322         put_dax(pmem->dax_dev);
 323         del_gendisk(pmem->disk);
 324         put_disk(pmem->disk);
 325 }
 326
 327 static void pmem_release_pgmap_ops(void *__pgmap)
 328 {
 329         dev_pagemap_put_ops();
 330 }
 331
 332 static void fsdax_pagefree(struct page *page, void *data)
 333 {
 334         wake_up_var(&page->_refcount);
 335 }
 336
 337 static int setup_pagemap_fsdax(struct device *dev, struct dev_pagemap *pgmap)
 338 {
 339         dev_pagemap_get_ops();
 340         if (devm_add_action_or_reset(dev, pmem_release_pgmap_ops, pgmap))
 341                 return -ENOMEM;
 342         pgmap->type = MEMORY_DEVICE_FS_DAX;
 343         pgmap->page_free = fsdax_pagefree;
 344
 345         return 0;
 346 }
 347
 348 static int pmem_attach_disk(struct device *dev,
 349                 struct nd_namespace_common *ndns)
 350 {
 351         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 352         struct nd_region *nd_region = to_nd_region(dev->parent);
 353         int nid = dev_to_node(dev), fua;
 354         struct resource *res = &nsio->res;
 355         struct resource bb_res;
 356         struct nd_pfn *nd_pfn = NULL;
 357         struct dax_device *dax_dev;
 358         struct nd_pfn_sb *pfn_sb;
 359         struct pmem_device *pmem;
 360         struct request_queue *q;
 361         struct device *gendev;
 362         struct gendisk *disk;
 363         void *addr;
 364         int rc;
 365
 366         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 367         if (!pmem)
 368                 return -ENOMEM;
 369
 370         /* while nsio_rw_bytes is active, parse a pfn info block if present */
 371         if (is_nd_pfn(dev)) {
 372                 nd_pfn = to_nd_pfn(dev);
 373                 rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
 374                 if (rc)
 375                         return rc;
 376         }
 377
 378         /* we're attaching a block device, disable raw namespace access */
 379         devm_nsio_disable(dev, nsio);
 380
 381         dev_set_drvdata(dev, pmem);
 382         pmem->phys_addr = res->start;
 383         pmem->size = resource_size(res);
 384         fua = nvdimm_has_flush(nd_region);
 385         if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
 386                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 387                 fua = 0;
 388         }
 389
 390         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 391                                 dev_name(&ndns->dev))) {
 392                 dev_warn(dev, "could not reserve region %pR\n", res);
 393                 return -EBUSY;
 394         }
 395
 396         q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev), NULL);
 397         if (!q)
 398                 return -ENOMEM;
 399
 400         if (devm_add_action_or_reset(dev, pmem_release_queue, q))
 401                 return -ENOMEM;
 402
 403         pmem->pfn_flags = PFN_DEV;
 404         pmem->pgmap.ref = &q->q_usage_counter;
 405         if (is_nd_pfn(dev)) {
 406                 if (setup_pagemap_fsdax(dev, &pmem->pgmap))
 407                         return -ENOMEM;
 408                 addr = devm_memremap_pages(dev, &pmem->pgmap);
 409                 pfn_sb = nd_pfn->pfn_sb;
 410                 pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
 411                 pmem->pfn_pad = resource_size(res) -
 412                         resource_size(&pmem->pgmap.res);
 413                 pmem->pfn_flags |= PFN_MAP;
 414                 memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
 415                 bb_res.start += pmem->data_offset;
 416         } else if (pmem_should_map_pages(dev)) {
 417                 memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
 418                 pmem->pgmap.altmap_valid = false;
 419                 if (setup_pagemap_fsdax(dev, &pmem->pgmap))
 420                         return -ENOMEM;
 421                 addr = devm_memremap_pages(dev, &pmem->pgmap);
 422                 pmem->pfn_flags |= PFN_MAP;
 423                 memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
 424         } else
 425                 addr = devm_memremap(dev, pmem->phys_addr,
 426                                 pmem->size, ARCH_MEMREMAP_PMEM);
 427
 428         /*
 429          * At release time the queue must be frozen before
 430          * devm_memremap_pages is unwound
 431          */
 432         if (devm_add_action_or_reset(dev, pmem_freeze_queue, q))
 433                 return -ENOMEM;
 434
 435         if (IS_ERR(addr))
 436                 return PTR_ERR(addr);
 437         pmem->virt_addr = addr;
 438
 439         blk_queue_write_cache(q, true, fua);
 440         blk_queue_make_request(q, pmem_make_request);
 441         blk_queue_physical_block_size(q, PAGE_SIZE);
 442         blk_queue_logical_block_size(q, pmem_sector_size(ndns));
 443         blk_queue_max_hw_sectors(q, UINT_MAX);
 444         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 445         if (pmem->pfn_flags & PFN_MAP)
 446                 blk_queue_flag_set(QUEUE_FLAG_DAX, q);
 447         q->queuedata = pmem;
 448
 449         disk = alloc_disk_node(0, nid);
 450         if (!disk)
 451                 return -ENOMEM;
 452         pmem->disk = disk;
 453
 454         disk->fops              = &pmem_fops;
 455         disk->queue             = q;
 456         disk->flags             = GENHD_FL_EXT_DEVT;
 457         disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNCHRONOUS_IO;
 458         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 459         set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
 460                         / 512);
 461         if (devm_init_badblocks(dev, &pmem->bb))
 462                 return -ENOMEM;
 463         nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_res);
 464         disk->bb = &pmem->bb;
 465
 466         dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops);
 467         if (!dax_dev) {
 468                 put_disk(disk);
 469                 return -ENOMEM;
 470         }
 471         dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
 472         pmem->dax_dev = dax_dev;
 473
 474         gendev = disk_to_dev(disk);
 475         gendev->groups = pmem_attribute_groups;
 476
 477         device_add_disk(dev, disk, NULL);
 478         if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
 479                 return -ENOMEM;
 480
 481         revalidate_disk(disk);
 482
 483         pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
 484                                           "badblocks");
 485         if (!pmem->bb_state)
 486                 dev_warn(dev, "'badblocks' notification disabled\n");
 487
 488         return 0;
 489 }
 490
 491 static int nd_pmem_probe(struct device *dev)
 492 {
 493         struct nd_namespace_common *ndns;
 494
 495         ndns = nvdimm_namespace_common_probe(dev);
 496         if (IS_ERR(ndns))
 497                 return PTR_ERR(ndns);
 498
 499         if (devm_nsio_enable(dev, to_nd_namespace_io(&ndns->dev)))
 500                 return -ENXIO;
 501
 502         if (is_nd_btt(dev))
 503                 return nvdimm_namespace_attach_btt(ndns);
 504
 505         if (is_nd_pfn(dev))
 506                 return pmem_attach_disk(dev, ndns);
 507
 508         /* if we find a valid info-block we'll come back as that personality */
 509         if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
 510                         || nd_dax_probe(dev, ndns) == 0)
 511                 return -ENXIO;
 512
 513         /* ...otherwise we're just a raw pmem device */
 514         return pmem_attach_disk(dev, ndns);
 515 }
 516
 517 static int nd_pmem_remove(struct device *dev)
 518 {
 519         struct pmem_device *pmem = dev_get_drvdata(dev);
 520
 521         if (is_nd_btt(dev))
 522                 nvdimm_namespace_detach_btt(to_nd_btt(dev));
 523         else {
 524                 /*
 525                  * Note, this assumes device_lock() context to not race
 526                  * nd_pmem_notify()
 527                  */
 528                 sysfs_put(pmem->bb_state);
 529                 pmem->bb_state = NULL;
 530         }
 531         nvdimm_flush(to_nd_region(dev->parent));
 532
 533         return 0;
 534 }
 535
 536 static void nd_pmem_shutdown(struct device *dev)
 537 {
 538         nvdimm_flush(to_nd_region(dev->parent));
 539 }
 540
 541 static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
 542 {
 543         struct nd_region *nd_region;
 544         resource_size_t offset = 0, end_trunc = 0;
 545         struct nd_namespace_common *ndns;
 546         struct nd_namespace_io *nsio;
 547         struct resource res;
 548         struct badblocks *bb;
 549         struct kernfs_node *bb_state;
 550
 551         if (event != NVDIMM_REVALIDATE_POISON)
 552                 return;
 553
 554         if (is_nd_btt(dev)) {
 555                 struct nd_btt *nd_btt = to_nd_btt(dev);
 556
 557                 ndns = nd_btt->ndns;
 558                 nd_region = to_nd_region(ndns->dev.parent);
 559                 nsio = to_nd_namespace_io(&ndns->dev);
 560                 bb = &nsio->bb;
 561                 bb_state = NULL;
 562         } else {
 563                 struct pmem_device *pmem = dev_get_drvdata(dev);
 564
 565                 nd_region = to_region(pmem);
 566                 bb = &pmem->bb;
 567                 bb_state = pmem->bb_state;
 568
 569                 if (is_nd_pfn(dev)) {
 570                         struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 571                         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 572
 573                         ndns = nd_pfn->ndns;
 574                         offset = pmem->data_offset +
 575                                         __le32_to_cpu(pfn_sb->start_pad);
 576                         end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 577                 } else {
 578                         ndns = to_ndns(dev);
 579                 }
 580
 581                 nsio = to_nd_namespace_io(&ndns->dev);
 582         }
 583
 584         res.start = nsio->res.start + offset;
 585         res.end = nsio->res.end - end_trunc;
 586         nvdimm_badblocks_populate(nd_region, bb, &res);
 587         if (bb_state)
 588                 sysfs_notify_dirent(bb_state);
 589 }
 590
 591 MODULE_ALIAS("pmem");
 592 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 593 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 594 static struct nd_device_driver nd_pmem_driver = {
 595         .probe = nd_pmem_probe,
 596         .remove = nd_pmem_remove,
 597         .notify = nd_pmem_notify,
 598         .shutdown = nd_pmem_shutdown,
 599         .drv = {
 600                 .name = "nd_pmem",
 601         },
 602         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 603 };
 604
 605 module_nd_driver(nd_pmem_driver);
 606
 607 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 608 MODULE_LICENSE("GPL v2");