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