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