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/pfn_t.h>
  29 #include <linux/slab.h>
  30 #include <linux/pmem.h>
  31 #include <linux/nd.h>
  32 #include "pfn.h"
  33 #include "nd.h"
  34
  35 struct pmem_device {
  36         struct request_queue    *pmem_queue;
  37         struct gendisk          *pmem_disk;
  38         struct nd_namespace_common *ndns;
  39
  40         /* One contiguous memory region per device */
  41         phys_addr_t             phys_addr;
  42         /* when non-zero this device is hosting a 'pfn' instance */
  43         phys_addr_t             data_offset;
  44         unsigned long           pfn_flags;
  45         void __pmem             *virt_addr;
  46         size_t                  size;
  47         struct badblocks        bb;
  48 };
  49
  50 static int pmem_major;
  51
  52 static bool is_bad_pmem(struct badblocks *bb, sector_t sector, unsigned int len)
  53 {
  54         if (bb->count) {
  55                 sector_t first_bad;
  56                 int num_bad;
  57
  58                 return !!badblocks_check(bb, sector, len / 512, &first_bad,
  59                                 &num_bad);
  60         }
  61
  62         return false;
  63 }
  64
  65 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
  66                         unsigned int len, unsigned int off, int rw,
  67                         sector_t sector)
  68 {
  69         void *mem = kmap_atomic(page);
  70         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
  71         void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
  72
  73         if (rw == READ) {
  74                 if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
  75                         return -EIO;
  76                 memcpy_from_pmem(mem + off, pmem_addr, len);
  77                 flush_dcache_page(page);
  78         } else {
  79                 flush_dcache_page(page);
  80                 memcpy_to_pmem(pmem_addr, mem + off, len);
  81         }
  82
  83         kunmap_atomic(mem);
  84         return 0;
  85 }
  86
  87 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
  88 {
  89         int rc = 0;
  90         bool do_acct;
  91         unsigned long start;
  92         struct bio_vec bvec;
  93         struct bvec_iter iter;
  94         struct block_device *bdev = bio->bi_bdev;
  95         struct pmem_device *pmem = bdev->bd_disk->private_data;
  96
  97         do_acct = nd_iostat_start(bio, &start);
  98         bio_for_each_segment(bvec, bio, iter) {
  99                 rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
 100                                 bvec.bv_offset, bio_data_dir(bio),
 101                                 iter.bi_sector);
 102                 if (rc) {
 103                         bio->bi_error = rc;
 104                         break;
 105                 }
 106         }
 107         if (do_acct)
 108                 nd_iostat_end(bio, start);
 109
 110         if (bio_data_dir(bio))
 111                 wmb_pmem();
 112
 113         bio_endio(bio);
 114         return BLK_QC_T_NONE;
 115 }
 116
 117 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 118                        struct page *page, int rw)
 119 {
 120         struct pmem_device *pmem = bdev->bd_disk->private_data;
 121         int rc;
 122
 123         rc = pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
 124         if (rw & WRITE)
 125                 wmb_pmem();
 126
 127         /*
 128          * The ->rw_page interface is subtle and tricky.  The core
 129          * retries on any error, so we can only invoke page_endio() in
 130          * the successful completion case.  Otherwise, we'll see crashes
 131          * caused by double completion.
 132          */
 133         if (rc == 0)
 134                 page_endio(page, rw & WRITE, 0);
 135
 136         return rc;
 137 }
 138
 139 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
 140                       void __pmem **kaddr, pfn_t *pfn)
 141 {
 142         struct pmem_device *pmem = bdev->bd_disk->private_data;
 143         resource_size_t offset = sector * 512 + pmem->data_offset;
 144
 145         *kaddr = pmem->virt_addr + offset;
 146         *pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
 147
 148         return pmem->size - offset;
 149 }
 150
 151 static const struct block_device_operations pmem_fops = {
 152         .owner =                THIS_MODULE,
 153         .rw_page =              pmem_rw_page,
 154         .direct_access =        pmem_direct_access,
 155         .revalidate_disk =      nvdimm_revalidate_disk,
 156 };
 157
 158 static struct pmem_device *pmem_alloc(struct device *dev,
 159                 struct resource *res, int id)
 160 {
 161         struct pmem_device *pmem;
 162         struct request_queue *q;
 163
 164         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 165         if (!pmem)
 166                 return ERR_PTR(-ENOMEM);
 167
 168         pmem->phys_addr = res->start;
 169         pmem->size = resource_size(res);
 170         if (!arch_has_wmb_pmem())
 171                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 172
 173         if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
 174                         dev_name(dev))) {
 175                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
 176                                 &pmem->phys_addr, pmem->size);
 177                 return ERR_PTR(-EBUSY);
 178         }
 179
 180         q = blk_alloc_queue_node(GFP_KERNEL, dev_to_node(dev));
 181         if (!q)
 182                 return ERR_PTR(-ENOMEM);
 183
 184         pmem->pfn_flags = PFN_DEV;
 185         if (pmem_should_map_pages(dev)) {
 186                 pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res,
 187                                 NULL);
 188                 pmem->pfn_flags |= PFN_MAP;
 189         } else
 190                 pmem->virt_addr = (void __pmem *) devm_memremap(dev,
 191                                 pmem->phys_addr, pmem->size,
 192                                 ARCH_MEMREMAP_PMEM);
 193
 194         if (IS_ERR(pmem->virt_addr)) {
 195                 blk_cleanup_queue(q);
 196                 return (void __force *) pmem->virt_addr;
 197         }
 198
 199         pmem->pmem_queue = q;
 200         return pmem;
 201 }
 202
 203 static void pmem_detach_disk(struct pmem_device *pmem)
 204 {
 205         if (!pmem->pmem_disk)
 206                 return;
 207
 208         del_gendisk(pmem->pmem_disk);
 209         put_disk(pmem->pmem_disk);
 210         blk_cleanup_queue(pmem->pmem_queue);
 211 }
 212
 213 static int pmem_attach_disk(struct device *dev,
 214                 struct nd_namespace_common *ndns, struct pmem_device *pmem)
 215 {
 216         int nid = dev_to_node(dev);
 217         struct gendisk *disk;
 218
 219         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
 220         blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
 221         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
 222         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 223         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
 224
 225         disk = alloc_disk_node(0, nid);
 226         if (!disk) {
 227                 blk_cleanup_queue(pmem->pmem_queue);
 228                 return -ENOMEM;
 229         }
 230
 231         disk->major             = pmem_major;
 232         disk->first_minor       = 0;
 233         disk->fops              = &pmem_fops;
 234         disk->private_data      = pmem;
 235         disk->queue             = pmem->pmem_queue;
 236         disk->flags             = GENHD_FL_EXT_DEVT;
 237         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 238         disk->driverfs_dev = dev;
 239         set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
 240         pmem->pmem_disk = disk;
 241         devm_exit_badblocks(dev, &pmem->bb);
 242         if (devm_init_badblocks(dev, &pmem->bb))
 243                 return -ENOMEM;
 244         nvdimm_namespace_add_poison(ndns, &pmem->bb, pmem->data_offset);
 245
 246         disk->bb = &pmem->bb;
 247         add_disk(disk);
 248         revalidate_disk(disk);
 249
 250         return 0;
 251 }
 252
 253 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
 254                 resource_size_t offset, void *buf, size_t size, int rw)
 255 {
 256         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
 257
 258         if (unlikely(offset + size > pmem->size)) {
 259                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 260                 return -EFAULT;
 261         }
 262
 263         if (rw == READ) {
 264                 unsigned int sz_align = ALIGN(size + (offset & (512 - 1)), 512);
 265
 266                 if (unlikely(is_bad_pmem(&pmem->bb, offset / 512, sz_align)))
 267                         return -EIO;
 268                 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
 269         } else {
 270                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
 271                 wmb_pmem();
 272         }
 273
 274         return 0;
 275 }
 276
 277 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 278 {
 279         struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
 280         struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
 281         struct nd_namespace_common *ndns = nd_pfn->ndns;
 282         struct nd_region *nd_region;
 283         unsigned long npfns;
 284         phys_addr_t offset;
 285         u64 checksum;
 286         int rc;
 287
 288         if (!pfn_sb)
 289                 return -ENOMEM;
 290
 291         nd_pfn->pfn_sb = pfn_sb;
 292         rc = nd_pfn_validate(nd_pfn);
 293         if (rc == -ENODEV)
 294                 /* no info block, do init */;
 295         else
 296                 return rc;
 297
 298         nd_region = to_nd_region(nd_pfn->dev.parent);
 299         if (nd_region->ro) {
 300                 dev_info(&nd_pfn->dev,
 301                                 "%s is read-only, unable to init metadata\n",
 302                                 dev_name(&nd_region->dev));
 303                 goto err;
 304         }
 305
 306         memset(pfn_sb, 0, sizeof(*pfn_sb));
 307         npfns = (pmem->size - SZ_8K) / SZ_4K;
 308         /*
 309          * Note, we use 64 here for the standard size of struct page,
 310          * debugging options may cause it to be larger in which case the
 311          * implementation will limit the pfns advertised through
 312          * ->direct_access() to those that are included in the memmap.
 313          */
 314         if (nd_pfn->mode == PFN_MODE_PMEM)
 315                 offset = ALIGN(SZ_8K + 64 * npfns, nd_pfn->align);
 316         else if (nd_pfn->mode == PFN_MODE_RAM)
 317                 offset = ALIGN(SZ_8K, nd_pfn->align);
 318         else
 319                 goto err;
 320
 321         npfns = (pmem->size - offset) / SZ_4K;
 322         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 323         pfn_sb->dataoff = cpu_to_le64(offset);
 324         pfn_sb->npfns = cpu_to_le64(npfns);
 325         memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
 326         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 327         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 328         pfn_sb->version_major = cpu_to_le16(1);
 329         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 330         pfn_sb->checksum = cpu_to_le64(checksum);
 331
 332         rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
 333         if (rc)
 334                 goto err;
 335
 336         return 0;
 337  err:
 338         nd_pfn->pfn_sb = NULL;
 339         kfree(pfn_sb);
 340         return -ENXIO;
 341 }
 342
 343 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
 344 {
 345         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 346         struct pmem_device *pmem;
 347
 348         /* free pmem disk */
 349         pmem = dev_get_drvdata(&nd_pfn->dev);
 350         pmem_detach_disk(pmem);
 351
 352         /* release nd_pfn resources */
 353         kfree(nd_pfn->pfn_sb);
 354         nd_pfn->pfn_sb = NULL;
 355
 356         return 0;
 357 }
 358
 359 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 360 {
 361         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 362         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 363         struct device *dev = &nd_pfn->dev;
 364         struct nd_region *nd_region;
 365         struct vmem_altmap *altmap;
 366         struct nd_pfn_sb *pfn_sb;
 367         struct pmem_device *pmem;
 368         phys_addr_t offset;
 369         int rc;
 370         struct vmem_altmap __altmap = {
 371                 .base_pfn = __phys_to_pfn(nsio->res.start),
 372                 .reserve = __phys_to_pfn(SZ_8K),
 373         };
 374
 375         if (!nd_pfn->uuid || !nd_pfn->ndns)
 376                 return -ENODEV;
 377
 378         nd_region = to_nd_region(dev->parent);
 379         rc = nd_pfn_init(nd_pfn);
 380         if (rc)
 381                 return rc;
 382
 383         pfn_sb = nd_pfn->pfn_sb;
 384         offset = le64_to_cpu(pfn_sb->dataoff);
 385         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 386         if (nd_pfn->mode == PFN_MODE_RAM) {
 387                 if (offset < SZ_8K)
 388                         return -EINVAL;
 389                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 390                 altmap = NULL;
 391         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 392                 nd_pfn->npfns = (resource_size(&nsio->res) - offset)
 393                         / PAGE_SIZE;
 394                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 395                         dev_info(&nd_pfn->dev,
 396                                         "number of pfns truncated from %lld to %ld\n",
 397                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 398                                         nd_pfn->npfns);
 399                 altmap = & __altmap;
 400                 altmap->free = __phys_to_pfn(offset - SZ_8K);
 401                 altmap->alloc = 0;
 402         } else {
 403                 rc = -ENXIO;
 404                 goto err;
 405         }
 406
 407         /* establish pfn range for lookup, and switch to direct map */
 408         pmem = dev_get_drvdata(dev);
 409         devm_memunmap(dev, (void __force *) pmem->virt_addr);
 410         pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res,
 411                         altmap);
 412         pmem->pfn_flags |= PFN_MAP;
 413         if (IS_ERR(pmem->virt_addr)) {
 414                 rc = PTR_ERR(pmem->virt_addr);
 415                 goto err;
 416         }
 417
 418         /* attach pmem disk in "pfn-mode" */
 419         pmem->data_offset = offset;
 420         rc = pmem_attach_disk(dev, ndns, pmem);
 421         if (rc)
 422                 goto err;
 423
 424         return rc;
 425  err:
 426         nvdimm_namespace_detach_pfn(ndns);
 427         return rc;
 428 }
 429
 430 static int nd_pmem_probe(struct device *dev)
 431 {
 432         struct nd_region *nd_region = to_nd_region(dev->parent);
 433         struct nd_namespace_common *ndns;
 434         struct nd_namespace_io *nsio;
 435         struct pmem_device *pmem;
 436
 437         ndns = nvdimm_namespace_common_probe(dev);
 438         if (IS_ERR(ndns))
 439                 return PTR_ERR(ndns);
 440
 441         nsio = to_nd_namespace_io(&ndns->dev);
 442         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
 443         if (IS_ERR(pmem))
 444                 return PTR_ERR(pmem);
 445
 446         pmem->ndns = ndns;
 447         dev_set_drvdata(dev, pmem);
 448         ndns->rw_bytes = pmem_rw_bytes;
 449         if (devm_init_badblocks(dev, &pmem->bb))
 450                 return -ENOMEM;
 451         nvdimm_namespace_add_poison(ndns, &pmem->bb, 0);
 452
 453         if (is_nd_btt(dev)) {
 454                 /* btt allocates its own request_queue */
 455                 blk_cleanup_queue(pmem->pmem_queue);
 456                 pmem->pmem_queue = NULL;
 457                 return nvdimm_namespace_attach_btt(ndns);
 458         }
 459
 460         if (is_nd_pfn(dev))
 461                 return nvdimm_namespace_attach_pfn(ndns);
 462
 463         if (nd_btt_probe(ndns, pmem) == 0 || nd_pfn_probe(ndns, pmem) == 0) {
 464                 /*
 465                  * We'll come back as either btt-pmem, or pfn-pmem, so
 466                  * drop the queue allocation for now.
 467                  */
 468                 blk_cleanup_queue(pmem->pmem_queue);
 469                 return -ENXIO;
 470         }
 471
 472         return pmem_attach_disk(dev, ndns, pmem);
 473 }
 474
 475 static int nd_pmem_remove(struct device *dev)
 476 {
 477         struct pmem_device *pmem = dev_get_drvdata(dev);
 478
 479         if (is_nd_btt(dev))
 480                 nvdimm_namespace_detach_btt(pmem->ndns);
 481         else if (is_nd_pfn(dev))
 482                 nvdimm_namespace_detach_pfn(pmem->ndns);
 483         else
 484                 pmem_detach_disk(pmem);
 485
 486         return 0;
 487 }
 488
 489 MODULE_ALIAS("pmem");
 490 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 491 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 492 static struct nd_device_driver nd_pmem_driver = {
 493         .probe = nd_pmem_probe,
 494         .remove = nd_pmem_remove,
 495         .drv = {
 496                 .name = "nd_pmem",
 497         },
 498         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 499 };
 500
 501 static int __init pmem_init(void)
 502 {
 503         int error;
 504
 505         pmem_major = register_blkdev(0, "pmem");
 506         if (pmem_major < 0)
 507                 return pmem_major;
 508
 509         error = nd_driver_register(&nd_pmem_driver);
 510         if (error) {
 511                 unregister_blkdev(pmem_major, "pmem");
 512                 return error;
 513         }
 514
 515         return 0;
 516 }
 517 module_init(pmem_init);
 518
 519 static void pmem_exit(void)
 520 {
 521         driver_unregister(&nd_pmem_driver.drv);
 522         unregister_blkdev(pmem_major, "pmem");
 523 }
 524 module_exit(pmem_exit);
 525
 526 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 527 MODULE_LICENSE("GPL v2");