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