drivers/nvdimm/pfn_devs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
   4  */
   5 #include <linux/memremap.h>
   6 #include <linux/blkdev.h>
   7 #include <linux/device.h>
   8 #include <linux/genhd.h>
   9 #include <linux/sizes.h>
  10 #include <linux/slab.h>
  11 #include <linux/fs.h>
  12 #include <linux/mm.h>
  13 #include "nd-core.h"
  14 #include "pfn.h"
  15 #include "nd.h"
  16
  17 static void nd_pfn_release(struct device *dev)
  18 {
  19         struct nd_region *nd_region = to_nd_region(dev->parent);
  20         struct nd_pfn *nd_pfn = to_nd_pfn(dev);
  21
  22         dev_dbg(dev, "trace\n");
  23         nd_detach_ndns(&nd_pfn->dev, &nd_pfn->ndns);
  24         ida_simple_remove(&nd_region->pfn_ida, nd_pfn->id);
  25         kfree(nd_pfn->uuid);
  26         kfree(nd_pfn);
  27 }
  28
  29 struct nd_pfn *to_nd_pfn(struct device *dev)
  30 {
  31         struct nd_pfn *nd_pfn = container_of(dev, struct nd_pfn, dev);
  32
  33         WARN_ON(!is_nd_pfn(dev));
  34         return nd_pfn;
  35 }
  36 EXPORT_SYMBOL(to_nd_pfn);
  37
  38 static ssize_t mode_show(struct device *dev,
  39                 struct device_attribute *attr, char *buf)
  40 {
  41         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  42
  43         switch (nd_pfn->mode) {
  44         case PFN_MODE_RAM:
  45                 return sprintf(buf, "ram\n");
  46         case PFN_MODE_PMEM:
  47                 return sprintf(buf, "pmem\n");
  48         default:
  49                 return sprintf(buf, "none\n");
  50         }
  51 }
  52
  53 static ssize_t mode_store(struct device *dev,
  54                 struct device_attribute *attr, const char *buf, size_t len)
  55 {
  56         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  57         ssize_t rc = 0;
  58
  59         nd_device_lock(dev);
  60         nvdimm_bus_lock(dev);
  61         if (dev->driver)
  62                 rc = -EBUSY;
  63         else {
  64                 size_t n = len - 1;
  65
  66                 if (strncmp(buf, "pmem\n", n) == 0
  67                                 || strncmp(buf, "pmem", n) == 0) {
  68                         nd_pfn->mode = PFN_MODE_PMEM;
  69                 } else if (strncmp(buf, "ram\n", n) == 0
  70                                 || strncmp(buf, "ram", n) == 0)
  71                         nd_pfn->mode = PFN_MODE_RAM;
  72                 else if (strncmp(buf, "none\n", n) == 0
  73                                 || strncmp(buf, "none", n) == 0)
  74                         nd_pfn->mode = PFN_MODE_NONE;
  75                 else
  76                         rc = -EINVAL;
  77         }
  78         dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
  79                         buf[len - 1] == '\n' ? "" : "\n");
  80         nvdimm_bus_unlock(dev);
  81         nd_device_unlock(dev);
  82
  83         return rc ? rc : len;
  84 }
  85 static DEVICE_ATTR_RW(mode);
  86
  87 static ssize_t align_show(struct device *dev,
  88                 struct device_attribute *attr, char *buf)
  89 {
  90         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  91
  92         return sprintf(buf, "%ld\n", nd_pfn->align);
  93 }
  94
  95 static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments)
  96 {
  97
  98         alignments[0] = PAGE_SIZE;
  99
 100         if (has_transparent_hugepage()) {
 101                 alignments[1] = HPAGE_PMD_SIZE;
 102                 if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 103                         alignments[2] = HPAGE_PUD_SIZE;
 104         }
 105
 106         return alignments;
 107 }
 108
 109 /*
 110  * Use pmd mapping if supported as default alignment
 111  */
 112 static unsigned long nd_pfn_default_alignment(void)
 113 {
 114
 115         if (has_transparent_hugepage())
 116                 return HPAGE_PMD_SIZE;
 117         return PAGE_SIZE;
 118 }
 119
 120 static ssize_t align_store(struct device *dev,
 121                 struct device_attribute *attr, const char *buf, size_t len)
 122 {
 123         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 124         unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
 125         ssize_t rc;
 126
 127         nd_device_lock(dev);
 128         nvdimm_bus_lock(dev);
 129         rc = nd_size_select_store(dev, buf, &nd_pfn->align,
 130                         nd_pfn_supported_alignments(aligns));
 131         dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
 132                         buf[len - 1] == '\n' ? "" : "\n");
 133         nvdimm_bus_unlock(dev);
 134         nd_device_unlock(dev);
 135
 136         return rc ? rc : len;
 137 }
 138 static DEVICE_ATTR_RW(align);
 139
 140 static ssize_t uuid_show(struct device *dev,
 141                 struct device_attribute *attr, char *buf)
 142 {
 143         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 144
 145         if (nd_pfn->uuid)
 146                 return sprintf(buf, "%pUb\n", nd_pfn->uuid);
 147         return sprintf(buf, "\n");
 148 }
 149
 150 static ssize_t uuid_store(struct device *dev,
 151                 struct device_attribute *attr, const char *buf, size_t len)
 152 {
 153         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 154         ssize_t rc;
 155
 156         nd_device_lock(dev);
 157         rc = nd_uuid_store(dev, &nd_pfn->uuid, buf, len);
 158         dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
 159                         buf[len - 1] == '\n' ? "" : "\n");
 160         nd_device_unlock(dev);
 161
 162         return rc ? rc : len;
 163 }
 164 static DEVICE_ATTR_RW(uuid);
 165
 166 static ssize_t namespace_show(struct device *dev,
 167                 struct device_attribute *attr, char *buf)
 168 {
 169         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 170         ssize_t rc;
 171
 172         nvdimm_bus_lock(dev);
 173         rc = sprintf(buf, "%s\n", nd_pfn->ndns
 174                         ? dev_name(&nd_pfn->ndns->dev) : "");
 175         nvdimm_bus_unlock(dev);
 176         return rc;
 177 }
 178
 179 static ssize_t namespace_store(struct device *dev,
 180                 struct device_attribute *attr, const char *buf, size_t len)
 181 {
 182         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 183         ssize_t rc;
 184
 185         nd_device_lock(dev);
 186         nvdimm_bus_lock(dev);
 187         rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 188         dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
 189                         buf[len - 1] == '\n' ? "" : "\n");
 190         nvdimm_bus_unlock(dev);
 191         nd_device_unlock(dev);
 192
 193         return rc;
 194 }
 195 static DEVICE_ATTR_RW(namespace);
 196
 197 static ssize_t resource_show(struct device *dev,
 198                 struct device_attribute *attr, char *buf)
 199 {
 200         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 201         ssize_t rc;
 202
 203         nd_device_lock(dev);
 204         if (dev->driver) {
 205                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 206                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 207                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 208                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 209                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 210
 211                 rc = sprintf(buf, "%#llx\n", (unsigned long long) nsio->res.start
 212                                 + start_pad + offset);
 213         } else {
 214                 /* no address to convey if the pfn instance is disabled */
 215                 rc = -ENXIO;
 216         }
 217         nd_device_unlock(dev);
 218
 219         return rc;
 220 }
 221 static DEVICE_ATTR(resource, 0400, resource_show, NULL);
 222
 223 static ssize_t size_show(struct device *dev,
 224                 struct device_attribute *attr, char *buf)
 225 {
 226         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 227         ssize_t rc;
 228
 229         nd_device_lock(dev);
 230         if (dev->driver) {
 231                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 232                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 233                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 234                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 235                 u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 236                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 237
 238                 rc = sprintf(buf, "%llu\n", (unsigned long long)
 239                                 resource_size(&nsio->res) - start_pad
 240                                 - end_trunc - offset);
 241         } else {
 242                 /* no size to convey if the pfn instance is disabled */
 243                 rc = -ENXIO;
 244         }
 245         nd_device_unlock(dev);
 246
 247         return rc;
 248 }
 249 static DEVICE_ATTR_RO(size);
 250
 251 static ssize_t supported_alignments_show(struct device *dev,
 252                 struct device_attribute *attr, char *buf)
 253 {
 254         unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
 255
 256         return nd_size_select_show(0,
 257                         nd_pfn_supported_alignments(aligns), buf);
 258 }
 259 static DEVICE_ATTR_RO(supported_alignments);
 260
 261 static struct attribute *nd_pfn_attributes[] = {
 262         &dev_attr_mode.attr,
 263         &dev_attr_namespace.attr,
 264         &dev_attr_uuid.attr,
 265         &dev_attr_align.attr,
 266         &dev_attr_resource.attr,
 267         &dev_attr_size.attr,
 268         &dev_attr_supported_alignments.attr,
 269         NULL,
 270 };
 271
 272 static struct attribute_group nd_pfn_attribute_group = {
 273         .attrs = nd_pfn_attributes,
 274 };
 275
 276 const struct attribute_group *nd_pfn_attribute_groups[] = {
 277         &nd_pfn_attribute_group,
 278         &nd_device_attribute_group,
 279         &nd_numa_attribute_group,
 280         NULL,
 281 };
 282
 283 static const struct device_type nd_pfn_device_type = {
 284         .name = "nd_pfn",
 285         .release = nd_pfn_release,
 286         .groups = nd_pfn_attribute_groups,
 287 };
 288
 289 bool is_nd_pfn(struct device *dev)
 290 {
 291         return dev ? dev->type == &nd_pfn_device_type : false;
 292 }
 293 EXPORT_SYMBOL(is_nd_pfn);
 294
 295 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 296                 struct nd_namespace_common *ndns)
 297 {
 298         struct device *dev;
 299
 300         if (!nd_pfn)
 301                 return NULL;
 302
 303         nd_pfn->mode = PFN_MODE_NONE;
 304         nd_pfn->align = nd_pfn_default_alignment();
 305         dev = &nd_pfn->dev;
 306         device_initialize(&nd_pfn->dev);
 307         if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
 308                 dev_dbg(&ndns->dev, "failed, already claimed by %s\n",
 309                                 dev_name(ndns->claim));
 310                 put_device(dev);
 311                 return NULL;
 312         }
 313         return dev;
 314 }
 315
 316 static struct nd_pfn *nd_pfn_alloc(struct nd_region *nd_region)
 317 {
 318         struct nd_pfn *nd_pfn;
 319         struct device *dev;
 320
 321         nd_pfn = kzalloc(sizeof(*nd_pfn), GFP_KERNEL);
 322         if (!nd_pfn)
 323                 return NULL;
 324
 325         nd_pfn->id = ida_simple_get(&nd_region->pfn_ida, 0, 0, GFP_KERNEL);
 326         if (nd_pfn->id < 0) {
 327                 kfree(nd_pfn);
 328                 return NULL;
 329         }
 330
 331         dev = &nd_pfn->dev;
 332         dev_set_name(dev, "pfn%d.%d", nd_region->id, nd_pfn->id);
 333         dev->type = &nd_pfn_device_type;
 334         dev->parent = &nd_region->dev;
 335
 336         return nd_pfn;
 337 }
 338
 339 struct device *nd_pfn_create(struct nd_region *nd_region)
 340 {
 341         struct nd_pfn *nd_pfn;
 342         struct device *dev;
 343
 344         if (!is_memory(&nd_region->dev))
 345                 return NULL;
 346
 347         nd_pfn = nd_pfn_alloc(nd_region);
 348         dev = nd_pfn_devinit(nd_pfn, NULL);
 349
 350         __nd_device_register(dev);
 351         return dev;
 352 }
 353
 354 /*
 355  * nd_pfn_clear_memmap_errors() clears any errors in the volatile memmap
 356  * space associated with the namespace. If the memmap is set to DRAM, then
 357  * this is a no-op. Since the memmap area is freshly initialized during
 358  * probe, we have an opportunity to clear any badblocks in this area.
 359  */
 360 static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn)
 361 {
 362         struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
 363         struct nd_namespace_common *ndns = nd_pfn->ndns;
 364         void *zero_page = page_address(ZERO_PAGE(0));
 365         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 366         int num_bad, meta_num, rc, bb_present;
 367         sector_t first_bad, meta_start;
 368         struct nd_namespace_io *nsio;
 369
 370         if (nd_pfn->mode != PFN_MODE_PMEM)
 371                 return 0;
 372
 373         nsio = to_nd_namespace_io(&ndns->dev);
 374         meta_start = (SZ_4K + sizeof(*pfn_sb)) >> 9;
 375         meta_num = (le64_to_cpu(pfn_sb->dataoff) >> 9) - meta_start;
 376
 377         /*
 378          * re-enable the namespace with correct size so that we can access
 379          * the device memmap area.
 380          */
 381         devm_namespace_disable(&nd_pfn->dev, ndns);
 382         rc = devm_namespace_enable(&nd_pfn->dev, ndns, le64_to_cpu(pfn_sb->dataoff));
 383         if (rc)
 384                 return rc;
 385
 386         do {
 387                 unsigned long zero_len;
 388                 u64 nsoff;
 389
 390                 bb_present = badblocks_check(&nd_region->bb, meta_start,
 391                                 meta_num, &first_bad, &num_bad);
 392                 if (bb_present) {
 393                         dev_dbg(&nd_pfn->dev, "meta: %x badblocks at %llx\n",
 394                                         num_bad, first_bad);
 395                         nsoff = ALIGN_DOWN((nd_region->ndr_start
 396                                         + (first_bad << 9)) - nsio->res.start,
 397                                         PAGE_SIZE);
 398                         zero_len = ALIGN(num_bad << 9, PAGE_SIZE);
 399                         while (zero_len) {
 400                                 unsigned long chunk = min(zero_len, PAGE_SIZE);
 401
 402                                 rc = nvdimm_write_bytes(ndns, nsoff, zero_page,
 403                                                         chunk, 0);
 404                                 if (rc)
 405                                         break;
 406
 407                                 zero_len -= chunk;
 408                                 nsoff += chunk;
 409                         }
 410                         if (rc) {
 411                                 dev_err(&nd_pfn->dev,
 412                                         "error clearing %x badblocks at %llx\n",
 413                                         num_bad, first_bad);
 414                                 return rc;
 415                         }
 416                 }
 417         } while (bb_present);
 418
 419         return 0;
 420 }
 421
 422 static bool nd_supported_alignment(unsigned long align)
 423 {
 424         int i;
 425         unsigned long supported[MAX_NVDIMM_ALIGN] = { [0] = 0, };
 426
 427         if (align == 0)
 428                 return false;
 429
 430         nd_pfn_supported_alignments(supported);
 431         for (i = 0; supported[i]; i++)
 432                 if (align == supported[i])
 433                         return true;
 434         return false;
 435 }
 436
 437 /**
 438  * nd_pfn_validate - read and validate info-block
 439  * @nd_pfn: fsdax namespace runtime state / properties
 440  * @sig: 'devdax' or 'fsdax' signature
 441  *
 442  * Upon return the info-block buffer contents (->pfn_sb) are
 443  * indeterminate when validation fails, and a coherent info-block
 444  * otherwise.
 445  */
 446 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 447 {
 448         u64 checksum, offset;
 449         enum nd_pfn_mode mode;
 450         struct nd_namespace_io *nsio;
 451         unsigned long align, start_pad;
 452         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 453         struct nd_namespace_common *ndns = nd_pfn->ndns;
 454         const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
 455
 456         if (!pfn_sb || !ndns)
 457                 return -ENODEV;
 458
 459         if (!is_memory(nd_pfn->dev.parent))
 460                 return -ENODEV;
 461
 462         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))
 463                 return -ENXIO;
 464
 465         if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
 466                 return -ENODEV;
 467
 468         checksum = le64_to_cpu(pfn_sb->checksum);
 469         pfn_sb->checksum = 0;
 470         if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
 471                 return -ENODEV;
 472         pfn_sb->checksum = cpu_to_le64(checksum);
 473
 474         if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
 475                 return -ENODEV;
 476
 477         if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
 478                 pfn_sb->start_pad = 0;
 479                 pfn_sb->end_trunc = 0;
 480         }
 481
 482         if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 483                 pfn_sb->align = 0;
 484
 485         if (__le16_to_cpu(pfn_sb->version_minor) < 4) {
 486                 pfn_sb->page_struct_size = cpu_to_le16(64);
 487                 pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
 488         }
 489
 490         switch (le32_to_cpu(pfn_sb->mode)) {
 491         case PFN_MODE_RAM:
 492         case PFN_MODE_PMEM:
 493                 break;
 494         default:
 495                 return -ENXIO;
 496         }
 497
 498         align = le32_to_cpu(pfn_sb->align);
 499         offset = le64_to_cpu(pfn_sb->dataoff);
 500         start_pad = le32_to_cpu(pfn_sb->start_pad);
 501         if (align == 0)
 502                 align = 1UL << ilog2(offset);
 503         mode = le32_to_cpu(pfn_sb->mode);
 504
 505         if ((le32_to_cpu(pfn_sb->page_size) > PAGE_SIZE) &&
 506                         (mode == PFN_MODE_PMEM)) {
 507                 dev_err(&nd_pfn->dev,
 508                                 "init failed, page size mismatch %d\n",
 509                                 le32_to_cpu(pfn_sb->page_size));
 510                 return -EOPNOTSUPP;
 511         }
 512
 513         if ((le16_to_cpu(pfn_sb->page_struct_size) < sizeof(struct page)) &&
 514                         (mode == PFN_MODE_PMEM)) {
 515                 dev_err(&nd_pfn->dev,
 516                                 "init failed, struct page size mismatch %d\n",
 517                                 le16_to_cpu(pfn_sb->page_struct_size));
 518                 return -EOPNOTSUPP;
 519         }
 520
 521         /*
 522          * Check whether the we support the alignment. For Dax if the
 523          * superblock alignment is not matching, we won't initialize
 524          * the device.
 525          */
 526         if (!nd_supported_alignment(align) &&
 527                         !memcmp(pfn_sb->signature, DAX_SIG, PFN_SIG_LEN)) {
 528                 dev_err(&nd_pfn->dev, "init failed, alignment mismatch: "
 529                                 "%ld:%ld\n", nd_pfn->align, align);
 530                 return -EOPNOTSUPP;
 531         }
 532
 533         if (!nd_pfn->uuid) {
 534                 /*
 535                  * When probing a namepace via nd_pfn_probe() the uuid
 536                  * is NULL (see: nd_pfn_devinit()) we init settings from
 537                  * pfn_sb
 538                  */
 539                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 540                 if (!nd_pfn->uuid)
 541                         return -ENOMEM;
 542                 nd_pfn->align = align;
 543                 nd_pfn->mode = mode;
 544         } else {
 545                 /*
 546                  * When probing a pfn / dax instance we validate the
 547                  * live settings against the pfn_sb
 548                  */
 549                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 550                         return -ENODEV;
 551
 552                 /*
 553                  * If the uuid validates, but other settings mismatch
 554                  * return EINVAL because userspace has managed to change
 555                  * the configuration without specifying new
 556                  * identification.
 557                  */
 558                 if (nd_pfn->align != align || nd_pfn->mode != mode) {
 559                         dev_err(&nd_pfn->dev,
 560                                         "init failed, settings mismatch\n");
 561                         dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
 562                                         nd_pfn->align, align, nd_pfn->mode,
 563                                         mode);
 564                         return -EINVAL;
 565                 }
 566         }
 567
 568         if (align > nvdimm_namespace_capacity(ndns)) {
 569                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
 570                                 align, nvdimm_namespace_capacity(ndns));
 571                 return -EINVAL;
 572         }
 573
 574         /*
 575          * These warnings are verbose because they can only trigger in
 576          * the case where the physical address alignment of the
 577          * namespace has changed since the pfn superblock was
 578          * established.
 579          */
 580         nsio = to_nd_namespace_io(&ndns->dev);
 581         if (offset >= resource_size(&nsio->res)) {
 582                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
 583                                 dev_name(&ndns->dev));
 584                 return -EBUSY;
 585         }
 586
 587         if ((align && !IS_ALIGNED(nsio->res.start + offset + start_pad, align))
 588                         || !IS_ALIGNED(offset, PAGE_SIZE)) {
 589                 dev_err(&nd_pfn->dev,
 590                                 "bad offset: %#llx dax disabled align: %#lx\n",
 591                                 offset, align);
 592                 return -ENXIO;
 593         }
 594
 595         return 0;
 596 }
 597 EXPORT_SYMBOL(nd_pfn_validate);
 598
 599 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 600 {
 601         int rc;
 602         struct nd_pfn *nd_pfn;
 603         struct device *pfn_dev;
 604         struct nd_pfn_sb *pfn_sb;
 605         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 606
 607         if (ndns->force_raw)
 608                 return -ENODEV;
 609
 610         switch (ndns->claim_class) {
 611         case NVDIMM_CCLASS_NONE:
 612         case NVDIMM_CCLASS_PFN:
 613                 break;
 614         default:
 615                 return -ENODEV;
 616         }
 617
 618         nvdimm_bus_lock(&ndns->dev);
 619         nd_pfn = nd_pfn_alloc(nd_region);
 620         pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 621         nvdimm_bus_unlock(&ndns->dev);
 622         if (!pfn_dev)
 623                 return -ENOMEM;
 624         pfn_sb = devm_kmalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
 625         nd_pfn = to_nd_pfn(pfn_dev);
 626         nd_pfn->pfn_sb = pfn_sb;
 627         rc = nd_pfn_validate(nd_pfn, PFN_SIG);
 628         dev_dbg(dev, "pfn: %s\n", rc == 0 ? dev_name(pfn_dev) : "<none>");
 629         if (rc < 0) {
 630                 nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 631                 put_device(pfn_dev);
 632         } else
 633                 __nd_device_register(pfn_dev);
 634
 635         return rc;
 636 }
 637 EXPORT_SYMBOL(nd_pfn_probe);
 638
 639 /*
 640  * We hotplug memory at sub-section granularity, pad the reserved area
 641  * from the previous section base to the namespace base address.
 642  */
 643 static unsigned long init_altmap_base(resource_size_t base)
 644 {
 645         unsigned long base_pfn = PHYS_PFN(base);
 646
 647         return SUBSECTION_ALIGN_DOWN(base_pfn);
 648 }
 649
 650 static unsigned long init_altmap_reserve(resource_size_t base)
 651 {
 652         unsigned long reserve = nd_info_block_reserve() >> PAGE_SHIFT;
 653         unsigned long base_pfn = PHYS_PFN(base);
 654
 655         reserve += base_pfn - SUBSECTION_ALIGN_DOWN(base_pfn);
 656         return reserve;
 657 }
 658
 659 static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 660 {
 661         struct resource *res = &pgmap->res;
 662         struct vmem_altmap *altmap = &pgmap->altmap;
 663         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 664         u64 offset = le64_to_cpu(pfn_sb->dataoff);
 665         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 666         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 667         u32 reserve = nd_info_block_reserve();
 668         struct nd_namespace_common *ndns = nd_pfn->ndns;
 669         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 670         resource_size_t base = nsio->res.start + start_pad;
 671         resource_size_t end = nsio->res.end - end_trunc;
 672         struct vmem_altmap __altmap = {
 673                 .base_pfn = init_altmap_base(base),
 674                 .reserve = init_altmap_reserve(base),
 675                 .end_pfn = PHYS_PFN(end),
 676         };
 677
 678         memcpy(res, &nsio->res, sizeof(*res));
 679         res->start += start_pad;
 680         res->end -= end_trunc;
 681
 682         if (nd_pfn->mode == PFN_MODE_RAM) {
 683                 if (offset < reserve)
 684                         return -EINVAL;
 685                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 686         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 687                 nd_pfn->npfns = PHYS_PFN((resource_size(res) - offset));
 688                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 689                         dev_info(&nd_pfn->dev,
 690                                         "number of pfns truncated from %lld to %ld\n",
 691                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 692                                         nd_pfn->npfns);
 693                 memcpy(altmap, &__altmap, sizeof(*altmap));
 694                 altmap->free = PHYS_PFN(offset - reserve);
 695                 altmap->alloc = 0;
 696                 pgmap->flags |= PGMAP_ALTMAP_VALID;
 697         } else
 698                 return -ENXIO;
 699
 700         return 0;
 701 }
 702
 703 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 704 {
 705         struct nd_namespace_common *ndns = nd_pfn->ndns;
 706         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 707         resource_size_t start, size;
 708         struct nd_region *nd_region;
 709         unsigned long npfns, align;
 710         u32 end_trunc;
 711         struct nd_pfn_sb *pfn_sb;
 712         phys_addr_t offset;
 713         const char *sig;
 714         u64 checksum;
 715         int rc;
 716
 717         pfn_sb = devm_kmalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
 718         if (!pfn_sb)
 719                 return -ENOMEM;
 720
 721         nd_pfn->pfn_sb = pfn_sb;
 722         if (is_nd_dax(&nd_pfn->dev))
 723                 sig = DAX_SIG;
 724         else
 725                 sig = PFN_SIG;
 726
 727         rc = nd_pfn_validate(nd_pfn, sig);
 728         if (rc == 0)
 729                 return nd_pfn_clear_memmap_errors(nd_pfn);
 730         if (rc != -ENODEV)
 731                 return rc;
 732
 733         /* no info block, do init */;
 734         memset(pfn_sb, 0, sizeof(*pfn_sb));
 735
 736         nd_region = to_nd_region(nd_pfn->dev.parent);
 737         if (nd_region->ro) {
 738                 dev_info(&nd_pfn->dev,
 739                                 "%s is read-only, unable to init metadata\n",
 740                                 dev_name(&nd_region->dev));
 741                 return -ENXIO;
 742         }
 743
 744         /*
 745          * Note, we use 64 here for the standard size of struct page,
 746          * debugging options may cause it to be larger in which case the
 747          * implementation will limit the pfns advertised through
 748          * ->direct_access() to those that are included in the memmap.
 749          */
 750         start = nsio->res.start;
 751         size = resource_size(&nsio->res);
 752         npfns = PHYS_PFN(size - SZ_8K);
 753         align = max(nd_pfn->align, SUBSECTION_SIZE);
 754         end_trunc = start + size - ALIGN_DOWN(start + size, align);
 755         if (nd_pfn->mode == PFN_MODE_PMEM) {
 756                 /*
 757                  * The altmap should be padded out to the block size used
 758                  * when populating the vmemmap. This *should* be equal to
 759                  * PMD_SIZE for most architectures.
 760                  *
 761                  * Also make sure size of struct page is less than 64. We
 762                  * want to make sure we use large enough size here so that
 763                  * we don't have a dynamic reserve space depending on
 764                  * struct page size. But we also want to make sure we notice
 765                  * when we end up adding new elements to struct page.
 766                  */
 767                 BUILD_BUG_ON(sizeof(struct page) > MAX_STRUCT_PAGE_SIZE);
 768                 offset = ALIGN(start + SZ_8K + MAX_STRUCT_PAGE_SIZE * npfns, align)
 769                         - start;
 770         } else if (nd_pfn->mode == PFN_MODE_RAM)
 771                 offset = ALIGN(start + SZ_8K, align) - start;
 772         else
 773                 return -ENXIO;
 774
 775         if (offset >= size) {
 776                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 777                                 dev_name(&ndns->dev));
 778                 return -ENXIO;
 779         }
 780
 781         npfns = PHYS_PFN(size - offset - end_trunc);
 782         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 783         pfn_sb->dataoff = cpu_to_le64(offset);
 784         pfn_sb->npfns = cpu_to_le64(npfns);
 785         memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
 786         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 787         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 788         pfn_sb->version_major = cpu_to_le16(1);
 789         pfn_sb->version_minor = cpu_to_le16(4);
 790         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 791         pfn_sb->align = cpu_to_le32(nd_pfn->align);
 792         pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE);
 793         pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
 794         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 795         pfn_sb->checksum = cpu_to_le64(checksum);
 796
 797         rc = nd_pfn_clear_memmap_errors(nd_pfn);
 798         if (rc)
 799                 return rc;
 800
 801         return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0);
 802 }
 803
 804 /*
 805  * Determine the effective resource range and vmem_altmap from an nd_pfn
 806  * instance.
 807  */
 808 int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
 809 {
 810         int rc;
 811
 812         if (!nd_pfn->uuid || !nd_pfn->ndns)
 813                 return -ENODEV;
 814
 815         rc = nd_pfn_init(nd_pfn);
 816         if (rc)
 817                 return rc;
 818
 819         /* we need a valid pfn_sb before we can init a dev_pagemap */
 820         return __nvdimm_setup_pfn(nd_pfn, pgmap);
 821 }
 822 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);