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