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