drivers/nvdimm/pfn_devs.c

   1 /*
   2  * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  */
  13 #include <linux/memremap.h>
  14 #include <linux/blkdev.h>
  15 #include <linux/device.h>
  16 #include <linux/genhd.h>
  17 #include <linux/sizes.h>
  18 #include <linux/slab.h>
  19 #include <linux/fs.h>
  20 #include <linux/mm.h>
  21 #include "nd-core.h"
  22 #include "pfn.h"
  23 #include "nd.h"
  24
  25 static void nd_pfn_release(struct device *dev)
  26 {
  27         struct nd_region *nd_region = to_nd_region(dev->parent);
  28         struct nd_pfn *nd_pfn = to_nd_pfn(dev);
  29
  30         dev_dbg(dev, "%s\n", __func__);
  31         nd_detach_ndns(&nd_pfn->dev, &nd_pfn->ndns);
  32         ida_simple_remove(&nd_region->pfn_ida, nd_pfn->id);
  33         kfree(nd_pfn->uuid);
  34         kfree(nd_pfn);
  35 }
  36
  37 static struct device_type nd_pfn_device_type = {
  38         .name = "nd_pfn",
  39         .release = nd_pfn_release,
  40 };
  41
  42 bool is_nd_pfn(struct device *dev)
  43 {
  44         return dev ? dev->type == &nd_pfn_device_type : false;
  45 }
  46 EXPORT_SYMBOL(is_nd_pfn);
  47
  48 struct nd_pfn *to_nd_pfn(struct device *dev)
  49 {
  50         struct nd_pfn *nd_pfn = container_of(dev, struct nd_pfn, dev);
  51
  52         WARN_ON(!is_nd_pfn(dev));
  53         return nd_pfn;
  54 }
  55 EXPORT_SYMBOL(to_nd_pfn);
  56
  57 static ssize_t mode_show(struct device *dev,
  58                 struct device_attribute *attr, char *buf)
  59 {
  60         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  61
  62         switch (nd_pfn->mode) {
  63         case PFN_MODE_RAM:
  64                 return sprintf(buf, "ram\n");
  65         case PFN_MODE_PMEM:
  66                 return sprintf(buf, "pmem\n");
  67         default:
  68                 return sprintf(buf, "none\n");
  69         }
  70 }
  71
  72 static ssize_t mode_store(struct device *dev,
  73                 struct device_attribute *attr, const char *buf, size_t len)
  74 {
  75         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  76         ssize_t rc = 0;
  77
  78         device_lock(dev);
  79         nvdimm_bus_lock(dev);
  80         if (dev->driver)
  81                 rc = -EBUSY;
  82         else {
  83                 size_t n = len - 1;
  84
  85                 if (strncmp(buf, "pmem\n", n) == 0
  86                                 || strncmp(buf, "pmem", n) == 0) {
  87                         nd_pfn->mode = PFN_MODE_PMEM;
  88                 } else if (strncmp(buf, "ram\n", n) == 0
  89                                 || strncmp(buf, "ram", n) == 0)
  90                         nd_pfn->mode = PFN_MODE_RAM;
  91                 else if (strncmp(buf, "none\n", n) == 0
  92                                 || strncmp(buf, "none", n) == 0)
  93                         nd_pfn->mode = PFN_MODE_NONE;
  94                 else
  95                         rc = -EINVAL;
  96         }
  97         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
  98                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
  99         nvdimm_bus_unlock(dev);
 100         device_unlock(dev);
 101
 102         return rc ? rc : len;
 103 }
 104 static DEVICE_ATTR_RW(mode);
 105
 106 static ssize_t align_show(struct device *dev,
 107                 struct device_attribute *attr, char *buf)
 108 {
 109         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 110
 111         return sprintf(buf, "%lx\n", nd_pfn->align);
 112 }
 113
 114 static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)
 115 {
 116         unsigned long val;
 117         int rc;
 118
 119         rc = kstrtoul(buf, 0, &val);
 120         if (rc)
 121                 return rc;
 122
 123         if (!is_power_of_2(val) || val < PAGE_SIZE || val > SZ_1G)
 124                 return -EINVAL;
 125
 126         if (nd_pfn->dev.driver)
 127                 return -EBUSY;
 128         else
 129                 nd_pfn->align = val;
 130
 131         return 0;
 132 }
 133
 134 static ssize_t align_store(struct device *dev,
 135                 struct device_attribute *attr, const char *buf, size_t len)
 136 {
 137         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 138         ssize_t rc;
 139
 140         device_lock(dev);
 141         nvdimm_bus_lock(dev);
 142         rc = __align_store(nd_pfn, buf);
 143         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 144                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 145         nvdimm_bus_unlock(dev);
 146         device_unlock(dev);
 147
 148         return rc ? rc : len;
 149 }
 150 static DEVICE_ATTR_RW(align);
 151
 152 static ssize_t uuid_show(struct device *dev,
 153                 struct device_attribute *attr, char *buf)
 154 {
 155         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 156
 157         if (nd_pfn->uuid)
 158                 return sprintf(buf, "%pUb\n", nd_pfn->uuid);
 159         return sprintf(buf, "\n");
 160 }
 161
 162 static ssize_t uuid_store(struct device *dev,
 163                 struct device_attribute *attr, const char *buf, size_t len)
 164 {
 165         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 166         ssize_t rc;
 167
 168         device_lock(dev);
 169         rc = nd_uuid_store(dev, &nd_pfn->uuid, buf, len);
 170         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 171                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 172         device_unlock(dev);
 173
 174         return rc ? rc : len;
 175 }
 176 static DEVICE_ATTR_RW(uuid);
 177
 178 static ssize_t namespace_show(struct device *dev,
 179                 struct device_attribute *attr, char *buf)
 180 {
 181         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 182         ssize_t rc;
 183
 184         nvdimm_bus_lock(dev);
 185         rc = sprintf(buf, "%s\n", nd_pfn->ndns
 186                         ? dev_name(&nd_pfn->ndns->dev) : "");
 187         nvdimm_bus_unlock(dev);
 188         return rc;
 189 }
 190
 191 static ssize_t namespace_store(struct device *dev,
 192                 struct device_attribute *attr, const char *buf, size_t len)
 193 {
 194         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 195         ssize_t rc;
 196
 197         device_lock(dev);
 198         nvdimm_bus_lock(dev);
 199         rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 200         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 201                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 202         nvdimm_bus_unlock(dev);
 203         device_unlock(dev);
 204
 205         return rc;
 206 }
 207 static DEVICE_ATTR_RW(namespace);
 208
 209 static ssize_t resource_show(struct device *dev,
 210                 struct device_attribute *attr, char *buf)
 211 {
 212         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 213         ssize_t rc;
 214
 215         device_lock(dev);
 216         if (dev->driver) {
 217                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 218                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 219                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 220                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 221                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 222
 223                 rc = sprintf(buf, "%#llx\n", (unsigned long long) nsio->res.start
 224                                 + start_pad + offset);
 225         } else {
 226                 /* no address to convey if the pfn instance is disabled */
 227                 rc = -ENXIO;
 228         }
 229         device_unlock(dev);
 230
 231         return rc;
 232 }
 233 static DEVICE_ATTR_RO(resource);
 234
 235 static ssize_t size_show(struct device *dev,
 236                 struct device_attribute *attr, char *buf)
 237 {
 238         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 239         ssize_t rc;
 240
 241         device_lock(dev);
 242         if (dev->driver) {
 243                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 244                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 245                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 246                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 247                 u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 248                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 249
 250                 rc = sprintf(buf, "%llu\n", (unsigned long long)
 251                                 resource_size(&nsio->res) - start_pad
 252                                 - end_trunc - offset);
 253         } else {
 254                 /* no size to convey if the pfn instance is disabled */
 255                 rc = -ENXIO;
 256         }
 257         device_unlock(dev);
 258
 259         return rc;
 260 }
 261 static DEVICE_ATTR_RO(size);
 262
 263 static struct attribute *nd_pfn_attributes[] = {
 264         &dev_attr_mode.attr,
 265         &dev_attr_namespace.attr,
 266         &dev_attr_uuid.attr,
 267         &dev_attr_align.attr,
 268         &dev_attr_resource.attr,
 269         &dev_attr_size.attr,
 270         NULL,
 271 };
 272
 273 struct attribute_group nd_pfn_attribute_group = {
 274         .attrs = nd_pfn_attributes,
 275 };
 276
 277 static const struct attribute_group *nd_pfn_attribute_groups[] = {
 278         &nd_pfn_attribute_group,
 279         &nd_device_attribute_group,
 280         &nd_numa_attribute_group,
 281         NULL,
 282 };
 283
 284 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 285                 struct nd_namespace_common *ndns)
 286 {
 287         struct device *dev = &nd_pfn->dev;
 288
 289         if (!nd_pfn)
 290                 return NULL;
 291
 292         nd_pfn->mode = PFN_MODE_NONE;
 293         nd_pfn->align = HPAGE_SIZE;
 294         dev = &nd_pfn->dev;
 295         device_initialize(&nd_pfn->dev);
 296         if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
 297                 dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
 298                                 __func__, dev_name(ndns->claim));
 299                 put_device(dev);
 300                 return NULL;
 301         }
 302         return dev;
 303 }
 304
 305 static struct nd_pfn *nd_pfn_alloc(struct nd_region *nd_region)
 306 {
 307         struct nd_pfn *nd_pfn;
 308         struct device *dev;
 309
 310         nd_pfn = kzalloc(sizeof(*nd_pfn), GFP_KERNEL);
 311         if (!nd_pfn)
 312                 return NULL;
 313
 314         nd_pfn->id = ida_simple_get(&nd_region->pfn_ida, 0, 0, GFP_KERNEL);
 315         if (nd_pfn->id < 0) {
 316                 kfree(nd_pfn);
 317                 return NULL;
 318         }
 319
 320         dev = &nd_pfn->dev;
 321         dev_set_name(dev, "pfn%d.%d", nd_region->id, nd_pfn->id);
 322         dev->groups = nd_pfn_attribute_groups;
 323         dev->type = &nd_pfn_device_type;
 324         dev->parent = &nd_region->dev;
 325
 326         return nd_pfn;
 327 }
 328
 329 struct device *nd_pfn_create(struct nd_region *nd_region)
 330 {
 331         struct nd_pfn *nd_pfn;
 332         struct device *dev;
 333
 334         if (!is_nd_pmem(&nd_region->dev))
 335                 return NULL;
 336
 337         nd_pfn = nd_pfn_alloc(nd_region);
 338         dev = nd_pfn_devinit(nd_pfn, NULL);
 339
 340         __nd_device_register(dev);
 341         return dev;
 342 }
 343
 344 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 345 {
 346         u64 checksum, offset;
 347         struct nd_namespace_io *nsio;
 348         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 349         struct nd_namespace_common *ndns = nd_pfn->ndns;
 350         const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
 351
 352         if (!pfn_sb || !ndns)
 353                 return -ENODEV;
 354
 355         if (!is_nd_pmem(nd_pfn->dev.parent))
 356                 return -ENODEV;
 357
 358         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb)))
 359                 return -ENXIO;
 360
 361         if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
 362                 return -ENODEV;
 363
 364         checksum = le64_to_cpu(pfn_sb->checksum);
 365         pfn_sb->checksum = 0;
 366         if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
 367                 return -ENODEV;
 368         pfn_sb->checksum = cpu_to_le64(checksum);
 369
 370         if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
 371                 return -ENODEV;
 372
 373         if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
 374                 pfn_sb->start_pad = 0;
 375                 pfn_sb->end_trunc = 0;
 376         }
 377
 378         if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 379                 pfn_sb->align = 0;
 380
 381         switch (le32_to_cpu(pfn_sb->mode)) {
 382         case PFN_MODE_RAM:
 383         case PFN_MODE_PMEM:
 384                 break;
 385         default:
 386                 return -ENXIO;
 387         }
 388
 389         if (!nd_pfn->uuid) {
 390                 /* from probe we allocate */
 391                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 392                 if (!nd_pfn->uuid)
 393                         return -ENOMEM;
 394         } else {
 395                 /* from init we validate */
 396                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 397                         return -ENODEV;
 398         }
 399
 400         if (nd_pfn->align == 0)
 401                 nd_pfn->align = le32_to_cpu(pfn_sb->align);
 402         if (nd_pfn->align > nvdimm_namespace_capacity(ndns)) {
 403                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
 404                                 nd_pfn->align, nvdimm_namespace_capacity(ndns));
 405                 return -EINVAL;
 406         }
 407
 408         /*
 409          * These warnings are verbose because they can only trigger in
 410          * the case where the physical address alignment of the
 411          * namespace has changed since the pfn superblock was
 412          * established.
 413          */
 414         offset = le64_to_cpu(pfn_sb->dataoff);
 415         nsio = to_nd_namespace_io(&ndns->dev);
 416         if (offset >= resource_size(&nsio->res)) {
 417                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
 418                                 dev_name(&ndns->dev));
 419                 return -EBUSY;
 420         }
 421
 422         if ((nd_pfn->align && !IS_ALIGNED(offset, nd_pfn->align))
 423                         || !IS_ALIGNED(offset, PAGE_SIZE)) {
 424                 dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
 425                                 offset);
 426                 return -ENXIO;
 427         }
 428
 429         return 0;
 430 }
 431 EXPORT_SYMBOL(nd_pfn_validate);
 432
 433 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 434 {
 435         int rc;
 436         struct nd_pfn *nd_pfn;
 437         struct device *pfn_dev;
 438         struct nd_pfn_sb *pfn_sb;
 439         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 440
 441         if (ndns->force_raw)
 442                 return -ENODEV;
 443
 444         nvdimm_bus_lock(&ndns->dev);
 445         nd_pfn = nd_pfn_alloc(nd_region);
 446         pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 447         nvdimm_bus_unlock(&ndns->dev);
 448         if (!pfn_dev)
 449                 return -ENOMEM;
 450         pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
 451         nd_pfn = to_nd_pfn(pfn_dev);
 452         nd_pfn->pfn_sb = pfn_sb;
 453         rc = nd_pfn_validate(nd_pfn, PFN_SIG);
 454         dev_dbg(dev, "%s: pfn: %s\n", __func__,
 455                         rc == 0 ? dev_name(pfn_dev) : "<none>");
 456         if (rc < 0) {
 457                 __nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 458                 put_device(pfn_dev);
 459         } else
 460                 __nd_device_register(pfn_dev);
 461
 462         return rc;
 463 }
 464 EXPORT_SYMBOL(nd_pfn_probe);
 465
 466 /*
 467  * We hotplug memory at section granularity, pad the reserved area from
 468  * the previous section base to the namespace base address.
 469  */
 470 static unsigned long init_altmap_base(resource_size_t base)
 471 {
 472         unsigned long base_pfn = PHYS_PFN(base);
 473
 474         return PFN_SECTION_ALIGN_DOWN(base_pfn);
 475 }
 476
 477 static unsigned long init_altmap_reserve(resource_size_t base)
 478 {
 479         unsigned long reserve = PHYS_PFN(SZ_8K);
 480         unsigned long base_pfn = PHYS_PFN(base);
 481
 482         reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
 483         return reserve;
 484 }
 485
 486 static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 487                 struct resource *res, struct vmem_altmap *altmap)
 488 {
 489         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 490         u64 offset = le64_to_cpu(pfn_sb->dataoff);
 491         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 492         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 493         struct nd_namespace_common *ndns = nd_pfn->ndns;
 494         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 495         resource_size_t base = nsio->res.start + start_pad;
 496         struct vmem_altmap __altmap = {
 497                 .base_pfn = init_altmap_base(base),
 498                 .reserve = init_altmap_reserve(base),
 499         };
 500
 501         memcpy(res, &nsio->res, sizeof(*res));
 502         res->start += start_pad;
 503         res->end -= end_trunc;
 504
 505         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 506         if (nd_pfn->mode == PFN_MODE_RAM) {
 507                 if (offset < SZ_8K)
 508                         return ERR_PTR(-EINVAL);
 509                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 510                 altmap = NULL;
 511         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 512                 nd_pfn->npfns = (resource_size(res) - offset) / PAGE_SIZE;
 513                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 514                         dev_info(&nd_pfn->dev,
 515                                         "number of pfns truncated from %lld to %ld\n",
 516                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 517                                         nd_pfn->npfns);
 518                 memcpy(altmap, &__altmap, sizeof(*altmap));
 519                 altmap->free = PHYS_PFN(offset - SZ_8K);
 520                 altmap->alloc = 0;
 521         } else
 522                 return ERR_PTR(-ENXIO);
 523
 524         return altmap;
 525 }
 526
 527 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 528 {
 529         u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 530         struct nd_namespace_common *ndns = nd_pfn->ndns;
 531         u32 start_pad = 0, end_trunc = 0;
 532         resource_size_t start, size;
 533         struct nd_namespace_io *nsio;
 534         struct nd_region *nd_region;
 535         struct nd_pfn_sb *pfn_sb;
 536         unsigned long npfns;
 537         phys_addr_t offset;
 538         const char *sig;
 539         u64 checksum;
 540         int rc;
 541
 542         pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
 543         if (!pfn_sb)
 544                 return -ENOMEM;
 545
 546         nd_pfn->pfn_sb = pfn_sb;
 547         if (is_nd_dax(&nd_pfn->dev))
 548                 sig = DAX_SIG;
 549         else
 550                 sig = PFN_SIG;
 551         rc = nd_pfn_validate(nd_pfn, sig);
 552         if (rc != -ENODEV)
 553                 return rc;
 554
 555         /* no info block, do init */;
 556         nd_region = to_nd_region(nd_pfn->dev.parent);
 557         if (nd_region->ro) {
 558                 dev_info(&nd_pfn->dev,
 559                                 "%s is read-only, unable to init metadata\n",
 560                                 dev_name(&nd_region->dev));
 561                 return -ENXIO;
 562         }
 563
 564         memset(pfn_sb, 0, sizeof(*pfn_sb));
 565
 566         /*
 567          * Check if pmem collides with 'System RAM' when section aligned and
 568          * trim it accordingly
 569          */
 570         nsio = to_nd_namespace_io(&ndns->dev);
 571         start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
 572         size = resource_size(&nsio->res);
 573         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 574                                 IORES_DESC_NONE) == REGION_MIXED) {
 575                 start = nsio->res.start;
 576                 start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
 577         }
 578
 579         start = nsio->res.start;
 580         size = PHYS_SECTION_ALIGN_UP(start + size) - start;
 581         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 582                                 IORES_DESC_NONE) == REGION_MIXED) {
 583                 size = resource_size(&nsio->res);
 584                 end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
 585         }
 586
 587         if (start_pad + end_trunc)
 588                 dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
 589                                 dev_name(&ndns->dev), start_pad + end_trunc);
 590
 591         /*
 592          * Note, we use 64 here for the standard size of struct page,
 593          * debugging options may cause it to be larger in which case the
 594          * implementation will limit the pfns advertised through
 595          * ->direct_access() to those that are included in the memmap.
 596          */
 597         start += start_pad;
 598         size = resource_size(&nsio->res);
 599         npfns = (size - start_pad - end_trunc - SZ_8K) / SZ_4K;
 600         if (nd_pfn->mode == PFN_MODE_PMEM) {
 601                 unsigned long memmap_size;
 602
 603                 /*
 604                  * vmemmap_populate_hugepages() allocates the memmap array in
 605                  * HPAGE_SIZE chunks.
 606                  */
 607                 memmap_size = ALIGN(64 * npfns, HPAGE_SIZE);
 608                 offset = ALIGN(start + SZ_8K + memmap_size + dax_label_reserve,
 609                                 nd_pfn->align) - start;
 610         } else if (nd_pfn->mode == PFN_MODE_RAM)
 611                 offset = ALIGN(start + SZ_8K + dax_label_reserve,
 612                                 nd_pfn->align) - start;
 613         else
 614                 return -ENXIO;
 615
 616         if (offset + start_pad + end_trunc >= size) {
 617                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 618                                 dev_name(&ndns->dev));
 619                 return -ENXIO;
 620         }
 621
 622         npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
 623         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 624         pfn_sb->dataoff = cpu_to_le64(offset);
 625         pfn_sb->npfns = cpu_to_le64(npfns);
 626         memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
 627         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 628         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 629         pfn_sb->version_major = cpu_to_le16(1);
 630         pfn_sb->version_minor = cpu_to_le16(2);
 631         pfn_sb->start_pad = cpu_to_le32(start_pad);
 632         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 633         pfn_sb->align = cpu_to_le32(nd_pfn->align);
 634         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 635         pfn_sb->checksum = cpu_to_le64(checksum);
 636
 637         return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
 638 }
 639
 640 /*
 641  * Determine the effective resource range and vmem_altmap from an nd_pfn
 642  * instance.
 643  */
 644 struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 645                 struct resource *res, struct vmem_altmap *altmap)
 646 {
 647         int rc;
 648
 649         if (!nd_pfn->uuid || !nd_pfn->ndns)
 650                 return ERR_PTR(-ENODEV);
 651
 652         rc = nd_pfn_init(nd_pfn);
 653         if (rc)
 654                 return ERR_PTR(rc);
 655
 656         /* we need a valid pfn_sb before we can init a vmem_altmap */
 657         return __nvdimm_setup_pfn(nd_pfn, res, altmap);
 658 }
 659 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);