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 struct nd_pfn *to_nd_pfn_safe(struct device *dev)
  58 {
  59         /*
  60          * pfn device attributes are re-used by dax device instances, so we
  61          * need to be careful to correct device-to-nd_pfn conversion.
  62          */
  63         if (is_nd_pfn(dev))
  64                 return to_nd_pfn(dev);
  65
  66         if (is_nd_dax(dev)) {
  67                 struct nd_dax *nd_dax = to_nd_dax(dev);
  68
  69                 return &nd_dax->nd_pfn;
  70         }
  71
  72         WARN_ON(1);
  73         return NULL;
  74 }
  75
  76 static ssize_t mode_show(struct device *dev,
  77                 struct device_attribute *attr, char *buf)
  78 {
  79         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  80
  81         switch (nd_pfn->mode) {
  82         case PFN_MODE_RAM:
  83                 return sprintf(buf, "ram\n");
  84         case PFN_MODE_PMEM:
  85                 return sprintf(buf, "pmem\n");
  86         default:
  87                 return sprintf(buf, "none\n");
  88         }
  89 }
  90
  91 static ssize_t mode_store(struct device *dev,
  92                 struct device_attribute *attr, const char *buf, size_t len)
  93 {
  94         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
  95         ssize_t rc = 0;
  96
  97         device_lock(dev);
  98         nvdimm_bus_lock(dev);
  99         if (dev->driver)
 100                 rc = -EBUSY;
 101         else {
 102                 size_t n = len - 1;
 103
 104                 if (strncmp(buf, "pmem\n", n) == 0
 105                                 || strncmp(buf, "pmem", n) == 0) {
 106                         nd_pfn->mode = PFN_MODE_PMEM;
 107                 } else if (strncmp(buf, "ram\n", n) == 0
 108                                 || strncmp(buf, "ram", n) == 0)
 109                         nd_pfn->mode = PFN_MODE_RAM;
 110                 else if (strncmp(buf, "none\n", n) == 0
 111                                 || strncmp(buf, "none", n) == 0)
 112                         nd_pfn->mode = PFN_MODE_NONE;
 113                 else
 114                         rc = -EINVAL;
 115         }
 116         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 117                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 118         nvdimm_bus_unlock(dev);
 119         device_unlock(dev);
 120
 121         return rc ? rc : len;
 122 }
 123 static DEVICE_ATTR_RW(mode);
 124
 125 static ssize_t align_show(struct device *dev,
 126                 struct device_attribute *attr, char *buf)
 127 {
 128         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 129
 130         return sprintf(buf, "%lx\n", nd_pfn->align);
 131 }
 132
 133 static ssize_t __align_store(struct nd_pfn *nd_pfn, const char *buf)
 134 {
 135         unsigned long val;
 136         int rc;
 137
 138         rc = kstrtoul(buf, 0, &val);
 139         if (rc)
 140                 return rc;
 141
 142         if (!is_power_of_2(val) || val < PAGE_SIZE || val > SZ_1G)
 143                 return -EINVAL;
 144
 145         if (nd_pfn->dev.driver)
 146                 return -EBUSY;
 147         else
 148                 nd_pfn->align = val;
 149
 150         return 0;
 151 }
 152
 153 static ssize_t align_store(struct device *dev,
 154                 struct device_attribute *attr, const char *buf, size_t len)
 155 {
 156         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 157         ssize_t rc;
 158
 159         device_lock(dev);
 160         nvdimm_bus_lock(dev);
 161         rc = __align_store(nd_pfn, buf);
 162         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 163                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 164         nvdimm_bus_unlock(dev);
 165         device_unlock(dev);
 166
 167         return rc ? rc : len;
 168 }
 169 static DEVICE_ATTR_RW(align);
 170
 171 static ssize_t uuid_show(struct device *dev,
 172                 struct device_attribute *attr, char *buf)
 173 {
 174         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 175
 176         if (nd_pfn->uuid)
 177                 return sprintf(buf, "%pUb\n", nd_pfn->uuid);
 178         return sprintf(buf, "\n");
 179 }
 180
 181 static ssize_t uuid_store(struct device *dev,
 182                 struct device_attribute *attr, const char *buf, size_t len)
 183 {
 184         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 185         ssize_t rc;
 186
 187         device_lock(dev);
 188         rc = nd_uuid_store(dev, &nd_pfn->uuid, buf, len);
 189         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 190                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 191         device_unlock(dev);
 192
 193         return rc ? rc : len;
 194 }
 195 static DEVICE_ATTR_RW(uuid);
 196
 197 static ssize_t namespace_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         nvdimm_bus_lock(dev);
 204         rc = sprintf(buf, "%s\n", nd_pfn->ndns
 205                         ? dev_name(&nd_pfn->ndns->dev) : "");
 206         nvdimm_bus_unlock(dev);
 207         return rc;
 208 }
 209
 210 static ssize_t namespace_store(struct device *dev,
 211                 struct device_attribute *attr, const char *buf, size_t len)
 212 {
 213         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 214         ssize_t rc;
 215
 216         device_lock(dev);
 217         nvdimm_bus_lock(dev);
 218         rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 219         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 220                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 221         nvdimm_bus_unlock(dev);
 222         device_unlock(dev);
 223
 224         return rc;
 225 }
 226 static DEVICE_ATTR_RW(namespace);
 227
 228 static ssize_t resource_show(struct device *dev,
 229                 struct device_attribute *attr, char *buf)
 230 {
 231         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 232         ssize_t rc;
 233
 234         device_lock(dev);
 235         if (dev->driver) {
 236                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 237                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 238                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 239                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 240                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 241
 242                 rc = sprintf(buf, "%#llx\n", (unsigned long long) nsio->res.start
 243                                 + start_pad + offset);
 244         } else {
 245                 /* no address to convey if the pfn instance is disabled */
 246                 rc = -ENXIO;
 247         }
 248         device_unlock(dev);
 249
 250         return rc;
 251 }
 252 static DEVICE_ATTR_RO(resource);
 253
 254 static ssize_t size_show(struct device *dev,
 255                 struct device_attribute *attr, char *buf)
 256 {
 257         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 258         ssize_t rc;
 259
 260         device_lock(dev);
 261         if (dev->driver) {
 262                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 263                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 264                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 265                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 266                 u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 267                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 268
 269                 rc = sprintf(buf, "%llu\n", (unsigned long long)
 270                                 resource_size(&nsio->res) - start_pad
 271                                 - end_trunc - offset);
 272         } else {
 273                 /* no size to convey if the pfn instance is disabled */
 274                 rc = -ENXIO;
 275         }
 276         device_unlock(dev);
 277
 278         return rc;
 279 }
 280 static DEVICE_ATTR_RO(size);
 281
 282 static struct attribute *nd_pfn_attributes[] = {
 283         &dev_attr_mode.attr,
 284         &dev_attr_namespace.attr,
 285         &dev_attr_uuid.attr,
 286         &dev_attr_align.attr,
 287         &dev_attr_resource.attr,
 288         &dev_attr_size.attr,
 289         NULL,
 290 };
 291
 292 struct attribute_group nd_pfn_attribute_group = {
 293         .attrs = nd_pfn_attributes,
 294 };
 295
 296 static const struct attribute_group *nd_pfn_attribute_groups[] = {
 297         &nd_pfn_attribute_group,
 298         &nd_device_attribute_group,
 299         &nd_numa_attribute_group,
 300         NULL,
 301 };
 302
 303 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 304                 struct nd_namespace_common *ndns)
 305 {
 306         struct device *dev = &nd_pfn->dev;
 307
 308         if (!nd_pfn)
 309                 return NULL;
 310
 311         nd_pfn->mode = PFN_MODE_NONE;
 312         nd_pfn->align = HPAGE_SIZE;
 313         dev = &nd_pfn->dev;
 314         device_initialize(&nd_pfn->dev);
 315         if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
 316                 dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
 317                                 __func__, dev_name(ndns->claim));
 318                 put_device(dev);
 319                 return NULL;
 320         }
 321         return dev;
 322 }
 323
 324 static struct nd_pfn *nd_pfn_alloc(struct nd_region *nd_region)
 325 {
 326         struct nd_pfn *nd_pfn;
 327         struct device *dev;
 328
 329         nd_pfn = kzalloc(sizeof(*nd_pfn), GFP_KERNEL);
 330         if (!nd_pfn)
 331                 return NULL;
 332
 333         nd_pfn->id = ida_simple_get(&nd_region->pfn_ida, 0, 0, GFP_KERNEL);
 334         if (nd_pfn->id < 0) {
 335                 kfree(nd_pfn);
 336                 return NULL;
 337         }
 338
 339         dev = &nd_pfn->dev;
 340         dev_set_name(dev, "pfn%d.%d", nd_region->id, nd_pfn->id);
 341         dev->groups = nd_pfn_attribute_groups;
 342         dev->type = &nd_pfn_device_type;
 343         dev->parent = &nd_region->dev;
 344
 345         return nd_pfn;
 346 }
 347
 348 struct device *nd_pfn_create(struct nd_region *nd_region)
 349 {
 350         struct nd_pfn *nd_pfn;
 351         struct device *dev;
 352
 353         if (!is_nd_pmem(&nd_region->dev))
 354                 return NULL;
 355
 356         nd_pfn = nd_pfn_alloc(nd_region);
 357         dev = nd_pfn_devinit(nd_pfn, NULL);
 358
 359         __nd_device_register(dev);
 360         return dev;
 361 }
 362
 363 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 364 {
 365         u64 checksum, offset;
 366         struct nd_namespace_io *nsio;
 367         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 368         struct nd_namespace_common *ndns = nd_pfn->ndns;
 369         const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
 370
 371         if (!pfn_sb || !ndns)
 372                 return -ENODEV;
 373
 374         if (!is_nd_pmem(nd_pfn->dev.parent))
 375                 return -ENODEV;
 376
 377         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb)))
 378                 return -ENXIO;
 379
 380         if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
 381                 return -ENODEV;
 382
 383         checksum = le64_to_cpu(pfn_sb->checksum);
 384         pfn_sb->checksum = 0;
 385         if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
 386                 return -ENODEV;
 387         pfn_sb->checksum = cpu_to_le64(checksum);
 388
 389         if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
 390                 return -ENODEV;
 391
 392         if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
 393                 pfn_sb->start_pad = 0;
 394                 pfn_sb->end_trunc = 0;
 395         }
 396
 397         if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 398                 pfn_sb->align = 0;
 399
 400         switch (le32_to_cpu(pfn_sb->mode)) {
 401         case PFN_MODE_RAM:
 402         case PFN_MODE_PMEM:
 403                 break;
 404         default:
 405                 return -ENXIO;
 406         }
 407
 408         if (!nd_pfn->uuid) {
 409                 /* from probe we allocate */
 410                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 411                 if (!nd_pfn->uuid)
 412                         return -ENOMEM;
 413         } else {
 414                 /* from init we validate */
 415                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 416                         return -ENODEV;
 417         }
 418
 419         if (nd_pfn->align > nvdimm_namespace_capacity(ndns)) {
 420                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
 421                                 nd_pfn->align, nvdimm_namespace_capacity(ndns));
 422                 return -EINVAL;
 423         }
 424
 425         /*
 426          * These warnings are verbose because they can only trigger in
 427          * the case where the physical address alignment of the
 428          * namespace has changed since the pfn superblock was
 429          * established.
 430          */
 431         offset = le64_to_cpu(pfn_sb->dataoff);
 432         nsio = to_nd_namespace_io(&ndns->dev);
 433         if (offset >= resource_size(&nsio->res)) {
 434                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
 435                                 dev_name(&ndns->dev));
 436                 return -EBUSY;
 437         }
 438
 439         nd_pfn->align = le32_to_cpu(pfn_sb->align);
 440         if (!is_power_of_2(offset) || offset < PAGE_SIZE) {
 441                 dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
 442                                 offset);
 443                 return -ENXIO;
 444         }
 445
 446         return 0;
 447 }
 448 EXPORT_SYMBOL(nd_pfn_validate);
 449
 450 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 451 {
 452         int rc;
 453         struct nd_pfn *nd_pfn;
 454         struct device *pfn_dev;
 455         struct nd_pfn_sb *pfn_sb;
 456         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 457
 458         if (ndns->force_raw)
 459                 return -ENODEV;
 460
 461         nvdimm_bus_lock(&ndns->dev);
 462         nd_pfn = nd_pfn_alloc(nd_region);
 463         pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 464         nvdimm_bus_unlock(&ndns->dev);
 465         if (!pfn_dev)
 466                 return -ENOMEM;
 467         pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
 468         nd_pfn = to_nd_pfn(pfn_dev);
 469         nd_pfn->pfn_sb = pfn_sb;
 470         rc = nd_pfn_validate(nd_pfn, PFN_SIG);
 471         dev_dbg(dev, "%s: pfn: %s\n", __func__,
 472                         rc == 0 ? dev_name(pfn_dev) : "<none>");
 473         if (rc < 0) {
 474                 __nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 475                 put_device(pfn_dev);
 476         } else
 477                 __nd_device_register(pfn_dev);
 478
 479         return rc;
 480 }
 481 EXPORT_SYMBOL(nd_pfn_probe);
 482
 483 /*
 484  * We hotplug memory at section granularity, pad the reserved area from
 485  * the previous section base to the namespace base address.
 486  */
 487 static unsigned long init_altmap_base(resource_size_t base)
 488 {
 489         unsigned long base_pfn = PHYS_PFN(base);
 490
 491         return PFN_SECTION_ALIGN_DOWN(base_pfn);
 492 }
 493
 494 static unsigned long init_altmap_reserve(resource_size_t base)
 495 {
 496         unsigned long reserve = PHYS_PFN(SZ_8K);
 497         unsigned long base_pfn = PHYS_PFN(base);
 498
 499         reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
 500         return reserve;
 501 }
 502
 503 static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 504                 struct resource *res, struct vmem_altmap *altmap)
 505 {
 506         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 507         u64 offset = le64_to_cpu(pfn_sb->dataoff);
 508         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 509         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 510         struct nd_namespace_common *ndns = nd_pfn->ndns;
 511         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 512         resource_size_t base = nsio->res.start + start_pad;
 513         struct vmem_altmap __altmap = {
 514                 .base_pfn = init_altmap_base(base),
 515                 .reserve = init_altmap_reserve(base),
 516         };
 517
 518         memcpy(res, &nsio->res, sizeof(*res));
 519         res->start += start_pad;
 520         res->end -= end_trunc;
 521
 522         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 523         if (nd_pfn->mode == PFN_MODE_RAM) {
 524                 if (offset < SZ_8K)
 525                         return ERR_PTR(-EINVAL);
 526                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 527                 altmap = NULL;
 528         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 529                 nd_pfn->npfns = (resource_size(res) - offset) / PAGE_SIZE;
 530                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 531                         dev_info(&nd_pfn->dev,
 532                                         "number of pfns truncated from %lld to %ld\n",
 533                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 534                                         nd_pfn->npfns);
 535                 memcpy(altmap, &__altmap, sizeof(*altmap));
 536                 altmap->free = PHYS_PFN(offset - SZ_8K);
 537                 altmap->alloc = 0;
 538         } else
 539                 return ERR_PTR(-ENXIO);
 540
 541         return altmap;
 542 }
 543
 544 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 545 {
 546         u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 547         struct nd_namespace_common *ndns = nd_pfn->ndns;
 548         u32 start_pad = 0, end_trunc = 0;
 549         resource_size_t start, size;
 550         struct nd_namespace_io *nsio;
 551         struct nd_region *nd_region;
 552         struct nd_pfn_sb *pfn_sb;
 553         unsigned long npfns;
 554         phys_addr_t offset;
 555         const char *sig;
 556         u64 checksum;
 557         int rc;
 558
 559         pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
 560         if (!pfn_sb)
 561                 return -ENOMEM;
 562
 563         nd_pfn->pfn_sb = pfn_sb;
 564         if (is_nd_dax(&nd_pfn->dev))
 565                 sig = DAX_SIG;
 566         else
 567                 sig = PFN_SIG;
 568         rc = nd_pfn_validate(nd_pfn, sig);
 569         if (rc != -ENODEV)
 570                 return rc;
 571
 572         /* no info block, do init */;
 573         nd_region = to_nd_region(nd_pfn->dev.parent);
 574         if (nd_region->ro) {
 575                 dev_info(&nd_pfn->dev,
 576                                 "%s is read-only, unable to init metadata\n",
 577                                 dev_name(&nd_region->dev));
 578                 return -ENXIO;
 579         }
 580
 581         memset(pfn_sb, 0, sizeof(*pfn_sb));
 582
 583         /*
 584          * Check if pmem collides with 'System RAM' when section aligned and
 585          * trim it accordingly
 586          */
 587         nsio = to_nd_namespace_io(&ndns->dev);
 588         start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
 589         size = resource_size(&nsio->res);
 590         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 591                                 IORES_DESC_NONE) == REGION_MIXED) {
 592                 start = nsio->res.start;
 593                 start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
 594         }
 595
 596         start = nsio->res.start;
 597         size = PHYS_SECTION_ALIGN_UP(start + size) - start;
 598         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 599                                 IORES_DESC_NONE) == REGION_MIXED) {
 600                 size = resource_size(&nsio->res);
 601                 end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
 602         }
 603
 604         if (start_pad + end_trunc)
 605                 dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
 606                                 dev_name(&ndns->dev), start_pad + end_trunc);
 607
 608         /*
 609          * Note, we use 64 here for the standard size of struct page,
 610          * debugging options may cause it to be larger in which case the
 611          * implementation will limit the pfns advertised through
 612          * ->direct_access() to those that are included in the memmap.
 613          */
 614         start += start_pad;
 615         size = resource_size(&nsio->res);
 616         npfns = (size - start_pad - end_trunc - SZ_8K) / SZ_4K;
 617         if (nd_pfn->mode == PFN_MODE_PMEM)
 618                 offset = ALIGN(start + SZ_8K + 64 * npfns + dax_label_reserve,
 619                                 nd_pfn->align) - start;
 620         else if (nd_pfn->mode == PFN_MODE_RAM)
 621                 offset = ALIGN(start + SZ_8K + dax_label_reserve,
 622                                 nd_pfn->align) - start;
 623         else
 624                 return -ENXIO;
 625
 626         if (offset + start_pad + end_trunc >= size) {
 627                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 628                                 dev_name(&ndns->dev));
 629                 return -ENXIO;
 630         }
 631
 632         npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
 633         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 634         pfn_sb->dataoff = cpu_to_le64(offset);
 635         pfn_sb->npfns = cpu_to_le64(npfns);
 636         memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
 637         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 638         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 639         pfn_sb->version_major = cpu_to_le16(1);
 640         pfn_sb->version_minor = cpu_to_le16(2);
 641         pfn_sb->start_pad = cpu_to_le32(start_pad);
 642         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 643         pfn_sb->align = cpu_to_le32(nd_pfn->align);
 644         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 645         pfn_sb->checksum = cpu_to_le64(checksum);
 646
 647         return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
 648 }
 649
 650 /*
 651  * Determine the effective resource range and vmem_altmap from an nd_pfn
 652  * instance.
 653  */
 654 struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 655                 struct resource *res, struct vmem_altmap *altmap)
 656 {
 657         int rc;
 658
 659         if (!nd_pfn->uuid || !nd_pfn->ndns)
 660                 return ERR_PTR(-ENODEV);
 661
 662         rc = nd_pfn_init(nd_pfn);
 663         if (rc)
 664                 return ERR_PTR(rc);
 665
 666         /* we need a valid pfn_sb before we can init a vmem_altmap */
 667         return __nvdimm_setup_pfn(nd_pfn, res, altmap);
 668 }
 669 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);