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, "%ld\n", nd_pfn->align);
 112 }
 113
 114 static const unsigned long *nd_pfn_supported_alignments(void)
 115 {
 116         /*
 117          * This needs to be a non-static variable because the *_SIZE
 118          * macros aren't always constants.
 119          */
 120         const unsigned long supported_alignments[] = {
 121                 PAGE_SIZE,
 122 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 123                 HPAGE_PMD_SIZE,
 124 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 125                 HPAGE_PUD_SIZE,
 126 #endif
 127 #endif
 128                 0,
 129         };
 130         static unsigned long data[ARRAY_SIZE(supported_alignments)];
 131
 132         memcpy(data, supported_alignments, sizeof(data));
 133
 134         return data;
 135 }
 136
 137 static ssize_t align_store(struct device *dev,
 138                 struct device_attribute *attr, const char *buf, size_t len)
 139 {
 140         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 141         ssize_t rc;
 142
 143         device_lock(dev);
 144         nvdimm_bus_lock(dev);
 145         rc = nd_size_select_store(dev, buf, &nd_pfn->align,
 146                         nd_pfn_supported_alignments());
 147         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 148                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 149         nvdimm_bus_unlock(dev);
 150         device_unlock(dev);
 151
 152         return rc ? rc : len;
 153 }
 154 static DEVICE_ATTR_RW(align);
 155
 156 static ssize_t uuid_show(struct device *dev,
 157                 struct device_attribute *attr, char *buf)
 158 {
 159         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 160
 161         if (nd_pfn->uuid)
 162                 return sprintf(buf, "%pUb\n", nd_pfn->uuid);
 163         return sprintf(buf, "\n");
 164 }
 165
 166 static ssize_t uuid_store(struct device *dev,
 167                 struct device_attribute *attr, const char *buf, size_t len)
 168 {
 169         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 170         ssize_t rc;
 171
 172         device_lock(dev);
 173         rc = nd_uuid_store(dev, &nd_pfn->uuid, buf, len);
 174         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 175                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 176         device_unlock(dev);
 177
 178         return rc ? rc : len;
 179 }
 180 static DEVICE_ATTR_RW(uuid);
 181
 182 static ssize_t namespace_show(struct device *dev,
 183                 struct device_attribute *attr, char *buf)
 184 {
 185         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 186         ssize_t rc;
 187
 188         nvdimm_bus_lock(dev);
 189         rc = sprintf(buf, "%s\n", nd_pfn->ndns
 190                         ? dev_name(&nd_pfn->ndns->dev) : "");
 191         nvdimm_bus_unlock(dev);
 192         return rc;
 193 }
 194
 195 static ssize_t namespace_store(struct device *dev,
 196                 struct device_attribute *attr, const char *buf, size_t len)
 197 {
 198         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 199         ssize_t rc;
 200
 201         device_lock(dev);
 202         nvdimm_bus_lock(dev);
 203         rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
 204         dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
 205                         rc, buf, buf[len - 1] == '\n' ? "" : "\n");
 206         nvdimm_bus_unlock(dev);
 207         device_unlock(dev);
 208
 209         return rc;
 210 }
 211 static DEVICE_ATTR_RW(namespace);
 212
 213 static ssize_t resource_show(struct device *dev,
 214                 struct device_attribute *attr, char *buf)
 215 {
 216         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 217         ssize_t rc;
 218
 219         device_lock(dev);
 220         if (dev->driver) {
 221                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 222                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 223                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 224                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 225                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 226
 227                 rc = sprintf(buf, "%#llx\n", (unsigned long long) nsio->res.start
 228                                 + start_pad + offset);
 229         } else {
 230                 /* no address to convey if the pfn instance is disabled */
 231                 rc = -ENXIO;
 232         }
 233         device_unlock(dev);
 234
 235         return rc;
 236 }
 237 static DEVICE_ATTR_RO(resource);
 238
 239 static ssize_t size_show(struct device *dev,
 240                 struct device_attribute *attr, char *buf)
 241 {
 242         struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 243         ssize_t rc;
 244
 245         device_lock(dev);
 246         if (dev->driver) {
 247                 struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 248                 u64 offset = __le64_to_cpu(pfn_sb->dataoff);
 249                 struct nd_namespace_common *ndns = nd_pfn->ndns;
 250                 u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 251                 u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 252                 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 253
 254                 rc = sprintf(buf, "%llu\n", (unsigned long long)
 255                                 resource_size(&nsio->res) - start_pad
 256                                 - end_trunc - offset);
 257         } else {
 258                 /* no size to convey if the pfn instance is disabled */
 259                 rc = -ENXIO;
 260         }
 261         device_unlock(dev);
 262
 263         return rc;
 264 }
 265 static DEVICE_ATTR_RO(size);
 266
 267 static ssize_t supported_alignments_show(struct device *dev,
 268                 struct device_attribute *attr, char *buf)
 269 {
 270         return nd_size_select_show(0, nd_pfn_supported_alignments(), buf);
 271 }
 272 static DEVICE_ATTR_RO(supported_alignments);
 273
 274 static struct attribute *nd_pfn_attributes[] = {
 275         &dev_attr_mode.attr,
 276         &dev_attr_namespace.attr,
 277         &dev_attr_uuid.attr,
 278         &dev_attr_align.attr,
 279         &dev_attr_resource.attr,
 280         &dev_attr_size.attr,
 281         &dev_attr_supported_alignments.attr,
 282         NULL,
 283 };
 284
 285 static umode_t pfn_visible(struct kobject *kobj, struct attribute *a, int n)
 286 {
 287         if (a == &dev_attr_resource.attr)
 288                 return 0400;
 289         return a->mode;
 290 }
 291
 292 struct attribute_group nd_pfn_attribute_group = {
 293         .attrs = nd_pfn_attributes,
 294         .is_visible = pfn_visible,
 295 };
 296
 297 static const struct attribute_group *nd_pfn_attribute_groups[] = {
 298         &nd_pfn_attribute_group,
 299         &nd_device_attribute_group,
 300         &nd_numa_attribute_group,
 301         NULL,
 302 };
 303
 304 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 305                 struct nd_namespace_common *ndns)
 306 {
 307         struct device *dev = &nd_pfn->dev;
 308
 309         if (!nd_pfn)
 310                 return NULL;
 311
 312         nd_pfn->mode = PFN_MODE_NONE;
 313         nd_pfn->align = PFN_DEFAULT_ALIGNMENT;
 314         dev = &nd_pfn->dev;
 315         device_initialize(&nd_pfn->dev);
 316         if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
 317                 dev_dbg(&ndns->dev, "%s failed, already claimed by %s\n",
 318                                 __func__, dev_name(ndns->claim));
 319                 put_device(dev);
 320                 return NULL;
 321         }
 322         return dev;
 323 }
 324
 325 static struct nd_pfn *nd_pfn_alloc(struct nd_region *nd_region)
 326 {
 327         struct nd_pfn *nd_pfn;
 328         struct device *dev;
 329
 330         nd_pfn = kzalloc(sizeof(*nd_pfn), GFP_KERNEL);
 331         if (!nd_pfn)
 332                 return NULL;
 333
 334         nd_pfn->id = ida_simple_get(&nd_region->pfn_ida, 0, 0, GFP_KERNEL);
 335         if (nd_pfn->id < 0) {
 336                 kfree(nd_pfn);
 337                 return NULL;
 338         }
 339
 340         dev = &nd_pfn->dev;
 341         dev_set_name(dev, "pfn%d.%d", nd_region->id, nd_pfn->id);
 342         dev->groups = nd_pfn_attribute_groups;
 343         dev->type = &nd_pfn_device_type;
 344         dev->parent = &nd_region->dev;
 345
 346         return nd_pfn;
 347 }
 348
 349 struct device *nd_pfn_create(struct nd_region *nd_region)
 350 {
 351         struct nd_pfn *nd_pfn;
 352         struct device *dev;
 353
 354         if (!is_memory(&nd_region->dev))
 355                 return NULL;
 356
 357         nd_pfn = nd_pfn_alloc(nd_region);
 358         dev = nd_pfn_devinit(nd_pfn, NULL);
 359
 360         __nd_device_register(dev);
 361         return dev;
 362 }
 363
 364 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 365 {
 366         u64 checksum, offset;
 367         enum nd_pfn_mode mode;
 368         struct nd_namespace_io *nsio;
 369         unsigned long align, start_pad;
 370         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 371         struct nd_namespace_common *ndns = nd_pfn->ndns;
 372         const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
 373
 374         if (!pfn_sb || !ndns)
 375                 return -ENODEV;
 376
 377         if (!is_memory(nd_pfn->dev.parent))
 378                 return -ENODEV;
 379
 380         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))
 381                 return -ENXIO;
 382
 383         if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
 384                 return -ENODEV;
 385
 386         checksum = le64_to_cpu(pfn_sb->checksum);
 387         pfn_sb->checksum = 0;
 388         if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
 389                 return -ENODEV;
 390         pfn_sb->checksum = cpu_to_le64(checksum);
 391
 392         if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
 393                 return -ENODEV;
 394
 395         if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
 396                 pfn_sb->start_pad = 0;
 397                 pfn_sb->end_trunc = 0;
 398         }
 399
 400         if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 401                 pfn_sb->align = 0;
 402
 403         switch (le32_to_cpu(pfn_sb->mode)) {
 404         case PFN_MODE_RAM:
 405         case PFN_MODE_PMEM:
 406                 break;
 407         default:
 408                 return -ENXIO;
 409         }
 410
 411         align = le32_to_cpu(pfn_sb->align);
 412         offset = le64_to_cpu(pfn_sb->dataoff);
 413         start_pad = le32_to_cpu(pfn_sb->start_pad);
 414         if (align == 0)
 415                 align = 1UL << ilog2(offset);
 416         mode = le32_to_cpu(pfn_sb->mode);
 417
 418         if (!nd_pfn->uuid) {
 419                 /*
 420                  * When probing a namepace via nd_pfn_probe() the uuid
 421                  * is NULL (see: nd_pfn_devinit()) we init settings from
 422                  * pfn_sb
 423                  */
 424                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 425                 if (!nd_pfn->uuid)
 426                         return -ENOMEM;
 427                 nd_pfn->align = align;
 428                 nd_pfn->mode = mode;
 429         } else {
 430                 /*
 431                  * When probing a pfn / dax instance we validate the
 432                  * live settings against the pfn_sb
 433                  */
 434                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 435                         return -ENODEV;
 436
 437                 /*
 438                  * If the uuid validates, but other settings mismatch
 439                  * return EINVAL because userspace has managed to change
 440                  * the configuration without specifying new
 441                  * identification.
 442                  */
 443                 if (nd_pfn->align != align || nd_pfn->mode != mode) {
 444                         dev_err(&nd_pfn->dev,
 445                                         "init failed, settings mismatch\n");
 446                         dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
 447                                         nd_pfn->align, align, nd_pfn->mode,
 448                                         mode);
 449                         return -EINVAL;
 450                 }
 451         }
 452
 453         if (align > nvdimm_namespace_capacity(ndns)) {
 454                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
 455                                 align, nvdimm_namespace_capacity(ndns));
 456                 return -EINVAL;
 457         }
 458
 459         /*
 460          * These warnings are verbose because they can only trigger in
 461          * the case where the physical address alignment of the
 462          * namespace has changed since the pfn superblock was
 463          * established.
 464          */
 465         nsio = to_nd_namespace_io(&ndns->dev);
 466         if (offset >= resource_size(&nsio->res)) {
 467                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
 468                                 dev_name(&ndns->dev));
 469                 return -EBUSY;
 470         }
 471
 472         if ((align && !IS_ALIGNED(nsio->res.start + offset + start_pad, align))
 473                         || !IS_ALIGNED(offset, PAGE_SIZE)) {
 474                 dev_err(&nd_pfn->dev,
 475                                 "bad offset: %#llx dax disabled align: %#lx\n",
 476                                 offset, align);
 477                 return -ENXIO;
 478         }
 479
 480         return 0;
 481 }
 482 EXPORT_SYMBOL(nd_pfn_validate);
 483
 484 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 485 {
 486         int rc;
 487         struct nd_pfn *nd_pfn;
 488         struct device *pfn_dev;
 489         struct nd_pfn_sb *pfn_sb;
 490         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 491
 492         if (ndns->force_raw)
 493                 return -ENODEV;
 494
 495         switch (ndns->claim_class) {
 496         case NVDIMM_CCLASS_NONE:
 497         case NVDIMM_CCLASS_PFN:
 498                 break;
 499         default:
 500                 return -ENODEV;
 501         }
 502
 503         nvdimm_bus_lock(&ndns->dev);
 504         nd_pfn = nd_pfn_alloc(nd_region);
 505         pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 506         nvdimm_bus_unlock(&ndns->dev);
 507         if (!pfn_dev)
 508                 return -ENOMEM;
 509         pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
 510         nd_pfn = to_nd_pfn(pfn_dev);
 511         nd_pfn->pfn_sb = pfn_sb;
 512         rc = nd_pfn_validate(nd_pfn, PFN_SIG);
 513         dev_dbg(dev, "%s: pfn: %s\n", __func__,
 514                         rc == 0 ? dev_name(pfn_dev) : "<none>");
 515         if (rc < 0) {
 516                 nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 517                 put_device(pfn_dev);
 518         } else
 519                 __nd_device_register(pfn_dev);
 520
 521         return rc;
 522 }
 523 EXPORT_SYMBOL(nd_pfn_probe);
 524
 525 /*
 526  * We hotplug memory at section granularity, pad the reserved area from
 527  * the previous section base to the namespace base address.
 528  */
 529 static unsigned long init_altmap_base(resource_size_t base)
 530 {
 531         unsigned long base_pfn = PHYS_PFN(base);
 532
 533         return PFN_SECTION_ALIGN_DOWN(base_pfn);
 534 }
 535
 536 static unsigned long init_altmap_reserve(resource_size_t base)
 537 {
 538         unsigned long reserve = PHYS_PFN(SZ_8K);
 539         unsigned long base_pfn = PHYS_PFN(base);
 540
 541         reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
 542         return reserve;
 543 }
 544
 545 static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 546                 struct resource *res, struct vmem_altmap *altmap)
 547 {
 548         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 549         u64 offset = le64_to_cpu(pfn_sb->dataoff);
 550         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 551         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 552         struct nd_namespace_common *ndns = nd_pfn->ndns;
 553         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 554         resource_size_t base = nsio->res.start + start_pad;
 555         struct vmem_altmap __altmap = {
 556                 .base_pfn = init_altmap_base(base),
 557                 .reserve = init_altmap_reserve(base),
 558         };
 559
 560         memcpy(res, &nsio->res, sizeof(*res));
 561         res->start += start_pad;
 562         res->end -= end_trunc;
 563
 564         if (nd_pfn->mode == PFN_MODE_RAM) {
 565                 if (offset < SZ_8K)
 566                         return ERR_PTR(-EINVAL);
 567                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 568                 altmap = NULL;
 569         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 570                 nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
 571                                         - offset) / PAGE_SIZE);
 572                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 573                         dev_info(&nd_pfn->dev,
 574                                         "number of pfns truncated from %lld to %ld\n",
 575                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 576                                         nd_pfn->npfns);
 577                 memcpy(altmap, &__altmap, sizeof(*altmap));
 578                 altmap->free = PHYS_PFN(offset - SZ_8K);
 579                 altmap->alloc = 0;
 580         } else
 581                 return ERR_PTR(-ENXIO);
 582
 583         return altmap;
 584 }
 585
 586 static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys)
 587 {
 588         return min_t(u64, PHYS_SECTION_ALIGN_DOWN(phys),
 589                         ALIGN_DOWN(phys, nd_pfn->align));
 590 }
 591
 592 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 593 {
 594         u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 595         struct nd_namespace_common *ndns = nd_pfn->ndns;
 596         u32 start_pad = 0, end_trunc = 0;
 597         resource_size_t start, size;
 598         struct nd_namespace_io *nsio;
 599         struct nd_region *nd_region;
 600         struct nd_pfn_sb *pfn_sb;
 601         unsigned long npfns;
 602         phys_addr_t offset;
 603         const char *sig;
 604         u64 checksum;
 605         int rc;
 606
 607         pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
 608         if (!pfn_sb)
 609                 return -ENOMEM;
 610
 611         nd_pfn->pfn_sb = pfn_sb;
 612         if (is_nd_dax(&nd_pfn->dev))
 613                 sig = DAX_SIG;
 614         else
 615                 sig = PFN_SIG;
 616         rc = nd_pfn_validate(nd_pfn, sig);
 617         if (rc != -ENODEV)
 618                 return rc;
 619
 620         /* no info block, do init */;
 621         nd_region = to_nd_region(nd_pfn->dev.parent);
 622         if (nd_region->ro) {
 623                 dev_info(&nd_pfn->dev,
 624                                 "%s is read-only, unable to init metadata\n",
 625                                 dev_name(&nd_region->dev));
 626                 return -ENXIO;
 627         }
 628
 629         memset(pfn_sb, 0, sizeof(*pfn_sb));
 630
 631         /*
 632          * Check if pmem collides with 'System RAM' when section aligned and
 633          * trim it accordingly
 634          */
 635         nsio = to_nd_namespace_io(&ndns->dev);
 636         start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
 637         size = resource_size(&nsio->res);
 638         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 639                                 IORES_DESC_NONE) == REGION_MIXED) {
 640                 start = nsio->res.start;
 641                 start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
 642         }
 643
 644         start = nsio->res.start;
 645         size = PHYS_SECTION_ALIGN_UP(start + size) - start;
 646         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 647                                 IORES_DESC_NONE) == REGION_MIXED
 648                         || !IS_ALIGNED(start + resource_size(&nsio->res),
 649                                 nd_pfn->align)) {
 650                 size = resource_size(&nsio->res);
 651                 end_trunc = start + size - phys_pmem_align_down(nd_pfn,
 652                                 start + size);
 653         }
 654
 655         if (start_pad + end_trunc)
 656                 dev_info(&nd_pfn->dev, "%s alignment collision, truncate %d bytes\n",
 657                                 dev_name(&ndns->dev), start_pad + end_trunc);
 658
 659         /*
 660          * Note, we use 64 here for the standard size of struct page,
 661          * debugging options may cause it to be larger in which case the
 662          * implementation will limit the pfns advertised through
 663          * ->direct_access() to those that are included in the memmap.
 664          */
 665         start += start_pad;
 666         size = resource_size(&nsio->res);
 667         npfns = PFN_SECTION_ALIGN_UP((size - start_pad - end_trunc - SZ_8K)
 668                         / PAGE_SIZE);
 669         if (nd_pfn->mode == PFN_MODE_PMEM) {
 670                 /*
 671                  * The altmap should be padded out to the block size used
 672                  * when populating the vmemmap. This *should* be equal to
 673                  * PMD_SIZE for most architectures.
 674                  */
 675                 offset = ALIGN(start + SZ_8K + 64 * npfns + dax_label_reserve,
 676                                 max(nd_pfn->align, PMD_SIZE)) - start;
 677         } else if (nd_pfn->mode == PFN_MODE_RAM)
 678                 offset = ALIGN(start + SZ_8K + dax_label_reserve,
 679                                 nd_pfn->align) - start;
 680         else
 681                 return -ENXIO;
 682
 683         if (offset + start_pad + end_trunc >= size) {
 684                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 685                                 dev_name(&ndns->dev));
 686                 return -ENXIO;
 687         }
 688
 689         npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
 690         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 691         pfn_sb->dataoff = cpu_to_le64(offset);
 692         pfn_sb->npfns = cpu_to_le64(npfns);
 693         memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
 694         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 695         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 696         pfn_sb->version_major = cpu_to_le16(1);
 697         pfn_sb->version_minor = cpu_to_le16(2);
 698         pfn_sb->start_pad = cpu_to_le32(start_pad);
 699         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 700         pfn_sb->align = cpu_to_le32(nd_pfn->align);
 701         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 702         pfn_sb->checksum = cpu_to_le64(checksum);
 703
 704         return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0);
 705 }
 706
 707 /*
 708  * Determine the effective resource range and vmem_altmap from an nd_pfn
 709  * instance.
 710  */
 711 struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 712                 struct resource *res, struct vmem_altmap *altmap)
 713 {
 714         int rc;
 715
 716         if (!nd_pfn->uuid || !nd_pfn->ndns)
 717                 return ERR_PTR(-ENODEV);
 718
 719         rc = nd_pfn_init(nd_pfn);
 720         if (rc)
 721                 return ERR_PTR(rc);
 722
 723         /* we need a valid pfn_sb before we can init a vmem_altmap */
 724         return __nvdimm_setup_pfn(nd_pfn, res, altmap);
 725 }
 726 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);