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 struct attribute_group nd_pfn_attribute_group = {
 286         .attrs = nd_pfn_attributes,
 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 = &nd_pfn->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, "%s failed, already claimed by %s\n",
 310                                 __func__, 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 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 357 {
 358         u64 checksum, offset;
 359         unsigned long align;
 360         enum nd_pfn_mode mode;
 361         struct nd_namespace_io *nsio;
 362         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 363         struct nd_namespace_common *ndns = nd_pfn->ndns;
 364         const u8 *parent_uuid = nd_dev_to_uuid(&ndns->dev);
 365
 366         if (!pfn_sb || !ndns)
 367                 return -ENODEV;
 368
 369         if (!is_memory(nd_pfn->dev.parent))
 370                 return -ENODEV;
 371
 372         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))
 373                 return -ENXIO;
 374
 375         if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
 376                 return -ENODEV;
 377
 378         checksum = le64_to_cpu(pfn_sb->checksum);
 379         pfn_sb->checksum = 0;
 380         if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
 381                 return -ENODEV;
 382         pfn_sb->checksum = cpu_to_le64(checksum);
 383
 384         if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
 385                 return -ENODEV;
 386
 387         if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
 388                 pfn_sb->start_pad = 0;
 389                 pfn_sb->end_trunc = 0;
 390         }
 391
 392         if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 393                 pfn_sb->align = 0;
 394
 395         switch (le32_to_cpu(pfn_sb->mode)) {
 396         case PFN_MODE_RAM:
 397         case PFN_MODE_PMEM:
 398                 break;
 399         default:
 400                 return -ENXIO;
 401         }
 402
 403         align = le32_to_cpu(pfn_sb->align);
 404         offset = le64_to_cpu(pfn_sb->dataoff);
 405         if (align == 0)
 406                 align = 1UL << ilog2(offset);
 407         mode = le32_to_cpu(pfn_sb->mode);
 408
 409         if (!nd_pfn->uuid) {
 410                 /*
 411                  * When probing a namepace via nd_pfn_probe() the uuid
 412                  * is NULL (see: nd_pfn_devinit()) we init settings from
 413                  * pfn_sb
 414                  */
 415                 nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 416                 if (!nd_pfn->uuid)
 417                         return -ENOMEM;
 418                 nd_pfn->align = align;
 419                 nd_pfn->mode = mode;
 420         } else {
 421                 /*
 422                  * When probing a pfn / dax instance we validate the
 423                  * live settings against the pfn_sb
 424                  */
 425                 if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 426                         return -ENODEV;
 427
 428                 /*
 429                  * If the uuid validates, but other settings mismatch
 430                  * return EINVAL because userspace has managed to change
 431                  * the configuration without specifying new
 432                  * identification.
 433                  */
 434                 if (nd_pfn->align != align || nd_pfn->mode != mode) {
 435                         dev_err(&nd_pfn->dev,
 436                                         "init failed, settings mismatch\n");
 437                         dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
 438                                         nd_pfn->align, align, nd_pfn->mode,
 439                                         mode);
 440                         return -EINVAL;
 441                 }
 442         }
 443
 444         if (align > nvdimm_namespace_capacity(ndns)) {
 445                 dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
 446                                 align, nvdimm_namespace_capacity(ndns));
 447                 return -EINVAL;
 448         }
 449
 450         /*
 451          * These warnings are verbose because they can only trigger in
 452          * the case where the physical address alignment of the
 453          * namespace has changed since the pfn superblock was
 454          * established.
 455          */
 456         nsio = to_nd_namespace_io(&ndns->dev);
 457         if (offset >= resource_size(&nsio->res)) {
 458                 dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
 459                                 dev_name(&ndns->dev));
 460                 return -EBUSY;
 461         }
 462
 463         if ((align && !IS_ALIGNED(offset, align))
 464                         || !IS_ALIGNED(offset, PAGE_SIZE)) {
 465                 dev_err(&nd_pfn->dev,
 466                                 "bad offset: %#llx dax disabled align: %#lx\n",
 467                                 offset, align);
 468                 return -ENXIO;
 469         }
 470
 471         return 0;
 472 }
 473 EXPORT_SYMBOL(nd_pfn_validate);
 474
 475 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
 476 {
 477         int rc;
 478         struct nd_pfn *nd_pfn;
 479         struct device *pfn_dev;
 480         struct nd_pfn_sb *pfn_sb;
 481         struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
 482
 483         if (ndns->force_raw)
 484                 return -ENODEV;
 485
 486         switch (ndns->claim_class) {
 487         case NVDIMM_CCLASS_NONE:
 488         case NVDIMM_CCLASS_PFN:
 489                 break;
 490         default:
 491                 return -ENODEV;
 492         }
 493
 494         nvdimm_bus_lock(&ndns->dev);
 495         nd_pfn = nd_pfn_alloc(nd_region);
 496         pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
 497         nvdimm_bus_unlock(&ndns->dev);
 498         if (!pfn_dev)
 499                 return -ENOMEM;
 500         pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
 501         nd_pfn = to_nd_pfn(pfn_dev);
 502         nd_pfn->pfn_sb = pfn_sb;
 503         rc = nd_pfn_validate(nd_pfn, PFN_SIG);
 504         dev_dbg(dev, "%s: pfn: %s\n", __func__,
 505                         rc == 0 ? dev_name(pfn_dev) : "<none>");
 506         if (rc < 0) {
 507                 nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 508                 put_device(pfn_dev);
 509         } else
 510                 __nd_device_register(pfn_dev);
 511
 512         return rc;
 513 }
 514 EXPORT_SYMBOL(nd_pfn_probe);
 515
 516 /*
 517  * We hotplug memory at section granularity, pad the reserved area from
 518  * the previous section base to the namespace base address.
 519  */
 520 static unsigned long init_altmap_base(resource_size_t base)
 521 {
 522         unsigned long base_pfn = PHYS_PFN(base);
 523
 524         return PFN_SECTION_ALIGN_DOWN(base_pfn);
 525 }
 526
 527 static unsigned long init_altmap_reserve(resource_size_t base)
 528 {
 529         unsigned long reserve = PHYS_PFN(SZ_8K);
 530         unsigned long base_pfn = PHYS_PFN(base);
 531
 532         reserve += base_pfn - PFN_SECTION_ALIGN_DOWN(base_pfn);
 533         return reserve;
 534 }
 535
 536 static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 537                 struct resource *res, struct vmem_altmap *altmap)
 538 {
 539         struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 540         u64 offset = le64_to_cpu(pfn_sb->dataoff);
 541         u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
 542         u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
 543         struct nd_namespace_common *ndns = nd_pfn->ndns;
 544         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 545         resource_size_t base = nsio->res.start + start_pad;
 546         struct vmem_altmap __altmap = {
 547                 .base_pfn = init_altmap_base(base),
 548                 .reserve = init_altmap_reserve(base),
 549         };
 550
 551         memcpy(res, &nsio->res, sizeof(*res));
 552         res->start += start_pad;
 553         res->end -= end_trunc;
 554
 555         if (nd_pfn->mode == PFN_MODE_RAM) {
 556                 if (offset < SZ_8K)
 557                         return ERR_PTR(-EINVAL);
 558                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 559                 altmap = NULL;
 560         } else if (nd_pfn->mode == PFN_MODE_PMEM) {
 561                 nd_pfn->npfns = PFN_SECTION_ALIGN_UP((resource_size(res)
 562                                         - offset) / PAGE_SIZE);
 563                 if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
 564                         dev_info(&nd_pfn->dev,
 565                                         "number of pfns truncated from %lld to %ld\n",
 566                                         le64_to_cpu(nd_pfn->pfn_sb->npfns),
 567                                         nd_pfn->npfns);
 568                 memcpy(altmap, &__altmap, sizeof(*altmap));
 569                 altmap->free = PHYS_PFN(offset - SZ_8K);
 570                 altmap->alloc = 0;
 571         } else
 572                 return ERR_PTR(-ENXIO);
 573
 574         return altmap;
 575 }
 576
 577 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 578 {
 579         u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 580         struct nd_namespace_common *ndns = nd_pfn->ndns;
 581         u32 start_pad = 0, end_trunc = 0;
 582         resource_size_t start, size;
 583         struct nd_namespace_io *nsio;
 584         struct nd_region *nd_region;
 585         struct nd_pfn_sb *pfn_sb;
 586         unsigned long npfns;
 587         phys_addr_t offset;
 588         const char *sig;
 589         u64 checksum;
 590         int rc;
 591
 592         pfn_sb = devm_kzalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
 593         if (!pfn_sb)
 594                 return -ENOMEM;
 595
 596         nd_pfn->pfn_sb = pfn_sb;
 597         if (is_nd_dax(&nd_pfn->dev))
 598                 sig = DAX_SIG;
 599         else
 600                 sig = PFN_SIG;
 601         rc = nd_pfn_validate(nd_pfn, sig);
 602         if (rc != -ENODEV)
 603                 return rc;
 604
 605         /* no info block, do init */;
 606         nd_region = to_nd_region(nd_pfn->dev.parent);
 607         if (nd_region->ro) {
 608                 dev_info(&nd_pfn->dev,
 609                                 "%s is read-only, unable to init metadata\n",
 610                                 dev_name(&nd_region->dev));
 611                 return -ENXIO;
 612         }
 613
 614         memset(pfn_sb, 0, sizeof(*pfn_sb));
 615
 616         /*
 617          * Check if pmem collides with 'System RAM' when section aligned and
 618          * trim it accordingly
 619          */
 620         nsio = to_nd_namespace_io(&ndns->dev);
 621         start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
 622         size = resource_size(&nsio->res);
 623         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 624                                 IORES_DESC_NONE) == REGION_MIXED) {
 625                 start = nsio->res.start;
 626                 start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
 627         }
 628
 629         start = nsio->res.start;
 630         size = PHYS_SECTION_ALIGN_UP(start + size) - start;
 631         if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
 632                                 IORES_DESC_NONE) == REGION_MIXED) {
 633                 size = resource_size(&nsio->res);
 634                 end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size);
 635         }
 636
 637         if (start_pad + end_trunc)
 638                 dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n",
 639                                 dev_name(&ndns->dev), start_pad + end_trunc);
 640
 641         /*
 642          * Note, we use 64 here for the standard size of struct page,
 643          * debugging options may cause it to be larger in which case the
 644          * implementation will limit the pfns advertised through
 645          * ->direct_access() to those that are included in the memmap.
 646          */
 647         start += start_pad;
 648         size = resource_size(&nsio->res);
 649         npfns = PFN_SECTION_ALIGN_UP((size - start_pad - end_trunc - SZ_8K)
 650                         / PAGE_SIZE);
 651         if (nd_pfn->mode == PFN_MODE_PMEM) {
 652                 /*
 653                  * The altmap should be padded out to the block size used
 654                  * when populating the vmemmap. This *should* be equal to
 655                  * PMD_SIZE for most architectures.
 656                  */
 657                 offset = ALIGN(start + SZ_8K + 64 * npfns + dax_label_reserve,
 658                                 max(nd_pfn->align, PMD_SIZE)) - start;
 659         } else if (nd_pfn->mode == PFN_MODE_RAM)
 660                 offset = ALIGN(start + SZ_8K + dax_label_reserve,
 661                                 nd_pfn->align) - start;
 662         else
 663                 return -ENXIO;
 664
 665         if (offset + start_pad + end_trunc >= size) {
 666                 dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
 667                                 dev_name(&ndns->dev));
 668                 return -ENXIO;
 669         }
 670
 671         npfns = (size - offset - start_pad - end_trunc) / SZ_4K;
 672         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 673         pfn_sb->dataoff = cpu_to_le64(offset);
 674         pfn_sb->npfns = cpu_to_le64(npfns);
 675         memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
 676         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 677         memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 678         pfn_sb->version_major = cpu_to_le16(1);
 679         pfn_sb->version_minor = cpu_to_le16(2);
 680         pfn_sb->start_pad = cpu_to_le32(start_pad);
 681         pfn_sb->end_trunc = cpu_to_le32(end_trunc);
 682         pfn_sb->align = cpu_to_le32(nd_pfn->align);
 683         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 684         pfn_sb->checksum = cpu_to_le64(checksum);
 685
 686         return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0);
 687 }
 688
 689 /*
 690  * Determine the effective resource range and vmem_altmap from an nd_pfn
 691  * instance.
 692  */
 693 struct vmem_altmap *nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 694                 struct resource *res, struct vmem_altmap *altmap)
 695 {
 696         int rc;
 697
 698         if (!nd_pfn->uuid || !nd_pfn->ndns)
 699                 return ERR_PTR(-ENODEV);
 700
 701         rc = nd_pfn_init(nd_pfn);
 702         if (rc)
 703                 return ERR_PTR(rc);
 704
 705         /* we need a valid pfn_sb before we can init a vmem_altmap */
 706         return __nvdimm_setup_pfn(nd_pfn, res, altmap);
 707 }
 708 EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);