drivers/nvdimm/pmem.c

   1 /*
   2  * Persistent Memory Driver
   3  *
   4  * Copyright (c) 2014-2015, Intel Corporation.
   5  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
   6  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  */
  17
  18 #include <asm/cacheflush.h>
  19 #include <linux/blkdev.h>
  20 #include <linux/hdreg.h>
  21 #include <linux/init.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/module.h>
  24 #include <linux/memory_hotplug.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/slab.h>
  28 #include <linux/pmem.h>
  29 #include <linux/nd.h>
  30 #include "pfn.h"
  31 #include "nd.h"
  32
  33 struct pmem_device {
  34         struct request_queue    *pmem_queue;
  35         struct gendisk          *pmem_disk;
  36         struct nd_namespace_common *ndns;
  37
  38         /* One contiguous memory region per device */
  39         phys_addr_t             phys_addr;
  40         /* when non-zero this device is hosting a 'pfn' instance */
  41         phys_addr_t             data_offset;
  42         void __pmem             *virt_addr;
  43         size_t                  size;
  44 };
  45
  46 static int pmem_major;
  47
  48 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
  49                         unsigned int len, unsigned int off, int rw,
  50                         sector_t sector)
  51 {
  52         void *mem = kmap_atomic(page);
  53         phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
  54         void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
  55
  56         if (rw == READ) {
  57                 memcpy_from_pmem(mem + off, pmem_addr, len);
  58                 flush_dcache_page(page);
  59         } else {
  60                 flush_dcache_page(page);
  61                 memcpy_to_pmem(pmem_addr, mem + off, len);
  62         }
  63
  64         kunmap_atomic(mem);
  65 }
  66
  67 static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
  68 {
  69         bool do_acct;
  70         unsigned long start;
  71         struct bio_vec bvec;
  72         struct bvec_iter iter;
  73         struct block_device *bdev = bio->bi_bdev;
  74         struct pmem_device *pmem = bdev->bd_disk->private_data;
  75
  76         do_acct = nd_iostat_start(bio, &start);
  77         bio_for_each_segment(bvec, bio, iter)
  78                 pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
  79                                 bio_data_dir(bio), iter.bi_sector);
  80         if (do_acct)
  81                 nd_iostat_end(bio, start);
  82
  83         if (bio_data_dir(bio))
  84                 wmb_pmem();
  85
  86         bio_endio(bio);
  87         return BLK_QC_T_NONE;
  88 }
  89
  90 static int pmem_rw_page(struct block_device *bdev, sector_t sector,
  91                        struct page *page, int rw)
  92 {
  93         struct pmem_device *pmem = bdev->bd_disk->private_data;
  94
  95         pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
  96         if (rw & WRITE)
  97                 wmb_pmem();
  98         page_endio(page, rw & WRITE, 0);
  99
 100         return 0;
 101 }
 102
 103 static long pmem_direct_access(struct block_device *bdev, sector_t sector,
 104                       void __pmem **kaddr, unsigned long *pfn)
 105 {
 106         struct pmem_device *pmem = bdev->bd_disk->private_data;
 107         resource_size_t offset = sector * 512 + pmem->data_offset;
 108         resource_size_t size;
 109
 110         if (pmem->data_offset) {
 111                 /*
 112                  * Limit the direct_access() size to what is covered by
 113                  * the memmap
 114                  */
 115                 size = (pmem->size - offset) & ~ND_PFN_MASK;
 116         } else
 117                 size = pmem->size - offset;
 118
 119         /* FIXME convert DAX to comprehend that this mapping has a lifetime */
 120         *kaddr = pmem->virt_addr + offset;
 121         *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
 122
 123         return size;
 124 }
 125
 126 static const struct block_device_operations pmem_fops = {
 127         .owner =                THIS_MODULE,
 128         .rw_page =              pmem_rw_page,
 129         .direct_access =        pmem_direct_access,
 130         .revalidate_disk =      nvdimm_revalidate_disk,
 131 };
 132
 133 static struct pmem_device *pmem_alloc(struct device *dev,
 134                 struct resource *res, int id)
 135 {
 136         struct pmem_device *pmem;
 137
 138         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 139         if (!pmem)
 140                 return ERR_PTR(-ENOMEM);
 141
 142         pmem->phys_addr = res->start;
 143         pmem->size = resource_size(res);
 144         if (!arch_has_wmb_pmem())
 145                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 146
 147         if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
 148                         dev_name(dev))) {
 149                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
 150                                 &pmem->phys_addr, pmem->size);
 151                 return ERR_PTR(-EBUSY);
 152         }
 153
 154         if (pmem_should_map_pages(dev)) {
 155                 void *addr = devm_memremap_pages(dev, res);
 156
 157                 if (IS_ERR(addr))
 158                         return addr;
 159                 pmem->virt_addr = (void __pmem *) addr;
 160         } else {
 161                 pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr,
 162                                 pmem->size);
 163                 if (!pmem->virt_addr)
 164                         return ERR_PTR(-ENXIO);
 165         }
 166
 167         return pmem;
 168 }
 169
 170 static void pmem_detach_disk(struct pmem_device *pmem)
 171 {
 172         if (!pmem->pmem_disk)
 173                 return;
 174
 175         del_gendisk(pmem->pmem_disk);
 176         put_disk(pmem->pmem_disk);
 177         blk_cleanup_queue(pmem->pmem_queue);
 178 }
 179
 180 static int pmem_attach_disk(struct device *dev,
 181                 struct nd_namespace_common *ndns, struct pmem_device *pmem)
 182 {
 183         struct gendisk *disk;
 184
 185         pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
 186         if (!pmem->pmem_queue)
 187                 return -ENOMEM;
 188
 189         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
 190         blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
 191         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
 192         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 193         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
 194
 195         disk = alloc_disk(0);
 196         if (!disk) {
 197                 blk_cleanup_queue(pmem->pmem_queue);
 198                 return -ENOMEM;
 199         }
 200
 201         disk->major             = pmem_major;
 202         disk->first_minor       = 0;
 203         disk->fops              = &pmem_fops;
 204         disk->private_data      = pmem;
 205         disk->queue             = pmem->pmem_queue;
 206         disk->flags             = GENHD_FL_EXT_DEVT;
 207         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 208         disk->driverfs_dev = dev;
 209         set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
 210         pmem->pmem_disk = disk;
 211
 212         add_disk(disk);
 213         revalidate_disk(disk);
 214
 215         return 0;
 216 }
 217
 218 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
 219                 resource_size_t offset, void *buf, size_t size, int rw)
 220 {
 221         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
 222
 223         if (unlikely(offset + size > pmem->size)) {
 224                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 225                 return -EFAULT;
 226         }
 227
 228         if (rw == READ)
 229                 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
 230         else {
 231                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
 232                 wmb_pmem();
 233         }
 234
 235         return 0;
 236 }
 237
 238 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 239 {
 240         struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
 241         struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
 242         struct nd_namespace_common *ndns = nd_pfn->ndns;
 243         struct nd_region *nd_region;
 244         unsigned long npfns;
 245         phys_addr_t offset;
 246         u64 checksum;
 247         int rc;
 248
 249         if (!pfn_sb)
 250                 return -ENOMEM;
 251
 252         nd_pfn->pfn_sb = pfn_sb;
 253         rc = nd_pfn_validate(nd_pfn);
 254         if (rc == 0 || rc == -EBUSY)
 255                 return rc;
 256
 257         /* section alignment for simple hotplug */
 258         if (nvdimm_namespace_capacity(ndns) < ND_PFN_ALIGN
 259                         || pmem->phys_addr & ND_PFN_MASK)
 260                 return -ENODEV;
 261
 262         nd_region = to_nd_region(nd_pfn->dev.parent);
 263         if (nd_region->ro) {
 264                 dev_info(&nd_pfn->dev,
 265                                 "%s is read-only, unable to init metadata\n",
 266                                 dev_name(&nd_region->dev));
 267                 goto err;
 268         }
 269
 270         memset(pfn_sb, 0, sizeof(*pfn_sb));
 271         npfns = (pmem->size - SZ_8K) / SZ_4K;
 272         /*
 273          * Note, we use 64 here for the standard size of struct page,
 274          * debugging options may cause it to be larger in which case the
 275          * implementation will limit the pfns advertised through
 276          * ->direct_access() to those that are included in the memmap.
 277          */
 278         if (nd_pfn->mode == PFN_MODE_PMEM)
 279                 offset = ALIGN(SZ_8K + 64 * npfns, PMD_SIZE);
 280         else if (nd_pfn->mode == PFN_MODE_RAM)
 281                 offset = SZ_8K;
 282         else
 283                 goto err;
 284
 285         npfns = (pmem->size - offset) / SZ_4K;
 286         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 287         pfn_sb->dataoff = cpu_to_le64(offset);
 288         pfn_sb->npfns = cpu_to_le64(npfns);
 289         memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
 290         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 291         pfn_sb->version_major = cpu_to_le16(1);
 292         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 293         pfn_sb->checksum = cpu_to_le64(checksum);
 294
 295         rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
 296         if (rc)
 297                 goto err;
 298
 299         return 0;
 300  err:
 301         nd_pfn->pfn_sb = NULL;
 302         kfree(pfn_sb);
 303         return -ENXIO;
 304 }
 305
 306 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
 307 {
 308         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 309         struct pmem_device *pmem;
 310
 311         /* free pmem disk */
 312         pmem = dev_get_drvdata(&nd_pfn->dev);
 313         pmem_detach_disk(pmem);
 314
 315         /* release nd_pfn resources */
 316         kfree(nd_pfn->pfn_sb);
 317         nd_pfn->pfn_sb = NULL;
 318
 319         return 0;
 320 }
 321
 322 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 323 {
 324         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 325         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 326         struct device *dev = &nd_pfn->dev;
 327         struct vmem_altmap *altmap;
 328         struct nd_region *nd_region;
 329         struct nd_pfn_sb *pfn_sb;
 330         struct pmem_device *pmem;
 331         phys_addr_t offset;
 332         int rc;
 333
 334         if (!nd_pfn->uuid || !nd_pfn->ndns)
 335                 return -ENODEV;
 336
 337         nd_region = to_nd_region(dev->parent);
 338         rc = nd_pfn_init(nd_pfn);
 339         if (rc)
 340                 return rc;
 341
 342         if (PAGE_SIZE != SZ_4K) {
 343                 dev_err(dev, "only supported on systems with 4K PAGE_SIZE\n");
 344                 return -ENXIO;
 345         }
 346         if (nsio->res.start & ND_PFN_MASK) {
 347                 dev_err(dev, "%s not memory hotplug section aligned\n",
 348                                 dev_name(&ndns->dev));
 349                 return -ENXIO;
 350         }
 351
 352         pfn_sb = nd_pfn->pfn_sb;
 353         offset = le64_to_cpu(pfn_sb->dataoff);
 354         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 355         if (nd_pfn->mode == PFN_MODE_RAM) {
 356                 if (offset != SZ_8K)
 357                         return -EINVAL;
 358                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 359                 altmap = NULL;
 360         } else {
 361                 rc = -ENXIO;
 362                 goto err;
 363         }
 364
 365         /* establish pfn range for lookup, and switch to direct map */
 366         pmem = dev_get_drvdata(dev);
 367         memunmap_pmem(dev, pmem->virt_addr);
 368         pmem->virt_addr = (void __pmem *)devm_memremap_pages(dev, &nsio->res);
 369         if (IS_ERR(pmem->virt_addr)) {
 370                 rc = PTR_ERR(pmem->virt_addr);
 371                 goto err;
 372         }
 373
 374         /* attach pmem disk in "pfn-mode" */
 375         pmem->data_offset = offset;
 376         rc = pmem_attach_disk(dev, ndns, pmem);
 377         if (rc)
 378                 goto err;
 379
 380         return rc;
 381  err:
 382         nvdimm_namespace_detach_pfn(ndns);
 383         return rc;
 384 }
 385
 386 static int nd_pmem_probe(struct device *dev)
 387 {
 388         struct nd_region *nd_region = to_nd_region(dev->parent);
 389         struct nd_namespace_common *ndns;
 390         struct nd_namespace_io *nsio;
 391         struct pmem_device *pmem;
 392
 393         ndns = nvdimm_namespace_common_probe(dev);
 394         if (IS_ERR(ndns))
 395                 return PTR_ERR(ndns);
 396
 397         nsio = to_nd_namespace_io(&ndns->dev);
 398         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
 399         if (IS_ERR(pmem))
 400                 return PTR_ERR(pmem);
 401
 402         pmem->ndns = ndns;
 403         dev_set_drvdata(dev, pmem);
 404         ndns->rw_bytes = pmem_rw_bytes;
 405
 406         if (is_nd_btt(dev))
 407                 return nvdimm_namespace_attach_btt(ndns);
 408
 409         if (is_nd_pfn(dev))
 410                 return nvdimm_namespace_attach_pfn(ndns);
 411
 412         if (nd_btt_probe(ndns, pmem) == 0) {
 413                 /* we'll come back as btt-pmem */
 414                 return -ENXIO;
 415         }
 416
 417         if (nd_pfn_probe(ndns, pmem) == 0) {
 418                 /* we'll come back as pfn-pmem */
 419                 return -ENXIO;
 420         }
 421
 422         return pmem_attach_disk(dev, ndns, pmem);
 423 }
 424
 425 static int nd_pmem_remove(struct device *dev)
 426 {
 427         struct pmem_device *pmem = dev_get_drvdata(dev);
 428
 429         if (is_nd_btt(dev))
 430                 nvdimm_namespace_detach_btt(pmem->ndns);
 431         else if (is_nd_pfn(dev))
 432                 nvdimm_namespace_detach_pfn(pmem->ndns);
 433         else
 434                 pmem_detach_disk(pmem);
 435
 436         return 0;
 437 }
 438
 439 MODULE_ALIAS("pmem");
 440 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 441 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 442 static struct nd_device_driver nd_pmem_driver = {
 443         .probe = nd_pmem_probe,
 444         .remove = nd_pmem_remove,
 445         .drv = {
 446                 .name = "nd_pmem",
 447         },
 448         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 449 };
 450
 451 static int __init pmem_init(void)
 452 {
 453         int error;
 454
 455         pmem_major = register_blkdev(0, "pmem");
 456         if (pmem_major < 0)
 457                 return pmem_major;
 458
 459         error = nd_driver_register(&nd_pmem_driver);
 460         if (error) {
 461                 unregister_blkdev(pmem_major, "pmem");
 462                 return error;
 463         }
 464
 465         return 0;
 466 }
 467 module_init(pmem_init);
 468
 469 static void pmem_exit(void)
 470 {
 471         driver_unregister(&nd_pmem_driver.drv);
 472         unregister_blkdev(pmem_major, "pmem");
 473 }
 474 module_exit(pmem_exit);
 475
 476 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 477 MODULE_LICENSE("GPL v2");