kernel/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
 109         *kaddr = pmem->virt_addr + offset;
 110         *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
 111
 112         return pmem->size - offset;
 113 }
 114
 115 static const struct block_device_operations pmem_fops = {
 116         .owner =                THIS_MODULE,
 117         .rw_page =              pmem_rw_page,
 118         .direct_access =        pmem_direct_access,
 119         .revalidate_disk =      nvdimm_revalidate_disk,
 120 };
 121
 122 static struct pmem_device *pmem_alloc(struct device *dev,
 123                 struct resource *res, int id)
 124 {
 125         struct pmem_device *pmem;
 126
 127         pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
 128         if (!pmem)
 129                 return ERR_PTR(-ENOMEM);
 130
 131         pmem->phys_addr = res->start;
 132         pmem->size = resource_size(res);
 133         if (!arch_has_wmb_pmem())
 134                 dev_warn(dev, "unable to guarantee persistence of writes\n");
 135
 136         if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
 137                         dev_name(dev))) {
 138                 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
 139                                 &pmem->phys_addr, pmem->size);
 140                 return ERR_PTR(-EBUSY);
 141         }
 142
 143         if (pmem_should_map_pages(dev))
 144                 pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res);
 145         else
 146                 pmem->virt_addr = (void __pmem *) devm_memremap(dev,
 147                                 pmem->phys_addr, pmem->size,
 148                                 ARCH_MEMREMAP_PMEM);
 149
 150         if (IS_ERR(pmem->virt_addr))
 151                 return (void __force *) pmem->virt_addr;
 152
 153         return pmem;
 154 }
 155
 156 static void pmem_detach_disk(struct pmem_device *pmem)
 157 {
 158         if (!pmem->pmem_disk)
 159                 return;
 160
 161         del_gendisk(pmem->pmem_disk);
 162         put_disk(pmem->pmem_disk);
 163         blk_cleanup_queue(pmem->pmem_queue);
 164 }
 165
 166 static int pmem_attach_disk(struct device *dev,
 167                 struct nd_namespace_common *ndns, struct pmem_device *pmem)
 168 {
 169         int nid = dev_to_node(dev);
 170         struct gendisk *disk;
 171
 172         pmem->pmem_queue = blk_alloc_queue_node(GFP_KERNEL, nid);
 173         if (!pmem->pmem_queue)
 174                 return -ENOMEM;
 175
 176         blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
 177         blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
 178         blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
 179         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 180         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
 181
 182         disk = alloc_disk_node(0, nid);
 183         if (!disk) {
 184                 blk_cleanup_queue(pmem->pmem_queue);
 185                 return -ENOMEM;
 186         }
 187
 188         disk->major             = pmem_major;
 189         disk->first_minor       = 0;
 190         disk->fops              = &pmem_fops;
 191         disk->private_data      = pmem;
 192         disk->queue             = pmem->pmem_queue;
 193         disk->flags             = GENHD_FL_EXT_DEVT;
 194         nvdimm_namespace_disk_name(ndns, disk->disk_name);
 195         disk->driverfs_dev = dev;
 196         set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
 197         pmem->pmem_disk = disk;
 198
 199         add_disk(disk);
 200         revalidate_disk(disk);
 201
 202         return 0;
 203 }
 204
 205 static int pmem_rw_bytes(struct nd_namespace_common *ndns,
 206                 resource_size_t offset, void *buf, size_t size, int rw)
 207 {
 208         struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
 209
 210         if (unlikely(offset + size > pmem->size)) {
 211                 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
 212                 return -EFAULT;
 213         }
 214
 215         if (rw == READ)
 216                 memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
 217         else {
 218                 memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
 219                 wmb_pmem();
 220         }
 221
 222         return 0;
 223 }
 224
 225 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 226 {
 227         struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
 228         struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
 229         struct nd_namespace_common *ndns = nd_pfn->ndns;
 230         struct nd_region *nd_region;
 231         unsigned long npfns;
 232         phys_addr_t offset;
 233         u64 checksum;
 234         int rc;
 235
 236         if (!pfn_sb)
 237                 return -ENOMEM;
 238
 239         nd_pfn->pfn_sb = pfn_sb;
 240         rc = nd_pfn_validate(nd_pfn);
 241         if (rc == 0 || rc == -EBUSY)
 242                 return rc;
 243
 244         /* section alignment for simple hotplug */
 245         if (nvdimm_namespace_capacity(ndns) < ND_PFN_ALIGN
 246                         || pmem->phys_addr & ND_PFN_MASK)
 247                 return -ENODEV;
 248
 249         nd_region = to_nd_region(nd_pfn->dev.parent);
 250         if (nd_region->ro) {
 251                 dev_info(&nd_pfn->dev,
 252                                 "%s is read-only, unable to init metadata\n",
 253                                 dev_name(&nd_region->dev));
 254                 goto err;
 255         }
 256
 257         memset(pfn_sb, 0, sizeof(*pfn_sb));
 258         npfns = (pmem->size - SZ_8K) / SZ_4K;
 259         /*
 260          * Note, we use 64 here for the standard size of struct page,
 261          * debugging options may cause it to be larger in which case the
 262          * implementation will limit the pfns advertised through
 263          * ->direct_access() to those that are included in the memmap.
 264          */
 265         if (nd_pfn->mode == PFN_MODE_PMEM)
 266                 offset = ALIGN(SZ_8K + 64 * npfns, PMD_SIZE);
 267         else if (nd_pfn->mode == PFN_MODE_RAM)
 268                 offset = SZ_8K;
 269         else
 270                 goto err;
 271
 272         npfns = (pmem->size - offset) / SZ_4K;
 273         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
 274         pfn_sb->dataoff = cpu_to_le64(offset);
 275         pfn_sb->npfns = cpu_to_le64(npfns);
 276         memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
 277         memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 278         pfn_sb->version_major = cpu_to_le16(1);
 279         checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 280         pfn_sb->checksum = cpu_to_le64(checksum);
 281
 282         rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
 283         if (rc)
 284                 goto err;
 285
 286         return 0;
 287  err:
 288         nd_pfn->pfn_sb = NULL;
 289         kfree(pfn_sb);
 290         return -ENXIO;
 291 }
 292
 293 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
 294 {
 295         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 296         struct pmem_device *pmem;
 297
 298         /* free pmem disk */
 299         pmem = dev_get_drvdata(&nd_pfn->dev);
 300         pmem_detach_disk(pmem);
 301
 302         /* release nd_pfn resources */
 303         kfree(nd_pfn->pfn_sb);
 304         nd_pfn->pfn_sb = NULL;
 305
 306         return 0;
 307 }
 308
 309 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
 310 {
 311         struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 312         struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
 313         struct device *dev = &nd_pfn->dev;
 314         struct vmem_altmap *altmap;
 315         struct nd_region *nd_region;
 316         struct nd_pfn_sb *pfn_sb;
 317         struct pmem_device *pmem;
 318         phys_addr_t offset;
 319         int rc;
 320
 321         if (!nd_pfn->uuid || !nd_pfn->ndns)
 322                 return -ENODEV;
 323
 324         nd_region = to_nd_region(dev->parent);
 325         rc = nd_pfn_init(nd_pfn);
 326         if (rc)
 327                 return rc;
 328
 329         if (PAGE_SIZE != SZ_4K) {
 330                 dev_err(dev, "only supported on systems with 4K PAGE_SIZE\n");
 331                 return -ENXIO;
 332         }
 333         if (nsio->res.start & ND_PFN_MASK) {
 334                 dev_err(dev, "%s not memory hotplug section aligned\n",
 335                                 dev_name(&ndns->dev));
 336                 return -ENXIO;
 337         }
 338
 339         pfn_sb = nd_pfn->pfn_sb;
 340         offset = le64_to_cpu(pfn_sb->dataoff);
 341         nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 342         if (nd_pfn->mode == PFN_MODE_RAM) {
 343                 if (offset != SZ_8K)
 344                         return -EINVAL;
 345                 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
 346                 altmap = NULL;
 347         } else {
 348                 rc = -ENXIO;
 349                 goto err;
 350         }
 351
 352         /* establish pfn range for lookup, and switch to direct map */
 353         pmem = dev_get_drvdata(dev);
 354         devm_memunmap(dev, (void __force *) pmem->virt_addr);
 355         pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res);
 356         if (IS_ERR(pmem->virt_addr)) {
 357                 rc = PTR_ERR(pmem->virt_addr);
 358                 goto err;
 359         }
 360
 361         /* attach pmem disk in "pfn-mode" */
 362         pmem->data_offset = offset;
 363         rc = pmem_attach_disk(dev, ndns, pmem);
 364         if (rc)
 365                 goto err;
 366
 367         return rc;
 368  err:
 369         nvdimm_namespace_detach_pfn(ndns);
 370         return rc;
 371 }
 372
 373 static int nd_pmem_probe(struct device *dev)
 374 {
 375         struct nd_region *nd_region = to_nd_region(dev->parent);
 376         struct nd_namespace_common *ndns;
 377         struct nd_namespace_io *nsio;
 378         struct pmem_device *pmem;
 379
 380         ndns = nvdimm_namespace_common_probe(dev);
 381         if (IS_ERR(ndns))
 382                 return PTR_ERR(ndns);
 383
 384         nsio = to_nd_namespace_io(&ndns->dev);
 385         pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
 386         if (IS_ERR(pmem))
 387                 return PTR_ERR(pmem);
 388
 389         pmem->ndns = ndns;
 390         dev_set_drvdata(dev, pmem);
 391         ndns->rw_bytes = pmem_rw_bytes;
 392
 393         if (is_nd_btt(dev))
 394                 return nvdimm_namespace_attach_btt(ndns);
 395
 396         if (is_nd_pfn(dev))
 397                 return nvdimm_namespace_attach_pfn(ndns);
 398
 399         if (nd_btt_probe(ndns, pmem) == 0) {
 400                 /* we'll come back as btt-pmem */
 401                 return -ENXIO;
 402         }
 403
 404         if (nd_pfn_probe(ndns, pmem) == 0) {
 405                 /* we'll come back as pfn-pmem */
 406                 return -ENXIO;
 407         }
 408
 409         return pmem_attach_disk(dev, ndns, pmem);
 410 }
 411
 412 static int nd_pmem_remove(struct device *dev)
 413 {
 414         struct pmem_device *pmem = dev_get_drvdata(dev);
 415
 416         if (is_nd_btt(dev))
 417                 nvdimm_namespace_detach_btt(pmem->ndns);
 418         else if (is_nd_pfn(dev))
 419                 nvdimm_namespace_detach_pfn(pmem->ndns);
 420         else
 421                 pmem_detach_disk(pmem);
 422
 423         return 0;
 424 }
 425
 426 MODULE_ALIAS("pmem");
 427 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
 428 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
 429 static struct nd_device_driver nd_pmem_driver = {
 430         .probe = nd_pmem_probe,
 431         .remove = nd_pmem_remove,
 432         .drv = {
 433                 .name = "nd_pmem",
 434         },
 435         .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
 436 };
 437
 438 static int __init pmem_init(void)
 439 {
 440         int error;
 441
 442         pmem_major = register_blkdev(0, "pmem");
 443         if (pmem_major < 0)
 444                 return pmem_major;
 445
 446         error = nd_driver_register(&nd_pmem_driver);
 447         if (error) {
 448                 unregister_blkdev(pmem_major, "pmem");
 449                 return error;
 450         }
 451
 452         return 0;
 453 }
 454 module_init(pmem_init);
 455
 456 static void pmem_exit(void)
 457 {
 458         driver_unregister(&nd_pmem_driver.drv);
 459         unregister_blkdev(pmem_major, "pmem");
 460 }
 461 module_exit(pmem_exit);
 462
 463 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
 464 MODULE_LICENSE("GPL v2");