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 void 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 } 88 89 static int pmem_rw_page(struct block_device *bdev, sector_t sector, 90 struct page *page, int rw) 91 { 92 struct pmem_device *pmem = bdev->bd_disk->private_data; 93 94 pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector); 95 if (rw & WRITE) 96 wmb_pmem(); 97 page_endio(page, rw & WRITE, 0); 98 99 return 0; 100 } 101 102 static long pmem_direct_access(struct block_device *bdev, sector_t sector, 103 void __pmem **kaddr, unsigned long *pfn) 104 { 105 struct pmem_device *pmem = bdev->bd_disk->private_data; 106 resource_size_t offset = sector * 512 + pmem->data_offset; 107 resource_size_t size; 108 109 if (pmem->data_offset) { 110 /* 111 * Limit the direct_access() size to what is covered by 112 * the memmap 113 */ 114 size = (pmem->size - offset) & ~ND_PFN_MASK; 115 } else 116 size = pmem->size - offset; 117 118 /* FIXME convert DAX to comprehend that this mapping has a lifetime */ 119 *kaddr = pmem->virt_addr + offset; 120 *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT; 121 122 return size; 123 } 124 125 static const struct block_device_operations pmem_fops = { 126 .owner = THIS_MODULE, 127 .rw_page = pmem_rw_page, 128 .direct_access = pmem_direct_access, 129 .revalidate_disk = nvdimm_revalidate_disk, 130 }; 131 132 static struct pmem_device *pmem_alloc(struct device *dev, 133 struct resource *res, int id) 134 { 135 struct pmem_device *pmem; 136 137 pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL); 138 if (!pmem) 139 return ERR_PTR(-ENOMEM); 140 141 pmem->phys_addr = res->start; 142 pmem->size = resource_size(res); 143 if (!arch_has_wmb_pmem()) 144 dev_warn(dev, "unable to guarantee persistence of writes\n"); 145 146 if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size, 147 dev_name(dev))) { 148 dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n", 149 &pmem->phys_addr, pmem->size); 150 return ERR_PTR(-EBUSY); 151 } 152 153 if (pmem_should_map_pages(dev)) { 154 void *addr = devm_memremap_pages(dev, res); 155 156 if (IS_ERR(addr)) 157 return addr; 158 pmem->virt_addr = (void __pmem *) addr; 159 } else { 160 pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr, 161 pmem->size); 162 if (!pmem->virt_addr) 163 return ERR_PTR(-ENXIO); 164 } 165 166 return pmem; 167 } 168 169 static void pmem_detach_disk(struct pmem_device *pmem) 170 { 171 if (!pmem->pmem_disk) 172 return; 173 174 del_gendisk(pmem->pmem_disk); 175 put_disk(pmem->pmem_disk); 176 blk_cleanup_queue(pmem->pmem_queue); 177 } 178 179 static int pmem_attach_disk(struct device *dev, 180 struct nd_namespace_common *ndns, struct pmem_device *pmem) 181 { 182 struct gendisk *disk; 183 184 pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL); 185 if (!pmem->pmem_queue) 186 return -ENOMEM; 187 188 blk_queue_make_request(pmem->pmem_queue, pmem_make_request); 189 blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE); 190 blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX); 191 blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY); 192 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue); 193 194 disk = alloc_disk(0); 195 if (!disk) { 196 blk_cleanup_queue(pmem->pmem_queue); 197 return -ENOMEM; 198 } 199 200 disk->major = pmem_major; 201 disk->first_minor = 0; 202 disk->fops = &pmem_fops; 203 disk->private_data = pmem; 204 disk->queue = pmem->pmem_queue; 205 disk->flags = GENHD_FL_EXT_DEVT; 206 nvdimm_namespace_disk_name(ndns, disk->disk_name); 207 disk->driverfs_dev = dev; 208 set_capacity(disk, (pmem->size - pmem->data_offset) / 512); 209 pmem->pmem_disk = disk; 210 211 add_disk(disk); 212 revalidate_disk(disk); 213 214 return 0; 215 } 216 217 static int pmem_rw_bytes(struct nd_namespace_common *ndns, 218 resource_size_t offset, void *buf, size_t size, int rw) 219 { 220 struct pmem_device *pmem = dev_get_drvdata(ndns->claim); 221 222 if (unlikely(offset + size > pmem->size)) { 223 dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n"); 224 return -EFAULT; 225 } 226 227 if (rw == READ) 228 memcpy_from_pmem(buf, pmem->virt_addr + offset, size); 229 else { 230 memcpy_to_pmem(pmem->virt_addr + offset, buf, size); 231 wmb_pmem(); 232 } 233 234 return 0; 235 } 236 237 static int nd_pfn_init(struct nd_pfn *nd_pfn) 238 { 239 struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL); 240 struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev); 241 struct nd_namespace_common *ndns = nd_pfn->ndns; 242 struct nd_region *nd_region; 243 unsigned long npfns; 244 phys_addr_t offset; 245 u64 checksum; 246 int rc; 247 248 if (!pfn_sb) 249 return -ENOMEM; 250 251 nd_pfn->pfn_sb = pfn_sb; 252 rc = nd_pfn_validate(nd_pfn); 253 if (rc == 0 || rc == -EBUSY) 254 return rc; 255 256 /* section alignment for simple hotplug */ 257 if (nvdimm_namespace_capacity(ndns) < ND_PFN_ALIGN 258 || pmem->phys_addr & ND_PFN_MASK) 259 return -ENODEV; 260 261 nd_region = to_nd_region(nd_pfn->dev.parent); 262 if (nd_region->ro) { 263 dev_info(&nd_pfn->dev, 264 "%s is read-only, unable to init metadata\n", 265 dev_name(&nd_region->dev)); 266 goto err; 267 } 268 269 memset(pfn_sb, 0, sizeof(*pfn_sb)); 270 npfns = (pmem->size - SZ_8K) / SZ_4K; 271 /* 272 * Note, we use 64 here for the standard size of struct page, 273 * debugging options may cause it to be larger in which case the 274 * implementation will limit the pfns advertised through 275 * ->direct_access() to those that are included in the memmap. 276 */ 277 if (nd_pfn->mode == PFN_MODE_PMEM) 278 offset = ALIGN(SZ_8K + 64 * npfns, PMD_SIZE); 279 else if (nd_pfn->mode == PFN_MODE_RAM) 280 offset = SZ_8K; 281 else 282 goto err; 283 284 npfns = (pmem->size - offset) / SZ_4K; 285 pfn_sb->mode = cpu_to_le32(nd_pfn->mode); 286 pfn_sb->dataoff = cpu_to_le64(offset); 287 pfn_sb->npfns = cpu_to_le64(npfns); 288 memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN); 289 memcpy(pfn_sb->uuid, nd_pfn->uuid, 16); 290 pfn_sb->version_major = cpu_to_le16(1); 291 checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb); 292 pfn_sb->checksum = cpu_to_le64(checksum); 293 294 rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb)); 295 if (rc) 296 goto err; 297 298 return 0; 299 err: 300 nd_pfn->pfn_sb = NULL; 301 kfree(pfn_sb); 302 return -ENXIO; 303 } 304 305 static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns) 306 { 307 struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim); 308 struct pmem_device *pmem; 309 310 /* free pmem disk */ 311 pmem = dev_get_drvdata(&nd_pfn->dev); 312 pmem_detach_disk(pmem); 313 314 /* release nd_pfn resources */ 315 kfree(nd_pfn->pfn_sb); 316 nd_pfn->pfn_sb = NULL; 317 318 return 0; 319 } 320 321 static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns) 322 { 323 struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev); 324 struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim); 325 struct device *dev = &nd_pfn->dev; 326 struct vmem_altmap *altmap; 327 struct nd_region *nd_region; 328 struct nd_pfn_sb *pfn_sb; 329 struct pmem_device *pmem; 330 phys_addr_t offset; 331 int rc; 332 333 if (!nd_pfn->uuid || !nd_pfn->ndns) 334 return -ENODEV; 335 336 nd_region = to_nd_region(dev->parent); 337 rc = nd_pfn_init(nd_pfn); 338 if (rc) 339 return rc; 340 341 if (PAGE_SIZE != SZ_4K) { 342 dev_err(dev, "only supported on systems with 4K PAGE_SIZE\n"); 343 return -ENXIO; 344 } 345 if (nsio->res.start & ND_PFN_MASK) { 346 dev_err(dev, "%s not memory hotplug section aligned\n", 347 dev_name(&ndns->dev)); 348 return -ENXIO; 349 } 350 351 pfn_sb = nd_pfn->pfn_sb; 352 offset = le64_to_cpu(pfn_sb->dataoff); 353 nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode); 354 if (nd_pfn->mode == PFN_MODE_RAM) { 355 if (offset != SZ_8K) 356 return -EINVAL; 357 nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns); 358 altmap = NULL; 359 } else { 360 rc = -ENXIO; 361 goto err; 362 } 363 364 /* establish pfn range for lookup, and switch to direct map */ 365 pmem = dev_get_drvdata(dev); 366 memunmap_pmem(dev, pmem->virt_addr); 367 pmem->virt_addr = (void __pmem *)devm_memremap_pages(dev, &nsio->res); 368 if (IS_ERR(pmem->virt_addr)) { 369 rc = PTR_ERR(pmem->virt_addr); 370 goto err; 371 } 372 373 /* attach pmem disk in "pfn-mode" */ 374 pmem->data_offset = offset; 375 rc = pmem_attach_disk(dev, ndns, pmem); 376 if (rc) 377 goto err; 378 379 return rc; 380 err: 381 nvdimm_namespace_detach_pfn(ndns); 382 return rc; 383 } 384 385 static int nd_pmem_probe(struct device *dev) 386 { 387 struct nd_region *nd_region = to_nd_region(dev->parent); 388 struct nd_namespace_common *ndns; 389 struct nd_namespace_io *nsio; 390 struct pmem_device *pmem; 391 392 ndns = nvdimm_namespace_common_probe(dev); 393 if (IS_ERR(ndns)) 394 return PTR_ERR(ndns); 395 396 nsio = to_nd_namespace_io(&ndns->dev); 397 pmem = pmem_alloc(dev, &nsio->res, nd_region->id); 398 if (IS_ERR(pmem)) 399 return PTR_ERR(pmem); 400 401 pmem->ndns = ndns; 402 dev_set_drvdata(dev, pmem); 403 ndns->rw_bytes = pmem_rw_bytes; 404 405 if (is_nd_btt(dev)) 406 return nvdimm_namespace_attach_btt(ndns); 407 408 if (is_nd_pfn(dev)) 409 return nvdimm_namespace_attach_pfn(ndns); 410 411 if (nd_btt_probe(ndns, pmem) == 0) { 412 /* we'll come back as btt-pmem */ 413 return -ENXIO; 414 } 415 416 if (nd_pfn_probe(ndns, pmem) == 0) { 417 /* we'll come back as pfn-pmem */ 418 return -ENXIO; 419 } 420 421 return pmem_attach_disk(dev, ndns, pmem); 422 } 423 424 static int nd_pmem_remove(struct device *dev) 425 { 426 struct pmem_device *pmem = dev_get_drvdata(dev); 427 428 if (is_nd_btt(dev)) 429 nvdimm_namespace_detach_btt(pmem->ndns); 430 else if (is_nd_pfn(dev)) 431 nvdimm_namespace_detach_pfn(pmem->ndns); 432 else 433 pmem_detach_disk(pmem); 434 435 return 0; 436 } 437 438 MODULE_ALIAS("pmem"); 439 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO); 440 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM); 441 static struct nd_device_driver nd_pmem_driver = { 442 .probe = nd_pmem_probe, 443 .remove = nd_pmem_remove, 444 .drv = { 445 .name = "nd_pmem", 446 }, 447 .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM, 448 }; 449 450 static int __init pmem_init(void) 451 { 452 int error; 453 454 pmem_major = register_blkdev(0, "pmem"); 455 if (pmem_major < 0) 456 return pmem_major; 457 458 error = nd_driver_register(&nd_pmem_driver); 459 if (error) { 460 unregister_blkdev(pmem_major, "pmem"); 461 return error; 462 } 463 464 return 0; 465 } 466 module_init(pmem_init); 467 468 static void pmem_exit(void) 469 { 470 driver_unregister(&nd_pmem_driver.drv); 471 unregister_blkdev(pmem_major, "pmem"); 472 } 473 module_exit(pmem_exit); 474 475 MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>"); 476 MODULE_LICENSE("GPL v2"); 477