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