531 lines · c
1// SPDX-License-Identifier: GPL-2.02/* Copyright(c) 2015 Intel Corporation. All rights reserved. */3#include <linux/device.h>4#include <linux/io.h>5#include <linux/kasan.h>6#include <linux/memory_hotplug.h>7#include <linux/memremap.h>8#include <linux/pfn_t.h>9#include <linux/swap.h>10#include <linux/mm.h>11#include <linux/mmzone.h>12#include <linux/swapops.h>13#include <linux/types.h>14#include <linux/wait_bit.h>15#include <linux/xarray.h>16#include "internal.h"17 18static DEFINE_XARRAY(pgmap_array);19 20/*21 * The memremap() and memremap_pages() interfaces are alternately used22 * to map persistent memory namespaces. These interfaces place different23 * constraints on the alignment and size of the mapping (namespace).24 * memremap() can map individual PAGE_SIZE pages. memremap_pages() can25 * only map subsections (2MB), and at least one architecture (PowerPC)26 * the minimum mapping granularity of memremap_pages() is 16MB.27 *28 * The role of memremap_compat_align() is to communicate the minimum29 * arch supported alignment of a namespace such that it can freely30 * switch modes without violating the arch constraint. Namely, do not31 * allow a namespace to be PAGE_SIZE aligned since that namespace may be32 * reconfigured into a mode that requires SUBSECTION_SIZE alignment.33 */34#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN35unsigned long memremap_compat_align(void)36{37 return SUBSECTION_SIZE;38}39EXPORT_SYMBOL_GPL(memremap_compat_align);40#endif41 42#ifdef CONFIG_FS_DAX43DEFINE_STATIC_KEY_FALSE(devmap_managed_key);44EXPORT_SYMBOL(devmap_managed_key);45 46static void devmap_managed_enable_put(struct dev_pagemap *pgmap)47{48 if (pgmap->type == MEMORY_DEVICE_FS_DAX)49 static_branch_dec(&devmap_managed_key);50}51 52static void devmap_managed_enable_get(struct dev_pagemap *pgmap)53{54 if (pgmap->type == MEMORY_DEVICE_FS_DAX)55 static_branch_inc(&devmap_managed_key);56}57#else58static void devmap_managed_enable_get(struct dev_pagemap *pgmap)59{60}61static void devmap_managed_enable_put(struct dev_pagemap *pgmap)62{63}64#endif /* CONFIG_FS_DAX */65 66static void pgmap_array_delete(struct range *range)67{68 xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->end),69 NULL, GFP_KERNEL);70 synchronize_rcu();71}72 73static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id)74{75 struct range *range = &pgmap->ranges[range_id];76 unsigned long pfn = PHYS_PFN(range->start);77 78 if (range_id)79 return pfn;80 return pfn + vmem_altmap_offset(pgmap_altmap(pgmap));81}82 83bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)84{85 int i;86 87 for (i = 0; i < pgmap->nr_range; i++) {88 struct range *range = &pgmap->ranges[i];89 90 if (pfn >= PHYS_PFN(range->start) &&91 pfn <= PHYS_PFN(range->end))92 return pfn >= pfn_first(pgmap, i);93 }94 95 return false;96}97 98static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id)99{100 const struct range *range = &pgmap->ranges[range_id];101 102 return (range->start + range_len(range)) >> PAGE_SHIFT;103}104 105static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id)106{107 return (pfn_end(pgmap, range_id) -108 pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift;109}110 111static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)112{113 struct range *range = &pgmap->ranges[range_id];114 struct page *first_page;115 116 /* make sure to access a memmap that was actually initialized */117 first_page = pfn_to_page(pfn_first(pgmap, range_id));118 119 /* pages are dead and unused, undo the arch mapping */120 mem_hotplug_begin();121 remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start),122 PHYS_PFN(range_len(range)));123 if (pgmap->type == MEMORY_DEVICE_PRIVATE) {124 __remove_pages(PHYS_PFN(range->start),125 PHYS_PFN(range_len(range)), NULL);126 } else {127 arch_remove_memory(range->start, range_len(range),128 pgmap_altmap(pgmap));129 kasan_remove_zero_shadow(__va(range->start), range_len(range));130 }131 mem_hotplug_done();132 133 untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);134 pgmap_array_delete(range);135}136 137void memunmap_pages(struct dev_pagemap *pgmap)138{139 int i;140 141 percpu_ref_kill(&pgmap->ref);142 if (pgmap->type != MEMORY_DEVICE_PRIVATE &&143 pgmap->type != MEMORY_DEVICE_COHERENT)144 for (i = 0; i < pgmap->nr_range; i++)145 percpu_ref_put_many(&pgmap->ref, pfn_len(pgmap, i));146 147 wait_for_completion(&pgmap->done);148 149 for (i = 0; i < pgmap->nr_range; i++)150 pageunmap_range(pgmap, i);151 percpu_ref_exit(&pgmap->ref);152 153 WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");154 devmap_managed_enable_put(pgmap);155}156EXPORT_SYMBOL_GPL(memunmap_pages);157 158static void devm_memremap_pages_release(void *data)159{160 memunmap_pages(data);161}162 163static void dev_pagemap_percpu_release(struct percpu_ref *ref)164{165 struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);166 167 complete(&pgmap->done);168}169 170static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,171 int range_id, int nid)172{173 const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE;174 struct range *range = &pgmap->ranges[range_id];175 struct dev_pagemap *conflict_pgmap;176 int error, is_ram;177 178 if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0,179 "altmap not supported for multiple ranges\n"))180 return -EINVAL;181 182 conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL);183 if (conflict_pgmap) {184 WARN(1, "Conflicting mapping in same section\n");185 put_dev_pagemap(conflict_pgmap);186 return -ENOMEM;187 }188 189 conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL);190 if (conflict_pgmap) {191 WARN(1, "Conflicting mapping in same section\n");192 put_dev_pagemap(conflict_pgmap);193 return -ENOMEM;194 }195 196 is_ram = region_intersects(range->start, range_len(range),197 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);198 199 if (is_ram != REGION_DISJOINT) {200 WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",201 is_ram == REGION_MIXED ? "mixed" : "ram",202 range->start, range->end);203 return -ENXIO;204 }205 206 error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start),207 PHYS_PFN(range->end), pgmap, GFP_KERNEL));208 if (error)209 return error;210 211 if (nid < 0)212 nid = numa_mem_id();213 214 error = track_pfn_remap(NULL, ¶ms->pgprot, PHYS_PFN(range->start), 0,215 range_len(range));216 if (error)217 goto err_pfn_remap;218 219 if (!mhp_range_allowed(range->start, range_len(range), !is_private)) {220 error = -EINVAL;221 goto err_kasan;222 }223 224 mem_hotplug_begin();225 226 /*227 * For device private memory we call add_pages() as we only need to228 * allocate and initialize struct page for the device memory. More-229 * over the device memory is un-accessible thus we do not want to230 * create a linear mapping for the memory like arch_add_memory()231 * would do.232 *233 * For all other device memory types, which are accessible by234 * the CPU, we do want the linear mapping and thus use235 * arch_add_memory().236 */237 if (is_private) {238 error = add_pages(nid, PHYS_PFN(range->start),239 PHYS_PFN(range_len(range)), params);240 } else {241 error = kasan_add_zero_shadow(__va(range->start), range_len(range));242 if (error) {243 mem_hotplug_done();244 goto err_kasan;245 }246 247 error = arch_add_memory(nid, range->start, range_len(range),248 params);249 }250 251 if (!error) {252 struct zone *zone;253 254 zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];255 move_pfn_range_to_zone(zone, PHYS_PFN(range->start),256 PHYS_PFN(range_len(range)), params->altmap,257 MIGRATE_MOVABLE);258 }259 260 mem_hotplug_done();261 if (error)262 goto err_add_memory;263 264 /*265 * Initialization of the pages has been deferred until now in order266 * to allow us to do the work while not holding the hotplug lock.267 */268 memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],269 PHYS_PFN(range->start),270 PHYS_PFN(range_len(range)), pgmap);271 if (pgmap->type != MEMORY_DEVICE_PRIVATE &&272 pgmap->type != MEMORY_DEVICE_COHERENT)273 percpu_ref_get_many(&pgmap->ref, pfn_len(pgmap, range_id));274 return 0;275 276err_add_memory:277 if (!is_private)278 kasan_remove_zero_shadow(__va(range->start), range_len(range));279err_kasan:280 untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);281err_pfn_remap:282 pgmap_array_delete(range);283 return error;284}285 286 287/*288 * Not device managed version of devm_memremap_pages, undone by289 * memunmap_pages(). Please use devm_memremap_pages if you have a struct290 * device available.291 */292void *memremap_pages(struct dev_pagemap *pgmap, int nid)293{294 struct mhp_params params = {295 .altmap = pgmap_altmap(pgmap),296 .pgmap = pgmap,297 .pgprot = PAGE_KERNEL,298 };299 const int nr_range = pgmap->nr_range;300 int error, i;301 302 if (WARN_ONCE(!nr_range, "nr_range must be specified\n"))303 return ERR_PTR(-EINVAL);304 305 switch (pgmap->type) {306 case MEMORY_DEVICE_PRIVATE:307 if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {308 WARN(1, "Device private memory not supported\n");309 return ERR_PTR(-EINVAL);310 }311 if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {312 WARN(1, "Missing migrate_to_ram method\n");313 return ERR_PTR(-EINVAL);314 }315 if (!pgmap->ops->page_free) {316 WARN(1, "Missing page_free method\n");317 return ERR_PTR(-EINVAL);318 }319 if (!pgmap->owner) {320 WARN(1, "Missing owner\n");321 return ERR_PTR(-EINVAL);322 }323 break;324 case MEMORY_DEVICE_COHERENT:325 if (!pgmap->ops->page_free) {326 WARN(1, "Missing page_free method\n");327 return ERR_PTR(-EINVAL);328 }329 if (!pgmap->owner) {330 WARN(1, "Missing owner\n");331 return ERR_PTR(-EINVAL);332 }333 break;334 case MEMORY_DEVICE_FS_DAX:335 if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {336 WARN(1, "File system DAX not supported\n");337 return ERR_PTR(-EINVAL);338 }339 params.pgprot = pgprot_decrypted(params.pgprot);340 break;341 case MEMORY_DEVICE_GENERIC:342 break;343 case MEMORY_DEVICE_PCI_P2PDMA:344 params.pgprot = pgprot_noncached(params.pgprot);345 break;346 default:347 WARN(1, "Invalid pgmap type %d\n", pgmap->type);348 break;349 }350 351 init_completion(&pgmap->done);352 error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,353 GFP_KERNEL);354 if (error)355 return ERR_PTR(error);356 357 devmap_managed_enable_get(pgmap);358 359 /*360 * Clear the pgmap nr_range as it will be incremented for each361 * successfully processed range. This communicates how many362 * regions to unwind in the abort case.363 */364 pgmap->nr_range = 0;365 error = 0;366 for (i = 0; i < nr_range; i++) {367 error = pagemap_range(pgmap, ¶ms, i, nid);368 if (error)369 break;370 pgmap->nr_range++;371 }372 373 if (i < nr_range) {374 memunmap_pages(pgmap);375 pgmap->nr_range = nr_range;376 return ERR_PTR(error);377 }378 379 return __va(pgmap->ranges[0].start);380}381EXPORT_SYMBOL_GPL(memremap_pages);382 383/**384 * devm_memremap_pages - remap and provide memmap backing for the given resource385 * @dev: hosting device for @res386 * @pgmap: pointer to a struct dev_pagemap387 *388 * Notes:389 * 1/ At a minimum the range and type members of @pgmap must be initialized390 * by the caller before passing it to this function391 *392 * 2/ The altmap field may optionally be initialized, in which case393 * PGMAP_ALTMAP_VALID must be set in pgmap->flags.394 *395 * 3/ The ref field may optionally be provided, in which pgmap->ref must be396 * 'live' on entry and will be killed and reaped at397 * devm_memremap_pages_release() time, or if this routine fails.398 *399 * 4/ range is expected to be a host memory range that could feasibly be400 * treated as a "System RAM" range, i.e. not a device mmio range, but401 * this is not enforced.402 */403void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)404{405 int error;406 void *ret;407 408 ret = memremap_pages(pgmap, dev_to_node(dev));409 if (IS_ERR(ret))410 return ret;411 412 error = devm_add_action_or_reset(dev, devm_memremap_pages_release,413 pgmap);414 if (error)415 return ERR_PTR(error);416 return ret;417}418EXPORT_SYMBOL_GPL(devm_memremap_pages);419 420void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)421{422 devm_release_action(dev, devm_memremap_pages_release, pgmap);423}424EXPORT_SYMBOL_GPL(devm_memunmap_pages);425 426/**427 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn428 * @pfn: page frame number to lookup page_map429 * @pgmap: optional known pgmap that already has a reference430 *431 * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap432 * is non-NULL but does not cover @pfn the reference to it will be released.433 */434struct dev_pagemap *get_dev_pagemap(unsigned long pfn,435 struct dev_pagemap *pgmap)436{437 resource_size_t phys = PFN_PHYS(pfn);438 439 /*440 * In the cached case we're already holding a live reference.441 */442 if (pgmap) {443 if (phys >= pgmap->range.start && phys <= pgmap->range.end)444 return pgmap;445 put_dev_pagemap(pgmap);446 }447 448 /* fall back to slow path lookup */449 rcu_read_lock();450 pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));451 if (pgmap && !percpu_ref_tryget_live_rcu(&pgmap->ref))452 pgmap = NULL;453 rcu_read_unlock();454 455 return pgmap;456}457EXPORT_SYMBOL_GPL(get_dev_pagemap);458 459void free_zone_device_folio(struct folio *folio)460{461 if (WARN_ON_ONCE(!folio->page.pgmap->ops ||462 !folio->page.pgmap->ops->page_free))463 return;464 465 mem_cgroup_uncharge(folio);466 467 /*468 * Note: we don't expect anonymous compound pages yet. Once supported469 * and we could PTE-map them similar to THP, we'd have to clear470 * PG_anon_exclusive on all tail pages.471 */472 if (folio_test_anon(folio)) {473 VM_BUG_ON_FOLIO(folio_test_large(folio), folio);474 __ClearPageAnonExclusive(folio_page(folio, 0));475 }476 477 /*478 * When a device managed page is freed, the folio->mapping field479 * may still contain a (stale) mapping value. For example, the480 * lower bits of folio->mapping may still identify the folio as an481 * anonymous folio. Ultimately, this entire field is just stale482 * and wrong, and it will cause errors if not cleared.483 *484 * For other types of ZONE_DEVICE pages, migration is either485 * handled differently or not done at all, so there is no need486 * to clear folio->mapping.487 */488 folio->mapping = NULL;489 folio->page.pgmap->ops->page_free(folio_page(folio, 0));490 491 if (folio->page.pgmap->type != MEMORY_DEVICE_PRIVATE &&492 folio->page.pgmap->type != MEMORY_DEVICE_COHERENT)493 /*494 * Reset the refcount to 1 to prepare for handing out the page495 * again.496 */497 folio_set_count(folio, 1);498 else499 put_dev_pagemap(folio->page.pgmap);500}501 502void zone_device_page_init(struct page *page)503{504 /*505 * Drivers shouldn't be allocating pages after calling506 * memunmap_pages().507 */508 WARN_ON_ONCE(!percpu_ref_tryget_live(&page->pgmap->ref));509 set_page_count(page, 1);510 lock_page(page);511}512EXPORT_SYMBOL_GPL(zone_device_page_init);513 514#ifdef CONFIG_FS_DAX515bool __put_devmap_managed_folio_refs(struct folio *folio, int refs)516{517 if (folio->page.pgmap->type != MEMORY_DEVICE_FS_DAX)518 return false;519 520 /*521 * fsdax page refcounts are 1-based, rather than 0-based: if522 * refcount is 1, then the page is free and the refcount is523 * stable because nobody holds a reference on the page.524 */525 if (folio_ref_sub_return(folio, refs) == 1)526 wake_up_var(&folio->_refcount);527 return true;528}529EXPORT_SYMBOL(__put_devmap_managed_folio_refs);530#endif /* CONFIG_FS_DAX */531