diff options
Diffstat (limited to 'kernel/memremap.c')
| -rw-r--r-- | kernel/memremap.c | 374 |
1 files changed, 0 insertions, 374 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c deleted file mode 100644 index 6e1970719dc2..000000000000 --- a/kernel/memremap.c +++ /dev/null @@ -1,374 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* Copyright(c) 2015 Intel Corporation. All rights reserved. */ -#include <linux/device.h> -#include <linux/io.h> -#include <linux/kasan.h> -#include <linux/memory_hotplug.h> -#include <linux/mm.h> -#include <linux/pfn_t.h> -#include <linux/swap.h> -#include <linux/swapops.h> -#include <linux/types.h> -#include <linux/wait_bit.h> -#include <linux/xarray.h> -#include <linux/hmm.h> - -static DEFINE_XARRAY(pgmap_array); -#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1) -#define SECTION_SIZE (1UL << PA_SECTION_SHIFT) - -#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) -vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, - unsigned long addr, - swp_entry_t entry, - unsigned int flags, - pmd_t *pmdp) -{ - struct page *page = device_private_entry_to_page(entry); - struct hmm_devmem *devmem; - - devmem = container_of(page->pgmap, typeof(*devmem), pagemap); - - /* - * The page_fault() callback must migrate page back to system memory - * so that CPU can access it. This might fail for various reasons - * (device issue, device was unsafely unplugged, ...). When such - * error conditions happen, the callback must return VM_FAULT_SIGBUS. - * - * Note that because memory cgroup charges are accounted to the device - * memory, this should never fail because of memory restrictions (but - * allocation of regular system page might still fail because we are - * out of memory). - * - * There is a more in-depth description of what that callback can and - * cannot do, in include/linux/memremap.h - */ - return devmem->page_fault(vma, addr, page, flags, pmdp); -} -#endif /* CONFIG_DEVICE_PRIVATE */ - -static void pgmap_array_delete(struct resource *res) -{ - xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end), - NULL, GFP_KERNEL); - synchronize_rcu(); -} - -static unsigned long pfn_first(struct dev_pagemap *pgmap) -{ - const struct resource *res = &pgmap->res; - struct vmem_altmap *altmap = &pgmap->altmap; - unsigned long pfn; - - pfn = res->start >> PAGE_SHIFT; - if (pgmap->altmap_valid) - pfn += vmem_altmap_offset(altmap); - return pfn; -} - -static unsigned long pfn_end(struct dev_pagemap *pgmap) -{ - const struct resource *res = &pgmap->res; - - return (res->start + resource_size(res)) >> PAGE_SHIFT; -} - -static unsigned long pfn_next(unsigned long pfn) -{ - if (pfn % 1024 == 0) - cond_resched(); - return pfn + 1; -} - -#define for_each_device_pfn(pfn, map) \ - for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn)) - -static void devm_memremap_pages_release(void *data) -{ - struct dev_pagemap *pgmap = data; - struct device *dev = pgmap->dev; - struct resource *res = &pgmap->res; - resource_size_t align_start, align_size; - unsigned long pfn; - int nid; - - pgmap->kill(pgmap->ref); - for_each_device_pfn(pfn, pgmap) - put_page(pfn_to_page(pfn)); - pgmap->cleanup(pgmap->ref); - - /* pages are dead and unused, undo the arch mapping */ - align_start = res->start & ~(SECTION_SIZE - 1); - align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) - - align_start; - - nid = page_to_nid(pfn_to_page(align_start >> PAGE_SHIFT)); - - mem_hotplug_begin(); - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - pfn = align_start >> PAGE_SHIFT; - __remove_pages(page_zone(pfn_to_page(pfn)), pfn, - align_size >> PAGE_SHIFT, NULL); - } else { - arch_remove_memory(nid, align_start, align_size, - pgmap->altmap_valid ? &pgmap->altmap : NULL); - kasan_remove_zero_shadow(__va(align_start), align_size); - } - mem_hotplug_done(); - - untrack_pfn(NULL, PHYS_PFN(align_start), align_size); - pgmap_array_delete(res); - dev_WARN_ONCE(dev, pgmap->altmap.alloc, - "%s: failed to free all reserved pages\n", __func__); -} - -/** - * devm_memremap_pages - remap and provide memmap backing for the given resource - * @dev: hosting device for @res - * @pgmap: pointer to a struct dev_pagemap - * - * Notes: - * 1/ At a minimum the res, ref and type members of @pgmap must be initialized - * by the caller before passing it to this function - * - * 2/ The altmap field may optionally be initialized, in which case altmap_valid - * must be set to true - * - * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped - * at devm_memremap_pages_release() time, or if this routine fails. - * - * 4/ res is expected to be a host memory range that could feasibly be - * treated as a "System RAM" range, i.e. not a device mmio range, but - * this is not enforced. - */ -void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) -{ - resource_size_t align_start, align_size, align_end; - struct vmem_altmap *altmap = pgmap->altmap_valid ? - &pgmap->altmap : NULL; - struct resource *res = &pgmap->res; - struct dev_pagemap *conflict_pgmap; - struct mhp_restrictions restrictions = { - /* - * We do not want any optional features only our own memmap - */ - .altmap = altmap, - }; - pgprot_t pgprot = PAGE_KERNEL; - int error, nid, is_ram; - - if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) { - WARN(1, "Missing reference count teardown definition\n"); - return ERR_PTR(-EINVAL); - } - - align_start = res->start & ~(SECTION_SIZE - 1); - align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE) - - align_start; - align_end = align_start + align_size - 1; - - conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL); - if (conflict_pgmap) { - dev_WARN(dev, "Conflicting mapping in same section\n"); - put_dev_pagemap(conflict_pgmap); - error = -ENOMEM; - goto err_array; - } - - conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL); - if (conflict_pgmap) { - dev_WARN(dev, "Conflicting mapping in same section\n"); - put_dev_pagemap(conflict_pgmap); - error = -ENOMEM; - goto err_array; - } - - is_ram = region_intersects(align_start, align_size, - IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); - - if (is_ram != REGION_DISJOINT) { - WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__, - is_ram == REGION_MIXED ? "mixed" : "ram", res); - error = -ENXIO; - goto err_array; - } - - pgmap->dev = dev; - - error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start), - PHYS_PFN(res->end), pgmap, GFP_KERNEL)); - if (error) - goto err_array; - - nid = dev_to_node(dev); - if (nid < 0) - nid = numa_mem_id(); - - error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0, - align_size); - if (error) - goto err_pfn_remap; - - mem_hotplug_begin(); - - /* - * For device private memory we call add_pages() as we only need to - * allocate and initialize struct page for the device memory. More- - * over the device memory is un-accessible thus we do not want to - * create a linear mapping for the memory like arch_add_memory() - * would do. - * - * For all other device memory types, which are accessible by - * the CPU, we do want the linear mapping and thus use - * arch_add_memory(). - */ - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - error = add_pages(nid, align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, &restrictions); - } else { - error = kasan_add_zero_shadow(__va(align_start), align_size); - if (error) { - mem_hotplug_done(); - goto err_kasan; - } - - error = arch_add_memory(nid, align_start, align_size, - &restrictions); - } - - if (!error) { - struct zone *zone; - - zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; - move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, altmap); - } - - mem_hotplug_done(); - if (error) - goto err_add_memory; - - /* - * Initialization of the pages has been deferred until now in order - * to allow us to do the work while not holding the hotplug lock. - */ - memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], - align_start >> PAGE_SHIFT, - align_size >> PAGE_SHIFT, pgmap); - percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap)); - - error = devm_add_action_or_reset(dev, devm_memremap_pages_release, - pgmap); - if (error) - return ERR_PTR(error); - - return __va(res->start); - - err_add_memory: - kasan_remove_zero_shadow(__va(align_start), align_size); - err_kasan: - untrack_pfn(NULL, PHYS_PFN(align_start), align_size); - err_pfn_remap: - pgmap_array_delete(res); - err_array: - pgmap->kill(pgmap->ref); - pgmap->cleanup(pgmap->ref); - - return ERR_PTR(error); -} -EXPORT_SYMBOL_GPL(devm_memremap_pages); - -void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) -{ - devm_release_action(dev, devm_memremap_pages_release, pgmap); -} -EXPORT_SYMBOL_GPL(devm_memunmap_pages); - -unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) -{ - /* number of pfns from base where pfn_to_page() is valid */ - return altmap->reserve + altmap->free; -} - -void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) -{ - altmap->alloc -= nr_pfns; -} - -/** - * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn - * @pfn: page frame number to lookup page_map - * @pgmap: optional known pgmap that already has a reference - * - * If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap - * is non-NULL but does not cover @pfn the reference to it will be released. - */ -struct dev_pagemap *get_dev_pagemap(unsigned long pfn, - struct dev_pagemap *pgmap) -{ - resource_size_t phys = PFN_PHYS(pfn); - - /* - * In the cached case we're already holding a live reference. - */ - if (pgmap) { - if (phys >= pgmap->res.start && phys <= pgmap->res.end) - return pgmap; - put_dev_pagemap(pgmap); - } - - /* fall back to slow path lookup */ - rcu_read_lock(); - pgmap = xa_load(&pgmap_array, PHYS_PFN(phys)); - if (pgmap && !percpu_ref_tryget_live(pgmap->ref)) - pgmap = NULL; - rcu_read_unlock(); - - return pgmap; -} -EXPORT_SYMBOL_GPL(get_dev_pagemap); - -#ifdef CONFIG_DEV_PAGEMAP_OPS -DEFINE_STATIC_KEY_FALSE(devmap_managed_key); -EXPORT_SYMBOL(devmap_managed_key); -static atomic_t devmap_enable; - -/* - * Toggle the static key for ->page_free() callbacks when dev_pagemap - * pages go idle. - */ -void dev_pagemap_get_ops(void) -{ - if (atomic_inc_return(&devmap_enable) == 1) - static_branch_enable(&devmap_managed_key); -} -EXPORT_SYMBOL_GPL(dev_pagemap_get_ops); - -void dev_pagemap_put_ops(void) -{ - if (atomic_dec_and_test(&devmap_enable)) - static_branch_disable(&devmap_managed_key); -} -EXPORT_SYMBOL_GPL(dev_pagemap_put_ops); - -void __put_devmap_managed_page(struct page *page) -{ - int count = page_ref_dec_return(page); - - /* - * If refcount is 1 then page is freed and refcount is stable as nobody - * holds a reference on the page. - */ - if (count == 1) { - /* Clear Active bit in case of parallel mark_page_accessed */ - __ClearPageActive(page); - __ClearPageWaiters(page); - - mem_cgroup_uncharge(page); - - page->pgmap->page_free(page, page->pgmap->data); - } else if (!count) - __put_page(page); -} -EXPORT_SYMBOL(__put_devmap_managed_page); -#endif /* CONFIG_DEV_PAGEMAP_OPS */ |