+++ /dev/null
-/* 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));
-
- /* 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 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)
- 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);
- return ERR_PTR(-ENOMEM);
- }
-
- 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);
- return ERR_PTR(-ENOMEM);
- }
-
- 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);
- return ERR_PTR(error);
-}
-EXPORT_SYMBOL_GPL(devm_memremap_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 */
git.samba.org / sfrench / cifs-2.6.git / blobdiff