Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 406 insertions, 0 deletions

diff --git a/kernel/memremap.c b/kernel/memremap.c
new file mode 100644
index 000000000..331baad8e
--- /dev/null
+++ b/kernel/memremap.c
@@ -0,0 +1,406 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
+#include <linux/radix-tree.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/pfn_t.h>
+#include <linux/io.h>
+#include <linux/kasan.h>
+#include <linux/mm.h>
+#include <linux/memory_hotplug.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/wait_bit.h>
+
+static DEFINE_MUTEX(pgmap_lock);
+static RADIX_TREE(pgmap_radix, GFP_KERNEL);
+#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
+#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
+
+static unsigned long order_at(struct resource *res, unsigned long pgoff)
+{
+	unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff;
+	unsigned long nr_pages, mask;
+
+	nr_pages = PHYS_PFN(resource_size(res));
+	if (nr_pages == pgoff)
+		return ULONG_MAX;
+
+	/*
+	 * What is the largest aligned power-of-2 range available from
+	 * this resource pgoff to the end of the resource range,
+	 * considering the alignment of the current pgoff?
+	 */
+	mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff);
+	if (!mask)
+		return ULONG_MAX;
+
+	return find_first_bit(&mask, BITS_PER_LONG);
+}
+
+#define foreach_order_pgoff(res, order, pgoff) \
+	for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \
+			pgoff += 1UL << order, order = order_at((res), pgoff))
+
+#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);
+
+	/*
+	 * 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 page->pgmap->page_fault(vma, addr, page, flags, pmdp);
+}
+EXPORT_SYMBOL(device_private_entry_fault);
+#endif /* CONFIG_DEVICE_PRIVATE */
+
+static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
+{
+	unsigned long pgoff, order;
+
+	mutex_lock(&pgmap_lock);
+	foreach_order_pgoff(res, order, pgoff) {
+		if (pgoff >= end_pgoff)
+			break;
+		radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
+	}
+	mutex_unlock(&pgmap_lock);
+
+	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;
+	struct page *first_page;
+	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;
+
+	/* make sure to access a memmap that was actually initialized */
+	first_page = pfn_to_page(pfn_first(pgmap));
+
+	nid = page_to_nid(first_page);
+
+	mem_hotplug_begin();
+	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+		pfn = align_start >> PAGE_SHIFT;
+		__remove_pages(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_radix_release(res, -1);
+	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;
+	unsigned long pfn, pgoff, order;
+	pgprot_t pgprot = PAGE_KERNEL;
+	int error, nid, is_ram;
+	struct dev_pagemap *conflict_pgmap;
+
+	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;
+
+	mutex_lock(&pgmap_lock);
+	error = 0;
+
+	foreach_order_pgoff(res, order, pgoff) {
+		error = __radix_tree_insert(&pgmap_radix,
+				PHYS_PFN(res->start) + pgoff, order, pgmap);
+		if (error) {
+			dev_err(dev, "%s: failed: %d\n", __func__, error);
+			break;
+		}
+	}
+	mutex_unlock(&pgmap_lock);
+	if (error)
+		goto err_radix;
+
+	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, NULL, false);
+	} 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, altmap,
+				false);
+	}
+
+	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;
+
+	for_each_device_pfn(pfn, pgmap) {
+		struct page *page = pfn_to_page(pfn);
+
+		/*
+		 * ZONE_DEVICE pages union ->lru with a ->pgmap back
+		 * pointer.  It is a bug if a ZONE_DEVICE page is ever
+		 * freed or placed on a driver-private list.  Seed the
+		 * storage with LIST_POISON* values.
+		 */
+		list_del(&page->lru);
+		page->pgmap = pgmap;
+		percpu_ref_get(pgmap->ref);
+	}
+
+	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:
+ err_radix:
+	pgmap_radix_release(res, pgoff);
+ 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 = radix_tree_lookup(&pgmap_radix, 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 */