Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 550 insertions, 0 deletions

diff --git a/mm/memremap.c b/mm/memremap.c
new file mode 100644
index 000000000..bee85560a
--- /dev/null
+++ b/mm/memremap.c
@@ -0,0 +1,550 @@
+// 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/memremap.h>
+#include <linux/pfn_t.h>
+#include <linux/swap.h>
+#include <linux/mmzone.h>
+#include <linux/swapops.h>
+#include <linux/types.h>
+#include <linux/wait_bit.h>
+#include <linux/xarray.h>
+#include "internal.h"
+
+static DEFINE_XARRAY(pgmap_array);
+
+/*
+ * The memremap() and memremap_pages() interfaces are alternately used
+ * to map persistent memory namespaces. These interfaces place different
+ * constraints on the alignment and size of the mapping (namespace).
+ * memremap() can map individual PAGE_SIZE pages. memremap_pages() can
+ * only map subsections (2MB), and at least one architecture (PowerPC)
+ * the minimum mapping granularity of memremap_pages() is 16MB.
+ *
+ * The role of memremap_compat_align() is to communicate the minimum
+ * arch supported alignment of a namespace such that it can freely
+ * switch modes without violating the arch constraint. Namely, do not
+ * allow a namespace to be PAGE_SIZE aligned since that namespace may be
+ * reconfigured into a mode that requires SUBSECTION_SIZE alignment.
+ */
+#ifndef CONFIG_ARCH_HAS_MEMREMAP_COMPAT_ALIGN
+unsigned long memremap_compat_align(void)
+{
+	return SUBSECTION_SIZE;
+}
+EXPORT_SYMBOL_GPL(memremap_compat_align);
+#endif
+
+#ifdef CONFIG_FS_DAX
+DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
+EXPORT_SYMBOL(devmap_managed_key);
+
+static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
+{
+	if (pgmap->type == MEMORY_DEVICE_FS_DAX)
+		static_branch_dec(&devmap_managed_key);
+}
+
+static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
+{
+	if (pgmap->type == MEMORY_DEVICE_FS_DAX)
+		static_branch_inc(&devmap_managed_key);
+}
+#else
+static void devmap_managed_enable_get(struct dev_pagemap *pgmap)
+{
+}
+static void devmap_managed_enable_put(struct dev_pagemap *pgmap)
+{
+}
+#endif /* CONFIG_FS_DAX */
+
+static void pgmap_array_delete(struct range *range)
+{
+	xa_store_range(&pgmap_array, PHYS_PFN(range->start), PHYS_PFN(range->end),
+			NULL, GFP_KERNEL);
+	synchronize_rcu();
+}
+
+static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id)
+{
+	struct range *range = &pgmap->ranges[range_id];
+	unsigned long pfn = PHYS_PFN(range->start);
+
+	if (range_id)
+		return pfn;
+	return pfn + vmem_altmap_offset(pgmap_altmap(pgmap));
+}
+
+bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
+{
+	int i;
+
+	for (i = 0; i < pgmap->nr_range; i++) {
+		struct range *range = &pgmap->ranges[i];
+
+		if (pfn >= PHYS_PFN(range->start) &&
+		    pfn <= PHYS_PFN(range->end))
+			return pfn >= pfn_first(pgmap, i);
+	}
+
+	return false;
+}
+
+static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id)
+{
+	const struct range *range = &pgmap->ranges[range_id];
+
+	return (range->start + range_len(range)) >> PAGE_SHIFT;
+}
+
+static unsigned long pfn_len(struct dev_pagemap *pgmap, unsigned long range_id)
+{
+	return (pfn_end(pgmap, range_id) -
+		pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift;
+}
+
+static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
+{
+	struct range *range = &pgmap->ranges[range_id];
+	struct page *first_page;
+
+	/* make sure to access a memmap that was actually initialized */
+	first_page = pfn_to_page(pfn_first(pgmap, range_id));
+
+	/* pages are dead and unused, undo the arch mapping */
+	mem_hotplug_begin();
+	remove_pfn_range_from_zone(page_zone(first_page), PHYS_PFN(range->start),
+				   PHYS_PFN(range_len(range)));
+	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
+		__remove_pages(PHYS_PFN(range->start),
+			       PHYS_PFN(range_len(range)), NULL);
+	} else {
+		arch_remove_memory(range->start, range_len(range),
+				pgmap_altmap(pgmap));
+		kasan_remove_zero_shadow(__va(range->start), range_len(range));
+	}
+	mem_hotplug_done();
+
+	untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
+	pgmap_array_delete(range);
+}
+
+void memunmap_pages(struct dev_pagemap *pgmap)
+{
+	int i;
+
+	percpu_ref_kill(&pgmap->ref);
+	if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
+	    pgmap->type != MEMORY_DEVICE_COHERENT)
+		for (i = 0; i < pgmap->nr_range; i++)
+			percpu_ref_put_many(&pgmap->ref, pfn_len(pgmap, i));
+
+	wait_for_completion(&pgmap->done);
+
+	for (i = 0; i < pgmap->nr_range; i++)
+		pageunmap_range(pgmap, i);
+	percpu_ref_exit(&pgmap->ref);
+
+	WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
+	devmap_managed_enable_put(pgmap);
+}
+EXPORT_SYMBOL_GPL(memunmap_pages);
+
+static void devm_memremap_pages_release(void *data)
+{
+	memunmap_pages(data);
+}
+
+static void dev_pagemap_percpu_release(struct percpu_ref *ref)
+{
+	struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);
+
+	complete(&pgmap->done);
+}
+
+static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
+		int range_id, int nid)
+{
+	const bool is_private = pgmap->type == MEMORY_DEVICE_PRIVATE;
+	struct range *range = &pgmap->ranges[range_id];
+	struct dev_pagemap *conflict_pgmap;
+	int error, is_ram;
+
+	if (WARN_ONCE(pgmap_altmap(pgmap) && range_id > 0,
+				"altmap not supported for multiple ranges\n"))
+		return -EINVAL;
+
+	conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->start), NULL);
+	if (conflict_pgmap) {
+		WARN(1, "Conflicting mapping in same section\n");
+		put_dev_pagemap(conflict_pgmap);
+		return -ENOMEM;
+	}
+
+	conflict_pgmap = get_dev_pagemap(PHYS_PFN(range->end), NULL);
+	if (conflict_pgmap) {
+		WARN(1, "Conflicting mapping in same section\n");
+		put_dev_pagemap(conflict_pgmap);
+		return -ENOMEM;
+	}
+
+	is_ram = region_intersects(range->start, range_len(range),
+		IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
+
+	if (is_ram != REGION_DISJOINT) {
+		WARN_ONCE(1, "attempted on %s region %#llx-%#llx\n",
+				is_ram == REGION_MIXED ? "mixed" : "ram",
+				range->start, range->end);
+		return -ENXIO;
+	}
+
+	error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(range->start),
+				PHYS_PFN(range->end), pgmap, GFP_KERNEL));
+	if (error)
+		return error;
+
+	if (nid < 0)
+		nid = numa_mem_id();
+
+	error = track_pfn_remap(NULL, &params->pgprot, PHYS_PFN(range->start), 0,
+			range_len(range));
+	if (error)
+		goto err_pfn_remap;
+
+	if (!mhp_range_allowed(range->start, range_len(range), !is_private)) {
+		error = -EINVAL;
+		goto err_kasan;
+	}
+
+	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 (is_private) {
+		error = add_pages(nid, PHYS_PFN(range->start),
+				PHYS_PFN(range_len(range)), params);
+	} else {
+		error = kasan_add_zero_shadow(__va(range->start), range_len(range));
+		if (error) {
+			mem_hotplug_done();
+			goto err_kasan;
+		}
+
+		error = arch_add_memory(nid, range->start, range_len(range),
+					params);
+	}
+
+	if (!error) {
+		struct zone *zone;
+
+		zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
+		move_pfn_range_to_zone(zone, PHYS_PFN(range->start),
+				PHYS_PFN(range_len(range)), params->altmap,
+				MIGRATE_MOVABLE);
+	}
+
+	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],
+				PHYS_PFN(range->start),
+				PHYS_PFN(range_len(range)), pgmap);
+	if (pgmap->type != MEMORY_DEVICE_PRIVATE &&
+	    pgmap->type != MEMORY_DEVICE_COHERENT)
+		percpu_ref_get_many(&pgmap->ref, pfn_len(pgmap, range_id));
+	return 0;
+
+err_add_memory:
+	if (!is_private)
+		kasan_remove_zero_shadow(__va(range->start), range_len(range));
+err_kasan:
+	untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
+err_pfn_remap:
+	pgmap_array_delete(range);
+	return error;
+}
+
+
+/*
+ * Not device managed version of devm_memremap_pages, undone by
+ * memunmap_pages().  Please use devm_memremap_pages if you have a struct
+ * device available.
+ */
+void *memremap_pages(struct dev_pagemap *pgmap, int nid)
+{
+	struct mhp_params params = {
+		.altmap = pgmap_altmap(pgmap),
+		.pgmap = pgmap,
+		.pgprot = PAGE_KERNEL,
+	};
+	const int nr_range = pgmap->nr_range;
+	int error, i;
+
+	if (WARN_ONCE(!nr_range, "nr_range must be specified\n"))
+		return ERR_PTR(-EINVAL);
+
+	switch (pgmap->type) {
+	case MEMORY_DEVICE_PRIVATE:
+		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
+			WARN(1, "Device private memory not supported\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
+			WARN(1, "Missing migrate_to_ram method\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->ops->page_free) {
+			WARN(1, "Missing page_free method\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->owner) {
+			WARN(1, "Missing owner\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
+	case MEMORY_DEVICE_COHERENT:
+		if (!pgmap->ops->page_free) {
+			WARN(1, "Missing page_free method\n");
+			return ERR_PTR(-EINVAL);
+		}
+		if (!pgmap->owner) {
+			WARN(1, "Missing owner\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
+	case MEMORY_DEVICE_FS_DAX:
+		if (IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
+			WARN(1, "File system DAX not supported\n");
+			return ERR_PTR(-EINVAL);
+		}
+		params.pgprot = pgprot_decrypted(params.pgprot);
+		break;
+	case MEMORY_DEVICE_GENERIC:
+		break;
+	case MEMORY_DEVICE_PCI_P2PDMA:
+		params.pgprot = pgprot_noncached(params.pgprot);
+		break;
+	default:
+		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
+		break;
+	}
+
+	init_completion(&pgmap->done);
+	error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,
+				GFP_KERNEL);
+	if (error)
+		return ERR_PTR(error);
+
+	devmap_managed_enable_get(pgmap);
+
+	/*
+	 * Clear the pgmap nr_range as it will be incremented for each
+	 * successfully processed range. This communicates how many
+	 * regions to unwind in the abort case.
+	 */
+	pgmap->nr_range = 0;
+	error = 0;
+	for (i = 0; i < nr_range; i++) {
+		error = pagemap_range(pgmap, &params, i, nid);
+		if (error)
+			break;
+		pgmap->nr_range++;
+	}
+
+	if (i < nr_range) {
+		memunmap_pages(pgmap);
+		pgmap->nr_range = nr_range;
+		return ERR_PTR(error);
+	}
+
+	return __va(pgmap->ranges[0].start);
+}
+EXPORT_SYMBOL_GPL(memremap_pages);
+
+/**
+ * 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 range 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
+ *    PGMAP_ALTMAP_VALID must be set in pgmap->flags.
+ *
+ * 3/ The ref field may optionally be provided, in which 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/ range 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)
+{
+	int error;
+	void *ret;
+
+	ret = memremap_pages(pgmap, dev_to_node(dev));
+	if (IS_ERR(ret))
+		return ret;
+
+	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
+			pgmap);
+	if (error)
+		return ERR_PTR(error);
+	return ret;
+}
+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 */
+	if (altmap)
+		return altmap->reserve + altmap->free;
+	return 0;
+}
+
+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->range.start && phys <= pgmap->range.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_rcu(&pgmap->ref))
+		pgmap = NULL;
+	rcu_read_unlock();
+
+	return pgmap;
+}
+EXPORT_SYMBOL_GPL(get_dev_pagemap);
+
+void free_zone_device_page(struct page *page)
+{
+	if (WARN_ON_ONCE(!page->pgmap->ops || !page->pgmap->ops->page_free))
+		return;
+
+	mem_cgroup_uncharge(page_folio(page));
+
+	/*
+	 * Note: we don't expect anonymous compound pages yet. Once supported
+	 * and we could PTE-map them similar to THP, we'd have to clear
+	 * PG_anon_exclusive on all tail pages.
+	 */
+	VM_BUG_ON_PAGE(PageAnon(page) && PageCompound(page), page);
+	if (PageAnon(page))
+		__ClearPageAnonExclusive(page);
+
+	/*
+	 * When a device managed page is freed, the page->mapping field
+	 * may still contain a (stale) mapping value. For example, the
+	 * lower bits of page->mapping may still identify the page as an
+	 * anonymous page. Ultimately, this entire field is just stale
+	 * and wrong, and it will cause errors if not cleared.  One
+	 * example is:
+	 *
+	 *  migrate_vma_pages()
+	 *    migrate_vma_insert_page()
+	 *      page_add_new_anon_rmap()
+	 *        __page_set_anon_rmap()
+	 *          ...checks page->mapping, via PageAnon(page) call,
+	 *            and incorrectly concludes that the page is an
+	 *            anonymous page. Therefore, it incorrectly,
+	 *            silently fails to set up the new anon rmap.
+	 *
+	 * For other types of ZONE_DEVICE pages, migration is either
+	 * handled differently or not done at all, so there is no need
+	 * to clear page->mapping.
+	 */
+	page->mapping = NULL;
+	page->pgmap->ops->page_free(page);
+
+	if (page->pgmap->type != MEMORY_DEVICE_PRIVATE &&
+	    page->pgmap->type != MEMORY_DEVICE_COHERENT)
+		/*
+		 * Reset the page count to 1 to prepare for handing out the page
+		 * again.
+		 */
+		set_page_count(page, 1);
+	else
+		put_dev_pagemap(page->pgmap);
+}
+
+void zone_device_page_init(struct page *page)
+{
+	/*
+	 * Drivers shouldn't be allocating pages after calling
+	 * memunmap_pages().
+	 */
+	WARN_ON_ONCE(!percpu_ref_tryget_live(&page->pgmap->ref));
+	set_page_count(page, 1);
+	lock_page(page);
+}
+EXPORT_SYMBOL_GPL(zone_device_page_init);
+
+#ifdef CONFIG_FS_DAX
+bool __put_devmap_managed_page_refs(struct page *page, int refs)
+{
+	if (page->pgmap->type != MEMORY_DEVICE_FS_DAX)
+		return false;
+
+	/*
+	 * fsdax page refcounts are 1-based, rather than 0-based: if
+	 * refcount is 1, then the page is free and the refcount is
+	 * stable because nobody holds a reference on the page.
+	 */
+	if (page_ref_sub_return(page, refs) == 1)
+		wake_up_var(&page->_refcount);
+	return true;
+}
+EXPORT_SYMBOL(__put_devmap_managed_page_refs);
+#endif /* CONFIG_FS_DAX */