1 files changed, 418 insertions, 229 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 5e93a52d4f2c..611d20ab966d 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
 /**************************************************************************
  *
  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
@@ -30,174 +31,149 @@
 
 #define pr_fmt(fmt) "[TTM] " fmt
 
+#include <linux/cc_platform.h>
+#include <linux/debugfs.h>
+#include <linux/export.h>
+#include <linux/file.h>
+#include <linux/module.h>
 #include <linux/sched.h>
-#include <linux/highmem.h>
-#include <linux/pagemap.h>
 #include <linux/shmem_fs.h>
-#include <linux/file.h>
-#include <linux/swap.h>
-#include <linux/slab.h>
-#include <linux/export.h>
 #include <drm/drm_cache.h>
-#include <drm/drm_mem_util.h>
-#include <drm/ttm/ttm_module.h>
-#include <drm/ttm/ttm_bo_driver.h>
-#include <drm/ttm/ttm_placement.h>
-#include <drm/ttm/ttm_page_alloc.h>
+#include <drm/drm_device.h>
+#include <drm/drm_print.h>
+#include <drm/drm_util.h>
+#include <drm/ttm/ttm_backup.h>
+#include <drm/ttm/ttm_bo.h>
+#include <drm/ttm/ttm_tt.h>
 
-/**
- * Allocates storage for pointers to the pages that back the ttm.
- */
-static void ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
-{
-	ttm->pages = drm_calloc_large(ttm->num_pages, sizeof(void*));
-}
+#include "ttm_module.h"
+#include "ttm_pool_internal.h"
 
-static void ttm_dma_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
-{
-	ttm->ttm.pages = drm_calloc_large(ttm->ttm.num_pages, sizeof(void*));
-	ttm->dma_address = drm_calloc_large(ttm->ttm.num_pages,
-					    sizeof(*ttm->dma_address));
-}
+static unsigned long ttm_pages_limit;
 
-#ifdef CONFIG_X86
-static inline int ttm_tt_set_page_caching(struct page *p,
-					  enum ttm_caching_state c_old,
-					  enum ttm_caching_state c_new)
-{
-	int ret = 0;
+MODULE_PARM_DESC(pages_limit, "Limit for the allocated pages");
+module_param_named(pages_limit, ttm_pages_limit, ulong, 0644);
 
-	if (PageHighMem(p))
-		return 0;
+static unsigned long ttm_dma32_pages_limit;
 
-	if (c_old != tt_cached) {
-		/* p isn't in the default caching state, set it to
-		 * writeback first to free its current memtype. */
+MODULE_PARM_DESC(dma32_pages_limit, "Limit for the allocated DMA32 pages");
+module_param_named(dma32_pages_limit, ttm_dma32_pages_limit, ulong, 0644);
 
-		ret = set_pages_wb(p, 1);
-		if (ret)
-			return ret;
-	}
-
-	if (c_new == tt_wc)
-		ret = set_memory_wc((unsigned long) page_address(p), 1);
-	else if (c_new == tt_uncached)
-		ret = set_pages_uc(p, 1);
-
-	return ret;
-}
-#else /* CONFIG_X86 */
-static inline int ttm_tt_set_page_caching(struct page *p,
-					  enum ttm_caching_state c_old,
-					  enum ttm_caching_state c_new)
-{
-	return 0;
-}
-#endif /* CONFIG_X86 */
+static atomic_long_t ttm_pages_allocated;
+static atomic_long_t ttm_dma32_pages_allocated;
 
 /*
- * Change caching policy for the linear kernel map
- * for range of pages in a ttm.
+ * Allocates a ttm structure for the given BO.
  */
-
-static int ttm_tt_set_caching(struct ttm_tt *ttm,
-			      enum ttm_caching_state c_state)
+int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc)
 {
-	int i, j;
-	struct page *cur_page;
-	int ret;
+	struct ttm_device *bdev = bo->bdev;
+	struct drm_device *ddev = bo->base.dev;
+	uint32_t page_flags = 0;
 
-	if (ttm->caching_state == c_state)
-		return 0;
+	dma_resv_assert_held(bo->base.resv);
 
-	if (ttm->state == tt_unpopulated) {
-		/* Change caching but don't populate */
-		ttm->caching_state = c_state;
+	if (bo->ttm)
 		return 0;
-	}
-
-	if (ttm->caching_state == tt_cached)
-		drm_clflush_pages(ttm->pages, ttm->num_pages);
 
-	for (i = 0; i < ttm->num_pages; ++i) {
-		cur_page = ttm->pages[i];
-		if (likely(cur_page != NULL)) {
-			ret = ttm_tt_set_page_caching(cur_page,
-						      ttm->caching_state,
-						      c_state);
-			if (unlikely(ret != 0))
-				goto out_err;
-		}
+	switch (bo->type) {
+	case ttm_bo_type_device:
+		if (zero_alloc)
+			page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
+		break;
+	case ttm_bo_type_kernel:
+		break;
+	case ttm_bo_type_sg:
+		page_flags |= TTM_TT_FLAG_EXTERNAL;
+		break;
+	default:
+		pr_err("Illegal buffer object type\n");
+		return -EINVAL;
+	}
+	/*
+	 * When using dma_alloc_coherent with memory encryption the
+	 * mapped TT pages need to be decrypted or otherwise the drivers
+	 * will end up sending encrypted mem to the gpu.
+	 */
+	if (ttm_pool_uses_dma_alloc(&bdev->pool) &&
+	    cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
+		page_flags |= TTM_TT_FLAG_DECRYPTED;
+		drm_info_once(ddev, "TT memory decryption enabled.");
 	}
 
-	ttm->caching_state = c_state;
-
-	return 0;
+	bo->ttm = bdev->funcs->ttm_tt_create(bo, page_flags);
+	if (unlikely(bo->ttm == NULL))
+		return -ENOMEM;
 
-out_err:
-	for (j = 0; j < i; ++j) {
-		cur_page = ttm->pages[j];
-		if (likely(cur_page != NULL)) {
-			(void)ttm_tt_set_page_caching(cur_page, c_state,
-						      ttm->caching_state);
-		}
-	}
+	WARN_ON(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE &&
+		!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL));
 
-	return ret;
+	return 0;
 }
+EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_tt_create);
 
-int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
+/*
+ * Allocates storage for pointers to the pages that back the ttm.
+ */
+static int ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
-	enum ttm_caching_state state;
-
-	if (placement & TTM_PL_FLAG_WC)
-		state = tt_wc;
-	else if (placement & TTM_PL_FLAG_UNCACHED)
-		state = tt_uncached;
-	else
-		state = tt_cached;
+	ttm->pages = kvcalloc(ttm->num_pages, sizeof(void*), GFP_KERNEL);
+	if (!ttm->pages)
+		return -ENOMEM;
 
-	return ttm_tt_set_caching(ttm, state);
+	return 0;
 }
-EXPORT_SYMBOL(ttm_tt_set_placement_caching);
 
-void ttm_tt_destroy(struct ttm_tt *ttm)
+static int ttm_dma_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
-	if (unlikely(ttm == NULL))
-		return;
+	ttm->pages = kvcalloc(ttm->num_pages, sizeof(*ttm->pages) +
+			      sizeof(*ttm->dma_address), GFP_KERNEL);
+	if (!ttm->pages)
+		return -ENOMEM;
 
-	if (ttm->state == tt_bound) {
-		ttm_tt_unbind(ttm);
-	}
+	ttm->dma_address = (void *)(ttm->pages + ttm->num_pages);
+	return 0;
+}
 
-	if (likely(ttm->pages != NULL)) {
-		ttm->bdev->driver->ttm_tt_unpopulate(ttm);
-	}
+static int ttm_sg_tt_alloc_page_directory(struct ttm_tt *ttm)
+{
+	ttm->dma_address = kvcalloc(ttm->num_pages, sizeof(*ttm->dma_address),
+				    GFP_KERNEL);
+	if (!ttm->dma_address)
+		return -ENOMEM;
 
-	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP) &&
-	    ttm->swap_storage)
-		fput(ttm->swap_storage);
+	return 0;
+}
 
-	ttm->swap_storage = NULL;
-	ttm->func->destroy(ttm);
+void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
+{
+	bdev->funcs->ttm_tt_destroy(bdev, ttm);
 }
+EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_tt_destroy);
 
-int ttm_tt_init(struct ttm_tt *ttm, struct ttm_bo_device *bdev,
-		unsigned long size, uint32_t page_flags,
-		struct page *dummy_read_page)
+static void ttm_tt_init_fields(struct ttm_tt *ttm,
+			       struct ttm_buffer_object *bo,
+			       uint32_t page_flags,
+			       enum ttm_caching caching,
+			       unsigned long extra_pages)
 {
-	ttm->bdev = bdev;
-	ttm->glob = bdev->glob;
-	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	ttm->caching_state = tt_cached;
+	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
 	ttm->page_flags = page_flags;
-	ttm->dummy_read_page = dummy_read_page;
-	ttm->state = tt_unpopulated;
+	ttm->dma_address = NULL;
 	ttm->swap_storage = NULL;
+	ttm->sg = bo->sg;
+	ttm->caching = caching;
+	ttm->restore = NULL;
+	ttm->backup = NULL;
+}
+
+int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
+		uint32_t page_flags, enum ttm_caching caching,
+		unsigned long extra_pages)
+{
+	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);
 
-	ttm_tt_alloc_page_directory(ttm);
-	if (!ttm->pages) {
-		ttm_tt_destroy(ttm);
+	if (ttm_tt_alloc_page_directory(ttm)) {
 		pr_err("Failed allocating page table\n");
 		return -ENOMEM;
 	}
@@ -207,82 +183,46 @@ EXPORT_SYMBOL(ttm_tt_init);
 
 void ttm_tt_fini(struct ttm_tt *ttm)
 {
-	drm_free_large(ttm->pages);
-	ttm->pages = NULL;
-}
-EXPORT_SYMBOL(ttm_tt_fini);
+	WARN_ON(ttm->page_flags & TTM_TT_FLAG_PRIV_POPULATED);
 
-int ttm_dma_tt_init(struct ttm_dma_tt *ttm_dma, struct ttm_bo_device *bdev,
-		unsigned long size, uint32_t page_flags,
-		struct page *dummy_read_page)
-{
-	struct ttm_tt *ttm = &ttm_dma->ttm;
-
-	ttm->bdev = bdev;
-	ttm->glob = bdev->glob;
-	ttm->num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	ttm->caching_state = tt_cached;
-	ttm->page_flags = page_flags;
-	ttm->dummy_read_page = dummy_read_page;
-	ttm->state = tt_unpopulated;
+	if (ttm->swap_storage)
+		fput(ttm->swap_storage);
 	ttm->swap_storage = NULL;
 
-	INIT_LIST_HEAD(&ttm_dma->pages_list);
-	ttm_dma_tt_alloc_page_directory(ttm_dma);
-	if (!ttm->pages || !ttm_dma->dma_address) {
-		ttm_tt_destroy(ttm);
-		pr_err("Failed allocating page table\n");
-		return -ENOMEM;
+	if (ttm_tt_is_backed_up(ttm))
+		ttm_pool_drop_backed_up(ttm);
+	if (ttm->backup) {
+		ttm_backup_fini(ttm->backup);
+		ttm->backup = NULL;
 	}
-	return 0;
-}
-EXPORT_SYMBOL(ttm_dma_tt_init);
-
-void ttm_dma_tt_fini(struct ttm_dma_tt *ttm_dma)
-{
-	struct ttm_tt *ttm = &ttm_dma->ttm;
 
-	drm_free_large(ttm->pages);
+	if (ttm->pages)
+		kvfree(ttm->pages);
+	else
+		kvfree(ttm->dma_address);
 	ttm->pages = NULL;
-	drm_free_large(ttm_dma->dma_address);
-	ttm_dma->dma_address = NULL;
+	ttm->dma_address = NULL;
 }
-EXPORT_SYMBOL(ttm_dma_tt_fini);
+EXPORT_SYMBOL(ttm_tt_fini);
 
-void ttm_tt_unbind(struct ttm_tt *ttm)
+int ttm_sg_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
+		   uint32_t page_flags, enum ttm_caching caching)
 {
 	int ret;
 
-	if (ttm->state == tt_bound) {
-		ret = ttm->func->unbind(ttm);
-		BUG_ON(ret);
-		ttm->state = tt_unbound;
-	}
-}
-
-int ttm_tt_bind(struct ttm_tt *ttm, struct ttm_mem_reg *bo_mem)
-{
-	int ret = 0;
-
-	if (!ttm)
-		return -EINVAL;
-
-	if (ttm->state == tt_bound)
-		return 0;
-
-	ret = ttm->bdev->driver->ttm_tt_populate(ttm);
-	if (ret)
-		return ret;
-
-	ret = ttm->func->bind(ttm, bo_mem);
-	if (unlikely(ret != 0))
-		return ret;
-
-	ttm->state = tt_bound;
+	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);
 
+	if (page_flags & TTM_TT_FLAG_EXTERNAL)
+		ret = ttm_sg_tt_alloc_page_directory(ttm);
+	else
+		ret = ttm_dma_tt_alloc_page_directory(ttm);
+	if (ret) {
+		pr_err("Failed allocating page table\n");
+		return -ENOMEM;
+	}
 	return 0;
 }
-EXPORT_SYMBOL(ttm_tt_bind);
+EXPORT_SYMBOL(ttm_sg_tt_init);
 
 int ttm_tt_swapin(struct ttm_tt *ttm)
 {
@@ -290,88 +230,337 @@ int ttm_tt_swapin(struct ttm_tt *ttm)
 	struct file *swap_storage;
 	struct page *from_page;
 	struct page *to_page;
-	int i;
-	int ret = -ENOMEM;
+	gfp_t gfp_mask;
+	int i, ret;
 
 	swap_storage = ttm->swap_storage;
 	BUG_ON(swap_storage == NULL);
 
-	swap_space = file_inode(swap_storage)->i_mapping;
+	swap_space = swap_storage->f_mapping;
+	gfp_mask = mapping_gfp_mask(swap_space);
 
 	for (i = 0; i < ttm->num_pages; ++i) {
-		from_page = shmem_read_mapping_page(swap_space, i);
+		from_page = shmem_read_mapping_page_gfp(swap_space, i,
+							gfp_mask);
 		if (IS_ERR(from_page)) {
 			ret = PTR_ERR(from_page);
 			goto out_err;
 		}
 		to_page = ttm->pages[i];
-		if (unlikely(to_page == NULL))
+		if (unlikely(to_page == NULL)) {
+			ret = -ENOMEM;
 			goto out_err;
+		}
 
 		copy_highpage(to_page, from_page);
-		page_cache_release(from_page);
+		put_page(from_page);
 	}
 
-	if (!(ttm->page_flags & TTM_PAGE_FLAG_PERSISTENT_SWAP))
-		fput(swap_storage);
+	fput(swap_storage);
 	ttm->swap_storage = NULL;
-	ttm->page_flags &= ~TTM_PAGE_FLAG_SWAPPED;
+	ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
 
 	return 0;
+
 out_err:
 	return ret;
 }
+EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_tt_swapin);
 
-int ttm_tt_swapout(struct ttm_tt *ttm, struct file *persistent_swap_storage)
+/**
+ * ttm_tt_backup() - Helper to back up a struct ttm_tt.
+ * @bdev: The TTM device.
+ * @tt: The struct ttm_tt.
+ * @flags: Flags that govern the backup behaviour.
+ *
+ * Update the page accounting and call ttm_pool_shrink_tt to free pages
+ * or back them up.
+ *
+ * Return: Number of pages freed or swapped out, or negative error code on
+ * error.
+ */
+long ttm_tt_backup(struct ttm_device *bdev, struct ttm_tt *tt,
+		   const struct ttm_backup_flags flags)
 {
+	long ret;
+
+	if (WARN_ON(IS_ERR_OR_NULL(tt->backup)))
+		return 0;
+
+	ret = ttm_pool_backup(&bdev->pool, tt, &flags);
+	if (ret > 0) {
+		tt->page_flags &= ~TTM_TT_FLAG_PRIV_POPULATED;
+		tt->page_flags |= TTM_TT_FLAG_BACKED_UP;
+	}
+
+	return ret;
+}
+
+int ttm_tt_restore(struct ttm_device *bdev, struct ttm_tt *tt,
+		   const struct ttm_operation_ctx *ctx)
+{
+	int ret = ttm_pool_restore_and_alloc(&bdev->pool, tt, ctx);
+
+	if (ret)
+		return ret;
+
+	tt->page_flags &= ~TTM_TT_FLAG_BACKED_UP;
+
+	return 0;
+}
+EXPORT_SYMBOL(ttm_tt_restore);
+
+/**
+ * ttm_tt_swapout - swap out tt object
+ *
+ * @bdev: TTM device structure.
+ * @ttm: The struct ttm_tt.
+ * @gfp_flags: Flags to use for memory allocation.
+ *
+ * Swapout a TT object to a shmem_file, return number of pages swapped out or
+ * negative error code.
+ */
+int ttm_tt_swapout(struct ttm_device *bdev, struct ttm_tt *ttm,
+		   gfp_t gfp_flags)
+{
+	loff_t size = (loff_t)ttm->num_pages << PAGE_SHIFT;
 	struct address_space *swap_space;
 	struct file *swap_storage;
 	struct page *from_page;
 	struct page *to_page;
-	int i;
-	int ret = -ENOMEM;
-
-	BUG_ON(ttm->state != tt_unbound && ttm->state != tt_unpopulated);
-	BUG_ON(ttm->caching_state != tt_cached);
-
-	if (!persistent_swap_storage) {
-		swap_storage = shmem_file_setup("ttm swap",
-						ttm->num_pages << PAGE_SHIFT,
-						0);
-		if (unlikely(IS_ERR(swap_storage))) {
-			pr_err("Failed allocating swap storage\n");
-			return PTR_ERR(swap_storage);
-		}
-	} else
-		swap_storage = persistent_swap_storage;
+	int i, ret;
 
-	swap_space = file_inode(swap_storage)->i_mapping;
+	swap_storage = shmem_file_setup("ttm swap", size, 0);
+	if (IS_ERR(swap_storage)) {
+		pr_err("Failed allocating swap storage\n");
+		return PTR_ERR(swap_storage);
+	}
+
+	swap_space = swap_storage->f_mapping;
+	gfp_flags &= mapping_gfp_mask(swap_space);
 
 	for (i = 0; i < ttm->num_pages; ++i) {
 		from_page = ttm->pages[i];
 		if (unlikely(from_page == NULL))
 			continue;
-		to_page = shmem_read_mapping_page(swap_space, i);
-		if (unlikely(IS_ERR(to_page))) {
+
+		to_page = shmem_read_mapping_page_gfp(swap_space, i, gfp_flags);
+		if (IS_ERR(to_page)) {
 			ret = PTR_ERR(to_page);
 			goto out_err;
 		}
 		copy_highpage(to_page, from_page);
 		set_page_dirty(to_page);
 		mark_page_accessed(to_page);
-		page_cache_release(to_page);
+		put_page(to_page);
 	}
 
-	ttm->bdev->driver->ttm_tt_unpopulate(ttm);
+	ttm_tt_unpopulate(bdev, ttm);
 	ttm->swap_storage = swap_storage;
-	ttm->page_flags |= TTM_PAGE_FLAG_SWAPPED;
-	if (persistent_swap_storage)
-		ttm->page_flags |= TTM_PAGE_FLAG_PERSISTENT_SWAP;
+	ttm->page_flags |= TTM_TT_FLAG_SWAPPED;
+
+	return ttm->num_pages;
 
-	return 0;
 out_err:
-	if (!persistent_swap_storage)
-		fput(swap_storage);
+	fput(swap_storage);
 
 	return ret;
 }
+EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_tt_swapout);
+
+int ttm_tt_populate(struct ttm_device *bdev,
+		    struct ttm_tt *ttm, struct ttm_operation_ctx *ctx)
+{
+	int ret;
+
+	if (!ttm)
+		return -EINVAL;
+
+	if (ttm_tt_is_populated(ttm))
+		return 0;
+
+	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
+		atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
+		if (ttm_pool_uses_dma32(&bdev->pool))
+			atomic_long_add(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
+
+	while (atomic_long_read(&ttm_pages_allocated) > ttm_pages_limit ||
+	       atomic_long_read(&ttm_dma32_pages_allocated) >
+	       ttm_dma32_pages_limit) {
+
+		ret = ttm_global_swapout(ctx, GFP_KERNEL);
+		if (ret == 0)
+			break;
+		if (ret < 0)
+			goto error;
+	}
+
+	if (bdev->funcs->ttm_tt_populate)
+		ret = bdev->funcs->ttm_tt_populate(bdev, ttm, ctx);
+	else
+		ret = ttm_pool_alloc(&bdev->pool, ttm, ctx);
+	if (ret)
+		goto error;
+
+	ttm->page_flags |= TTM_TT_FLAG_PRIV_POPULATED;
+	ttm->page_flags &= ~TTM_TT_FLAG_BACKED_UP;
+	if (unlikely(ttm->page_flags & TTM_TT_FLAG_SWAPPED)) {
+		ret = ttm_tt_swapin(ttm);
+		if (unlikely(ret != 0)) {
+			ttm_tt_unpopulate(bdev, ttm);
+			return ret;
+		}
+	}
+
+	return 0;
+
+error:
+	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
+		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
+		if (ttm_pool_uses_dma32(&bdev->pool))
+			atomic_long_sub(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
+	return ret;
+}
+
+#if IS_ENABLED(CONFIG_DRM_TTM_KUNIT_TEST)
+EXPORT_SYMBOL(ttm_tt_populate);
+#endif
+
+void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
+{
+	if (!ttm_tt_is_populated(ttm))
+		return;
+
+	if (bdev->funcs->ttm_tt_unpopulate)
+		bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
+	else
+		ttm_pool_free(&bdev->pool, ttm);
+
+	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
+		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
+		if (ttm_pool_uses_dma32(&bdev->pool))
+			atomic_long_sub(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
+
+	ttm->page_flags &= ~TTM_TT_FLAG_PRIV_POPULATED;
+}
+EXPORT_SYMBOL_FOR_TESTS_ONLY(ttm_tt_unpopulate);
+
+#ifdef CONFIG_DEBUG_FS
+
+/* Test the shrinker functions and dump the result */
+static int ttm_tt_debugfs_shrink_show(struct seq_file *m, void *data)
+{
+	struct ttm_operation_ctx ctx = { false, false };
+
+	seq_printf(m, "%d\n", ttm_global_swapout(&ctx, GFP_KERNEL));
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ttm_tt_debugfs_shrink);
+
+#endif
+
+
+/*
+ * ttm_tt_mgr_init - register with the MM shrinker
+ *
+ * Register with the MM shrinker for swapping out BOs.
+ */
+void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages)
+{
+#ifdef CONFIG_DEBUG_FS
+	debugfs_create_file("tt_shrink", 0400, ttm_debugfs_root, NULL,
+			    &ttm_tt_debugfs_shrink_fops);
+#endif
+
+	if (!ttm_pages_limit)
+		ttm_pages_limit = num_pages;
+
+	if (!ttm_dma32_pages_limit)
+		ttm_dma32_pages_limit = num_dma32_pages;
+}
+
+static void ttm_kmap_iter_tt_map_local(struct ttm_kmap_iter *iter,
+				       struct iosys_map *dmap,
+				       pgoff_t i)
+{
+	struct ttm_kmap_iter_tt *iter_tt =
+		container_of(iter, typeof(*iter_tt), base);
+
+	iosys_map_set_vaddr(dmap, kmap_local_page_prot(iter_tt->tt->pages[i],
+						       iter_tt->prot));
+}
+
+static void ttm_kmap_iter_tt_unmap_local(struct ttm_kmap_iter *iter,
+					 struct iosys_map *map)
+{
+	kunmap_local(map->vaddr);
+}
+
+static const struct ttm_kmap_iter_ops ttm_kmap_iter_tt_ops = {
+	.map_local = ttm_kmap_iter_tt_map_local,
+	.unmap_local = ttm_kmap_iter_tt_unmap_local,
+	.maps_tt = true,
+};
+
+/**
+ * ttm_kmap_iter_tt_init - Initialize a struct ttm_kmap_iter_tt
+ * @iter_tt: The struct ttm_kmap_iter_tt to initialize.
+ * @tt: Struct ttm_tt holding page pointers of the struct ttm_resource.
+ *
+ * Return: Pointer to the embedded struct ttm_kmap_iter.
+ */
+struct ttm_kmap_iter *
+ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
+		      struct ttm_tt *tt)
+{
+	iter_tt->base.ops = &ttm_kmap_iter_tt_ops;
+	iter_tt->tt = tt;
+	if (tt)
+		iter_tt->prot = ttm_prot_from_caching(tt->caching, PAGE_KERNEL);
+	else
+		iter_tt->prot = PAGE_KERNEL;
+
+	return &iter_tt->base;
+}
+EXPORT_SYMBOL(ttm_kmap_iter_tt_init);
+
+unsigned long ttm_tt_pages_limit(void)
+{
+	return ttm_pages_limit;
+}
+EXPORT_SYMBOL(ttm_tt_pages_limit);
+
+/**
+ * ttm_tt_setup_backup() - Allocate and assign a backup structure for a ttm_tt
+ * @tt: The ttm_tt for wich to allocate and assign a backup structure.
+ *
+ * Assign a backup structure to be used for tt backup. This should
+ * typically be done at bo creation, to avoid allocations at shrinking
+ * time.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int ttm_tt_setup_backup(struct ttm_tt *tt)
+{
+	struct file *backup =
+		ttm_backup_shmem_create(((loff_t)tt->num_pages) << PAGE_SHIFT);
+
+	if (WARN_ON_ONCE(!(tt->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE)))
+		return -EINVAL;
+
+	if (IS_ERR(backup))
+		return PTR_ERR(backup);
+
+	if (tt->backup)
+		ttm_backup_fini(tt->backup);
+
+	tt->backup = backup;
+	return 0;
+}
+EXPORT_SYMBOL(ttm_tt_setup_backup);