drm/i915/gem: Typecheck page lookups

We need to check that we avoid integer overflows when looking up a page,
and so fix all the instances where we have mistakenly used a plain
integer instead of a more suitable long. Be pedantic and add integer
typechecking to the lookup so that we can be sure that we are safe.
And it also uses pgoff_t as our page lookups must remain compatible with
the page cache, pgoff_t is currently exactly unsigned long.

v2: Move added i915_utils's macro into drm_util header (Jani N)
v3: Make not use the same macro name on a function. (Mauro)
    For kernel-doc, macros and functions are handled in the same namespace,
    the same macro name on a function prevents ever adding documentation
    for it.
v4: Add kernel-doc markups to the kAPI functions and macros (Mauoro)
v5: Fix an alignment to match open parenthesis
v6: Rebase
v10: Use assert_typable instead of exactly_pgoff_t() macro. (Kees)
v11: Change the use of assert_typable to assert_same_typable (G.G)
v12: Change to use static_assert(__castable_to_type(n ,T)) style since
     the assert_same_typable() macro has been dropped. (G.G)
v13: Change the use of __castable_to_type() to castable_to_type()
     Remove an unnecessary header include line. (G.G)
v16: Fix "ERROR:SPACING" Checkpatch report (G.G)

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Co-developed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com> (v2)
Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org> (v3)
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com> (v5)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221228192252.917299-2-gwan-gyeong.mun@intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -427,10 +427,11 @@ void __i915_gem_object_invalidate_frontbuffer(struct drm_i915_gem_object *obj,
 static void
 i915_gem_object_read_from_page_kmap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
 {
+	pgoff_t idx = offset >> PAGE_SHIFT;
 	void *src_map;
 	void *src_ptr;
 
-	src_map = kmap_atomic(i915_gem_object_get_page(obj, offset >> PAGE_SHIFT));
+	src_map = kmap_atomic(i915_gem_object_get_page(obj, idx));
 
 	src_ptr = src_map + offset_in_page(offset);
 	if (!(obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_READ))
@@ -443,9 +444,10 @@ i915_gem_object_read_from_page_kmap(struct drm_i915_gem_object *obj, u64 offset,
 static void
 i915_gem_object_read_from_page_iomap(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
 {
+	pgoff_t idx = offset >> PAGE_SHIFT;
+	dma_addr_t dma = i915_gem_object_get_dma_address(obj, idx);
 	void __iomem *src_map;
 	void __iomem *src_ptr;
-	dma_addr_t dma = i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT);
 
 	src_map = io_mapping_map_wc(&obj->mm.region->iomap,
 				    dma - obj->mm.region->region.start,
@@ -484,6 +486,7 @@ static bool object_has_mappable_iomem(struct drm_i915_gem_object *obj)
  */
 int i915_gem_object_read_from_page(struct drm_i915_gem_object *obj, u64 offset, void *dst, int size)
 {
+	GEM_BUG_ON(overflows_type(offset >> PAGE_SHIFT, pgoff_t));
 	GEM_BUG_ON(offset >= obj->base.size);
 	GEM_BUG_ON(offset_in_page(offset) > PAGE_SIZE - size);
 	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));

drivers/gpu/drm/i915/gem/i915_gem_pages.c

@@ -521,14 +521,16 @@ void __i915_gem_object_release_map(struct drm_i915_gem_object *obj)
 }
 
 struct scatterlist *
-__i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
+__i915_gem_object_page_iter_get_sg(struct drm_i915_gem_object *obj,
 				   struct i915_gem_object_page_iter *iter,
-			 unsigned int n,
-			 unsigned int *offset,
-			 bool dma)
+				   pgoff_t n,
+				   unsigned int *offset)
+
 {
-	struct scatterlist *sg;
+	const bool dma = iter == &obj->mm.get_dma_page ||
+			 iter == &obj->ttm.get_io_page;
 	unsigned int idx, count;
+	struct scatterlist *sg;
 
 	might_sleep();
 	GEM_BUG_ON(n >= obj->base.size >> PAGE_SHIFT);
@@ -636,7 +638,7 @@ __i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
 }
 
 struct page *
-i915_gem_object_get_page(struct drm_i915_gem_object *obj, unsigned int n)
+__i915_gem_object_get_page(struct drm_i915_gem_object *obj, pgoff_t n)
 {
 	struct scatterlist *sg;
 	unsigned int offset;
@@ -649,8 +651,7 @@ i915_gem_object_get_page(struct drm_i915_gem_object *obj, unsigned int n)
 
 /* Like i915_gem_object_get_page(), but mark the returned page dirty */
 struct page *
-i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj,
-			       unsigned int n)
+__i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj, pgoff_t n)
 {
 	struct page *page;
 
@@ -662,9 +663,8 @@ i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj,
 }
 
 dma_addr_t
-i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
-				    unsigned long n,
-				    unsigned int *len)
+__i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
+				      pgoff_t n, unsigned int *len)
 {
 	struct scatterlist *sg;
 	unsigned int offset;
@@ -678,8 +678,7 @@ i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
 }
 
 dma_addr_t
-i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj,
-				unsigned long n)
+__i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj, pgoff_t n)
 {
 	return i915_gem_object_get_dma_address_len(obj, n, NULL);
 }

drivers/gpu/drm/i915/gem/i915_gem_ttm.c

@@ -689,7 +689,7 @@ static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
 	GEM_WARN_ON(bo->ttm);
 
 	base = obj->mm.region->iomap.base - obj->mm.region->region.start;
-	sg = __i915_gem_object_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs, true);
+	sg = i915_gem_object_page_iter_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs);
 
 	return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs;
 }

drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c

@@ -469,7 +469,8 @@ static int gpu_fill(struct intel_context *ce,
 static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
 {
 	const bool has_llc = HAS_LLC(to_i915(obj->base.dev));
-	unsigned int n, m, need_flush;
+	unsigned int need_flush;
+	unsigned long n, m;
 	int err;
 
 	i915_gem_object_lock(obj, NULL);
@@ -499,7 +500,8 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
 static noinline int cpu_check(struct drm_i915_gem_object *obj,
 			      unsigned int idx, unsigned int max)
 {
-	unsigned int n, m, needs_flush;
+	unsigned int needs_flush;
+	unsigned long n;
 	int err;
 
 	i915_gem_object_lock(obj, NULL);
@@ -508,7 +510,7 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
 		goto out_unlock;
 
 	for (n = 0; n < real_page_count(obj); n++) {
-		u32 *map;
+		u32 *map, m;
 
 		map = kmap_atomic(i915_gem_object_get_page(obj, n));
 		if (needs_flush & CLFLUSH_BEFORE)
@@ -516,7 +518,7 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
 
 		for (m = 0; m < max; m++) {
 			if (map[m] != m) {
-				pr_err("%pS: Invalid value at object %d page %d/%ld, offset %d/%d: found %x expected %x\n",
+				pr_err("%pS: Invalid value at object %d page %ld/%ld, offset %d/%d: found %x expected %x\n",
 				       __builtin_return_address(0), idx,
 				       n, real_page_count(obj), m, max,
 				       map[m], m);
@@ -527,7 +529,7 @@ static noinline int cpu_check(struct drm_i915_gem_object *obj,
 
 		for (; m < DW_PER_PAGE; m++) {
 			if (map[m] != STACK_MAGIC) {
-				pr_err("%pS: Invalid value at object %d page %d, offset %d: found %x expected %x (uninitialised)\n",
+				pr_err("%pS: Invalid value at object %d page %ld, offset %d: found %x expected %x (uninitialised)\n",
 				       __builtin_return_address(0), idx, n, m,
 				       map[m], STACK_MAGIC);
 				err = -EINVAL;

drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c

@@ -97,11 +97,11 @@ static int check_partial_mapping(struct drm_i915_gem_object *obj,
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_gtt_view view;
 	struct i915_vma *vma;
+	unsigned long offset;
 	unsigned long page;
 	u32 __iomem *io;
 	struct page *p;
 	unsigned int n;
-	u64 offset;
 	u32 *cpu;
 	int err;
 
@@ -158,7 +158,7 @@ static int check_partial_mapping(struct drm_i915_gem_object *obj,
 	cpu = kmap(p) + offset_in_page(offset);
 	drm_clflush_virt_range(cpu, sizeof(*cpu));
 	if (*cpu != (u32)page) {
-		pr_err("Partial view for %lu [%u] (offset=%llu, size=%u [%llu, row size %u], fence=%d, tiling=%d, stride=%d) misalignment, expected write to page (%llu + %u [0x%llx]) of 0x%x, found 0x%x\n",
+		pr_err("Partial view for %lu [%u] (offset=%llu, size=%u [%llu, row size %u], fence=%d, tiling=%d, stride=%d) misalignment, expected write to page (%lu + %u [0x%lx]) of 0x%x, found 0x%x\n",
 		       page, n,
 		       view.partial.offset,
 		       view.partial.size,
@@ -214,10 +214,10 @@ static int check_partial_mappings(struct drm_i915_gem_object *obj,
 	for_each_prime_number_from(page, 1, npages) {
 		struct i915_gtt_view view =
 			compute_partial_view(obj, page, MIN_CHUNK_PAGES);
+		unsigned long offset;
 		u32 __iomem *io;
 		struct page *p;
 		unsigned int n;
-		u64 offset;
 		u32 *cpu;
 
 		GEM_BUG_ON(view.partial.size > nreal);
@@ -254,7 +254,7 @@ static int check_partial_mappings(struct drm_i915_gem_object *obj,
 		cpu = kmap(p) + offset_in_page(offset);
 		drm_clflush_virt_range(cpu, sizeof(*cpu));
 		if (*cpu != (u32)page) {
-			pr_err("Partial view for %lu [%u] (offset=%llu, size=%u [%llu, row size %u], fence=%d, tiling=%d, stride=%d) misalignment, expected write to page (%llu + %u [0x%llx]) of 0x%x, found 0x%x\n",
+			pr_err("Partial view for %lu [%u] (offset=%llu, size=%u [%llu, row size %u], fence=%d, tiling=%d, stride=%d) misalignment, expected write to page (%lu + %u [0x%lx]) of 0x%x, found 0x%x\n",
 			       page, n,
 			       view.partial.offset,
 			       view.partial.size,

drivers/gpu/drm/i915/gem/selftests/i915_gem_object.c

@@ -33,10 +33,10 @@ static int igt_gem_object(void *arg)
 
 static int igt_gem_huge(void *arg)
 {
-	const unsigned int nreal = 509; /* just to be awkward */
+	const unsigned long nreal = 509; /* just to be awkward */
 	struct drm_i915_private *i915 = arg;
 	struct drm_i915_gem_object *obj;
-	unsigned int n;
+	unsigned long n;
 	int err;
 
 	/* Basic sanitycheck of our huge fake object allocation */
@@ -49,7 +49,7 @@ static int igt_gem_huge(void *arg)
 
 	err = i915_gem_object_pin_pages_unlocked(obj);
 	if (err) {
-		pr_err("Failed to allocate %u pages (%lu total), err=%d\n",
+		pr_err("Failed to allocate %lu pages (%lu total), err=%d\n",
 		       nreal, obj->base.size / PAGE_SIZE, err);
 		goto out;
 	}
@@ -57,7 +57,7 @@ static int igt_gem_huge(void *arg)
 	for (n = 0; n < obj->base.size / PAGE_SIZE; n++) {
 		if (i915_gem_object_get_page(obj, n) !=
 		    i915_gem_object_get_page(obj, n % nreal)) {
-			pr_err("Page lookup mismatch at index %u [%u]\n",
+			pr_err("Page lookup mismatch at index %lu [%lu]\n",
 			       n, n % nreal);
 			err = -EINVAL;
 			goto out_unpin;

drivers/gpu/drm/i915/i915_gem.c

@@ -229,8 +229,9 @@ i915_gem_shmem_pread(struct drm_i915_gem_object *obj,
 		     struct drm_i915_gem_pread *args)
 {
 	unsigned int needs_clflush;
-	unsigned int idx, offset;
 	char __user *user_data;
+	unsigned long offset;
+	pgoff_t idx;
 	u64 remain;
 	int ret;
 
@@ -383,13 +384,17 @@ i915_gem_gtt_pread(struct drm_i915_gem_object *obj,
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
+	unsigned long remain, offset;
 	intel_wakeref_t wakeref;
 	struct drm_mm_node node;
 	void __user *user_data;
 	struct i915_vma *vma;
-	u64 remain, offset;
 	int ret = 0;
 
+	if (overflows_type(args->size, remain) ||
+	    overflows_type(args->offset, offset))
+		return -EINVAL;
+
 	wakeref = intel_runtime_pm_get(&i915->runtime_pm);
 
 	vma = i915_gem_gtt_prepare(obj, &node, false);
@@ -540,13 +545,17 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj,
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
 	struct intel_runtime_pm *rpm = &i915->runtime_pm;
+	unsigned long remain, offset;
 	intel_wakeref_t wakeref;
 	struct drm_mm_node node;
 	struct i915_vma *vma;
-	u64 remain, offset;
 	void __user *user_data;
 	int ret = 0;
 
+	if (overflows_type(args->size, remain) ||
+	    overflows_type(args->offset, offset))
+		return -EINVAL;
+
 	if (i915_gem_object_has_struct_page(obj)) {
 		/*
 		 * Avoid waking the device up if we can fallback, as
@@ -654,8 +663,9 @@ i915_gem_shmem_pwrite(struct drm_i915_gem_object *obj,
 {
 	unsigned int partial_cacheline_write;
 	unsigned int needs_clflush;
-	unsigned int offset, idx;
 	void __user *user_data;
+	unsigned long offset;
+	pgoff_t idx;
 	u64 remain;
 	int ret;
 

drivers/gpu/drm/i915/i915_vma.c

@@ -936,7 +936,7 @@ rotate_pages(struct drm_i915_gem_object *obj, unsigned int offset,
 	     struct sg_table *st, struct scatterlist *sg)
 {
 	unsigned int column, row;
-	unsigned int src_idx;
+	pgoff_t src_idx;
 
 	for (column = 0; column < width; column++) {
 		unsigned int left;
@@ -1042,7 +1042,7 @@ add_padding_pages(unsigned int count,
 
 static struct scatterlist *
 remap_tiled_color_plane_pages(struct drm_i915_gem_object *obj,
-			      unsigned int offset, unsigned int alignment_pad,
+			      unsigned long offset, unsigned int alignment_pad,
 			      unsigned int width, unsigned int height,
 			      unsigned int src_stride, unsigned int dst_stride,
 			      struct sg_table *st, struct scatterlist *sg,
@@ -1101,7 +1101,7 @@ remap_tiled_color_plane_pages(struct drm_i915_gem_object *obj,
 
 static struct scatterlist *
 remap_contiguous_pages(struct drm_i915_gem_object *obj,
-		       unsigned int obj_offset,
+		       pgoff_t obj_offset,
 		       unsigned int count,
 		       struct sg_table *st, struct scatterlist *sg)
 {
@@ -1134,7 +1134,7 @@ remap_contiguous_pages(struct drm_i915_gem_object *obj,
 
 static struct scatterlist *
 remap_linear_color_plane_pages(struct drm_i915_gem_object *obj,
-			       unsigned int obj_offset, unsigned int alignment_pad,
+			       pgoff_t obj_offset, unsigned int alignment_pad,
 			       unsigned int size,
 			       struct sg_table *st, struct scatterlist *sg,
 			       unsigned int *gtt_offset)