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

1 files changed, 13 insertions, 14 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 05a27723ebb8..ecd86130b74f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/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,
-			 struct i915_gem_object_page_iter *iter,
-			 unsigned int n,
-			 unsigned int *offset,
-			 bool dma)
+__i915_gem_object_page_iter_get_sg(struct drm_i915_gem_object *obj,
+				   struct i915_gem_object_page_iter *iter,
+				   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 @@ lookup:
 }
 
 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);
 }