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Commit eb1dba0e authored by Maarten Maathuis's avatar Maarten Maathuis Committed by Ben Skeggs
Browse files

drm/nv50: align size of buffer object to the right boundaries. 



- In the current situation the padding that is added is dangerous to write
  to, userspace could potentially overwrite parts of another bo.
- Depth and stencil buffers are supposed to be large enough in general so
  the waste of memory should be acceptable.
- Alternatives are hiding the padding from users or splitting vram into 2
  zones.

Signed-off-by: default avatarMaarten Maathuis <madman2003@gmail.com>
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent 5025b431

drivers/gpu/drm/nouveau/nouveau_bo.c

+5 −5
Original line number Diff line number Diff line
@@ -65,8 +65,10 @@ nouveau_bo_fixup_align(struct drm_device *dev, 


	/*

	 * Some of the tile_flags have a periodic structure of N*4096 bytes,

	 * align to to that as well as the page size. Overallocate memory to

	 * avoid corruption of other buffer objects.

	 * align to to that as well as the page size. Align the size to the

	 * appropriate boundaries. This does imply that sizes are rounded up

	 * 3-7 pages, so be aware of this and do not waste memory by allocating

	 * many small buffers.

	 */

	if (dev_priv->card_type == NV_50) {

		uint32_t block_size = nouveau_mem_fb_amount(dev) >> 15;
@@ -77,22 +79,20 @@ nouveau_bo_fixup_align(struct drm_device *dev, 
		case 0x2800:

		case 0x4800:

		case 0x7a00:

			*size = roundup(*size, block_size);

			if (is_power_of_2(block_size)) {

				*size += 3 * block_size;

				for (i = 1; i < 10; i++) {

					*align = 12 * i * block_size;

					if (!(*align % 65536))

						break;

				}

			} else {

				*size += 6 * block_size;

				for (i = 1; i < 10; i++) {

					*align = 8 * i * block_size;

					if (!(*align % 65536))

						break;

				}

			}

			*size = roundup(*size, *align);

			break;

		default:

			break;