From eb1dba0ebaa5b7642b323fac148f9947522a48a8 Mon Sep 17 00:00:00 2001 From: Maarten Maathuis Date: Sun, 27 Dec 2009 12:22:07 +0100 Subject: [PATCH] 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: Maarten Maathuis Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_bo.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c index db0ed4c13f98..028719fddf76 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bo.c +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c @@ -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; -- 2.20.1