On Thu, Dec 18, 2014 at 09:51:26AM -0800, Bob Paauwe wrote: > When creating a fence for a tiled object, only fence the area that > makes up the actual tiles. The object may be larger than the tiled > area and if we allow those extra addresses to be fenced, they'll > get converted to addresses beyond where the object is mapped. This > opens up the possiblity of writes beyond the end of object. > > To prevent this, we adjust the size of the fence to only encompass > the area that makes up the actual tiles. The extra space is considered > un-tiled and now behaves as if it was a linear object. > > Testcase: igt/gem_tiled_fence_overflow > Reported-by: Dan Hettena <[email protected]> > Signed-off-by: Bob Paauwe <[email protected]>
Presuming this indeed blows up (I didn't try your test) this is one for Jani. Reviewed-by: Daniel Vetter <[email protected]> Cc: [email protected] Thanks, Daniel > --- > drivers/gpu/drm/i915/i915_gem.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index 67550ac..c9acbfa 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -3173,6 +3173,13 @@ static void i965_write_fence_reg(struct drm_device > *dev, int reg, > u32 size = i915_gem_obj_ggtt_size(obj); > uint64_t val; > > + /* Adjust fence size to match tiled area */ > + if (obj->tiling_mode != I915_TILING_NONE) { > + uint32_t row_size = obj->stride * > + (obj->tiling_mode == I915_TILING_Y ? 32 : 8); > + size = (size / row_size) * row_size; > + } > + > val = (uint64_t)((i915_gem_obj_ggtt_offset(obj) + size - 4096) & > 0xfffff000) << 32; > val |= i915_gem_obj_ggtt_offset(obj) & 0xfffff000; > -- > 2.1.0 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
