[Mesa-dev] [PATCH v2] nvc0/ir: clamp the UBO index for compute on Kepler

[Samuel Pitoiset]

We already check that the address is not "too far", but we should also
clamp the UBO index in order to avoid looking at the wrong place in the
driver cb. This is a pretty rare situation though.

v2: clamp the file index too

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Cc: "12.0" <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
index cb82216..52cb438 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
@@ -2183,7 +2183,15 @@ NVC0LoweringPass::handleLDST(Instruction *i)
          int8_t fileIndex = i->getSrc(0)->reg.fileIndex - 1;
          Value *ind = i->getIndirect(0, 1);
 
-         // TODO: clamp the offset to the maximum number of const buf.
+         if (ind) {
+            // Clamp the UBO index when an indirect access is used to avoid
+            // loading information from the wrong place in the driver cb.
+            ind = bld.mkOp2v(OP_MIN, TYPE_U32, ind,
+                             bld.mkOp2v(OP_ADD, TYPE_U32, bld.getSSA(),
+                                        bld.loadImm(NULL, fileIndex), ind),
+                             bld.loadImm(NULL, 12));
+         }
+
          if (i->src(0).isIndirect(1)) {
             Value *offset = bld.loadImm(NULL, i->getSrc(0)->reg.data.offset + typeSizeof(i->sType));
             Value *ptr = loadUboInfo64(ind, fileIndex * 16);
-- 
2.8.3