drm/nouveau/gr/gk104-: prevent reading non-existent regs in intr handler

Under certain circumstances the trapped address will contain subc 7,
which GK104 GR doesn't have anymore.

Notice this case to avoid causing additional priv ring faults.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c b/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c
index 3f05414c077ca3afffe106075dad10abd4fc7904..5606c25e5d02998fc415a5b9705d9a40868f2a10 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c
@@ -1097,9 +1097,14 @@ gf100_gr_intr(struct nvkm_subdev *subdev)
        u32 subc = (addr & 0x00070000) >> 16;
        u32 data = nv_rd32(priv, 0x400708);
        u32 code = nv_rd32(priv, 0x400110);
-       u32 class = nv_rd32(priv, 0x404200 + (subc * 4));
+       u32 class;
        int chid;
 
+       if (nv_device(priv)->card_type < NV_E0 || subc < 4)
+               class = nv_rd32(priv, 0x404200 + (subc * 4));
+       else
+               class = 0x0000;
+
        engctx = nvkm_engctx_get(engine, inst);
        chid   = pfifo->chid(pfifo, engctx);