vgsp: m84 - stage-4 CE read-back of the GR context image header and VEID0 subctx header

gsp_phys_rmcall_gr_img_probe=1: after the stage-4 GR sem proof the ladder
re-binds the rmcall channel to COPY0, copies image VA 0x2200000 and the subctx
header VA 0x22f3000 into the DST sysmem chunk through the real CE, dumps the
header pointers, and re-binds GR0. This is the missing read path for the
FBMEM context image (the GPC exception at QMD activation needs the image's
PATCH/PM/ZCULL/priv-map/global pointers and the subctx header content to be
compared against the expected VAs).

1 files changed, 19 insertions, 0 deletions

diff --git a/kernel/gsp_phys_gpu.c b/kernel/gsp_phys_gpu.c
index f094d36..e3ca2e8 100644
--- a/kernel/gsp_phys_gpu.c
+++ b/kernel/gsp_phys_gpu.c
@@ -796,6 +796,25 @@ unsigned int gsp_phys_rmcall_gr_lmem_tpc_size_value(void)
 EXPORT_SYMBOL_GPL(gsp_phys_rmcall_gr_lmem_tpc_size_value);
 
 /*
+ * m84 ctx-image probe (gsp_phys_rmcall_gr_img_probe; default 0). After the
+ * stage-4 GR sem proof the ladder re-binds the rmcall channel to COPY0,
+ * copies the first 4 KB of the MAIN context image and of the VEID0 subctx
+ * header into the DST sysmem chunk through the real CE, dumps them, and
+ * re-binds GR0. Diagnostic only; each failure is logged and ignored.
+ */
+static int gsp_phys_rmcall_gr_img_probe_param;
+module_param_named(gsp_phys_rmcall_gr_img_probe,
+		   gsp_phys_rmcall_gr_img_probe_param, int, 0644);
+MODULE_PARM_DESC(gsp_phys_rmcall_gr_img_probe,
+		 "Stage-4 CE read-back of the GR context image header + VEID0 subctx header (default 0)");
+
+int gsp_phys_rmcall_gr_img_probe_value(void)
+{
+	return gsp_phys_rmcall_gr_img_probe_param;
+}
+EXPORT_SYMBOL_GPL(gsp_phys_rmcall_gr_img_probe_value);
+
+/*
  * m83 sysmem error notifier (gsp_phys_rmcall_gr_notifier_sys; default 0).
  * The mode-35 V7 error notifier is normally a server FBMEM class-0x40 memory
  * object (unreadable). With 1 it is a host sysmem chunk registered as the