rocr: Put back scratch_backing_memory_byte_size

The scratch_backing_memory_byte_size is not used by CP, but it is
currently used by rocgdb. Putting the field back, but we need to find a
solution for alt_scratch_backing_memory_byte_size.

Also, completely disabling alternate scratch as we need some changes to
support debugger.

runtime/hsa-runtime/core/runtime/amd_aql_queue.cpp

@@ -1993,6 +1993,15 @@ void AqlQueue::InitScratchSRD() {
   amd_queue_.alt_scratch_backing_memory_location = queue_scratch_.alt_queue_process_offset;
 
   const auto& agent_props = agent_->properties();
+  const uint32_t num_xcc = agent_props.NumXcc;
+
+  // FIXME:  amd_queue_.scratch_backing_memory_byte_size is not used by CP, but it
+  // is used by the debugger. Putting back the scratch_backing_memory_byte_size
+  // field. But we need to find a location for alt_scratch_backing_memory_byte_size
+
+  // report size per XCC
+  amd_queue_.scratch_backing_memory_byte_size = queue_scratch_.main_size / num_xcc;
+  //amd_queue_.alt_scratch_backing_memory_byte_size = queue_scratch_.alt_size / num_xcc;
 
   // For backwards compatibility this field records the per-lane scratch
   // for a 64 lane wavefront. If scratch was allocated for 32 lane waves

runtime/hsa-runtime/core/util/flag.h

@@ -154,9 +154,11 @@ class Flag {
     enable_scratch_async_reclaim_ = (var == "0") ? false : true;
 
     var = os::GetEnvVar("HSA_ENABLE_SCRATCH_ALT");
-    //Temporary: Disable alternate scratch by default as it can cause occasional hangs
+    // Temporary: Completely disable alternate scratch because we need to update
-    //enable_scratch_alt_ = (var == "0") || !enable_scratch_async_reclaim_ ? false : true;
+    // the debugger so that it can tell whether a dispatch is using alternate scratch
-    enable_scratch_alt_ = (var == "1") && enable_scratch_async_reclaim_ ? true : false;
+    // instead of main scratch
+    // enable_scratch_alt_ = (var == "0") || !enable_scratch_async_reclaim_ ? false : true;
+    enable_scratch_alt_ = false;
 
     tools_lib_names_ = os::GetEnvVar("HSA_TOOLS_LIB");
 

runtime/hsa-runtime/inc/amd_hsa_queue.h

@@ -133,7 +133,7 @@ typedef struct AMD_QUEUE_ALIGN amd_queue_v2_s {
   uint32_t compute_tmpring_size;
   uint32_t scratch_resource_descriptor[4];
   uint64_t scratch_backing_memory_location;
-  uint32_t reserved3[2];
+  uint64_t scratch_backing_memory_byte_size;
   uint32_t scratch_wave64_lane_byte_size;
   amd_queue_properties32_t queue_properties;
   volatile uint64_t scratch_max_use_index;       /* V2 */