Introduce RSMI_DEBUG_INFINITE_LOOP

The environment variable RSMI_DEBUG_INFINITE_LOOP is introduced
to facilitate debugging RSMI in user applications. When this
env. variable is non-zero, an infinite loop will be entered in
rsmi_init(). At this point, a debugger can be attached and RSMI
can be debugger. This only applies to debug builds.

Change-Id: I23f6dd730fc965764295070de053314a1cc5b6aa

include/rocm_smi/rocm_smi_common.h

@@ -143,6 +143,13 @@ struct rsmi_func_id_iter_handle {
 };
 
 struct RocmSMI_env_vars {
+    // If RSMI_DEBUG_INFINITE_LOOP is non-zero, rsmi_init() will go into
+    // an infinite loop in debug builds. For release builds, this is
+    // ignored. This is useful for debugging RSMI applications with
+    // gdb. After attaching with gdb, the inf. loop can be exited and
+    // RSMI can be debugged.
+    uint32_t debug_inf_loop;
+
     // Bitfield that is AND'd with various RSMI_DEBUG_* bits to determine
     // which debugging information should be turned on. Env. variable
     // RSMI_DEBUG_BITFIELD is used to set all the debug info bits.

src/rocm_smi_main.cc

@@ -258,6 +258,8 @@ RocmSMI::Initialize(uint64_t flags) {
 
   GetEnvVariables();
 
+  while (env_vars_.debug_inf_loop) {}
+
   while (std::string(kAMDMonitorTypes[i]) != "") {
       amd_monitor_types_.insert(kAMDMonitorTypes[i]);
       ++i;
@@ -386,12 +388,14 @@ void RocmSMI::GetEnvVariables(void) {
   env_vars_.path_HWMon_root_override = nullptr;
   env_vars_.path_power_root_override = nullptr;
   env_vars_.enum_override = 0;
+  env_vars_.debug_inf_loop = 0;
 #else
   env_vars_.debug_output_bitfield = GetEnvVarUInteger("RSMI_DEBUG_BITFIELD");
   env_vars_.path_DRM_root_override   = getenv("RSMI_DEBUG_DRM_ROOT_OVERRIDE");
   env_vars_.path_HWMon_root_override = getenv("RSMI_DEBUG_HWMON_ROOT_OVERRIDE");
   env_vars_.path_power_root_override = getenv("RSMI_DEBUG_PP_ROOT_OVERRIDE");
   env_vars_.enum_override = GetEnvVarUInteger("RSMI_DEBUG_ENUM_OVERRIDE");
+  env_vars_.debug_inf_loop = GetEnvVarUInteger("RSMI_DEBUG_INFINITE_LOOP");
 #endif
 }