Kernel now starts a separate 'init' program

The 'init' program is the root process that is started by the kernel.
A separate 'init' program allows 'complex' child processes to fail and
call abort(), which was not possible if they where themselves the root
process.

Author: coderarjob

include/x86/asm/mos.inc

@@ -60,6 +60,7 @@
 
     %define BOOT1_FILE      "BOOT1   FLT"
     %define KERNEL_FILE     "KERNEL  FLT"
+    %define INIT_FILE       "INIT    FLT"
 %ifdef GRAPHICS_MODE_ENABLED
     %define GUI0_APP_FILE   "GUI0    FLT"
 %else

src/apps/CMakeLists.txt

@@ -61,9 +61,31 @@ link(
     LINK_LIBRARIES cm
     )
 
+# ---------------------------------------------------------------------------
+# Program - INIT
+# ---------------------------------------------------------------------------
+compile_lib(
+    NAME init
+    SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/init.c
+    FLAGS ${MOS_USER_GCC_FLAGS}
+    DEFINITIONS ${MOS_USER_GCC_DEFINITIONS} DEBUG PORT_E9_ENABLED
+    INCLUDE_DIRECTORIES ${MOS_USER_GCC_INCLUDE_DIRS}
+    )
+
+link(
+    FLATTEN
+    NAME init.flt
+    DEPENDS init crta
+    FLAGS ${MOS_LINKER_OPTIONS}
+    LINKER_FILE ${MOS_USER_LINKER_SCRIPT_FILE}
+    LINK_LIBRARIES cm
+    )
+
 #---------------------------------------------------------------------------
 # Add to the global 'build-all' target
 #---------------------------------------------------------------------------
+add_dependencies(build-all init.flt)
+
 if (MOS_GRAPHICS_ENABLED)
     add_dependencies(build-all gui0.flt)
 else()

src/apps/init.c

@@ -0,0 +1,31 @@
+/*
+ * -------------------------------------------------------------------------------------------------
+ * Megha Operating System V2 - Application - Init program
+ * -------------------------------------------------------------------------------------------------
+ */
+
+#include <cm.h>
+#include <debug.h>
+
+static void init_child_killed (OSIF_ProcessEvent const* const e)
+{
+#if defined(DEBUG) && defined(PORT_E9_ENABLED)
+    CM_DBG_INFO ("Child process exited. Code: %x", e->data);
+#else
+    (void)e;
+#endif
+}
+
+void proc_main()
+{
+    cm_process_register_event_handler (OSIF_PROCESS_EVENT_PROCCESS_CHILD_KILLED, init_child_killed);
+
+    cm_process_create ("MPDEMO.FLT", false);
+    while (1) {
+        cm_process_handle_events();
+    }
+
+    // Should not return!
+    // TODO: Place an assert() or panic() here.
+    CM_DBG_ERROR ("Init process returning");
+}

src/apps/mpdemo.c

@@ -84,8 +84,6 @@ void proc_main()
     wait_for_all_child_exit();
 
     cm_process_kill(1);
-    s_printString (37, 0, BLACK, WHITE,
-                   "Cannot kill process 0. Make kernel thread slower for demo.");
 }
 
 void thread0()

src/bootloader/x86/boot1/boot1.s

@@ -41,6 +41,7 @@ files:       db     KERNEL_FILE     , "KERNEL.FLT",0,0,0
              db     PROC1_FILE      , "PROC1.FLT",0,0,0,0
              db     MPDEMO_FILE     , "MPDEMO.FLT",0,0,0
 %endif
+             db     INIT_FILE       , "INIT.FLT",0,0,0,0,0
              db     0
 
 msg_welcome: db     13,10,OS_NAME,13,10

src/kernel/x86/kernel.c

@@ -220,15 +220,7 @@ static void run_root_process()
 {
     FUNC_ENTRY();
 
-#ifdef GRAPHICS_MODE_ENABLED
-    BootFileItem fileinfo = kboot_findBootFileItem("GUI0.FLT");
-#else
-    #ifdef MPDEMO
-    BootFileItem fileinfo = kboot_findBootFileItem("MPDEMO.FLT");
-    #else
-    BootFileItem fileinfo = kboot_findBootFileItem("PROC1.FLT");
-    #endif // MPDEMO
-#endif     // GRAPHICS_MODE_ENABLED
+    BootFileItem fileinfo = kboot_findBootFileItem("INIT.FLT");
 
     Physical startAddress = PHYSICAL (fileinfo.startLocation);
     SIZE lengthBytes      = (SIZE)fileinfo.length;