base: setup thread object for main thread in CRT0

For a main thread a thread object is created by the CRT0 before _main gets
called so that _main can already run in a generic environment that, e.g.,
catches stack overflows as a page-fault instead of corrupting the BSS.
Additionally dynamic programs have only one CRT0 - the one of the LDSO -
which does the initialization for both LDSO and program.

ref #989

base-linux/src/base/env/platform_env.cc

@@ -154,6 +154,10 @@ Platform_env::Local_parent &Platform_env::_parent()
 }
 
 
+void Platform_env::reinit(Native_capability::Dst, long) { }
+void Platform_env::reinit_main_thread(Rm_session_capability &) { }
+
+
 Platform_env::Platform_env()
 :
 	Platform_env_base(static_cap_cast<Ram_session>(_parent().session("Env::ram_session", "")),

base-linux/src/base/env/platform_env.h

@@ -432,13 +432,15 @@ namespace Genode {
 			 */
 			~Platform_env() { _parent().exit(0); }
 
-			/**
-			 * Reload parent capability and reinitialize environment resources
+			/*
+			 * Support functions for implementing fork on Noux.
+			 *
+			 * Not supported on Linux.
+			 *
+			 * See the documentation in 'base/src/base/env/platform_env.h'
 			 */
-			void reload_parent_cap(Capability<Parent>::Dst, long)
-			{
-				/* not supported on Linux */
-			}
+			void reinit(Native_capability::Dst, long);
+			void reinit_main_thread(Rm_session_capability &);
 
 
 			/*************************************

base-linux/src/base/thread/thread_env.cc

@@ -0,0 +1,49 @@
+/*
+ * \brief  Thread-environment support common to all programs
+ * \author Martin Stein
+ * \date   2013-12-13
+ */
+
+/*
+ * Copyright (C) 2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+/* Genode includes */
+#include <base/stdint.h>
+#include <base/env.h>
+
+using namespace Genode;
+
+extern addr_t * __initial_sp;
+
+/*
+ * Define 'lx_environ' pointer.
+ */
+char **lx_environ;
+
+/**
+ * Natively aligned memory location used in the lock implementation
+ */
+int main_thread_futex_counter __attribute__((aligned(sizeof(addr_t))));
+
+
+/*****************************
+ ** Startup library support **
+ *****************************/
+
+void prepare_init_main_thread()
+{
+	/*
+	 * Initialize the 'lx_environ' pointer
+	 *
+	 * environ = &argv[argc + 1]
+	 * __initial_sp[0] = argc (always 1 in Genode)
+	 * __initial_sp[1] = argv[0]
+	 * __initial_sp[2] = NULL
+	 * __initial_sp[3] = environ
+	 */
+	lx_environ = (char**)&__initial_sp[3];
+}

base-linux/src/base/thread/thread_linux.cc

@@ -1,6 +1,7 @@
 /*
  * \brief  Implementation of the Thread API via Linux threads
  * \author Norman Feske
+ * \author Martin Stein
  * \date   2006-06-13
  */
 
@@ -23,6 +24,7 @@
 
 using namespace Genode;
 
+extern int main_thread_futex_counter;
 
 static void empty_signal_handler(int) { }
 
@@ -67,9 +69,16 @@ void Thread_base::_thread_start()
 }
 
 
-void Thread_base::_init_platform_thread()
+void Thread_base::_init_platform_thread(Type type)
 {
-	_thread_cap = env()->cpu_session()->create_thread(_context->name);
+	/* for normal threads create an object at the CPU session */
+	if (type == NORMAL) {
+		_thread_cap = env()->cpu_session()->create_thread(_context->name);
+		return;
+	}
+	/* adjust initial object state for main threads */
+	tid().futex_counter = main_thread_futex_counter;
+	_thread_cap = env()->parent()->main_thread_cap();
 }
 
 

base-linux/src/core/thread_linux.cc

@@ -46,7 +46,7 @@ void Thread_base::_thread_start()
 }
 
 
-void Thread_base::_init_platform_thread() { }
+void Thread_base::_init_platform_thread(Type) { }
 
 
 void Thread_base::_deinit_platform_thread() { }

base-linux/src/platform/lx_hybrid.cc

@@ -401,7 +401,7 @@ void Thread_base::join()
 }
 
 
-Thread_base::Thread_base(const char *name, size_t stack_size)
+Thread_base::Thread_base(const char *name, size_t stack_size, Type)
 {
 	_tid.meta_data = new (env()->heap()) Thread_meta_data_created(this);
 

base-linux/src/platform/main_bootstrap.cc

@@ -1,61 +0,0 @@
-/*
- * \brief  Platform-specific helper functions for the _main() function
- * \author Christian Prochaska
- * \author Christian Helmuth
- * \date   2009-08-05
- */
-
-/*
- * Copyright (C) 2009-2013 Genode Labs GmbH
- *
- * This file is part of the Genode OS framework, which is distributed
- * under the terms of the GNU General Public License version 2.
- */
-
-#include <base/thread.h>
-#include <linux_syscalls.h>
-
-
-namespace Genode { void platform_main_bootstrap(); }
-
-
-/*
- * Define 'lx_environ' pointer.
- */
-char **lx_environ;
-
-
-/**
- * Natively aligned memory location used in the lock implementation
- */
-int main_thread_futex_counter __attribute__((aligned(sizeof(Genode::addr_t))));
-
-
-/**
- * Initial value of SP register (in crt0)
- */
-extern Genode::addr_t *__initial_sp;
-
-
-/**
- * Platform-specific bootstrap
- */
-void Genode::platform_main_bootstrap()
-{
-	static struct Bootstrap
-	{
-		Bootstrap()
-		{
-			/*
-			 * Initialize the 'lx_environ' pointer
-			 *
-			 * environ = &argv[argc + 1]
-			 * __initial_sp[0] = argc (always 1 in Genode)
-			 * __initial_sp[1] = argv[0]
-			 * __initial_sp[2] = NULL
-			 * __initial_sp[3] = environ
-			 */
-			lx_environ = (char**)&__initial_sp[3];
-		}
-	} bootstrap;
-}