lx_kit: use central signal handler for scheduling

This commit extends the Lx_kit initialization function by passing in
a signal handler that is used to perform the normally occurring
scheduler execution and is a follow-up change for the decoupling
scheduler execution commit.

Instead of burying the signal handler in the 'Lx_kit::Scheduler'
object it is provided by the main object where the driver is free
to perform any additional step before or after executing the scheduler.

Issue #4927
Fixes #4952

repos/dde_linux/src/app/wireguard/main.cc

@@ -50,7 +50,7 @@ class Wireguard::Main : private Entrypoint::Io_progress_handler,
 		Heap                              _heap                  { _env.ram(), _env.rm() };
 		Attached_rom_dataspace            _config_rom            { _env, "config" };
 		Signal_handler<Main>              _config_handler        { _env.ep(), *this, &Main::_handle_config };
-		Io_signal_handler<Main>           _signal_handler        { _env.ep(), *this, &Main::_handle_signal };
+		Signal_handler<Main>              _signal_handler        { _env.ep(), *this, &Main::_handle_signal };
 		Config_model                      _config_model          { _heap };
 		Signal_handler<Main>              _nic_ip_config_handler { _env.ep(), *this, &Main::_handle_nic_ip_config };
 		Nic_connection                    _nic_connection        { _env, _heap, _signal_handler, _config_rom.xml(), _timer, *this };
@@ -82,7 +82,7 @@ class Wireguard::Main : private Entrypoint::Io_progress_handler,
 		:
 			_env(env)
 		{
-			Lx_kit::initialize(_env);
+			Lx_kit::initialize(_env, _signal_handler);
 
 			/*
 			 * We have to call the static constructors because otherwise the

repos/dde_linux/src/include/lx_kit/env.h

@@ -33,13 +33,15 @@ namespace Lx_kit {
 	 *
 	 * \param env - pointer to Genode::Env used to construct object initially
 	 */
-	Env & env(Genode::Env * env = nullptr);
+	Env & env();
 }
 
 
 struct Lx_kit::Env
 {
-	Genode::Env        & env;
+	Genode::Env            & env;
+	Genode::Signal_context &_signal_dispatcher;
+
 	Genode::Heap         heap            { env.ram(), env.rm() };
 	Initcalls            initcalls       { heap                };
 	Pci_fixup_calls      pci_fixup_calls { heap                };
@@ -52,7 +54,12 @@ struct Lx_kit::Env
 	Device_list          devices         { env.ep(), heap, platform };
 	Lx_kit::Timeout      timeout         { timer, scheduler };
 
-	Env(Genode::Env & env) : env(env) { }
+	static void initialize(Genode::Env & env, Genode::Signal_context & sig_ctx);
+
+	Env(Genode::Env & env, Genode::Signal_context & sig_ctx)
+	: env(env), _signal_dispatcher(sig_ctx) { }
+
+	void submit_signal();
 };
 
 #endif /* _LX_KIT__ENV_H_ */

repos/dde_linux/src/include/lx_kit/init.h

@@ -16,11 +16,12 @@
 
 #include <base/env.h>
 #include <base/heap.h>
+#include <base/signal.h>
 
 namespace Lx_kit {
 	using namespace Genode;
 
-	void initialize(Env & env);
+	void initialize(Env & env, Genode::Signal_context & sig_ctx);
 	class Initcalls;
 
 	class Pci_fixup_calls;

repos/dde_linux/src/include/lx_kit/scheduler.h

@@ -43,9 +43,7 @@ class Lx_kit::Scheduler
 
 		void _idle_pre_post_process();
 
-		void _schedule();
+		void _execute();
-
-		Signal_handler<Scheduler> _execute_schedule;
 
 		Genode::Fifo<Lx_kit::Pending_irq> _pending_irqs { };
 
@@ -60,7 +58,7 @@ class Lx_kit::Scheduler
 		void add(Task & task);
 		void remove(Task & task);
 
-		void schedule() { _execute_schedule.local_submit(); }
+		void schedule();
 
 		void execute();
 
@@ -78,12 +76,7 @@ class Lx_kit::Scheduler
 		template <typename FN>
 		void for_each_task(FN const & fn);
 
-		Scheduler(Genode::Entrypoint &ep)
+		Scheduler(Genode::Entrypoint &ep) : _ep { ep } { }
-		:
-			_ep { ep },
-			_execute_schedule { _ep, *this,
-			                    &Scheduler::_schedule }
-		{ }
 };
 
 

repos/dde_linux/src/lib/lx_kit/env.cc

@@ -14,8 +14,30 @@
 #include <lx_kit/env.h>
 
 
-Lx_kit::Env & Lx_kit::env(Genode::Env * env)
+static Lx_kit::Env *_env_ptr;
+
+
+void Lx_kit::Env::initialize(Genode::Env & env,
+                             Genode::Signal_context & sig_ctx)
 {
-	static Lx_kit::Env environment(*env);
+	static Lx_kit::Env environment(env, sig_ctx);
-	return environment;
+	_env_ptr = &environment;
+}
+
+
+Lx_kit::Env & Lx_kit::env()
+{
+	if (!_env_ptr) {
+		Genode::error("Lx_kit::Env not initialized");
+		struct Env_not_initialized { };
+		throw Env_not_initialized();
+	}
+
+	return *_env_ptr;
+}
+
+
+void Lx_kit::Env::submit_signal()
+{
+	_signal_dispatcher.local_submit();
 }

repos/dde_linux/src/lib/lx_kit/init.cc

@@ -55,7 +55,7 @@ void Lx_kit::Pci_fixup_calls::execute(struct pci_dev *pci_dev)
 }
 
 
-void Lx_kit::initialize(Genode::Env & env)
+void Lx_kit::initialize(Genode::Env & env, Genode::Signal_context & sig_ctx)
 {
-	Lx_kit::env(&env);
+	Lx_kit::Env::initialize(env, sig_ctx);
 }

repos/dde_linux/src/lib/lx_kit/scheduler.cc

@@ -116,7 +116,7 @@ void Scheduler::execute()
 		Genode::sleep_forever();
 	}
 
-	_schedule();
+	_execute();
 }
 
 
@@ -124,7 +124,7 @@ void Scheduler::execute()
  * This signal handler function must only be called from within an EP
  * context, see check in 'execute()'.
  */
-void Scheduler::_schedule()
+void Scheduler::_execute()
 {
 	_idle_pre_post_process();
 
@@ -174,3 +174,9 @@ void Scheduler::_schedule()
 	/* clear current as no task is running */
 	_current = nullptr;
 }
+
+
+void Scheduler::schedule()
+{
+	Lx_kit::env().submit_signal();
+}

repos/dde_linux/src/lib/wifi/wlan.cc

@@ -244,17 +244,17 @@ void _wifi_report_mac_address(Net::Mac_address const &mac_address)
 struct Wlan
 {
 	Env                    &_env;
-	Io_signal_handler<Wlan> _signal_handler { _env.ep(), *this,
+	Signal_handler<Wlan> _signal_handler { _env.ep(), *this,
-	                                          &Wlan::_handle_signal };
+	                                       &Wlan::_handle_signal };
 
 	Dtb_helper _dtb_helper { _env };
 
 	void _handle_signal()
 	{
-		if (uplink_task_struct_ptr) {
+		if (uplink_task_struct_ptr)
 			lx_emul_task_unblock(uplink_task_struct_ptr);
-			Lx_kit::env().scheduler.schedule();
+
-		}
+		Lx_kit::env().scheduler.execute();
 
 		genode_uplink_notify_peers();
 	}
@@ -265,7 +265,7 @@ struct Wlan
 
 	Wlan(Env &env) : _env { env }
 	{
-		Lx_kit::initialize(env);
+		Lx_kit::initialize(env, _signal_handler);
 
 		genode_mac_address_reporter_init(env, Lx_kit::env().heap);
 

repos/dde_linux/src/test/driver_time/main.cc

@@ -32,9 +32,17 @@ struct Test::Driver
 {
 	Env      &env;
 
+	Signal_handler<Driver> _signal_handler {
+		env.ep(), *this, &Driver::_handle_signal };
+
+	void _handle_signal()
+	{
+		Lx_kit::env().scheduler.execute();
+	}
+
 	Driver(Env &env) : env(env)
 	{
-		Lx_kit::initialize(env);
+		Lx_kit::initialize(env, _signal_handler);
 
 		env.exec_static_constructors();
 

repos/pc/src/drivers/framebuffer/intel/pc/main.cc

@@ -52,6 +52,8 @@ struct Framebuffer::Driver
 	                                        &Driver::config_update };
 	Signal_handler<Driver>  timer_handler  { env.ep(), *this,
 	                                        &Driver::handle_timer };
+	Signal_handler<Driver>  scheduler_handler { env.ep(), *this,
+	                                           &Driver::handle_scheduler };
 
 	bool                    update_in_progress { false };
 	bool                    new_config_rom     { false };
@@ -109,9 +111,14 @@ struct Framebuffer::Driver
 		if (fb.constructed()) { fb->paint(); }
 	}
 
+	void handle_scheduler()
+	{
+		Lx_kit::env().scheduler.execute();
+	}
+
 	Driver(Env &env) : env(env)
 	{
-		Lx_kit::initialize(env);
+		Lx_kit::initialize(env, scheduler_handler);
 		env.exec_static_constructors();
 
 		config.sigh(config_handler);

repos/pc/src/drivers/nic/pc/main.cc

@@ -28,20 +28,12 @@ namespace Pc {
 
 extern task_struct *user_task_struct_ptr;
 
-struct Pc::Main : private Entrypoint::Io_progress_handler
+struct Pc::Main
 {
 	Env &_env;
 
 	Attached_rom_dataspace _config { _env, "config" };
 
-	/**
-	 * Entrypoint::Io_progress_handler
-	 */
-	void handle_io_progress() override
-	{
-		genode_uplink_notify_peers();
-	}
-
 	/**
 	 * Config update signal handler
 	 */
@@ -56,36 +48,21 @@ struct Pc::Main : private Entrypoint::Io_progress_handler
 	/**
 	 * Signal handler triggered by activity of the uplink connection
 	 */
-	Io_signal_handler<Main> _signal_handler { _env.ep(), *this, &Main::_handle_signal };
+	Signal_handler<Main> _signal_handler { _env.ep(), *this, &Main::_handle_signal };
-
-	unsigned _signal_handler_nesting_level = 0;
 
 	void _handle_signal()
 	{
-		_signal_handler_nesting_level++;
+		if (user_task_struct_ptr)
-
-		{
-			if (!user_task_struct_ptr)
-				return;
-
 			lx_emul_task_unblock(user_task_struct_ptr);
-			Lx_kit::env().scheduler.schedule();
-		}
 
-		/*
+		Lx_kit::env().scheduler.execute();
-		 * Process currently pending I/O signals before leaving the signal
-		 * handler to limit the rate of 'handle_io_progress' calls.
-		 */
-		if (_signal_handler_nesting_level == 1) {
-			while (_env.ep().dispatch_pending_io_signal());
-		}
 
-		_signal_handler_nesting_level--;
+		genode_uplink_notify_peers();
 	}
 
 	Main(Env &env) : _env(env)
 	{
-		Lx_kit::initialize(env);
+		Lx_kit::initialize(env, _signal_handler);
 
 		env.exec_static_constructors();
 
@@ -100,8 +77,6 @@ struct Pc::Main : private Entrypoint::Io_progress_handler
 		_handle_config();
 
 		lx_emul_start_kernel(nullptr);
-
-		env.ep().register_io_progress_handler(*this);
 	}
 };
 

repos/pc/src/drivers/usb_host/pc/main.cc

@@ -43,25 +43,19 @@ extern "C" int inhibit_pci_fixup(char const *name)
 }
 
 
-struct Main : private Entrypoint::Io_progress_handler
+struct Main
 {
 	Env                  & env;
 	Signal_handler<Main>   signal_handler { env.ep(), *this,
 	                                        &Main::handle_signal };
 	Sliced_heap            sliced_heap    { env.ram(), env.rm()  };
 
-	/**
-	 * Entrypoint::Io_progress_handler
-	 */
-	void handle_io_progress() override
-	{
-		genode_usb_notify_peers();
-	}
-
 	void handle_signal()
 	{
 		lx_user_handle_io();
 		Lx_kit::env().scheduler.execute();
+
+		genode_usb_notify_peers();
 	}
 
 	Main(Env & env) : env(env)
@@ -72,7 +66,7 @@ struct Main : private Entrypoint::Io_progress_handler
 			_bios_handoff = config.rom.xml().attribute_value("bios_handoff", true);
 		}
 
-		Lx_kit::initialize(env);
+		Lx_kit::initialize(env, signal_handler);
 		env.exec_static_constructors();
 
 		genode_usb_init(genode_env_ptr(env),
@@ -81,8 +75,6 @@ struct Main : private Entrypoint::Io_progress_handler
 		                &lx_emul_usb_rpc_callbacks);
 
 		lx_emul_start_kernel(nullptr);
-
-		env.ep().register_io_progress_handler(*this);
 	}
 };