Kernel: add Thread::queue_signal()

kernel/include/kernel/Thread.h

@@ -40,6 +40,7 @@ namespace Kernel
 		bool has_signal_to_execute() const;
 		void set_signal_done(int signal);
 		void handle_next_signal();
+		void queue_signal(int signal);
 
 		void set_return_rsp(uintptr_t& rsp) { m_return_rsp = &rsp; }
 		void set_return_rip(uintptr_t& rip) { m_return_rip = &rip; }
@@ -99,10 +100,9 @@ namespace Kernel
 
 		BAN::CircularQueue<int, 10>	m_signal_queue;
 		uint64_t					m_signal_mask		{ 0 };
-		bool						m_handling_signal	{ false };
+		int							m_handling_signal	{ 0 };
 		static_assert(_SIGMAX < 64);
 
-		friend class Process;
 		friend class Scheduler;
 	};
 	

kernel/kernel/Process.cpp

@@ -7,7 +7,6 @@
 #include <kernel/Memory/PageTableScope.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
-#include <kernel/Signal.h>
 #include <LibELF/ELF.h>
 #include <LibELF/Values.h>
 
@@ -826,7 +825,7 @@ namespace Kernel
 			if (process->pid() == pid)
 			{
 				if (signal)
-					process->m_threads.front()->m_signal_queue.push(signal);
+					process->m_threads.front()->queue_signal(signal);
 				return 0;
 			}
 		}
@@ -841,7 +840,7 @@ namespace Kernel
 		ASSERT(m_threads.size() == 1);
 		CriticalScope _;
 		Thread& current = Thread::current();
-		current.m_signal_queue.push(signal);
+		current.queue_signal(signal);
 		current.handle_next_signal();
 		return 0;
 	}

kernel/kernel/Thread.cpp

@@ -152,14 +152,12 @@ namespace Kernel
 	void Thread::set_signal_done(int signal)
 	{
 		ASSERT(!interrupts_enabled());
-		if (!m_handling_signal)
+		if (m_handling_signal == 0)
 			derrorln("set_signal_done called while not handling singal");
-		else if (m_signal_queue.empty())
-			derrorln("set_signal_done called and there are no signals in queue");
-		else if (m_signal_queue.front() != signal)
-			derrorln("set_signal_done called with wrong signal");
+		if (m_handling_signal != signal)
+			derrorln("set_signal_done called with invalid signal");
 		else
-			m_signal_queue.pop();
+			m_handling_signal = 0;
 	}
 
 	void Thread::handle_next_signal()
@@ -171,6 +169,7 @@ namespace Kernel
 
 		int signal = m_signal_queue.front();
 		ASSERT(signal >= _SIGMIN && signal <= _SIGMAX);
+		m_signal_queue.pop();
 
 		uintptr_t& return_rsp = this->return_rsp();
 		uintptr_t& return_rip = this->return_rip();
@@ -187,7 +186,7 @@ namespace Kernel
 			// call userspace signal handlers
 			// FIXME: signal trampoline should take a hash etc
 			//        to only allow marking signals done from it
-			m_handling_signal = true;
+			m_handling_signal = signal;
 			write_to_stack(return_rsp, return_rip);
 			write_to_stack(return_rsp, signal);
 			write_to_stack(return_rsp, signal_handler);
@@ -228,6 +227,9 @@ namespace Kernel
 				case SIGPROF:
 				case SIGVTALRM:
 				{
+					// NOTE: we cannot have schedulers temporary stack when
+					//       enabling interrupts
+					asm volatile("movq %0, %%rsp" :: "r"(m_return_rsp));
 					ENABLE_INTERRUPTS();
 					process().exit(128 + signal);
 					ASSERT_NOT_REACHED();
@@ -249,8 +251,19 @@ namespace Kernel
 					ASSERT_NOT_REACHED();
 			}
 		}
+	}
 
-		m_signal_queue.pop();
+	void Thread::queue_signal(int signal)
+	{
+		ASSERT(!interrupts_enabled());
+		if (m_signal_queue.full())
+		{
+			dwarnln("Signal queue full");
+			return;
+		}
+		m_signal_queue.push(signal);
+		if (this != &Thread::current())
+			Scheduler::get().unblock_thread(tid());
 	}
 
 	void Thread::validate_stack() const