Kernel: Add barebones per process virtual addresses

We now assign every (userspace) process its own MMU which we load
in scheduler. This allows every process to have separate virtual
address space.

This is very hackish implementations but it works for now

kernel/kernel/Process.cpp

@@ -1,7 +1,6 @@
 #include <BAN/StringView.h>
 #include <kernel/FS/VirtualFileSystem.h>
 #include <kernel/LockGuard.h>
-#include <kernel/Memory/MMU.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
 
@@ -39,12 +38,14 @@ namespace Kernel
 		auto* process = create_process();
 		TRY(process->m_working_directory.push_back('/'));
 		TRY(process->init_stdio());
-
+		process->m_mmu = new MMU();
+		ASSERT(process->m_mmu);
+		
 		TRY(process->add_thread(
 			[](void* entry_func)
 			{
 				Thread& current = Thread::current();
-				MMU::get().map_range(current.stack_base(), current.stack_size(), MMU::Flags::UserSupervisor | MMU::Flags::ReadWrite | MMU::Flags::Present);
+				Process::current().m_mmu->map_range(current.stack_base(), current.stack_size(), MMU::Flags::UserSupervisor | MMU::Flags::ReadWrite | MMU::Flags::Present);
 				current.jump_userspace((uintptr_t)entry_func);
 				ASSERT_NOT_REACHED();
 			}, (void*)entry

kernel/kernel/Scheduler.cpp

@@ -169,6 +169,11 @@ namespace Kernel
 		
 		Thread& current = current_thread();
 
+		if (current.has_process())
+			current.process().mmu().load();
+		else
+			MMU::get().load();
+
 		switch (current.state())
 		{
 			case Thread::State::NotStarted:
@@ -245,7 +250,6 @@ namespace Kernel
 
 	void Scheduler::set_current_process_done()
 	{
-		VERIFY_STI();
 		DISABLE_INTERRUPTS();
 
 		pid_t pid = m_current_thread->thread->process().pid();

kernel/kernel/kernel.cpp

@@ -134,7 +134,7 @@ extern "C" void kernel_main()
 	IDT::initialize();
 	dprintln("IDT initialized");	
 
-	MMU::intialize();
+	MMU::initialize();
 	dprintln("MMU initialized");
 
 	TerminalDriver* terminal_driver = VesaTerminalDriver::create();
@@ -194,8 +194,8 @@ static void init2(void* tty1)
 		}, nullptr
 	));
 
-	//jump_userspace();
-	//return;
+	jump_userspace();
+	return;
 
 	MUST(Process::create_kernel(
 		[](void*)