[kernel] Move pml4 create/delete into vm_space

vm_space and page_table continue to take over duties from
page_manager:

- creation and deletion of address spaces / pml4s
- cross-address-space copies for endpoints
- taking over pml4 ownership from process

Also fixed the bug where the wrong process was being set in the cpu
data.

To solve: now the kernel process has its own vm_space which is not
g_kernel_space.

src/kernel/objects/endpoint.cpp

@@ -1,7 +1,9 @@
 #include "objects/endpoint.h"
+#include "objects/process.h"
 #include "objects/thread.h"
 #include "page_manager.h"
 #include "scheduler.h"
+#include "vm_space.h"
 
 endpoint::endpoint() :
 	kobject(kobject::type::endpoint)
@@ -86,9 +88,9 @@ endpoint::do_message_copy(const endpoint::thread_data &sender, endpoint::thread_
 		return j6_err_insufficient;
 
 	page_manager *pm = page_manager::get();
-	void *send_data = pm->get_offset_from_mapped(sender.data, sender.th->tcb()->pml4);
-	void *recv_data = pm->get_offset_from_mapped(receiver.data, receiver.th->tcb()->pml4);
-	kutil::memcpy(recv_data, send_data, sender.len);
+	vm_space &source = sender.th->parent().space();
+	vm_space &dest = receiver.th->parent().space();
+	vm_space::copy(source, dest, sender.data, receiver.data, sender.len);
 	*receiver.len_p = sender.len;
 
 	// TODO: this will not work if non-contiguous pages are mapped!!

src/kernel/objects/process.cpp

@@ -7,10 +7,8 @@
 
 kutil::vector<process*> process::s_processes;
 
-process::process(page_table *pml4) :
+process::process() :
 	kobject(kobject::type::process),
-	m_pml4(pml4),
-	m_space(pml4),
 	m_next_handle(0),
 	m_state(state::running)
 {
@@ -41,7 +39,6 @@ process::exit(unsigned code)
 		thread->exit(code);
 	}
 	m_return_code = code;
-	page_manager::get()->delete_process_map(m_pml4);
 	assert_signal(j6_signal_process_exit);
 }
 
@@ -76,13 +73,7 @@ process::create_thread(uint8_t priority, bool user)
 
 	if (user) {
 		uintptr_t stack_top = stacks_top - (m_threads.count() * stack_size);
-		auto *pm = page_manager::get();
-		pm->map_pages(
-			stack_top - stack_size,
-			page_manager::page_count(stack_size),
-			true, // user stack
-			m_pml4);
-
+		m_space.allow(stack_top - stack_size, stack_size, true);
 		th->tcb()->rsp3 = stack_top;
 	}
 

src/kernel/objects/process.h

@@ -19,8 +19,7 @@ public:
 	constexpr static size_t stack_size = 0x4000;
 
 	/// Constructor.
-	/// \args pml4  Root of the process' page tables
-	process(page_table *pml4);
+	process();
 
 	/// Destructor.
 	virtual ~process();
@@ -35,9 +34,6 @@ public:
 	/// Update internal bookkeeping about threads.
 	void update();
 
-	/// Get the process' page table root
-	page_table * pml4() { return m_pml4; }
-
 	/// Get the process' virtual memory space
 	vm_space & space() { return m_space; }
 
@@ -75,7 +71,6 @@ public:
 private:
 	uint32_t m_return_code;
 
-	page_table *m_pml4;
 	vm_space m_space;
 
 	kutil::vector<thread*> m_threads;

src/kernel/objects/thread.cpp

@@ -17,7 +17,7 @@ thread::thread(process &parent, uint8_t pri, uintptr_t rsp0) :
 	m_wait_data(0),
 	m_wait_obj(0)
 {
-	m_tcb.pml4 = parent.pml4();
+	parent.space().initialize_tcb(m_tcb);
 	m_tcb.priority = pri;
 
 	if (!rsp0)

src/kernel/objects/thread.h

@@ -15,7 +15,7 @@ struct TCB
 	uintptr_t rsp;
 	uintptr_t rsp0;
 	uintptr_t rsp3;
-	page_table *pml4;
+	uintptr_t pml4;
 
 	uint8_t priority;
 	// note: 3 bytes padding