From a471243f83e6662550f954301865ac53d7a2acba Mon Sep 17 00:00:00 2001
From: Steffen Vogel <post@steffenvogel.de>
Date: Fri, 28 Nov 2014 01:42:41 +0100
Subject: [PATCH] added first version of userspace fork/kill support to new
 branch

---
 arch/x86/mm/page.c          |  3 +--
 include/eduos/tasks_types.h |  8 ++++++++
 kernel/tasks.c              | 15 ++++++++++++---
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/x86/mm/page.c b/arch/x86/mm/page.c
index a090d96..9dd1e99 100644
--- a/arch/x86/mm/page.c
+++ b/arch/x86/mm/page.c
@@ -175,7 +175,6 @@ int page_unmap(size_t viraddr, size_t npages)
 	return 0;
 }
 
-/* @todo: complete
 int page_map_drop()
 {
 	void traverse(int lvl, long vpn) {
@@ -246,7 +245,7 @@ int page_map_copy(size_t dest)
 	spinlock_unlock(&kslock);
 
 	return 0;
-}*/
+}
 
 void page_fault_handler(struct state *s)
 {
diff --git a/include/eduos/tasks_types.h b/include/eduos/tasks_types.h
index c122c40..4185283 100644
--- a/include/eduos/tasks_types.h
+++ b/include/eduos/tasks_types.h
@@ -39,7 +39,9 @@
 
 #include <eduos/stddef.h>
 #include <eduos/spinlock_types.h>
+
 #include <asm/tasks_types.h>
+#include <asm/atomic.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -73,6 +75,12 @@ typedef struct task {
 	void*			stack;
 	/// Task priority
 	uint8_t			prio;
+	/// Physical address of root page table
+	size_t				page_map;
+	/// Lock for page tables
+	spinlock_irqsave_t	page_lock;
+	/// usage in number of pages (including page map tables)
+	atomic_int32_t		user_usage;
 	/// next task in the queue
 	struct task*		next;
 	/// previous task in the queue
diff --git a/kernel/tasks.c b/kernel/tasks.c
index 4fdb0df..ed7d1d1 100644
--- a/kernel/tasks.c
+++ b/kernel/tasks.c
@@ -40,8 +40,8 @@
  * A task's id will be its position in this array.
  */
 static task_t task_table[MAX_TASKS] = { \
-		[0]                 = {0, TASK_IDLE, NULL, NULL, 0, NULL, NULL}, \
-		[1 ... MAX_TASKS-1] = {0, TASK_INVALID, NULL, NULL, 0, NULL, NULL}};
+		[0]                 = {0, TASK_IDLE, NULL, NULL, 0, NULL, SPINLOCK_IRQSAVE_INIT, ATOMIC_INIT(0), NULL, NULL}, \
+		[1 ... MAX_TASKS-1] = {0, TASK_INVALID, NULL, NULL, 0, NULL, SPINLOCK_IRQSAVE_INIT, ATOMIC_INIT(0), NULL, NULL}};
 
 static spinlock_irqsave_t table_lock = SPINLOCK_IRQSAVE_INIT;
 
@@ -53,7 +53,7 @@ extern const void boot_stack;
 /** @brief helper function for the assembly code to determine the current task
  * @return Pointer to the task_t structure of current task
  */
-task_t* get_current_task(void) 
+task_t* get_current_task(void)
 {
 	return current_task;
 }
@@ -160,6 +160,8 @@ void NORETURN abort(void) {
 }
 
 /** @brief Create a task with a specific entry point
+ *
+ * @todo Dont aquire table_lock for the whole task creation.
  *
  * @param id Pointer to a tid_t struct were the id shall be set
  * @param ep Pointer to the function the task shall start with
@@ -192,6 +194,13 @@ static int create_task(tid_t* id, entry_point_t ep, void* arg, uint8_t prio)
 			task_table[i].last_stack_pointer = NULL;
 			task_table[i].stack = create_stack(i);
 			task_table[i].prio = prio;
+			task_table[i].page_map = get_pages(1);
+			/** @todo: Check if get_pages(1) was successful */
+
+			spinlock_irqsave_init(&task_table[i].page_lock);
+			atomic_int32_set(&task_table[i].user_usage, 0);
+
+			//page_map_copy(&task_table[i]);
 
 			if (id)
 				*id = i;