Mixed changes

- Added automatic utcb map/prefaulting of forked tasks for fs0
  so that it does not need to explicitly request those tasks from mm0.
  Eliminating fs0 requests to mm0 reduce deadlock possibilities.

- Replaced kmalloc with a public malloc implementation because of a bug in kmalloc.
- Fixed a kfree bug. default_release_pages was trying to free page_array pages.

tasks/mm0/include/lib/malloc.h

@@ -0,0 +1,19 @@
+#ifndef __PRIVATE_MALLOC_H__
+#define __PRIVATE_MALLOC_H__
+
+#include <stddef.h>
+#include <string.h>
+
+void *kmalloc(size_t size);
+void kfree(void *blk);
+
+static inline void *kzalloc(size_t size)
+{
+	void *buf = kmalloc(size);
+
+	memset(buf, 0, size);
+	return buf;
+}
+
+
+#endif /*__PRIVATE_MALLOC_H__ */

tasks/mm0/include/shm.h

@@ -43,7 +43,7 @@ struct shm_descriptor {
 /* Initialises shared memory bookkeeping structures */
 void shm_init();
 
-void *shmat_shmget_internal(key_t key, void *shmaddr);
+void *shmat_shmget_internal(struct tcb *task, key_t key, void *shmaddr);
 struct vm_file *shm_new(key_t key, unsigned long npages);
 
 #endif /* __SHM_H__ */

tasks/mm0/include/task.h

@@ -101,5 +101,6 @@ void init_pm(struct initdata *initdata);
 
 struct tcb *task_create(struct task_ids *ids, unsigned int flags);
 int send_task_data(l4id_t requester);
+void task_map_prefault_utcb(struct tcb *mapper, struct tcb *owner);
 
 #endif /* __TASK_H__ */

tasks/mm0/include/vm_area.h

@@ -14,7 +14,7 @@
 #include <arch/mm.h>
 #include <lib/spinlock.h>
 
-#define DEBUG_FAULT_HANDLING
+// #define DEBUG_FAULT_HANDLING
 #ifdef DEBUG_FAULT_HANDLING
 #define dprintf(...)	printf(__VA_ARGS__)
 #else