vm: replace vm-region with address-space

address-space is a non-recursive data structure, which contains a flat list of vm_areas representing
mapped vm-objects.

userspace programs can no longer create sub-address-spaces. instead, they can reserve portions of
the address space, and use that reserved space to create mappings.

sched/core.c

@@ -6,7 +6,6 @@
 #include <kernel/sched.h>
 #include <kernel/task.h>
 #include <kernel/thread.h>
-#include <kernel/vm-region.h>
 
 extern kern_status_t setup_kernel_task(void);
 extern kern_status_t setup_idle_task(void);

sched/task.c

@@ -1,3 +1,4 @@
+#include <kernel/address-space.h>
 #include <kernel/channel.h>
 #include <kernel/clock.h>
 #include <kernel/cpu.h>
@@ -10,7 +11,6 @@
 #include <kernel/task.h>
 #include <kernel/thread.h>
 #include <kernel/util.h>
-#include <kernel/vm-region.h>
 
 #define TASK_CAST(p) OBJECT_C_CAST(struct task, t_base, &task_type, p)
 
@@ -95,15 +95,6 @@ kern_status_t setup_kernel_task(void)
 	__kernel_task->t_state = TASK_RUNNING;
 	__kernel_task->t_pmap = get_kernel_pmap();
 
-	vm_region_create(
-		NULL,
-		"root",
-		4,
-		VM_KERNEL_BASE,
-		VM_KERNEL_LIMIT - VM_KERNEL_BASE,
-		VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXEC | VM_PROT_SVR,
-		&__kernel_task->t_address_space);
-
 	snprintf(
 		__kernel_task->t_name,
 		sizeof __kernel_task->t_name,
@@ -195,16 +186,12 @@ struct task *task_create(const char *name, size_t name_len)
 
 	task->t_id = pid_alloc();
 	task->t_pmap = pmap;
-	vm_region_create(
-		NULL,
-		"root",
-		4,
+	address_space_create(
 		VM_USER_BASE,
-		VM_USER_LIMIT - VM_USER_BASE,
-		VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXEC | VM_PROT_USER,
+		VM_USER_LIMIT,
 		&task->t_address_space);
 
-	task->t_address_space->vr_pmap = pmap;
+	task->t_address_space->s_pmap = pmap;
 	task->t_state = TASK_RUNNING;
 	task->t_handles = handle_table_create();