diff --git a/src/arch/x86_64/interrupt/mod.rs b/src/arch/x86_64/interrupt/mod.rs
index efc692b..eb0fc3f 100644
--- a/src/arch/x86_64/interrupt/mod.rs
+++ b/src/arch/x86_64/interrupt/mod.rs
@@ -6,6 +6,19 @@ pub mod consts;
 
 pub use self::handler::TrapFrame;
 
+impl TrapFrame {
+    pub fn new_kernel_thread(entry: extern fn(), rsp: usize) -> Self {
+        use arch::gdt;
+        let mut tf = TrapFrame::default();
+        tf.iret.cs = gdt::KCODE_SELECTOR.0 as usize;
+        tf.iret.rip = entry as usize;
+        tf.iret.ss = gdt::KDATA_SELECTOR.0 as usize;
+        tf.iret.rsp = rsp;
+        tf.iret.rflags = 0x282;
+        tf
+    }
+}
+
 #[inline(always)]
 pub unsafe fn enable() {
     x86_64::instructions::interrupts::enable();
diff --git a/src/process.rs b/src/process.rs
deleted file mode 100644
index 03a0d72..0000000
--- a/src/process.rs
+++ /dev/null
@@ -1,156 +0,0 @@
-use alloc::{boxed::Box, string::String, btree_map::BTreeMap};
-use memory::{MemoryController, Stack};
-use spin::{Once, Mutex};
-
-/// 平台相关依赖：struct TrapFrame
-///
-/// ## 必须实现的特性
-///
-/// * Debug: 用于Debug输出
-use arch::interrupt::TrapFrame;
-
-pub fn init(mc: &mut MemoryController) {
-    PROCESSOR.call_once(|| {Mutex::new({
-        let mut processor = Processor::new(mc);
-        let initproc = Process::new_init(mc);
-        let idleproc = Process::new("idle", idle_thread, mc);
-        processor.add(initproc);
-        processor.add(idleproc);
-        processor
-    })});
-}
-
-static PROCESSOR: Once<Mutex<Processor>> = Once::new();
-
-/// Called by timer handler in arch
-/// 设置rsp，指向接下来要执行线程的 内核栈顶
-/// 之后中断处理例程会重置rsp，恢复对应线程的上下文
-pub fn schedule(rsp: &mut usize) {
-    PROCESSOR.try().unwrap().lock().schedule(rsp);
-}
-
-#[derive(Debug)]
-pub struct Process {
-    pid: Pid,
-    name: &'static str,
-    kstack: Stack,
-//    page_table: Box<PageTable>,
-    status: Status,
-    rsp: usize,
-}
-
-#[derive(Debug)]
-enum Status {
-    Uninit, Ready, Running, Sleeping(usize), Exited
-}
-
-struct Processor {
-    procs: BTreeMap<Pid, Box<Process>>,
-    current_pid: Pid,
-}
-
-type Pid = usize;
-
-impl Processor {
-    fn new(mc: &mut MemoryController) -> Self {
-        Processor {
-            procs: BTreeMap::<Pid, Box<Process>>::new(),
-            current_pid: 0,
-        }
-    }
-    fn alloc_pid(&self) -> Pid {
-        let mut next: Pid = 0;
-        for &i in self.procs.keys() {
-            if i != next {
-                return next;
-            } else {
-                next = i + 1;
-            }
-        }
-        return next;
-    }
-    fn add(&mut self, mut process: Box<Process>) {
-        let pid = self.alloc_pid();
-        process.pid = pid;
-        self.procs.insert(pid, process);
-    }
-    fn schedule(&mut self, rsp: &mut usize) {
-        let pid = self.find_next();
-        self.switch_to(pid, rsp);
-    }
-    fn find_next(&self) -> Pid {
-        *self.procs.keys()
-            .find(|&&i| i > self.current_pid)
-            .unwrap_or(self.procs.keys().nth(0).unwrap())
-    }
-    fn switch_to(&mut self, pid: Pid, rsp: &mut usize) {
-        // for debug print
-        let pid0 = self.current_pid;
-        let rsp0 = *rsp;
-
-        if pid == self.current_pid {
-            return;
-        }
-        {
-            let current = self.procs.get_mut(&self.current_pid).unwrap();
-            current.status = Status::Ready;
-            current.rsp = *rsp;
-        }
-        {
-            let process = self.procs.get_mut(&pid).unwrap();
-            process.status = Status::Running;
-            *rsp = process.rsp;
-            // TODO switch page table
-        }
-        self.current_pid = pid;
-        debug!("Processor: switch from {} to {}\n  rsp: {:#x} -> {:#x}", pid0, pid, rsp0, rsp);
-    }
-}
-
-impl Process {
-    /// Make a new kernel thread
-    fn new(name: &'static str, entry: extern fn(), mc: &mut MemoryController) -> Box<Self> {
-        let kstack = mc.alloc_stack(7).unwrap();
-        let rsp = unsafe{ (kstack.top() as *mut TrapFrame).offset(-1) } as usize;
-
-        let mut tf = unsafe{ &mut *(rsp as *mut TrapFrame) };
-
-        // TODO: move to arch
-        *tf = TrapFrame::default();
-        tf.iret.cs = 8;
-        tf.iret.rip = entry as usize;
-        tf.iret.ss = 24;
-        tf.iret.rsp = kstack.top();
-        tf.iret.rflags = 0x282;
-
-        Box::new(Process {
-            pid: 0,
-            name,
-            kstack,
-            status: Status::Ready,
-            rsp,
-        })
-    }
-    /// Make the first kernel thread `initproc`
-    /// Should be called only once
-    fn new_init(mc: &mut MemoryController) -> Box<Self> {
-        assert_has_not_been_called!();
-        Box::new(Process {
-            pid: 0,
-            name: "init",
-            kstack: mc.kernel_stack.take().unwrap(),
-            status: Status::Running,
-            rsp: 0, // will be set at first schedule
-        })
-    }
-}
-
-extern fn idle_thread() {
-    loop {
-        println!("idle ...");
-        let mut i = 0;
-        while i < 1 << 22 {
-            i += 1;
-        }
-    }
-}
\ No newline at end of file
diff --git a/src/process/mod.rs b/src/process/mod.rs
new file mode 100644
index 0000000..76beeef
--- /dev/null
+++ b/src/process/mod.rs
@@ -0,0 +1,45 @@
+use memory::MemoryController;
+use spin::{Once, Mutex};
+
+use self::process::*;
+use self::processor::*;
+
+mod process;
+mod processor;
+
+/// 平台相关依赖：struct TrapFrame
+///
+/// ## 必须实现的特性
+///
+/// * Debug: 用于Debug输出
+use arch::interrupt::TrapFrame;
+
+pub fn init(mc: &mut MemoryController) {
+    PROCESSOR.call_once(|| {Mutex::new({
+        let mut processor = Processor::new(mc);
+        let initproc = Process::new_init(mc);
+        let idleproc = Process::new("idle", idle_thread, mc);
+        processor.add(initproc);
+        processor.add(idleproc);
+        processor
+    })});
+}
+
+static PROCESSOR: Once<Mutex<Processor>> = Once::new();
+
+/// Called by timer handler in arch
+/// 设置rsp，指向接下来要执行线程的 内核栈顶
+/// 之后中断处理例程会重置rsp，恢复对应线程的上下文
+pub fn schedule(rsp: &mut usize) {
+    PROCESSOR.try().unwrap().lock().schedule(rsp);
+}
+
+extern fn idle_thread() {
+    loop {
+        println!("idle ...");
+        let mut i = 0;
+        while i < 1 << 22 {
+            i += 1;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/process/process.rs b/src/process/process.rs
new file mode 100644
index 0000000..5e95e66
--- /dev/null
+++ b/src/process/process.rs
@@ -0,0 +1,50 @@
+use super::*;
+use memory::Stack;
+
+#[derive(Debug)]
+pub struct Process {
+    pub(in process) pid: Pid,
+                    name: &'static str,
+                    kstack: Stack,
+    //    page_table: Box<PageTable>,
+    pub(in process) status: Status,
+    pub(in process) rsp: usize,
+}
+
+pub type Pid = usize;
+
+#[derive(Debug)]
+pub enum Status {
+    Ready, Running, Sleeping(usize), Exited
+}
+
+impl Process {
+    /// Make a new kernel thread
+    pub fn new(name: &'static str, entry: extern fn(), mc: &mut MemoryController) -> Self {
+        let kstack = mc.alloc_stack(7).unwrap();
+        let rsp = unsafe{ (kstack.top() as *mut TrapFrame).offset(-1) } as usize;
+
+        let tf = unsafe{ &mut *(rsp as *mut TrapFrame) };
+        *tf = TrapFrame::new_kernel_thread(entry, kstack.top());
+
+        Process {
+            pid: 0,
+            name,
+            kstack,
+            status: Status::Ready,
+            rsp,
+        }
+    }
+    /// Make the first kernel thread `initproc`
+    /// Should be called only once
+    pub fn new_init(mc: &mut MemoryController) -> Self {
+        assert_has_not_been_called!();
+        Process {
+            pid: 0,
+            name: "init",
+            kstack: mc.kernel_stack.take().unwrap(),
+            status: Status::Running,
+            rsp: 0, // will be set at first schedule
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/process/processor.rs b/src/process/processor.rs
new file mode 100644
index 0000000..b09e067
--- /dev/null
+++ b/src/process/processor.rs
@@ -0,0 +1,69 @@
+use alloc::BTreeMap;
+use super::*;
+
+#[derive(Debug)]
+pub struct Processor {
+    procs: BTreeMap<Pid, Process>,
+    current_pid: Pid,
+}
+
+impl Processor {
+    pub fn new(mc: &mut MemoryController) -> Self {
+        Processor {
+            procs: BTreeMap::<Pid, Process>::new(),
+            current_pid: 0,
+        }
+    }
+
+    fn alloc_pid(&self) -> Pid {
+        let mut next: Pid = 0;
+        for &i in self.procs.keys() {
+            if i != next {
+                return next;
+            } else {
+                next = i + 1;
+            }
+        }
+        return next;
+    }
+
+    pub fn add(&mut self, mut process: Process) {
+        let pid = self.alloc_pid();
+        process.pid = pid;
+        self.procs.insert(pid, process);
+    }
+
+    pub fn schedule(&mut self, rsp: &mut usize) {
+        let pid = self.find_next();
+        self.switch_to(pid, rsp);
+    }
+
+    fn find_next(&self) -> Pid {
+        *self.procs.keys()
+            .find(|&&i| i > self.current_pid)
+            .unwrap_or(self.procs.keys().nth(0).unwrap())
+    }
+
+    fn switch_to(&mut self, pid: Pid, rsp: &mut usize) {
+        // for debug print
+        let pid0 = self.current_pid;
+        let rsp0 = *rsp;
+
+        if pid == self.current_pid {
+            return;
+        }
+        {
+            let current = self.procs.get_mut(&self.current_pid).unwrap();
+            current.status = Status::Ready;
+            current.rsp = *rsp;
+        }
+        {
+            let process = self.procs.get_mut(&pid).unwrap();
+            process.status = Status::Running;
+            *rsp = process.rsp;
+            // TODO switch page table
+        }
+        self.current_pid = pid;
+        debug!("Processor: switch from {} to {}\n  rsp: {:#x} -> {:#x}", pid0, pid, rsp0, rsp);
+    }
+}
\ No newline at end of file