diff --git a/.gitignore b/.gitignore
index 679723a0..fe8b1fd3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,4 +5,9 @@ target
 /crate/memory/Cargo.lock
 /crate/bbl/Cargo.lock
 /crate/sync/Cargo.lock
-/crate/process/Cargo.lock
\ No newline at end of file
+/crate/process/Cargo.lock
+
+.DS_Store
+
+# for eclipse
+.project
diff --git a/crate/atags/Cargo.lock b/crate/atags/Cargo.lock
new file mode 100644
index 00000000..42d11ebd
--- /dev/null
+++ b/crate/atags/Cargo.lock
@@ -0,0 +1,14 @@
+[[package]]
+name = "atags"
+version = "0.1.0"
+dependencies = [
+ "volatile 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "volatile"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[metadata]
+"checksum volatile 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d9ca391c55768e479d5c2f8beb40c136df09257292a809ea514e82cfdfc15d00"
diff --git a/crate/atags/Cargo.toml b/crate/atags/Cargo.toml
new file mode 100644
index 00000000..3c095bfa
--- /dev/null
+++ b/crate/atags/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "atags"
+version = "0.1.0"
+authors = ["koumingyang <1761674434@qq.com>"]
+
+[dependencies]
\ No newline at end of file
diff --git a/crate/atags/src/atag.rs b/crate/atags/src/atag.rs
new file mode 100644
index 00000000..77f729a7
--- /dev/null
+++ b/crate/atags/src/atag.rs
@@ -0,0 +1,67 @@
+use raw;
+use core::slice;
+use core::str;
+
+pub use raw::{Core, Mem};
+
+/// An ATAG.
+#[derive(Debug, Copy, Clone)]
+pub enum Atag {
+    Core(raw::Core),
+    Mem(raw::Mem),
+    Cmd(&'static str),
+    Unknown(u32),
+    None
+}
+
+impl Atag {
+    /// Returns `Some` if this is a `Core` ATAG. Otherwise returns `None`.
+    pub fn core(self) -> Option<Core> {
+        match self {
+            Atag::Core(x) => Some(x),
+            _ => None,
+        }
+    }
+
+    /// Returns `Some` if this is a `Mem` ATAG. Otherwise returns `None`.
+    pub fn mem(self) -> Option<Mem> {
+        match self {
+            Atag::Mem(x) => Some(x),
+            _ => None,
+        }
+    }
+
+    /// Returns `Some` with the command line string if this is a `Cmd` ATAG.
+    /// Otherwise returns `None`.
+    pub fn cmd(self) -> Option<&'static str> {
+        match self {
+            Atag::Cmd(x) => Some(x),
+            _ => None,
+        }
+    }
+}
+
+// Convert between raw::* types and Atag wrapper.
+impl<'a> From<&'a raw::Atag> for Atag {
+    fn from(atag: &raw::Atag) -> Atag {
+        unsafe {
+            match (atag.tag, &atag.kind) {
+                (raw::Atag::CORE, &raw::Kind { core }) => Atag::Core(core),
+                (raw::Atag::MEM, &raw::Kind { mem }) => Atag::Mem(mem),
+                (raw::Atag::CMDLINE, &raw::Kind { ref cmd }) => {
+                    let mut cmd_ptr: *const u8 = &cmd.cmd as *const u8;
+                    let mut len: usize = 0;
+
+                    while *cmd_ptr.add(len) != 0 {
+                        len += 1;
+                    }
+
+                    let cmd_slice = slice::from_raw_parts(cmd_ptr, len);
+                    Atag::Cmd(str::from_utf8_unchecked(cmd_slice))
+                },
+                (raw::Atag::NONE, _) => Atag::None,
+                (id, _) => Atag::Unknown(id),
+            }
+        }
+    }
+}
diff --git a/crate/atags/src/atags.rs b/crate/atags/src/atags.rs
new file mode 100644
index 00000000..98b7522a
--- /dev/null
+++ b/crate/atags/src/atags.rs
@@ -0,0 +1,37 @@
+pub use atag::*;
+use raw;
+
+/// The address at which the firmware loads the ATAGS.
+const ATAG_BASE: usize = 0x100;
+
+/// An iterator over the ATAGS on this system.
+pub struct Atags {
+    ptr: &'static raw::Atag,
+}
+
+impl Atags {
+    /// Returns an instance of `Atags`, an iterator over ATAGS on this system.
+    pub fn get() -> Atags {
+        Atags {
+            ptr: unsafe { &*(ATAG_BASE as *const raw::Atag) }
+        }
+    }
+}
+
+impl Iterator for Atags {
+    type Item = Atag;
+
+    /// Iterate over Atags.  Returns a valid Atag until the iterator hits the
+    /// Atag::None.
+    fn next(&mut self) -> Option<Atag> {
+        let cur = self.ptr;
+        match cur.next() {
+            Some(next) => {
+                let result = Some(Atag::from(cur));
+                self.ptr = next;
+                result
+            },
+            None => None,
+        }
+    }
+}
diff --git a/crate/atags/src/lib.rs b/crate/atags/src/lib.rs
new file mode 100644
index 00000000..33c76c26
--- /dev/null
+++ b/crate/atags/src/lib.rs
@@ -0,0 +1,6 @@
+#![no_std]
+
+mod raw;
+mod atag;
+
+pub mod atags;
diff --git a/crate/atags/src/raw.rs b/crate/atags/src/raw.rs
new file mode 100644
index 00000000..abfd1669
--- /dev/null
+++ b/crate/atags/src/raw.rs
@@ -0,0 +1,67 @@
+/// A raw `ATAG` as laid out in memory.
+#[repr(C)]
+pub struct Atag {
+    pub dwords: u32,
+    pub tag: u32,
+    pub kind: Kind
+}
+
+impl Atag {
+    pub const NONE: u32 = 0x00000000;
+    pub const CORE: u32 = 0x54410001;
+    pub const MEM: u32 = 0x54410002;
+    pub const VIDEOTEXT: u32 = 0x54410003;
+    pub const RAMDISK: u32 = 0x54410004;
+    pub const INITRD2: u32 = 0x54420005;
+    pub const SERIAL: u32 = 0x54410006;
+    pub const REVISION: u32 = 0x54410007;
+    pub const VIDEOLFB: u32 = 0x54410008;
+    pub const CMDLINE: u32 = 0x54410009;
+
+    /// Returns the ATAG following `self`, if there is one.
+    pub fn next(&self) -> Option<&Atag> {
+        if self.tag == Atag::NONE {
+            None
+        } else {
+            let current = self as *const Atag as *const u32;
+            let next: &Atag = unsafe {
+                &*(current.add(self.dwords as usize) as *const Atag)
+            };
+
+            Some(next)
+        }
+    }
+}
+
+/// The possible variant of an ATAG.
+#[repr(C)]
+pub union Kind {
+    pub core: Core,
+    pub mem: Mem,
+    pub cmd: Cmd
+}
+
+/// A `CORE` ATAG.
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct Core {
+    pub flags: u32,
+    pub page_size: u32,
+    pub root_dev: u32
+}
+
+/// A `MEM` ATAG.
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct Mem {
+    pub size: u32,
+    pub start: u32
+}
+
+/// A `CMDLINE` ATAG.
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct Cmd {
+    /// The first byte of the command line string.
+    pub cmd: u8
+}
diff --git a/crate/bcm2837/Cargo.toml b/crate/bcm2837/Cargo.toml
new file mode 100644
index 00000000..3fb3e2e9
--- /dev/null
+++ b/crate/bcm2837/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "bcm2837"
+version = "0.1.0"
+authors = ["equation314 <equation618@gmail.com>"]
+
+[features]
+use_generic_timer = []
+
+[dependencies]
+volatile = "0.2.4"
+cortex-a = "2.2.2"
diff --git a/crate/bcm2837/src/gpio.rs b/crate/bcm2837/src/gpio.rs
new file mode 100644
index 00000000..1fb7fecb
--- /dev/null
+++ b/crate/bcm2837/src/gpio.rs
@@ -0,0 +1,163 @@
+use IO_BASE;
+use timer::delay;
+use core::marker::PhantomData;
+use volatile::{ReadOnly, Volatile, WriteOnly};
+
+/// The base address of the `GPIO` registers.
+const GPIO_BASE: usize = IO_BASE + 0x200000;
+
+/// An alternative GPIO function. (ref: peripherals 6.1, page 92)
+#[repr(u8)]
+pub enum Function {
+    Input = 0b000,
+    Output = 0b001,
+    Alt0 = 0b100,
+    Alt1 = 0b101,
+    Alt2 = 0b110,
+    Alt3 = 0b111,
+    Alt4 = 0b011,
+    Alt5 = 0b010,
+}
+
+/// GPIO registers starting from `GPIO_BASE` (ref: peripherals 6.1, page 90)
+#[repr(C)]
+#[allow(non_snake_case)]
+struct Registers {
+    FSEL: [Volatile<u32>; 6],
+    __reserved0: u32,
+    SET: [WriteOnly<u32>; 2],
+    __reserved1: u32,
+    CLR: [WriteOnly<u32>; 2],
+    __reserved2: u32,
+    LEV: [ReadOnly<u32>; 2],
+    __reserved3: u32,
+    EDS: [Volatile<u32>; 2],
+    __reserved4: u32,
+    REN: [Volatile<u32>; 2],
+    __reserved5: u32,
+    FEN: [Volatile<u32>; 2],
+    __reserved6: u32,
+    HEN: [Volatile<u32>; 2],
+    __reserved7: u32,
+    LEN: [Volatile<u32>; 2],
+    __reserved8: u32,
+    AREN: [Volatile<u32>; 2],
+    __reserved9: u32,
+    AFEN: [Volatile<u32>; 2],
+    __reserved10: u32,
+    PUD: Volatile<u32>,
+    PUDCLK: [Volatile<u32>; 2],
+}
+
+/// Possible states for a GPIO pin.
+pub enum Uninitialized {}
+pub enum Input {}
+pub enum Output {}
+pub enum Alt {}
+
+/// A GPIO pin in state `State`.
+///
+/// The `State` generic always corresponds to an uninstantiatable type that is
+/// use solely to mark and track the state of a given GPIO pin. A `Gpio`
+/// structure starts in the `Uninitialized` state and must be transitions into
+/// one of `Input`, `Output`, or `Alt` via the `into_input`, `into_output`, and
+/// `into_alt` methods before it can be used.
+pub struct Gpio<State> {
+    pin: u8,
+    registers: &'static mut Registers,
+    _state: PhantomData<State>,
+}
+
+impl<T> Gpio<T> {
+    /// Transitions `self` to state `S`, consuming `self` and returning a new
+    /// `Gpio` instance in state `S`. This method should _never_ be exposed to
+    /// the public!
+    #[inline(always)]
+    fn transition<S>(self) -> Gpio<S> {
+        Gpio {
+            pin: self.pin,
+            registers: self.registers,
+            _state: PhantomData,
+        }
+    }
+
+    /// Set the Gpio pull-up/pull-down state for values in `pin_value`
+    /// (ref: peripherals 6.1, page 101)
+    pub fn set_gpio_pd(&mut self, pud_value: u8) {
+        let index = if self.pin >= 32 { 1 } else { 0 };
+
+        self.registers.PUD.write(pud_value as u32);
+        delay(150);
+        self.registers.PUDCLK[index as usize].write((1 << self.pin) as u32);
+        delay(150);
+        self.registers.PUD.write(0);
+        self.registers.PUDCLK[index as usize].write(0);
+    }
+}
+
+impl Gpio<Uninitialized> {
+    /// Returns a new `GPIO` structure for pin number `pin`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `pin` > `53`.
+    pub fn new(pin: u8) -> Gpio<Uninitialized> {
+        if pin > 53 {
+            panic!("Gpio::new(): pin {} exceeds maximum of 53", pin);
+        }
+
+        Gpio {
+            registers: unsafe { &mut *(GPIO_BASE as *mut Registers) },
+            pin: pin,
+            _state: PhantomData,
+        }
+    }
+
+    /// Enables the alternative function `function` for `self`. Consumes self
+    /// and returns a `Gpio` structure in the `Alt` state.
+    pub fn into_alt(self, function: Function) -> Gpio<Alt> {
+        let select = (self.pin / 10) as usize;
+        let offset = 3 * (self.pin % 10) as usize;
+        self.registers.FSEL[select].update(|value| {
+            *value &= !(0b111 << offset);
+            *value |= (function as u32) << offset;
+        });
+        self.transition()
+    }
+
+    /// Sets this pin to be an _output_ pin. Consumes self and returns a `Gpio`
+    /// structure in the `Output` state.
+    pub fn into_output(self) -> Gpio<Output> {
+        self.into_alt(Function::Output).transition()
+    }
+
+    /// Sets this pin to be an _input_ pin. Consumes self and returns a `Gpio`
+    /// structure in the `Input` state.
+    pub fn into_input(self) -> Gpio<Input> {
+        self.into_alt(Function::Input).transition()
+    }
+}
+
+impl Gpio<Output> {
+    /// Sets (turns on) the pin.
+    pub fn set(&mut self) {
+        let index = if self.pin >= 32 { 1 } else { 0 };
+        self.registers.SET[index as usize].write(1 << (self.pin - index * 32));
+    }
+
+    /// Clears (turns off) the pin.
+    pub fn clear(&mut self) {
+        let index = if self.pin >= 32 { 1 } else { 0 };
+        self.registers.CLR[index as usize].write(1 << (self.pin - index * 32));
+    }
+}
+
+impl Gpio<Input> {
+    /// Reads the pin's value. Returns `true` if the level is high and `false`
+    /// if the level is low.
+    pub fn level(&mut self) -> bool {
+        let index = if self.pin >= 32 { 1 } else { 0 };
+        let high = 1 << (self.pin - index * 32);
+        (self.registers.LEV[index as usize].read() & high) == high
+    }
+}
diff --git a/crate/bcm2837/src/interrupt.rs b/crate/bcm2837/src/interrupt.rs
new file mode 100644
index 00000000..7324085a
--- /dev/null
+++ b/crate/bcm2837/src/interrupt.rs
@@ -0,0 +1,61 @@
+use IO_BASE;
+use volatile::{ReadOnly, Volatile};
+
+const INT_BASE: usize = IO_BASE + 0xB000 + 0x200;
+
+/// Allowed interrupts (ref: peripherals 7.5, page 113)
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub enum Interrupt {
+    Timer1 = 1,
+    Timer3 = 3,
+    Usb = 9,
+    Aux = 29,
+    Gpio0 = 49,
+    Gpio1 = 50,
+    Gpio2 = 51,
+    Gpio3 = 52,
+    Uart = 57,
+}
+
+/// Interrupts registers starting from `INT_BASE` (ref: peripherals 7.5, page 112)
+#[repr(C)]
+#[allow(non_snake_case)]
+struct Registers {
+    IRQBasicPending: ReadOnly<u32>,
+    IRQPending: [ReadOnly<u32>; 2],
+    FIQControl: Volatile<u32>,
+    EnableIRQ: [Volatile<u32>; 2],
+    EnableBasicIRQ: Volatile<u32>,
+    DisableIRQ: [Volatile<u32>; 2],
+    DisableBasicIRQ: Volatile<u32>,
+}
+
+/// An interrupt controller. Used to enable and disable interrupts as well as to
+/// check if an interrupt is pending.
+pub struct Controller {
+    registers: &'static mut Registers,
+}
+
+impl Controller {
+    /// Returns a new handle to the interrupt controller.
+    pub fn new() -> Controller {
+        Controller {
+            registers: unsafe { &mut *(INT_BASE as *mut Registers) },
+        }
+    }
+
+    /// Enables the interrupt `int`.
+    pub fn enable(&mut self, int: Interrupt) {
+        self.registers.EnableIRQ[int as usize / 32].write(1 << (int as usize) % 32);
+    }
+
+    /// Disables the interrupt `int`.
+    pub fn disable(&mut self, int: Interrupt) {
+        self.registers.DisableIRQ[int as usize / 32].write(1 << (int as usize) % 32);
+    }
+
+    /// Returns `true` if `int` is pending. Otherwise, returns `false`.
+    pub fn is_pending(&self, int: Interrupt) -> bool {
+        self.registers.IRQPending[int as usize / 32].read() & (1 << (int as usize) % 32) != 0
+    }
+}
diff --git a/crate/bcm2837/src/lib.rs b/crate/bcm2837/src/lib.rs
new file mode 100644
index 00000000..9635fdce
--- /dev/null
+++ b/crate/bcm2837/src/lib.rs
@@ -0,0 +1,11 @@
+#![no_std]
+#![feature(asm)]
+
+extern crate volatile;
+
+pub mod gpio;
+pub mod timer;
+pub mod mini_uart;
+pub mod interrupt;
+
+pub const IO_BASE: usize = 0x3F000000;
diff --git a/crate/bcm2837/src/mini_uart.rs b/crate/bcm2837/src/mini_uart.rs
new file mode 100644
index 00000000..28e2c13f
--- /dev/null
+++ b/crate/bcm2837/src/mini_uart.rs
@@ -0,0 +1,118 @@
+use IO_BASE;
+use gpio::{Function, Gpio};
+use volatile::{ReadOnly, Volatile};
+
+/// The base address for the `MU` registers.
+const MU_REG_BASE: usize = IO_BASE + 0x215040;
+
+/// The `AUXENB` register from page 9 of the BCM2837 documentation.
+const AUX_ENABLES: *mut Volatile<u8> = (IO_BASE + 0x215004) as *mut Volatile<u8>;
+
+/// Enum representing bit fields of the `AUX_MU_LSR_REG` register.
+#[repr(u8)]
+enum LsrStatus {
+    DataReady = 1,
+    TxAvailable = 1 << 5,
+}
+
+/// MU registers starting from `AUX_ENABLES` (ref: peripherals 2.1, page 8)
+#[repr(C)]
+#[allow(non_snake_case)]
+struct Registers {
+    AUX_MU_IO_REG: Volatile<u8>,
+    __r0: [u8; 3],
+    AUX_MU_IER_REG: Volatile<u8>,
+    __r1: [u8; 3],
+    AUX_MU_IIR_REG: Volatile<u8>,
+    __r2: [u8; 3],
+    AUX_MU_LCR_REG: Volatile<u8>,
+    __r3: [u8; 3],
+    AUX_MU_MCR_REG: Volatile<u8>,
+    __r4: [u8; 3],
+    AUX_MU_LSR_REG: ReadOnly<u8>,
+    __r5: [u8; 3],
+    AUX_MU_MSR_REG: ReadOnly<u8>,
+    __r6: [u8; 3],
+    AUX_MU_SCRATCH: Volatile<u8>,
+    __r7: [u8; 3],
+    AUX_MU_CNTL_REG: Volatile<u8>,
+    __r8: [u8; 3],
+    AUX_MU_STAT_REG: ReadOnly<u32>,
+    AUX_MU_BAUD_REG: Volatile<u16>,
+}
+
+/// The Raspberry Pi's "mini UART".
+pub struct MiniUart {
+    registers: &'static mut Registers,
+    timeout: Option<u32>,
+}
+
+impl MiniUart {
+    /// Initializes the mini UART by enabling it as an auxiliary peripheral,
+    /// setting the data size to 8 bits, setting the BAUD rate to ~115200 (baud
+    /// divider of 270), setting GPIO pins 14 and 15 to alternative function 5
+    /// (TXD1/RDXD1), and finally enabling the UART transmitter and receiver.
+    ///
+    /// By default, reads will never time out. To set a read timeout, use
+    /// `set_read_timeout()`.
+    pub fn new() -> MiniUart {
+        let registers = unsafe {
+            // Enable the mini UART as an auxiliary device.
+            (*AUX_ENABLES).write(1);
+            &mut *(MU_REG_BASE as *mut Registers)
+        };
+
+        Gpio::new(14).into_alt(Function::Alt5).set_gpio_pd(0);
+        Gpio::new(15).into_alt(Function::Alt5).set_gpio_pd(0);
+
+        registers.AUX_MU_CNTL_REG.write(0); // Disable auto flow control and disable receiver and transmitter (for now)
+        registers.AUX_MU_IER_REG.write(0); // Disable receive and transmit interrupts
+        registers.AUX_MU_LCR_REG.write(3); // Enable 8 bit mode
+        registers.AUX_MU_MCR_REG.write(0); // Set RTS line to be always high
+        registers.AUX_MU_BAUD_REG.write(270); // Set baud rate to 115200
+
+        registers.AUX_MU_CNTL_REG.write(3); // Finally, enable transmitter and receiver
+
+        MiniUart {
+            registers: registers,
+            timeout: None,
+        }
+    }
+
+    /// Set the read timeout to `milliseconds` milliseconds.
+    pub fn set_read_timeout(&mut self, milliseconds: u32) {
+        self.timeout = Some(milliseconds)
+    }
+
+    /// Write the byte `byte`. This method blocks until there is space available
+    /// in the output FIFO.
+    pub fn write_byte(&mut self, byte: u8) {
+        while self.registers.AUX_MU_LSR_REG.read() & (LsrStatus::TxAvailable as u8) == 0 {}
+        self.registers.AUX_MU_IO_REG.write(byte);
+    }
+
+    /// Returns `true` if there is at least one byte ready to be read. If this
+    /// method returns `true`, a subsequent call to `read_byte` is guaranteed to
+    /// return immediately. This method does not block.
+    pub fn has_byte(&self) -> bool {
+        self.registers.AUX_MU_LSR_REG.read() & (LsrStatus::DataReady as u8) != 0
+    }
+
+    /// Blocks until there is a byte ready to read. If a read timeout is set,
+    /// this method blocks for at most that amount of time. Otherwise, this
+    /// method blocks indefinitely until there is a byte to read.
+    ///
+    /// Returns `Ok(())` if a byte is ready to read. Returns `Err(())` if the
+    /// timeout expired while waiting for a byte to be ready. If this method
+    /// returns `Ok(())`, a subsequent call to `read_byte` is guaranteed to
+    /// return immediately.
+    pub fn wait_for_byte(&self) -> Result<(), ()> {
+        unimplemented!()
+    }
+
+    /// Reads a byte. Blocks indefinitely until a byte is ready to be read.
+    pub fn read_byte(&mut self) -> u8 {
+        while !self.has_byte() {}
+        self.registers.AUX_MU_IO_REG.read()
+    }
+}
diff --git a/crate/bcm2837/src/timer/generic_timer.rs b/crate/bcm2837/src/timer/generic_timer.rs
new file mode 100644
index 00000000..6c3c0c8a
--- /dev/null
+++ b/crate/bcm2837/src/timer/generic_timer.rs
@@ -0,0 +1,83 @@
+extern crate cortex_a;
+
+use self::cortex_a::regs::*;
+use volatile::*;
+
+/// The base address for the ARM generic timer, IRQs, mailboxes
+const GEN_TIMER_REG_BASE: usize = 0x40000000;
+
+/// Core interrupt sources (ref: QA7 4.10, page 16)
+#[repr(u8)]
+#[allow(dead_code)]
+#[allow(non_snake_case)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+enum CoreInterrupt {
+    CNTPSIRQ = 0,
+    CNTPNSIRQ = 1,
+    CNTHPIRQ = 2,
+    CNTVIRQ = 3,
+    Mailbox0 = 4,
+    Mailbox1 = 5,
+    Mailbox2 = 6,
+    Mailbox3 = 7,
+    Gpu = 8,
+    Pmu = 9,
+    AxiOutstanding = 10,
+    LocalTimer = 11,
+}
+
+/// Timer, IRQs, mailboxes registers (ref: QA7 chapter 4, page 7)
+#[allow(non_snake_case)]
+#[repr(C)]
+struct Registers {
+    CONTROL: Volatile<u32>,
+    _unused1: [Volatile<u32>; 8],
+    LOCAL_IRQ: Volatile<u32>,
+    _unused2: [Volatile<u32>; 3],
+    LOCAL_TIMER_CTL: Volatile<u32>,
+    LOCAL_TIMER_FLAGS: Volatile<u32>,
+    _unused3: Volatile<u32>,
+    CORE_TIMER_IRQCNTL: [Volatile<u32>; 4],
+    CORE_MAILBOX_IRQCNTL: [Volatile<u32>; 4],
+    CORE_IRQ_SRC: [Volatile<u32>; 4],
+}
+
+/// The ARM generic timer.
+pub struct Timer {
+    registers: &'static mut Registers,
+}
+
+impl Timer {
+    /// Returns a new instance of `Timer`.
+    pub fn new() -> Timer {
+        Timer {
+            registers: unsafe { &mut *(GEN_TIMER_REG_BASE as *mut Registers) },
+        }
+    }
+
+    /// Reads the generic timer's counter and returns the 64-bit counter value.
+    /// The returned value is the number of elapsed microseconds.
+    pub fn read(&self) -> u64 {
+        let cntfrq = CNTFRQ_EL0.get();
+        (CNTPCT_EL0.get() * 1000000 / (cntfrq as u64)) as u64
+    }
+
+    /// Sets up a match in timer 1 to occur `us` microseconds from now. If
+    /// interrupts for timer 1 are enabled and IRQs are unmasked, then a timer
+    /// interrupt will be issued in `us` microseconds.
+    pub fn tick_in(&mut self, us: u32) {
+        let cntfrq = CNTFRQ_EL0.get();
+        CNTP_TVAL_EL0.set(((cntfrq as f64) * (us as f64) / 1000000.0) as u32);
+    }
+
+    /// Initialization timer
+    pub fn init(&mut self) {
+        self.registers.CORE_TIMER_IRQCNTL[0].write(1 << (CoreInterrupt::CNTPNSIRQ as u8));
+        CNTP_CTL_EL0.write(CNTP_CTL_EL0::ENABLE::SET);
+    }
+
+    /// Returns `true` if timer interruption is pending. Otherwise, returns `false`.
+    pub fn is_pending(&self) -> bool {
+        self.registers.CORE_IRQ_SRC[0].read() & (1 << (CoreInterrupt::CNTPNSIRQ as u8)) != 0
+    }
+}
diff --git a/crate/bcm2837/src/timer/mod.rs b/crate/bcm2837/src/timer/mod.rs
new file mode 100644
index 00000000..f88b33d1
--- /dev/null
+++ b/crate/bcm2837/src/timer/mod.rs
@@ -0,0 +1,34 @@
+#[cfg(feature = "use_generic_timer")]
+mod generic_timer;
+#[cfg(feature = "use_generic_timer")]
+pub use self::generic_timer::Timer;
+
+#[cfg(not(feature = "use_generic_timer"))]
+mod system_timer;
+#[cfg(not(feature = "use_generic_timer"))]
+pub use self::system_timer::Timer;
+
+/// Initialization timer
+pub fn init() {
+    Timer::new().init();
+}
+
+/// Returns the current time in microseconds.
+pub fn current_time() -> u64 {
+    Timer::new().read()
+}
+
+/// Sets up a match in timer 1 to occur `us` microseconds from now. If
+/// interrupts for timer 1 are enabled and IRQs are unmasked, then a timer
+/// interrupt will be issued in `us` microseconds.
+pub fn tick_in(us: u32) {
+    Timer::new().tick_in(us);
+}
+
+/// wait for `cycle` CPU cycles
+#[inline(always)]
+pub fn delay(cycle: u32) {
+    for _ in 0..cycle {
+        unsafe { asm!("nop") }
+    }
+}
diff --git a/crate/bcm2837/src/timer/system_timer.rs b/crate/bcm2837/src/timer/system_timer.rs
new file mode 100644
index 00000000..cad2af46
--- /dev/null
+++ b/crate/bcm2837/src/timer/system_timer.rs
@@ -0,0 +1,69 @@
+use ::IO_BASE;
+use volatile::{ReadOnly, Volatile};
+use interrupt::{Controller, Interrupt};
+
+/// The base address for the ARM system timer registers.
+const TIMER_REG_BASE: usize = IO_BASE + 0x3000;
+
+/// System timer registers (ref: peripherals 12.1, page 172)
+#[repr(C)]
+#[allow(non_snake_case)]
+struct Registers {
+    CS: Volatile<u32>,
+    CLO: ReadOnly<u32>,
+    CHI: ReadOnly<u32>,
+    COMPARE: [Volatile<u32>; 4],
+}
+
+#[repr(u8)]
+#[allow(dead_code)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+enum SystemTimer {
+    Timer0 = 0,
+    Timer1 = 1,
+    Timer2 = 2,
+    Timer3 = 3,
+}
+
+/// The Raspberry Pi ARM system timer.
+pub struct Timer {
+    registers: &'static mut Registers,
+}
+
+impl Timer {
+    /// Returns a new instance of `Timer`.
+    pub fn new() -> Timer {
+        Timer {
+            registers: unsafe { &mut *(TIMER_REG_BASE as *mut Registers) },
+        }
+    }
+
+    /// Reads the system timer's counter and returns the 64-bit counter value.
+    /// The returned value is the number of elapsed microseconds.
+    pub fn read(&self) -> u64 {
+        let low = self.registers.CLO.read();
+        let high = self.registers.CHI.read();
+        ((high as u64) << 32) | (low as u64)
+    }
+
+    /// Sets up a match in timer 1 to occur `us` microseconds from now. If
+    /// interrupts for timer 1 are enabled and IRQs are unmasked, then a timer
+    /// interrupt will be issued in `us` microseconds.
+    pub fn tick_in(&mut self, us: u32) {
+        let current_low = self.registers.CLO.read();
+        let compare = current_low.wrapping_add(us);
+        self.registers.COMPARE[SystemTimer::Timer1 as usize].write(compare);
+        self.registers.CS.write(1 << (SystemTimer::Timer1 as usize)); // unmask
+    }
+
+    /// Initialization timer
+    pub fn init(&mut self) {
+        Controller::new().enable(Interrupt::Timer1);
+    }
+
+    /// Returns `true` if timer interruption is pending. Otherwise, returns `false`.
+    pub fn is_pending(&self) -> bool {
+        let controller = Controller::new();
+        controller.is_pending(Interrupt::Timer1)
+    }
+}
diff --git a/kernel/Cargo.lock b/kernel/Cargo.lock
index c60e52ff..4a525d84 100644
--- a/kernel/Cargo.lock
+++ b/kernel/Cargo.lock
@@ -16,6 +16,10 @@ dependencies = [
  "nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "atags"
+version = "0.1.0"
+
 [[package]]
 name = "bare-metal"
 version = "0.2.4"
@@ -28,6 +32,14 @@ dependencies = [
 name = "bbl"
 version = "0.1.0"
 
+[[package]]
+name = "bcm2837"
+version = "0.1.0"
+dependencies = [
+ "cortex-a 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "volatile 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bit-allocator"
 version = "0.1.0"
@@ -72,6 +84,14 @@ name = "cfg-if"
 version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "cortex-a"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "register 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fixedvec"
 version = "0.2.3"
@@ -179,6 +199,14 @@ dependencies = [
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "register"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "tock-registers 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "remove_dir_all"
 version = "0.5.1"
@@ -256,6 +284,11 @@ dependencies = [
  "remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "tock-registers"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "uart_16550"
 version = "0.1.0"
@@ -270,12 +303,15 @@ name = "ucore"
 version = "0.1.0"
 dependencies = [
  "apic 0.1.0 (git+https://github.com/wangrunji0408/APIC-Rust)",
+ "atags 0.1.0",
  "bbl 0.1.0",
+ "bcm2837 0.1.0",
  "bit-allocator 0.1.0",
  "bit_field 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "bootloader 0.3.4 (git+https://github.com/wangrunji0408/bootloader)",
  "cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cortex-a 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "linked_list_allocator 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -288,7 +324,7 @@ dependencies = [
  "uart_16550 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ucore-memory 0.1.0",
  "ucore-process 0.1.0",
- "volatile 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "volatile 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "x86_64 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "xmas-elf 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -325,7 +361,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "volatile"
-version = "0.1.0"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -404,6 +440,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bootloader 0.3.4 (git+https://github.com/wangrunji0408/bootloader)" = "<none>"
 "checksum cc 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "f159dfd43363c4d08055a07703eb7a3406b0dac4d0584d96965a3262db3c9d16"
 "checksum cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "082bb9b28e00d3c9d39cc03e64ce4cea0f1bb9b3fde493f0cbc008472d22bdf4"
+"checksum cortex-a 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2b187d0d728b4a99ba1d79f9671b976bcdd71a8a2c719585218fd2dc14a4d08c"
 "checksum fixedvec 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7c6c16d316ccdac21a4dd648e314e76facbbaf316e83ca137d0857a9c07419d0"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
@@ -419,6 +456,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum pulldown-cmark 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8361e81576d2e02643b04950e487ec172b687180da65c731c03cf336784e6c07"
 "checksum rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8356f47b32624fef5b3301c1be97e5944ecdd595409cc5da11d05f211db6cfbd"
 "checksum raw-cpuid 6.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "30a9d219c32c9132f7be513c18be77c9881c7107d2ab5569d205a6a0f0e6dc7d"
+"checksum register 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "e10f31b6d2299e5620986ad9fcdd66463e125ad72af4f403f9aedf7592d5ccdb"
 "checksum remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3488ba1b9a2084d38645c4c08276a1752dcbf2c7130d74f1569681ad5d2799c5"
 "checksum riscv 0.3.0 (git+https://github.com/riscv-and-rust-and-decaf/riscv)" = "<none>"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
@@ -429,11 +467,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum spin 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "ceac490aa12c567115b40b7b7fceca03a6c9d53d5defea066123debc83c5dc1f"
 "checksum static_assertions 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "389ce475f424f267dbed6479cbd8f126c5e1afb053b0acdaa019c74305fc65d1"
 "checksum tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "15f2b5fb00ccdf689e0149d1b1b3c03fead81c2b37735d812fa8bddbbf41b6d8"
+"checksum tock-registers 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3a385d94f3f62e60445a0adb9ff8d9621faa272234530d4c0f848ec98f88e316"
 "checksum uart_16550 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "269f953d8de3226f7c065c589c7b4a3e83d10a419c7c3b5e2e0f197e6acc966e"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum usize_conversions 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f70329e2cbe45d6c97a5112daad40c34cd9a4e18edb5a2a18fefeb584d8d25e5"
 "checksum ux 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "53d8df5dd8d07fedccd202de1887d94481fadaea3db70479f459e8163a1fab41"
-"checksum volatile 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "37c5d76c0f40ba4f8ac10ec4717d4e98ce3e58c5607eea36e9464226fc5e0a95"
+"checksum volatile 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "54d4343a2df2d65144a874f95950754ee7b7e8594f6027aae8c7d0f4858a3fe8"
 "checksum winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "92c1eb33641e276cfa214a0522acad57be5c56b10cb348b3c5117db75f3ac4b0"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/kernel/Cargo.toml b/kernel/Cargo.toml
index e9ee6b34..ba57b56b 100644
--- a/kernel/Cargo.toml
+++ b/kernel/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2018"
 [features]
 link_user_program = []
 no_bbl = []
+board_raspi3 = []
 
 [profile.dev]
 # MUST >= 1 : Enable RVO to avoid stack overflow
@@ -22,7 +23,7 @@ once = "0.3"
 xmas-elf = "0.6"
 bitflags = "1.0"
 bit_field = "0.9"
-volatile = "0.1"
+volatile = "0.2"
 linked_list_allocator = "0.6"
 lazy_static = { version = "1.2", features = ["spin_no_std"] }
 bit-allocator = { path = "../crate/bit-allocator" }
@@ -44,6 +45,11 @@ pc-keyboard = "0.3"
 riscv = { git = "https://github.com/riscv-and-rust-and-decaf/riscv" }
 bbl = { path = "../crate/bbl" }
 
+[target.'cfg(target_arch = "aarch64")'.dependencies]
+cortex-a = "2.2.1"
+atags = { path = "../crate/atags" }
+bcm2837 = { path = "../crate/bcm2837", features = ["use_generic_timer"] }
+
 [package.metadata.bootimage]
 default-target = "x86_64-blog_os.json"
 output = "target/x86_64-blog_os/bootimage.bin"
diff --git a/kernel/Makefile b/kernel/Makefile
index 471585c4..6a26d8c6 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -8,14 +8,17 @@
 # 	make clean					Clean
 #
 # Options:
-#   arch = x86_64 | riscv32
+#   arch = x86_64 | riscv32 | aarch64
 #   d    = int | in_asm | ...	QEMU debug info
 #   mode = debug | release
 #   LOG  = off | error | warn | info | debug | trace
 #   smp                         SMP core number
-#   board 						Only available on riscv32, build without bbl, run on board
+#   board = fpga				Only available on riscv32, build without bbl, run on board
+#         | raspi3				Only available on aarch64, run on Raspberry Pi 3 Model B/B+
 
 arch ?= riscv32
+board ?= raspi3
+prefix ?= $(arch)-none-elf
 mode ?= debug
 LOG  ?= debug
 smp  ?= 4
@@ -29,25 +32,40 @@ user_bin_path := ../user/target/$(arch)-ucore/debug
 user_bins := $(patsubst $(user_bin_path)/%.d, $(user_bin_path)/%, $(wildcard $(user_bin_path)/*.d))
 user_obj := build/$(arch)/user.o
 SFSIMG := ../user/ucore32.img
+
+### qemu options ###
 ifeq ($(arch), x86_64)
 qemu_opts := \
 	-drive format=raw,file=$(bootimage) \
 	-drive format=raw,file=$(SFSIMG),media=disk,cache=writeback \
 	-smp cores=$(smp) \
 	-serial mon:stdio \
-	-device isa-debug-exit
-endif
-ifeq ($(arch), riscv32)
+	-device isa-debug-exit \
+	-nographic
+else ifeq ($(arch), riscv32)
 qemu_opts := \
 	-machine virt \
 	-kernel $(bin) \
 	-nographic \
 	-smp cores=$(smp)
+else ifeq ($(arch), aarch64)
+qemu_opts := \
+	-machine $(board) \
+	-serial null -serial mon:stdio \
+	-nographic \
+	-kernel $(bin)
 endif
 
-ifdef board
+ifdef d
+qemu_opts := $(qemu_opts) -d $(d)
+endif
+
+### build args ###
+ifeq ($(arch), riscv32)
+ifeq ($(board), fpga)
 features := $(features) no_bbl
 endif
+endif
 
 # Link user binaries at ../user
 ifdef link_user
@@ -55,37 +73,26 @@ features := $(features) link_user_program
 assembly_object_files := $(assembly_object_files) $(user_obj)
 endif
 
-ifdef d
-qemu_opts := $(qemu_opts) -d $(d)
-endif
-
+features := $(features) board_$(board)
 build_args := --target $(target).json --features "$(features)"
 
 ifeq ($(mode), release)
 build_args := $(build_args) --release
 endif
 
-ifeq ($(OS),Windows_NT)
-uname := Win32
-else
-uname := $(shell uname)
-endif
 
-ifeq ($(uname), Darwin)
-prefix := x86_64-elf-
-endif
-ifeq ($(arch), riscv32)
-prefix := riscv64-unknown-elf-
-endif
 
-ld := $(prefix)ld
-objdump := $(prefix)objdump
-cc := $(prefix)gcc
-as := $(prefix)as
+### prefix ###
+ld := $(prefix)-ld
+objdump := $(prefix)-objdump
+objcopy := $(prefix)-objcopy
+cc := $(prefix)-gcc
+as := $(prefix)-as
+gdb := $(prefix)-gdb
 
 .PHONY: all clean run build asm doc justrun kernel
 
-all: $(kernel)
+all: kernel
 
 clean:
 	@cargo clean
@@ -99,8 +106,10 @@ run: build justrun
 justrun:
 	@qemu-system-$(arch) $(qemu_opts) || [ $$? -eq 11 ] # run qemu and assert it exit 11
 
-debug: $(bin)
+debug: $(kernel) $(bin)
 	@qemu-system-$(arch) $(qemu_opts) -s -S &
+	@sleep 1
+	@$(gdb) $(kernel) -x ../tools/gdbinit
 
 ifeq ($(arch), x86_64)
 build: kernel
@@ -118,20 +127,24 @@ sym:
 	@$(objdump) -t $(kernel) | less
 
 $(bin): kernel
-ifdef board
+ifeq ($(arch), riscv32)
+ifeq ($(board), fpga)
 	@cp $(kernel) $@
 else
 	@cd ../riscv-pk && \
-	 mkdir -p build && \
-	 cd build && \
-	 ../configure \
-	 	--enable-32bit \
-	 	--enable-logo \
-	 	--disable-fp-emulation \
-	 	--host=riscv64-unknown-elf \
-	 	--with-payload=$(abspath $(kernel)) && \
-	 make && \
-	 cp bbl ../../kernel/$@
+	mkdir -p build && \
+	cd build && \
+	../configure \
+		--enable-32bit \
+		--enable-logo \
+		--disable-fp-emulation \
+		--host=riscv64-unknown-elf \
+		--with-payload=$(abspath $(kernel)) && \
+	make && \
+	cp bbl ../../kernel/$@
+endif
+else ifeq ($(arch), aarch64)
+	$(objcopy) $(kernel) --strip-all -O binary $@
 endif
 
 kernel:
@@ -148,3 +161,24 @@ endif
 $(user_obj): $(user_bins)
 	@cd $(user_bin_path) && \
 		$(ld) -o $(abspath $@) $(patsubst %, -b binary %, $(notdir $(user_bins)))
+
+
+
+### install ###
+ifeq ($(board), raspi3)
+sd_card ?=
+
+ifeq ($(shell uname), Darwin)
+sd_card := /Volumes/boot
+else ifeq ($(shell uname), Linux)
+sd_card := /media/$(shell whoami)/boot
+endif
+
+ifdef sd_card
+.PHONY:
+install: $(bin)
+	cp $(bin) $(sd_card)/kernel8.img
+	sudo umount $(sd_card)
+endif
+
+endif
diff --git a/kernel/aarch64-blog_os.json b/kernel/aarch64-blog_os.json
new file mode 100644
index 00000000..b0c24dc8
--- /dev/null
+++ b/kernel/aarch64-blog_os.json
@@ -0,0 +1,35 @@
+{
+  "abi-blacklist": [
+    "stdcall",
+    "fastcall",
+    "vectorcall",
+    "thiscall",
+    "win64",
+    "sysv64"
+  ],
+  "arch": "aarch64",
+  "data-layout": "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128",
+  "executables": true,
+  "linker": "rust-lld",
+  "linker-flavor": "ld.lld",
+  "linker-is-gnu": true,
+  "pre-link-args": {
+    "ld.lld": [
+      "-Tsrc/arch/aarch64/boot/linker.ld"
+    ]
+  },
+  "llvm-target": "aarch64-unknown-none",
+  "no-compiler-rt": true,
+  "features": "+a53,+strict-align,-neon",
+  "max-atomic-width": 128,
+  "os": "none",
+  "panic": "abort",
+  "panic-strategy": "abort",
+  "relocation-model": "static",
+  "position-independent-executables": true,
+  "target-c-int-width": "32",
+  "target-endian": "little",
+  "target-pointer-width": "64",
+  "target-family": "unix",
+  "disable-redzone": true
+}
diff --git a/kernel/riscv32-blog_os.json b/kernel/riscv32-blog_os.json
index 33e9156e..ca35687d 100644
--- a/kernel/riscv32-blog_os.json
+++ b/kernel/riscv32-blog_os.json
@@ -32,4 +32,4 @@
     "msp430-interrupt",
     "x86-interrupt"
   ]
-}
\ No newline at end of file
+}
diff --git a/kernel/src/arch/aarch64/board/raspi3/irq.rs b/kernel/src/arch/aarch64/board/raspi3/irq.rs
new file mode 100644
index 00000000..e01a2c30
--- /dev/null
+++ b/kernel/src/arch/aarch64/board/raspi3/irq.rs
@@ -0,0 +1,11 @@
+use arch::interrupt::TrapFrame;
+use super::bcm2837::timer::Timer;
+use super::bcm2837::interrupt::{Controller, Interrupt};
+
+pub fn handle_irq(tf: &mut TrapFrame) {
+    let controller = Timer::new();
+    if controller.is_pending() {
+        super::timer::set_next();
+        ::trap::timer();
+    }
+}
diff --git a/kernel/src/arch/aarch64/board/raspi3/mod.rs b/kernel/src/arch/aarch64/board/raspi3/mod.rs
new file mode 100644
index 00000000..2b32a108
--- /dev/null
+++ b/kernel/src/arch/aarch64/board/raspi3/mod.rs
@@ -0,0 +1,18 @@
+//! Raspberry PI 3 Model B/B+
+
+extern crate bcm2837;
+
+pub mod irq;
+pub mod timer;
+pub mod serial;
+
+pub fn init() {
+    // FIXME
+    // assert_has_not_been_called!("board::init must be called only once");
+
+    unsafe {
+        serial::SERIAL_PORT.init();
+    }
+
+    println!("Hello Raspberry Pi!");
+}
diff --git a/kernel/src/arch/aarch64/board/raspi3/serial.rs b/kernel/src/arch/aarch64/board/raspi3/serial.rs
new file mode 100644
index 00000000..5434071f
--- /dev/null
+++ b/kernel/src/arch/aarch64/board/raspi3/serial.rs
@@ -0,0 +1,77 @@
+use super::bcm2837::mini_uart::MiniUart;
+
+use core::fmt;
+use spin::Mutex;
+
+/// Struct to get a global SerialPort interface
+pub struct SerialPort {
+    mu: Option<MiniUart>,
+}
+
+pub trait SerialRead {
+    fn receive(&mut self) -> u8;
+}
+
+impl SerialPort {
+    /// Creates a new instance of `SerialPort`.
+    const fn new() -> SerialPort {
+        SerialPort { mu: None }
+    }
+
+    /// Init a newly created SerialPort, can only be called once.
+    pub fn init(&mut self) {
+        // FIXME
+        // assert_has_not_been_called!("SerialPort::init must be called only once");
+        self.mu = Some(MiniUart::new());
+    }
+
+    /// Writes the byte `byte` to the UART device.
+    pub fn write_byte(&mut self, byte: u8) {
+        match &mut self.mu {
+            Some(mu) => mu.write_byte(byte),
+            None => panic!("SerialPort is not initialized"),
+        }
+    }
+
+    /// Reads a byte from the UART device, blocking until a byte is available.
+    pub fn read_byte(&mut self) -> u8 {
+        match &mut self.mu {
+            Some(mu) => return mu.read_byte(),
+            None => panic!("SerialPort is not initialized"),
+        }
+    }
+}
+
+impl SerialRead for SerialPort {
+    fn receive(&mut self) -> u8 {
+        self.read_byte()
+    }
+}
+
+impl fmt::Write for SerialPort {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for byte in s.bytes() {
+            match byte {
+                // Backspace
+                b'\x7f' => {
+                    self.write_byte(b'\x08');
+                    self.write_byte(b' ');
+                    self.write_byte(b'\x08');
+                }
+                // Return
+                b'\n' => {
+                    self.write_byte(b'\r');
+                    self.write_byte(b'\n');
+                }
+                // Others
+                _ => self.write_byte(byte),
+            }
+        }
+        Ok(())
+    }
+}
+
+// FIXME
+// pub static SERIAL_PORT: Mutex<SerialPort> = Mutex::new(SerialPort::new());
+pub static mut SERIAL_PORT: SerialPort = SerialPort::new();
+
diff --git a/kernel/src/arch/aarch64/board/raspi3/timer.rs b/kernel/src/arch/aarch64/board/raspi3/timer.rs
new file mode 100644
index 00000000..4cc0be0d
--- /dev/null
+++ b/kernel/src/arch/aarch64/board/raspi3/timer.rs
@@ -0,0 +1,17 @@
+use super::bcm2837::timer;
+use super::bcm2837::interrupt::{Controller, Interrupt};
+
+pub fn init() {
+    timer::init();
+    set_next();
+    info!("timer: init end");
+}
+
+pub fn get_cycle() -> u64 {
+    timer::current_time()
+}
+
+pub fn set_next() {
+    // 10 ms
+    timer::tick_in(10 * 1000);
+}
diff --git a/kernel/src/arch/aarch64/boot/boot.S b/kernel/src/arch/aarch64/boot/boot.S
new file mode 100644
index 00000000..b8a142e9
--- /dev/null
+++ b/kernel/src/arch/aarch64/boot/boot.S
@@ -0,0 +1,110 @@
+# TODO rewrite in Rust, use crate cortex-a
+
+.section .text.boot
+
+.global _start
+_start:
+    # read cpu affinity, start core 0, halt rest
+    mrs     x1, mpidr_el1
+    and     x1, x1, #3
+    cbz     x1, setup
+
+halt:
+    # core affinity != 0, halt it
+    wfe
+    b       halt
+
+setup:
+    # store the desired EL1 stack pointer in x1
+    adr     x1, _start
+
+    # use SP_ELx for Exception level ELx
+    msr     SPsel, #1
+
+    # read the current exception level into x0 (ref: C5.2.1)
+    mrs     x0, CurrentEL
+    and     x0, x0, #0b1100
+    lsr     x0, x0, #2
+
+switch_to_el2:
+    # switch to EL2 if we're in EL3. otherwise switch to EL1
+    cmp     x0, #2
+    beq     switch_to_el1
+
+    # set-up SCR_EL3 (bits 0, 4, 5, 7, 8, 10) (A53: 4.3.42)
+    mov     x0, #0x5b1
+    msr     scr_el3, x0
+
+    # set-up SPSR_EL3 (bits 0, 3, 6, 7, 8, 9) (ref: C5.2.20)
+    mov     x0, #0x3c9
+    msr     spsr_el3, x0
+
+    # switch
+    adr     x0, switch_to_el1
+    msr     elr_el3, x0
+
+    eret
+
+switch_to_el1:
+    # switch to EL1 if we're not already in EL1. otherwise continue with start
+    cmp     x0, #1
+    beq     set_stack
+
+    # set the stack-pointer for EL1
+    msr     sp_el1, x1
+
+    # set-up HCR_EL2, enable AArch64 in EL1 (bits 1, 31) (ref: D10.2.45)
+    mov     x0, #0x0002
+    movk    x0, #0x8000, lsl #16
+    msr     hcr_el2, x0
+
+    # don't trap accessing SVE registers (ref: D10.2.30)
+    msr     cptr_el2, xzr
+
+    # enable floating point and SVE (SIMD) (bits 20, 21) (ref: D10.2.29)
+    mrs     x0, cpacr_el1
+    orr     x0, x0, #(0x3 << 20)
+    msr     cpacr_el1, x0
+
+    # Set SCTLR to known state (RES1: 11, 20, 22, 23, 28, 29) (ref: D10.2.100)
+    mov     x0, #0x0800
+    movk    x0, #0x30d0, lsl #16
+    msr     sctlr_el1, x0
+
+    # set-up SPSR_EL2 (bits 0, 2, 6, 7, 8, 9) (ref: C5.2.19)
+    mov     x0, #0x3c5
+    msr     spsr_el2, x0
+
+    # enable CNTP for EL1/EL0 (ref: D7.5.2, D7.5.13)
+    # NOTE: This doesn't actually enable the counter stream.
+    mrs     x0, cnthctl_el2
+    orr     x0, x0, #3
+    msr     cnthctl_el2, x0
+    msr     cntvoff_el2, xzr
+
+    # switch
+    adr     x0, set_stack
+    msr     elr_el2, x0
+
+    eret
+
+set_stack:
+    # set the current stack pointer
+    mov     sp, x1
+
+zero_bss:
+    # load the start address and number of bytes in BSS section
+    ldr     x1, =__bss_start
+    ldr     x2, =__bss_length
+
+zero_bss_loop:
+    # zero out the BSS section, 64-bits at a time
+    cbz     x2, go_kmain
+    str     xzr, [x1], #8
+    sub     x2, x2, #8
+    cbnz    x2, zero_bss_loop
+
+go_kmain:
+    # jump to rust_main, which shouldn't return. halt if it does
+    bl      rust_main
+    b       halt
diff --git a/kernel/src/arch/aarch64/boot/linker.ld b/kernel/src/arch/aarch64/boot/linker.ld
new file mode 100644
index 00000000..ce4c0c2a
--- /dev/null
+++ b/kernel/src/arch/aarch64/boot/linker.ld
@@ -0,0 +1,39 @@
+ENTRY(_start)
+
+SECTIONS {
+  . = 0x80000; /* Raspbery Pi 3 Aarch64 (kernel8.img) load address */
+
+  /* start of the binary */
+  _start = .;
+
+  .text : {
+    KEEP(*(.text.boot)) /* from boot.S */
+    *(.text .text.* .gnu.linkonce.t*)
+  }
+
+  .rodata : {
+    *(.rodata .rodata.* .gnu.linkonce.r*)
+  }
+
+  .data : {
+    *(.data .data.* .gnu.linkonce.d*)
+  }
+
+  .bss (NOLOAD) : {
+    . = ALIGN(32);
+    __bss_start = .;
+    *(.bss .bss.*)
+    *(COMMON)
+    . = ALIGN(8);
+    __bss_end = .;
+  }
+
+  /* end of the binary */
+  _end = ALIGN(8);
+
+  /* number of bytes in BSS section and complete binary */
+  __bss_length = (__bss_end - __bss_start);
+  __binary_length = (_end - _start);
+
+  /DISCARD/ : { *(.comment) *(.gnu*) *(.note*) *(.eh_frame*) }
+}
diff --git a/kernel/src/arch/aarch64/consts.rs b/kernel/src/arch/aarch64/consts.rs
new file mode 100644
index 00000000..82d472bd
--- /dev/null
+++ b/kernel/src/arch/aarch64/consts.rs
@@ -0,0 +1,11 @@
+//! TODO: replace unmiplemented consts with real value
+const UNIMPLEMENTED: usize = 0;
+pub const KERNEL_OFFSET: usize = UNIMPLEMENTED;
+pub const KERNEL_PML4: usize = UNIMPLEMENTED;
+pub const KERNEL_HEAP_OFFSET: usize = UNIMPLEMENTED;
+pub const KERNEL_HEAP_SIZE: usize = 8 * 1024 * 1024;
+pub const MEMORY_OFFSET: usize = UNIMPLEMENTED;
+pub const MEMORY_END: usize = UNIMPLEMENTED;
+pub const USER_STACK_OFFSET: usize = UNIMPLEMENTED;
+pub const USER_STACK_SIZE: usize = UNIMPLEMENTED;
+pub const USER32_STACK_OFFSET: usize = UNIMPLEMENTED;
\ No newline at end of file
diff --git a/kernel/src/arch/aarch64/interrupt/context.rs b/kernel/src/arch/aarch64/interrupt/context.rs
new file mode 100644
index 00000000..df2b5b34
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/context.rs
@@ -0,0 +1,151 @@
+//! TrapFrame and context definitions for aarch64.
+
+#[repr(C)]
+#[derive(Default, Debug, Copy, Clone)]
+pub struct TrapFrame {
+    pub elr: usize,
+    pub spsr: usize,
+    pub sp: usize,
+    pub tpidr: usize,
+    // pub q0to31: [u128; 32], // disable SIMD/FP registers
+    pub x1to29: [usize; 29],
+    pub __reserved: usize,
+    pub x30: usize, // lr
+    pub x0: usize,
+}
+
+/// 用于在内核栈中构造新线程的中断帧
+impl TrapFrame {
+    fn new_kernel_thread(entry: extern fn(usize) -> !, arg: usize, sp: usize) -> Self {
+        use core::mem::zeroed;
+        let mut tf: Self = unsafe { zeroed() };
+        tf.x0 = arg;
+        tf.sp = sp;
+        tf.elr = entry as usize;
+        tf.spsr = 0b1101_00_0101; // To EL 1, enable IRQ
+        tf
+    }
+    fn new_user_thread(entry_addr: usize, sp: usize) -> Self {
+        use core::mem::zeroed;
+        let mut tf: Self = unsafe { zeroed() };
+        tf.sp = sp;
+        tf.elr = entry_addr;
+        tf.spsr = 0b1101_00_0000; // To EL 0, enable IRQ
+        tf
+    }
+    pub fn is_user(&self) -> bool {
+        unimplemented!()
+    }
+}
+
+/// 新线程的内核栈初始内容
+#[derive(Debug)]
+#[repr(C)]
+pub struct InitStack {
+    context: ContextData,
+    tf: TrapFrame,
+}
+
+impl InitStack {
+    unsafe fn push_at(self, stack_top: usize) -> Context {
+        let ptr = (stack_top as *mut Self).offset(-1);
+        *ptr = self;
+        Context(ptr as usize)
+    }
+}
+
+extern {
+    fn __trapret();
+}
+
+#[derive(Debug, Default)]
+#[repr(C)]
+struct ContextData {
+    x19to29: [usize; 11],
+    lr: usize,
+    ttbr0: usize,
+}
+
+impl ContextData {
+    fn new(ttbr0: usize) -> Self {
+        ContextData { lr: __trapret as usize, ttbr0, ..ContextData::default() }
+    }
+}
+
+
+#[derive(Debug)]
+pub struct Context(usize);
+
+impl Context {
+    /// Switch to another kernel thread.
+    ///
+    /// Defined in `trap.S`.
+    ///
+    /// Push all callee-saved registers at the current kernel stack.
+    /// Store current sp, switch to target.
+    /// Pop all callee-saved registers, then return to the target.
+    #[naked]
+    #[inline(never)]
+    pub unsafe extern fn switch(&mut self, target: &mut Self) {
+        asm!(
+        "
+        mov x10, #-(13 * 8)
+        add x8, sp, x10
+        str x8, [x0]
+        stp x19, x20, [x8], #16     // store callee-saved registers
+        stp x21, x22, [x8], #16
+        stp x23, x24, [x8], #16
+        stp x25, x26, [x8], #16
+        stp x27, x28, [x8], #16
+        stp x29, lr, [x8], #16
+        mrs x9, ttbr0_el1
+        str x9, [x8], #8
+
+        ldr x8, [x1]
+        ldp x19, x20, [x8], #16     // restore callee-saved registers
+        ldp x21, x22, [x8], #16
+        ldp x23, x24, [x8], #16
+        ldp x25, x26, [x8], #16
+        ldp x27, x28, [x8], #16
+        ldp x29, lr, [x8], #16
+        ldr x9, [x8], #8
+        mov sp, x8
+
+        msr ttbr0_el1, x9           // set new page directory
+        dsb ishst                   // ensure write has completed
+        tlbi vmalle1is              // invalidate the TLB entry for the entry that changes
+        dsb ish                     // ensure TLB invalidation is complete
+        isb                         // synchronize context on this processor
+
+        str xzr, [x1]
+        ret"
+        : : : : "volatile" );
+    }
+
+    pub unsafe fn null() -> Self {
+        Context(0)
+    }
+
+    pub unsafe fn new_kernel_thread(entry: extern fn(usize) -> !, arg: usize, kstack_top: usize, ttbr0: usize) -> Self {
+        InitStack {
+            context: ContextData::new(ttbr0),
+            tf: TrapFrame::new_kernel_thread(entry, arg, kstack_top),
+        }.push_at(kstack_top)
+    }
+    pub unsafe fn new_user_thread(entry_addr: usize, ustack_top: usize, kstack_top: usize, is32: bool, ttbr0: usize) -> Self {
+        InitStack {
+            context: ContextData::new(ttbr0),
+            tf: TrapFrame::new_user_thread(entry_addr, ustack_top),
+        }.push_at(kstack_top)
+    }
+    pub unsafe fn new_fork(tf: &TrapFrame, kstack_top: usize, ttbr0: usize) -> Self {
+        InitStack {
+            context: ContextData::new(ttbr0),
+            tf: {
+                let mut tf = tf.clone();
+                tf.x0 = 0;
+                tf
+            },
+        }.push_at(kstack_top)
+    }
+}
diff --git a/kernel/src/arch/aarch64/interrupt/handler.rs b/kernel/src/arch/aarch64/interrupt/handler.rs
new file mode 100644
index 00000000..85d1faf7
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/handler.rs
@@ -0,0 +1,79 @@
+//! Trap handler
+
+use arch::board::irq::handle_irq;
+use super::context::TrapFrame;
+use super::syndrome::Syndrome;
+
+global_asm!(include_str!("trap.S"));
+global_asm!(include_str!("vector.S"));
+
+#[repr(u16)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum Kind {
+    Synchronous = 0,
+    Irq = 1,
+    Fiq = 2,
+    SError = 3,
+}
+
+#[repr(u16)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub enum Source {
+    CurrentSpEl0 = 0,
+    CurrentSpElx = 1,
+    LowerAArch64 = 2,
+    LowerAArch32 = 3,
+}
+
+#[repr(C)]
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+pub struct Info {
+    source: Source,
+    kind: Kind,
+}
+
+/// This function is called when an exception occurs. The `info` parameter
+/// specifies the source and kind of exception that has occurred. The `esr` is
+/// the value of the exception syndrome register. Finally, `tf` is a pointer to
+/// the trap frame for the exception.
+#[no_mangle]
+pub extern "C" fn rust_trap(info: Info, esr: u32, tf: &mut TrapFrame) {
+    let syndrome = Syndrome::from(esr);
+    trace!("Interrupt: {:?} from: {:?}", syndrome, info);
+    match info.kind {
+        Kind::Synchronous => {
+            // syndrome is only valid with sync
+            match syndrome {
+                Syndrome::Brk(brk) => handle_break(brk, tf),
+                Syndrome::Svc(_) => handle_syscall(tf),
+                _ => ::trap::error(tf),
+            }
+        }
+        Kind::Irq => handle_irq(tf),
+        _ => ::trap::error(tf),
+    }
+    ::trap::before_return();
+    trace!("Interrupt end");
+}
+
+fn handle_break(num: u16, tf: &mut TrapFrame) {
+    // Skip the current brk instruction (ref: J1.1.2, page 6147)
+    tf.elr += 4;
+}
+
+fn handle_syscall(tf: &mut TrapFrame) {
+    // svc instruction has been skipped in syscall (ref: J1.1.2, page 6152)
+    let ret = ::syscall::syscall(
+        tf.x1to29[7] as usize,
+        [
+            tf.x0,
+            tf.x1to29[0],
+            tf.x1to29[1],
+            tf.x1to29[2],
+            tf.x1to29[3],
+            tf.x1to29[4],
+        ],
+        tf,
+    );
+    tf.x0 = ret as usize;
+}
diff --git a/kernel/src/arch/aarch64/interrupt/mod.rs b/kernel/src/arch/aarch64/interrupt/mod.rs
new file mode 100644
index 00000000..140e9b85
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/mod.rs
@@ -0,0 +1,50 @@
+//! Interrupt and exception for aarch64.
+
+mod handler;
+mod context;
+mod syndrome;
+
+use super::cortex_a::regs::*;
+pub use self::context::*;
+pub use self::handler::*;
+
+/// Set the exception vector address
+pub fn init() {
+    unsafe {
+        asm!(
+            "adr x0, __vectors;
+             msr vbar_el1, x0"
+        );
+    }
+}
+
+/// Enable the interrupt (only IRQ).
+#[inline(always)]
+pub unsafe fn enable() {
+    asm!("msr daifclr, #2");
+}
+
+/// Disable the interrupt (only IRQ).
+#[inline(always)]
+pub unsafe fn disable() {
+    asm!("msr daifset, #2");
+}
+
+/// Disable the interrupt and store the status.
+///
+/// return: status(usize)
+#[inline(always)]
+pub unsafe fn disable_and_store() -> usize {
+    let daif = DAIF.get() as usize;
+    disable();
+    daif
+}
+
+/// Use the original status to restore the process
+///
+/// Arguments:
+/// * flags:  original status(usize)
+#[inline(always)]
+pub unsafe fn restore(flags: usize) {
+    DAIF.set(flags as u32);
+}
diff --git a/kernel/src/arch/aarch64/interrupt/syndrome.rs b/kernel/src/arch/aarch64/interrupt/syndrome.rs
new file mode 100644
index 00000000..d466a5d2
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/syndrome.rs
@@ -0,0 +1,108 @@
+//! Exception syndrome from ESR
+
+#[derive(Debug, PartialEq, Copy, Clone)]
+pub enum Fault {
+    AddressSize,
+    Translation,
+    AccessFlag,
+    Permission,
+    Alignment,
+    TlbConflict,
+    Other(u8),
+}
+
+impl From<u32> for Fault {
+    fn from(val: u32) -> Fault {
+        use self::Fault::*;
+
+        // IFSC or DFSC bits (ref: D10.2.39, Page 2457~2464).
+        match val & 0b111100 {
+            0b000000 => AddressSize,
+            0b000100 => Translation,
+            0b001000 => AccessFlag,
+            0b001100 => Permission,
+            0b100000 => Alignment,
+            0b110000 => TlbConflict,
+            _ => Other((val & 0b111111) as u8),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Copy, Clone)]
+pub enum Syndrome {
+    Unknown,
+    WfiWfe,
+    McrMrc,
+    McrrMrrc,
+    LdcStc,
+    SimdFp,
+    Vmrs,
+    Mrrc,
+    IllegalExecutionState,
+    Svc(u16),
+    Hvc(u16),
+    Smc(u16),
+    MsrMrsSystem,
+    InstructionAbort { kind: Fault, level: u8 },
+    PCAlignmentFault,
+    DataAbort { kind: Fault, level: u8 },
+    SpAlignmentFault,
+    TrappedFpu,
+    SError,
+    Breakpoint,
+    Step,
+    Watchpoint,
+    Brk(u16),
+    Other(u32),
+}
+
+/// Converts a raw syndrome value (ESR) into a `Syndrome` (ref: D1.10.4, D10.2.39).
+impl From<u32> for Syndrome {
+    fn from(esr: u32) -> Syndrome {
+        use self::Syndrome::*;
+
+        let ec = esr >> 26;
+        let iss = esr & 0xFFFFFF;
+
+        match ec {
+            0b000000 => Unknown,
+            0b000001 => WfiWfe,
+            0b000011 => McrMrc,
+            0b000100 => McrrMrrc,
+            0b000101 => McrMrc,
+            0b000110 => LdcStc,
+            0b000111 => SimdFp,
+            0b001000 => Vmrs,
+            0b001100 => Mrrc,
+            0b001110 => IllegalExecutionState,
+            0b010001 => Svc((iss & 0xFFFF) as u16),
+            0b010010 => Hvc((iss & 0xFFFF) as u16),
+            0b010011 => Smc((iss & 0xFFFF) as u16),
+            0b010101 => Svc((iss & 0xFFFF) as u16),
+            0b010110 => Hvc((iss & 0xFFFF) as u16),
+            0b010111 => Smc((iss & 0xFFFF) as u16),
+            0b011000 => MsrMrsSystem,
+            0b100000 | 0b100001 => InstructionAbort {
+                kind: Fault::from(iss),
+                level: (iss & 0b11) as u8,
+            },
+            0b100010 => PCAlignmentFault,
+            0b100100 | 0b100101 => DataAbort {
+                kind: Fault::from(iss),
+                level: (iss & 0b11) as u8,
+            },
+            0b100110 => SpAlignmentFault,
+            0b101000 => TrappedFpu,
+            0b101100 => TrappedFpu,
+            0b101111 => SError,
+            0b110000 => Breakpoint,
+            0b110001 => Breakpoint,
+            0b110010 => Step,
+            0b110011 => Step,
+            0b110100 => Watchpoint,
+            0b110101 => Watchpoint,
+            0b111100 => Brk((iss & 0xFFFF) as u16),
+            other => Other(other),
+        }
+    }
+}
diff --git a/kernel/src/arch/aarch64/interrupt/trap.S b/kernel/src/arch/aarch64/interrupt/trap.S
new file mode 100644
index 00000000..331ba41a
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/trap.S
@@ -0,0 +1,103 @@
+.section .text
+
+.macro SAVE_ALL
+    # lr, x0 is saved in HANDLER
+    str     x29, [sp, #-16]!
+    stp     x27, x28, [sp, #-16]!
+    stp     x25, x26, [sp, #-16]!
+    stp     x23, x24, [sp, #-16]!
+    stp     x21, x22, [sp, #-16]!
+    stp     x19, x20, [sp, #-16]!
+    stp     x17, x18, [sp, #-16]!
+    stp     x15, x16, [sp, #-16]!
+    stp     x13, x14, [sp, #-16]!
+    stp     x11, x12, [sp, #-16]!
+    stp     x9, x10, [sp, #-16]!
+    stp     x7, x8, [sp, #-16]!
+    stp     x5, x6, [sp, #-16]!
+    stp     x3, x4, [sp, #-16]!
+    stp     x1, x2, [sp, #-16]!
+
+    # stp     q30, q31, [sp, #-32]!
+    # stp     q28, q29, [sp, #-32]!
+    # stp     q26, q27, [sp, #-32]!
+    # stp     q24, q25, [sp, #-32]!
+    # stp     q22, q23, [sp, #-32]!
+    # stp     q20, q21, [sp, #-32]!
+    # stp     q18, q19, [sp, #-32]!
+    # stp     q16, q17, [sp, #-32]!
+    # stp     q14, q15, [sp, #-32]!
+    # stp     q12, q13, [sp, #-32]!
+    # stp     q10, q11, [sp, #-32]!
+    # stp     q8, q9, [sp, #-32]!
+    # stp     q6, q7, [sp, #-32]!
+    # stp     q4, q5, [sp, #-32]!
+    # stp     q2, q3, [sp, #-32]!
+    # stp     q0, q1, [sp, #-32]!
+
+    mrs     x2, tpidr_el0
+    mrs     x1, sp_el0
+    stp     x1, x2, [sp, #-16]!
+
+    mrs     x2, spsr_el1
+    mrs     x1, elr_el1
+    stp     x1, x2, [sp, #-16]!
+.endm
+
+.macro RESTORE_ALL
+    ldp     x1, x2, [sp], #16
+    msr     elr_el1, x1
+    msr     spsr_el1, x2
+
+    ldp     x1, x2, [sp], #16
+    msr     sp_el0, x1
+    msr     tpidr_el0, x2
+
+    # ldp     q0, q1, [sp], #32
+    # ldp     q2, q3, [sp], #32
+    # ldp     q4, q5, [sp], #32
+    # ldp     q6, q7, [sp], #32
+    # ldp     q8, q9, [sp], #32
+    # ldp     q10, q11, [sp], #32
+    # ldp     q12, q13, [sp], #32
+    # ldp     q14, q15, [sp], #32
+    # ldp     q16, q17, [sp], #32
+    # ldp     q18, q19, [sp], #32
+    # ldp     q20, q21, [sp], #32
+    # ldp     q22, q23, [sp], #32
+    # ldp     q24, q25, [sp], #32
+    # ldp     q26, q27, [sp], #32
+    # ldp     q28, q29, [sp], #32
+    # ldp     q30, q31, [sp], #32
+
+    ldp     x1, x2, [sp], #16
+    ldp     x3, x4, [sp], #16
+    ldp     x5, x6, [sp], #16
+    ldp     x7, x8, [sp], #16
+    ldp     x9, x10, [sp], #16
+    ldp     x11, x12, [sp], #16
+    ldp     x13, x14, [sp], #16
+    ldp     x15, x16, [sp], #16
+    ldp     x17, x18, [sp], #16
+    ldp     x19, x20, [sp], #16
+    ldp     x21, x22, [sp], #16
+    ldp     x23, x24, [sp], #16
+    ldp     x25, x26, [sp], #16
+    ldp     x27, x28, [sp], #16
+    ldr     x29, [sp], #16
+    ldp     lr, x0, [sp], #16
+.endm
+
+.global __alltraps
+__alltraps:
+    SAVE_ALL
+
+    # x0 is set in HANDLER
+    mrs x1, esr_el1
+    mov x2, sp
+    bl rust_trap
+
+.global __trapret
+__trapret:
+    RESTORE_ALL
+    eret
diff --git a/kernel/src/arch/aarch64/interrupt/vector.S b/kernel/src/arch/aarch64/interrupt/vector.S
new file mode 100644
index 00000000..3a749f94
--- /dev/null
+++ b/kernel/src/arch/aarch64/interrupt/vector.S
@@ -0,0 +1,29 @@
+.section .text
+
+.macro HANDLER source kind
+    .align 7
+    stp     lr, x0, [sp, #-16]!
+    mov     x0, #\source
+    movk    x0, #\kind, lsl #16
+    b       __alltraps
+.endm
+
+.global __vectors
+.align 11
+__vectors:
+    HANDLER 0 0
+    HANDLER 0 1
+    HANDLER 0 2
+    HANDLER 0 3
+    HANDLER 1 0
+    HANDLER 1 1
+    HANDLER 1 2
+    HANDLER 1 3
+    HANDLER 2 0
+    HANDLER 2 1
+    HANDLER 2 2
+    HANDLER 2 3
+    HANDLER 3 0
+    HANDLER 3 1
+    HANDLER 3 2
+    HANDLER 3 3
diff --git a/kernel/src/arch/aarch64/io.rs b/kernel/src/arch/aarch64/io.rs
new file mode 100644
index 00000000..deda39c3
--- /dev/null
+++ b/kernel/src/arch/aarch64/io.rs
@@ -0,0 +1,18 @@
+//! Serial driver for aarch64.
+
+use core::fmt::{Arguments, Write};
+use super::board::serial::{SerialRead, SERIAL_PORT};
+
+pub fn getchar() -> char {
+    // FIXME
+    unsafe {
+        SERIAL_PORT.receive() as char
+    }
+}
+
+pub fn putfmt(fmt: Arguments) {
+    // FIXME
+    unsafe {
+        SERIAL_PORT.write_fmt(fmt).unwrap()
+    }
+}
diff --git a/kernel/src/arch/aarch64/memory.rs b/kernel/src/arch/aarch64/memory.rs
new file mode 100644
index 00000000..bf553546
--- /dev/null
+++ b/kernel/src/arch/aarch64/memory.rs
@@ -0,0 +1,35 @@
+//! Memory initialization for aarch64.
+
+use ucore_memory::PAGE_SIZE;
+use super::atags::atags::Atags;
+use super::super::HEAP_ALLOCATOR;
+
+/// Memory initialization.
+pub fn init() {
+    let (start, end) = memory_map().expect("failed to find memory map");
+    unsafe {
+        HEAP_ALLOCATOR.lock().init(start, end - start);
+    }
+    info!("memory: init end");
+}
+
+extern "C" {
+    static _end: u8;
+}
+
+/// Returns the (start address, end address) of the available memory on this
+/// system if it can be determined. If it cannot, `None` is returned.
+///
+/// This function is expected to return `Some` under all normal cirumstances.
+pub fn memory_map() -> Option<(usize, usize)> {
+    let binary_end = unsafe { (&_end as *const u8) as u32 };
+
+    let mut atags: Atags = Atags::get();
+    while let Some(atag) = atags.next() {
+        if let Some(mem) = atag.mem() {
+            return Some((binary_end as usize, (mem.start + mem.size) as usize));
+        }
+    }
+
+    None
+}
diff --git a/kernel/src/arch/aarch64/mod.rs b/kernel/src/arch/aarch64/mod.rs
new file mode 100644
index 00000000..58aa7846
--- /dev/null
+++ b/kernel/src/arch/aarch64/mod.rs
@@ -0,0 +1,30 @@
+//! Entrance and initialization for aarch64.
+
+extern crate atags;
+extern crate cortex_a;
+
+pub mod io;
+pub mod paging;
+pub mod memory;
+pub mod interrupt;
+pub mod consts;
+
+#[cfg(feature = "board_raspi3")]
+#[path = "board/raspi3/mod.rs"]
+pub mod board;
+
+pub use self::board::timer;
+
+/// The entry point of kernel
+#[no_mangle] // don't mangle the name of this function
+pub extern "C" fn rust_main() -> ! {
+    // Init board to enable serial port.
+    board::init();
+    ::logging::init(); // FIXME
+    interrupt::init();
+    memory::init();
+    timer::init();
+    ::kmain();
+}
+
+global_asm!(include_str!("boot/boot.S"));
diff --git a/kernel/src/arch/aarch64/paging.rs b/kernel/src/arch/aarch64/paging.rs
new file mode 100644
index 00000000..e9cc43e8
--- /dev/null
+++ b/kernel/src/arch/aarch64/paging.rs
@@ -0,0 +1,222 @@
+//! Page table implementations for aarch64.
+
+use ucore_memory::memory_set::*;
+use ucore_memory::paging::*;
+
+type VirtAddr = usize;
+type PhysAddr = usize;
+
+use alloc::alloc::{alloc, Layout};
+use memory::{active_table, alloc_frame, alloc_stack, dealloc_frame};
+
+/// TODO
+pub struct ActivePageTable {
+    // TODO
+}
+
+impl ActivePageTable {
+    /// TODO
+    pub unsafe fn new() -> Self {
+        unimplemented!()
+    }
+}
+
+impl PageTable for ActivePageTable {
+    type Entry = PageEntry;
+
+    fn map(&mut self, addr: VirtAddr, target: PhysAddr) -> &mut Self::Entry {
+        unimplemented!()
+    }
+    fn unmap(&mut self, addr: VirtAddr) {
+        unimplemented!()
+    }
+
+    fn get_entry(&mut self, addr: VirtAddr) -> &mut Self::Entry {
+        unimplemented!()
+    }
+
+    // For testing with mock
+    fn get_page_slice_mut<'a, 'b>(&'a mut self, addr: VirtAddr) -> &'b mut [u8] {
+        unimplemented!()
+    }
+
+    fn read(&mut self, addr: VirtAddr) -> u8 {
+        unimplemented!()
+    }
+
+    fn write(&mut self, addr: VirtAddr, data: u8) {
+        unimplemented!()
+    }
+}
+
+/// TODO
+pub struct PageEntry {
+    // TODO
+}
+
+impl Entry for PageEntry {
+    /// IMPORTANT!
+    /// This must be called after any change to ensure it become effective.
+    /// Usually this will make a flush to TLB/MMU.
+    fn update(&mut self) {
+        unimplemented!()
+    }
+
+    /// Will be set when accessed
+    fn accessed(&self) -> bool {
+        unimplemented!()
+    }
+
+    /// Will be set when written
+    fn dirty(&self) -> bool {
+        unimplemented!()
+    }
+
+    /// Will PageFault when try to write page where writable=0
+    fn writable(&self) -> bool {
+        unimplemented!()
+    }
+
+    /// Will PageFault when try to access page where present=0
+    fn present(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn clear_accessed(&mut self) {
+        unimplemented!()
+    }
+
+    fn clear_dirty(&mut self) {
+        unimplemented!()
+    }
+
+    fn set_writable(&mut self, value: bool) {
+        unimplemented!()
+    }
+
+    fn set_present(&mut self, value: bool) {
+        unimplemented!()
+    }
+
+    fn target(&self) -> PhysAddr {
+        unimplemented!()
+    }
+
+    fn set_target(&mut self, target: PhysAddr) {
+        unimplemented!()
+    }
+
+    // For Copy-on-write extension
+    fn writable_shared(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn readonly_shared(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn set_shared(&mut self, writable: bool) {
+        unimplemented!()
+    }
+
+    fn clear_shared(&mut self) {
+        unimplemented!()
+    }
+
+    // For Swap extension
+    fn swapped(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn set_swapped(&mut self, value: bool) {
+        unimplemented!()
+    }
+
+    fn user(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn set_user(&mut self, value: bool) {
+        unimplemented!()
+    }
+
+    fn execute(&self) -> bool {
+        unimplemented!()
+    }
+
+    fn set_execute(&mut self, value: bool) {
+        unimplemented!()
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+pub struct MockFrame(PhysAddr);
+
+impl MockFrame {
+    pub fn of_addr(addr: PhysAddr) -> Self {
+        MockFrame(addr)
+    }
+    pub fn start_address(&self) -> PhysAddr {
+        unimplemented!()
+    }
+    pub fn p2_index(&self) -> usize {
+        unimplemented!()
+    }
+    pub fn p1_index(&self) -> usize {
+        unimplemented!()
+    }
+    pub fn number(&self) -> usize {
+        unimplemented!()
+    }
+}
+
+/// TODO
+pub struct InactivePageTable0 {
+    p4_frame: MockFrame,
+}
+
+/// TODO
+impl InactivePageTable for InactivePageTable0 {
+    type Active = ActivePageTable;
+
+    fn new() -> Self {
+        unsafe {
+            let layout = Layout::new::<u64>();
+            let ptr = alloc(layout);
+            let frame = MockFrame::of_addr(*ptr as usize);
+            InactivePageTable0 { p4_frame: frame }
+        }
+    }
+
+    fn new_bare() -> Self {
+        unimplemented!()
+    }
+
+    fn edit(&mut self, f: impl FnOnce(&mut Self::Active)) {
+        unimplemented!()
+    }
+
+    unsafe fn activate(&self) {
+        unimplemented!()
+    }
+
+    unsafe fn with(&self, f: impl FnOnce()) {
+        unimplemented!()
+    }
+
+    fn token(&self) -> usize {
+        0
+    }
+
+    fn alloc_frame() -> Option<PhysAddr> {
+        alloc_frame()
+    }
+
+    fn dealloc_frame(target: PhysAddr) {
+        dealloc_frame(target)
+    }
+
+    fn alloc_stack() -> Stack {
+        alloc_stack()
+    }
+}
diff --git a/kernel/src/fs.rs b/kernel/src/fs.rs
index 76b3b961..fb3a6a86 100644
--- a/kernel/src/fs.rs
+++ b/kernel/src/fs.rs
@@ -156,4 +156,4 @@ impl INodeExt for INode {
         self.read_at(0, buf.as_mut_slice())?;
         Ok(buf)
     }
-}
\ No newline at end of file
+}
diff --git a/kernel/src/lib.rs b/kernel/src/lib.rs
index cc3b5430..043883e3 100644
--- a/kernel/src/lib.rs
+++ b/kernel/src/lib.rs
@@ -42,6 +42,10 @@ pub mod arch;
 #[path = "arch/riscv32/mod.rs"]
 pub mod arch;
 
+#[cfg(target_arch = "aarch64")]
+#[path = "arch/aarch64/mod.rs"]
+pub mod arch;
+
 pub fn kmain() -> ! {
     processor().run();
 
diff --git a/kernel/src/memory.rs b/kernel/src/memory.rs
index 3d1f463e..8ebca5f4 100644
--- a/kernel/src/memory.rs
+++ b/kernel/src/memory.rs
@@ -23,6 +23,10 @@ pub type FrameAlloc = BitAlloc64K;
 #[cfg(target_arch = "riscv32")]
 pub type FrameAlloc = BitAlloc4K;
 
+// Raspberry Pi 3 has 1G memory
+#[cfg(target_arch = "aarch64")]
+pub type FrameAlloc = BitAlloc64K;
+
 lazy_static! {
     pub static ref FRAME_ALLOCATOR: SpinNoIrqLock<FrameAlloc> = SpinNoIrqLock::new(FrameAlloc::default());
 }
diff --git a/kernel/src/process/context.rs b/kernel/src/process/context.rs
index 2039bd3b..c377f638 100644
--- a/kernel/src/process/context.rs
+++ b/kernel/src/process/context.rs
@@ -51,6 +51,15 @@ impl ContextImpl {
         })
     }
 
+    pub fn new_user_test(entry: extern fn(usize) -> !) -> Self {
+        let ms = MemorySet::new();
+        let user_stack = ::memory::alloc_stack();
+        Context {
+            arch: unsafe { ArchContext::new_user_thread(entry as usize, user_stack.top - 8, ms.kstack_top(), false, ms.token()) },
+            memory_set: ms,
+        }
+    }
+
     /// Make a new user thread from ELF data
     /*
     * @param:
diff --git a/kernel/src/process/mod.rs b/kernel/src/process/mod.rs
index b26144c9..1d2147d9 100644
--- a/kernel/src/process/mod.rs
+++ b/kernel/src/process/mod.rs
@@ -53,4 +53,4 @@ pub fn processor() -> &'static Processor {
 #[no_mangle]
 pub fn new_kernel_context(entry: extern fn(usize) -> !, arg: usize) -> Box<Context> {
     ContextImpl::new_kernel(entry, arg)
-}
\ No newline at end of file
+}
diff --git a/kernel/src/sync/mutex.rs b/kernel/src/sync/mutex.rs
index 92ac5582..4157ec3b 100644
--- a/kernel/src/sync/mutex.rs
+++ b/kernel/src/sync/mutex.rs
@@ -217,6 +217,8 @@ impl MutexSupport for Spin {
                 asm!("pause" :::: "volatile");
             #[cfg(target_arch = "riscv32")]
                 asm!("nop" :::: "volatile");
+            #[cfg(target_arch = "aarch64")]
+                asm!("yield" :::: "volatile");
         }
     }
     fn before_lock() -> Self::GuardData {}
@@ -247,6 +249,8 @@ impl MutexSupport for SpinNoIrq {
                 asm!("pause" :::: "volatile");
             #[cfg(target_arch = "riscv32")]
                 asm!("nop" :::: "volatile");
+            #[cfg(target_arch = "aarch64")]
+                asm!("yield" :::: "volatile");
         }
     }
     fn before_lock() -> Self::GuardData {
@@ -267,4 +271,4 @@ impl MutexSupport for Condvar {
     fn after_unlock(&self) {
         self.notify_one();
     }
-}
\ No newline at end of file
+}
diff --git a/tools/gdbinit b/tools/gdbinit
new file mode 100644
index 00000000..5041b6e7
--- /dev/null
+++ b/tools/gdbinit
@@ -0,0 +1,3 @@
+target remote :1234
+break rust_main
+continue
diff --git a/user/aarch64-ucore.json b/user/aarch64-ucore.json
new file mode 100644
index 00000000..357c2e3c
--- /dev/null
+++ b/user/aarch64-ucore.json
@@ -0,0 +1,30 @@
+{
+  "abi-blacklist": [
+    "stdcall",
+    "fastcall",
+    "vectorcall",
+    "thiscall",
+    "win64",
+    "sysv64"
+  ],
+  "arch": "aarch64",
+  "data-layout": "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128",
+  "executables": true,
+  "linker": "rust-lld",
+  "linker-flavor": "ld.lld",
+  "linker-is-gnu": true,
+  "llvm-target": "aarch64-unknown-none",
+  "no-compiler-rt": true,
+  "features": "+a53,+strict-align,-neon",
+  "max-atomic-width": 128,
+  "os": "none",
+  "panic": "abort",
+  "panic-strategy": "abort",
+  "relocation-model": "static",
+  "position-independent-executables": true,
+  "target-c-int-width": "32",
+  "target-endian": "little",
+  "target-pointer-width": "64",
+  "target-family": "unix",
+  "disable-redzone": true
+}
diff --git a/user/ucore-ulib/src/syscall.rs b/user/ucore-ulib/src/syscall.rs
index 5d8765b1..f7071429 100644
--- a/user/ucore-ulib/src/syscall.rs
+++ b/user/ucore-ulib/src/syscall.rs
@@ -44,6 +44,12 @@ fn sys_call(id: usize, arg0: usize, arg1: usize, arg2: usize, arg3: usize, arg4:
             : "{rax}" (id), "{rdi}" (arg0), "{rsi}" (arg1), "{rdx}" (arg2), "{rcx}" (arg3), "{r8}" (arg4), "{r9}" (arg5)
             : "memory"
             : "intel" "volatile");
+        #[cfg(target_arch = "aarch64")]
+            asm!("svc 0"
+            : "={x0}" (ret)
+            : "{x8}" (id), "{x0}" (arg0), "{x1}" (arg1), "{x2}" (arg2), "{x3}" (arg3), "{x4}" (arg4), "{x5}" (arg5)
+            : "memory"
+            : "volatile");
     }
     ret
 }
@@ -68,7 +74,7 @@ pub fn sys_open(path: &str, flags: usize) -> i32 {
 }
 
 pub fn sys_close(fd: usize) -> i32 {
-    sys_call(SYS_CLOSE, fd, 0 , 0, 0, 0, 0)
+    sys_call(SYS_CLOSE, fd, 0, 0, 0, 0, 0)
 }
 
 /// Fork the current process. Return the child's PID.
@@ -137,4 +143,4 @@ const SYS_FSYNC: usize = 111;
 const SYS_GETCWD: usize = 121;
 const SYS_GETDIRENTRY: usize = 128;
 const SYS_DUP: usize = 130;
-const SYS_LAB6_SET_PRIORITY: usize = 255;
\ No newline at end of file
+const SYS_LAB6_SET_PRIORITY: usize = 255;