diff --git a/.cargo/config.toml b/.cargo/config.toml
index 5ea31d4..8734cf2 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -1,5 +1,6 @@
 [alias]
 xtask = "run --package xtask --"
 make = "xtask make"
+asm = "xtask asm"
 gdb = "xtask gdb"
 image = "xtask image"
diff --git a/rustsbi-hifive-unmatched/src/early_trap.rs b/rustsbi-hifive-unmatched/src/early_trap.rs
new file mode 100644
index 0000000..c2c02d2
--- /dev/null
+++ b/rustsbi-hifive-unmatched/src/early_trap.rs
@@ -0,0 +1,110 @@
+use riscv::register::{
+    mstatus::Mstatus,
+    mtvec::{self, TrapMode},
+    mscratch,
+    mcause,
+    mtval
+};
+
+#[inline]
+pub fn init(hartid: usize) {
+    let stack_base = unsafe { &super::SBI_STACK } as *const _ as usize;
+    let stack = stack_base + (hartid + 1) * super::PER_HART_STACK_SIZE;
+    mscratch::write(stack);
+    let mut addr = early_trap_fail as usize;
+    if addr & 0x2 != 0 {
+        addr += 0x2; // 中断入口地址必须对齐到4个字节
+    }
+    unsafe { mtvec::write(addr, TrapMode::Direct) };
+}
+
+extern "C" fn rust_fail(ctx: &SupervisorContext) -> ! {
+    crate::println!("rustsbi: early init stage fail, context: {:x?}, mcause: {:?}, mtval: {:x}", ctx, mcause::read(), mtval::read());
+    loop {}
+}
+
+#[derive(Debug)]
+#[repr(C)]
+pub struct SupervisorContext {
+    pub ra: usize, // 0
+    pub sp: usize,
+    pub gp: usize,
+    pub tp: usize,
+    pub t0: usize,
+    pub t1: usize,
+    pub t2: usize,
+    pub s0: usize,
+    pub s1: usize,
+    pub a0: usize,
+    pub a1: usize,
+    pub a2: usize,
+    pub a3: usize,
+    pub a4: usize,
+    pub a5: usize,
+    pub a6: usize,
+    pub a7: usize,
+    pub s2: usize,
+    pub s3: usize,
+    pub s4: usize,
+    pub s5: usize,
+    pub s6: usize,
+    pub s7: usize,
+    pub s8: usize,
+    pub s9: usize,
+    pub s10: usize,
+    pub s11: usize,
+    pub t3: usize,
+    pub t4: usize,
+    pub t5: usize,
+    pub t6: usize,            // 30
+    pub mstatus: Mstatus,     // 31
+    pub mepc: usize,          // 32
+}
+
+#[naked]
+#[link_section = ".text"]
+pub unsafe extern "C" fn early_trap_fail() -> ! {
+    asm!( // sp:特权级栈,mscratch:特权级上下文
+        ".p2align 2",
+        "csrrw  sp, mscratch, sp", // 新mscratch:特权级栈, 新sp:特权级上下文
+        "addi   sp, sp, -33*8",
+        "sd     ra, 0*8(sp)
+        sd      gp, 2*8(sp)
+        sd      tp, 3*8(sp)
+        sd      t0, 4*8(sp)
+        sd      t1, 5*8(sp)
+        sd      t2, 6*8(sp)
+        sd      s0, 7*8(sp)
+        sd      s1, 8*8(sp)
+        sd      a0, 9*8(sp)
+        sd      a1, 10*8(sp)
+        sd      a2, 11*8(sp)
+        sd      a3, 12*8(sp)
+        sd      a4, 13*8(sp)
+        sd      a5, 14*8(sp)
+        sd      a6, 15*8(sp)
+        sd      a7, 16*8(sp)
+        sd      s2, 17*8(sp)
+        sd      s3, 18*8(sp)
+        sd      s4, 19*8(sp)
+        sd      s5, 20*8(sp)
+        sd      s6, 21*8(sp)
+        sd      s7, 22*8(sp)
+        sd      s8, 23*8(sp)
+        sd      s9, 24*8(sp)
+        sd     s10, 25*8(sp)
+        sd     s11, 26*8(sp)
+        sd      t3, 27*8(sp)
+        sd      t4, 28*8(sp)
+        sd      t5, 29*8(sp)
+        sd      t6, 30*8(sp)",
+        "csrr   t0, mstatus
+        sd      t0, 31*8(sp)",
+        "csrr   t1, mepc
+        sd      t1, 32*8(sp)",
+        "mv     a0, sp",
+        "j      {fail}",
+        fail = sym rust_fail,
+        options(noreturn)
+    )
+}
diff --git a/rustsbi-hifive-unmatched/src/main.rs b/rustsbi-hifive-unmatched/src/main.rs
index 5a419a8..3b47ebf 100644
--- a/rustsbi-hifive-unmatched/src/main.rs
+++ b/rustsbi-hifive-unmatched/src/main.rs
@@ -9,6 +9,7 @@
 
 mod runtime;
 mod peripheral;
+mod early_trap;
 
 use core::panic::PanicInfo;
 
@@ -27,10 +28,10 @@ fn rust_main(hartid: usize, opaque: usize) -> ! {
     if hartid == 0 {
         init_bss();
     }
-    runtime::init();
     if hartid == 0 {
         let uart = unsafe { peripheral::Uart::prev_bootloading_step() };
         init_stdout(uart);
+        early_trap::init(hartid);
         println!("rustsbi: hello world (1)!");
         print_misa();
         init_heap(); // 必须先加载堆内存，才能使用rustsbi框架
@@ -38,7 +39,8 @@ fn rust_main(hartid: usize, opaque: usize) -> ! {
         println!("rustsbi: hello world!");
         println!("rustsbi: hello world! {:x} {:x}", hartid, opaque);
     }
-    todo!()
+    runtime::init();
+    loop {}
 }
 
 fn init_bss() {
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index c8fd491..d53e1c5 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -24,6 +24,10 @@ fn main() {
             (about: "Build project")
             (@arg release: --release "Build artifacts in release mode, with optimizations")
         )
+        (@subcommand asm =>
+            (about: "View asm code for project")
+            (@arg release: --release "Build artifacts in release mode, with optimizations")
+        )
         (@subcommand image =>
             (about: "Build SD card partition image")
             (@arg release: --release "Build artifacts in release mode, with optimizations")
@@ -42,6 +46,12 @@ fn main() {
         }
         xtask_build_sbi(&xtask_env);
         xtask_binary_sbi(&xtask_env);
+    } else if let Some(matches) = matches.subcommand_matches("asm") {
+        if matches.is_present("release") {
+            xtask_env.compile_mode = CompileMode::Release;
+        }
+        xtask_build_sbi(&xtask_env);
+        xtask_asm_sbi(&xtask_env);
     } else if let Some(matches) = matches.subcommand_matches("image") {
         if matches.is_present("release") {
             xtask_env.compile_mode = CompileMode::Release;
@@ -93,6 +103,16 @@ fn xtask_binary_sbi(xtask_env: &XtaskEnv) {
     }
 }
 
+fn xtask_asm_sbi(xtask_env: &XtaskEnv) {
+    // @{{objdump}} -D {{test-kernel-elf}} | less
+    Command::new("riscv-none-embed-objdump")
+        .current_dir(dist_dir(xtask_env))
+        .arg("-d")
+        .arg("rustsbi-hifive-unmatched")
+        .status()
+        .unwrap();
+}
+
 fn xtask_unmatched_gdb(xtask_env: &XtaskEnv) {
     let mut command = Command::new("riscv-none-embed-gdb");
     command.current_dir(dist_dir(xtask_env));