diff --git a/user/Makefile b/user/Makefile
index 52ebf0a..185ca0f 100644
--- a/user/Makefile
+++ b/user/Makefile
@@ -2,4 +2,4 @@
 arch := riscv32
 
 all:
-	@RUST_TARGET_PATH=$(shell pwd) xargo build --target $(arch)-ucore
\ No newline at end of file
+	cargo xbuild --target $(arch)-ucore.json
\ No newline at end of file
diff --git a/user/Xargo.toml b/user/Xargo.toml
deleted file mode 100644
index f79cb96..0000000
--- a/user/Xargo.toml
+++ /dev/null
@@ -1,6 +0,0 @@
-[dependencies]
-alloc = {}
-
-[dependencies.compiler_builtins]
-features = ["mem"]
-stage = 1
diff --git a/user/riscv32-ucore.json b/user/riscv32-ucore.json
index ef98b18..621b0da 100644
--- a/user/riscv32-ucore.json
+++ b/user/riscv32-ucore.json
@@ -5,12 +5,17 @@
   "target-pointer-width": "32",
   "target-c-int-width": "32",
   "os": "none",
-  "arch": "riscv",
+  "arch": "riscv32",
   "cpu": "generic-rv32",
-  "features": "+m",
+  "features": "",
   "max-atomic-width": "32",
-  "linker": "riscv32-unknown-elf-ld",
+  "linker": "riscv64-unknown-elf-ld",
   "linker-flavor": "ld",
+  "pre-link-args": {
+    "ld": [
+      "-melf32lriscv"
+    ]
+  },
   "executables": true,
   "panic-strategy": "abort",
   "relocation-model": "static",
diff --git a/user/ucore-ulib/src/lang_items.rs b/user/ucore-ulib/src/lang_items.rs
index 5dcbec1..89e5334 100644
--- a/user/ucore-ulib/src/lang_items.rs
+++ b/user/ucore-ulib/src/lang_items.rs
@@ -1,4 +1,6 @@
 use syscall::sys_exit;
+use core::alloc::Layout;
+use core::panic::PanicInfo;
 
 #[linkage = "weak"]
 #[no_mangle]
@@ -7,8 +9,7 @@ fn main() {
 }
 
 #[no_mangle]
-pub extern fn _start(_argc: isize, _argv: *const *const u8) -> !
-{
+pub extern fn _start(_argc: isize, _argv: *const *const u8) -> ! {
     main();
     sys_exit(0)
 }
@@ -16,25 +17,35 @@ pub extern fn _start(_argc: isize, _argv: *const *const u8) -> !
 #[lang = "eh_personality"]
 fn eh_personality() {}
 
-#[cfg(target_arch = "x86_64")]
 #[panic_implementation]
-fn panic(info: &::core::panic::PanicInfo) -> ! {
+fn panic(info: &PanicInfo) -> ! {
     let location = info.location().unwrap();
     let message = info.message().unwrap();
     println!("\n\nPANIC in {} at line {}\n    {}", location.file(), location.line(), message);
     sys_exit(1)
 }
 
-#[cfg(target_arch = "riscv32")]
-#[lang = "panic_fmt"]
+#[lang = "oom"]
+fn oom(_: Layout) -> ! {
+    panic!("out of memory");
+}
+
 #[no_mangle]
-pub fn panic_fmt(fmt: ::core::fmt::Arguments, file: &'static str, line: u32, col: u32) -> ! {
-    println!("\n\nPANIC in {} at {}:{}\n    {}", file, line, col, fmt);
-    sys_exit(1)
+pub extern fn abort() -> ! {
+    sys_exit(2)
 }
 
-#[cfg(target_arch = "x86_64")]
-#[lang = "oom"]
-fn oom() -> ! {
-    panic!("out of memory");
+#[no_mangle]
+pub extern fn __mulsi3(mut a: u32, mut b: u32) -> u32 {
+    let mut r: u32 = 0;
+
+    while a > 0 {
+        if a & 1 > 0 {
+            r += b;
+        }
+        a >>= 1;
+        b <<= 1;
+    }
+
+    r
 }
\ No newline at end of file
diff --git a/user/ucore-ulib/src/lib.rs b/user/ucore-ulib/src/lib.rs
index c1c1cb7..fb4cf19 100644
--- a/user/ucore-ulib/src/lib.rs
+++ b/user/ucore-ulib/src/lib.rs
@@ -6,8 +6,6 @@
 #![feature(linkage)]
 #![feature(compiler_builtins_lib)]
 
-extern crate compiler_builtins;
-
 #[macro_use]
 pub mod syscall;
 pub mod lang_items;
\ No newline at end of file