diff --git a/Makefile b/Makefile
index a11cafb..3ea7054 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,17 @@
+# Examples:
+# 	make run					Run in debug
+#	make run int=1				Run with interrupt info by QEMU
+# 	make run mode=release		Run in release
+# 	make doc					Generate docs
+# 	make asm					Open the deassemble file of the last build
+# 	make clean					Clean
+
 arch ?= x86_64
 kernel := build/kernel-$(arch).bin
 iso := build/os-$(arch).iso
 target ?= $(arch)-blog_os
-rust_os := target/$(target)/debug/librust_ucore.a
+mode ?= debug
+rust_os := target/$(target)/$(mode)/librust_ucore.a
 
 boot_src := src/arch/$(arch)/boot
 linker_script := $(boot_src)/linker.ld
@@ -37,6 +46,12 @@ ifdef int
 qemu_opts := $(qemu_opts) -d int
 endif
 
+build_args := --target $(target) --features "$(features)"
+
+ifeq ($(mode), release)
+build_args := $(build_args) --release
+endif
+
 
 ifeq ($(OS),Windows_NT)
 uname := Win32
@@ -54,7 +69,7 @@ ld := $(prefix)ld
 objdump := $(prefix)objdump
 cc := $(prefix)gcc
 
-.PHONY: all clean run iso kernel build debug_asm doc
+.PHONY: all clean run iso kernel build asm doc
 
 all: $(kernel)
 
@@ -74,7 +89,7 @@ iso: $(iso)
 
 build: iso
 
-debug_asm:
+asm:
 	@$(objdump) -dS $(kernel) | less
 
 $(iso): $(kernel) $(grub_cfg)
@@ -89,7 +104,7 @@ $(kernel): kernel $(rust_os) $(assembly_object_files) $(linker_script)
 		$(assembly_object_files) $(rust_os)
 
 kernel:
-	@RUST_TARGET_PATH=$(shell pwd) CC=$(cc) xargo build --target $(target) --features "$(features)"
+	@RUSTFLAGS=-g RUST_TARGET_PATH=$(shell pwd) CC=$(cc) xargo build $(build_args)
 
 # compile assembly files
 build/arch/$(arch)/boot/%.o: $(boot_src)/%.asm
diff --git a/src/arch/x86_64/driver/apic/lapic.rs b/src/arch/x86_64/driver/apic/lapic.rs
index 80e2b54..2332e5f 100644
--- a/src/arch/x86_64/driver/apic/lapic.rs
+++ b/src/arch/x86_64/driver/apic/lapic.rs
@@ -36,8 +36,10 @@ pub fn start_ap(apicid: u8, addr: u32) {
 pub fn lapic_id() -> u8 {
 	unsafe{
         if lapic.is_null() {
+            warn!("lapic is null. return lapic id = 0");
             return 0;
         }
-		(*(lapic as *const u32).offset(0x0020/4) >> 24) as u8
+        let ptr = (lapic as *const u32).offset(0x0020 / 4);
+        (ptr.read_volatile() >> 24) as u8
 	}
 }
\ No newline at end of file
diff --git a/src/arch/x86_64/smp.rs b/src/arch/x86_64/smp.rs
index 9ab9f6d..f30818f 100644
--- a/src/arch/x86_64/smp.rs
+++ b/src/arch/x86_64/smp.rs
@@ -1,5 +1,6 @@
 use arch::driver::{acpi::AcpiResult, apic::start_ap};
 use memory::{MemoryController, PhysAddr};
+use core::ptr::{read_volatile, write_volatile};
 
 extern {
     fn entryother_start();  // physical addr of entryother
@@ -29,7 +30,7 @@ pub fn start_other_cores(acpi: &AcpiResult, mc: &mut MemoryController) {
             stack: 0x8000, // just enough stack to get us to entry64mp
         };
         start_ap(apic_id, ENTRYOTHER_ADDR);
-        while unsafe{ !STARTED[i as usize] } {}
+        while unsafe { !read_volatile(&STARTED[i as usize]) } {}
     }
 }
 
@@ -54,5 +55,5 @@ use consts::MAX_CPU_NUM;
 static mut STARTED: [bool; MAX_CPU_NUM] = [false; MAX_CPU_NUM];
 
 pub unsafe fn notify_started(cpu_id: u8) {
-    STARTED[cpu_id as usize] = true;
+    write_volatile(&mut STARTED[cpu_id as usize], true);
 }
\ No newline at end of file