diff --git a/ostd/src/arch/x86/boot/smp.rs b/ostd/src/arch/x86/boot/smp.rs
index 3b5ac609d..bd980ce56 100644
--- a/ostd/src/arch/x86/boot/smp.rs
+++ b/ostd/src/arch/x86/boot/smp.rs
@@ -92,37 +92,29 @@ fn fill_boot_stack_array_ptr() {
         .unwrap()
         .boot_stack_array;
 
-    // This is defined in the boot assembly code.
     extern "C" {
-        fn __ap_boot_stack_array_pointer();
+        static __ap_boot_stack_array_pointer: u64;
     }
-    let ap_boot_stack_arr_ptr: *mut u64 = __ap_boot_stack_array_pointer as usize as *mut u64;
-    log::debug!(
-        "Setting __ap_boot_stack_array_pointer={:#x?} for AP boot stacks",
-        ap_boot_stack_arr_ptr
-    );
 
-    // SAFETY: this pointer points to a static variable defined in the `ap_boot.S`.
+    // SAFETY: This pointer points to a static variable defined in the `ap_boot.S`.
+    let ptr = unsafe { &__ap_boot_stack_array_pointer as *const u64 as *mut u64 };
+    // SAFETY: We only write to it once.
     unsafe {
-        ap_boot_stack_arr_ptr.write_volatile(paddr_to_vaddr(pages.start_paddr()) as u64);
+        ptr.write_volatile(paddr_to_vaddr(pages.start_paddr()) as u64);
     }
 }
 
 fn fill_boot_pt_ptr() {
-    // This is defined in the boot assembly code.
     extern "C" {
-        fn __boot_page_table_pointer();
+        static __boot_page_table_pointer: u32;
     }
-    let boot_pt_ptr: *mut u32 = __boot_page_table_pointer as usize as *mut u32;
     let boot_pt = crate::mm::page_table::boot_pt::with_borrow(|pt| pt.root_address()).unwrap();
-    log::debug!(
-        "Setting __boot_page_table_pointer={:#x?} for AP boot page tables",
-        boot_pt
-    );
 
     // SAFETY: this pointer points to a static variable defined in the `ap_boot.S`.
+    let ptr = unsafe { &__boot_page_table_pointer as *const u32 as *mut u32 };
+    // SAFETY: We only write to it once.
     unsafe {
-        boot_pt_ptr.write_volatile(boot_pt as u32);
+        ptr.write_volatile(boot_pt as u32);
     }
 }