diff --git a/kernel/src/arch/riscv/layout.rs b/kernel/src/arch/riscv/layout.rs
index 068c032..1443af2 100644
--- a/kernel/src/arch/riscv/layout.rs
+++ b/kernel/src/arch/riscv/layout.rs
@@ -1,4 +1,5 @@
 use crate::utils::extern_addr::ExternSymbol;
+use crate::utils::size::KIB;
 
 extern "C" {
     static __kernel_start: ExternSymbol;
@@ -26,3 +27,5 @@ extern "C" {
     pub static __tbss_start: ExternSymbol;
     pub static __tbss_end: ExternSymbol;
 }
+
+pub const PAGE_SIZE: usize = 4 * KIB;
diff --git a/kernel/src/main.rs b/kernel/src/main.rs
index 308c0a7..a108475 100644
--- a/kernel/src/main.rs
+++ b/kernel/src/main.rs
@@ -5,6 +5,7 @@
 #![feature(asm_const)]
 #![feature(const_mut_refs)]
 #![feature(extern_types)]
+#![feature(let_chains)]
 #![feature(naked_functions)]
 #![feature(panic_info_message)]
 #![feature(stmt_expr_attributes)]
diff --git a/kernel/src/vspace/paging/mod.rs b/kernel/src/vspace/paging/mod.rs
index 3d5b817..f06e8cb 100644
--- a/kernel/src/vspace/paging/mod.rs
+++ b/kernel/src/vspace/paging/mod.rs
@@ -1,7 +1,7 @@
 mod entry;
 mod table;
 
-pub use crate::arch::vspace::*;
+pub use crate::arch::vspace::{Entry, Table};
 pub use entry::*;
 pub use table::*;