diff --git a/kernel/include/hos_defines.h b/kernel/include/hos_defines.h
index 5cd9ea4..073e029 100644
--- a/kernel/include/hos_defines.h
+++ b/kernel/include/hos_defines.h
@@ -4,10 +4,6 @@
 
 #include "hos_types.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #define KERNEL_OFFSET           0x00000000
 
 #define PAGE_LOG_SIZE           12
@@ -17,24 +13,31 @@ extern "C" {
 
 #define CONSOLE_MEMORY          0xB8000
 
-extern  u8_t    _code;
-extern  u8_t    _data;
-extern  u8_t    _bss;
-extern  u8_t    _end;
-
-#define KERNEL_CODE (&_code)
-#define KERNEL_DATA (&_data)
-#define KERNEL_BSS  (&_bss)
-#define KERNEL_END  (&_end)
+#define KERNEL_CODE             (&_code)
+#define KERNEL_DATA             (&_data)
+#define KERNEL_BSS              (&_bss)
+#define KERNEL_END              (&_end)
 
 #define KERNEL_PHYSICAL_ADDRESS ((u32_t)(KERNEL_CODE - KERNEL_OFFSET))
 #define KERNEL_VIRTUAL_ADDRESS  ((u32_t)KERNEL_CODE)
 #define KERNEL_SIZE             ((u32_t)(KERNEL_END - KERNEL_CODE))
 
-#define KERNEL_STACK_TOP        0x40000000
+#define KERNEL_STACK_TOP        0x20000000
 
 #define KERNEL_TIMER_FREQ       1000
 
+#define BUILD_BUG_ON(condition) \
+    ((void) sizeof(struct { int : -!!(condition); }))
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern  u8_t    _code;
+extern  u8_t    _data;
+extern  u8_t    _bss;
+extern  u8_t    _end;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/kernel/mm/stack.cc b/kernel/mm/stack.cc
index 30ebdf4..af413bb 100644
--- a/kernel/mm/stack.cc
+++ b/kernel/mm/stack.cc
@@ -9,6 +9,11 @@ void stack_bootstrap()
      * running from our temporary stack while segmentation is enabled,
      * set up the "permanent" stack for use while paging
      */
-    u32_t first_stack_page_base = mm_early_page_alloc();
-    mm_early_map(KERNEL_STACK_TOP - PAGE_SIZE, first_stack_page_base, 0, 1);
+    u32_t stack_page_virt = KERNEL_STACK_TOP - PAGE_SIZE;
+    for (int i = 0; i < STACK_INITIAL_SIZE; i++)
+    {
+        u32_t stack_page_phys = mm_early_page_alloc();
+        mm_early_map(stack_page_virt, stack_page_phys, 0, 1);
+        stack_page_virt -= PAGE_SIZE;
+    }
 }
diff --git a/kernel/mm/stack.h b/kernel/mm/stack.h
index d649e80..d704079 100644
--- a/kernel/mm/stack.h
+++ b/kernel/mm/stack.h
@@ -2,6 +2,8 @@
 #ifndef STACK_H
 #define STACK_H
 
+#define STACK_INITIAL_SIZE 2        /* number of initial stack pages */
+
 void stack_bootstrap();
 
 #endif