memory allocation

common.h

@@ -19,6 +19,7 @@ typedef uint32_t vaddr_t;
 #define va_start  __builtin_va_start
 #define va_end    __builtin_va_end
 #define va_arg    __builtin_va_arg
+#define PAGE_SIZE 4096
 
 void *memset(void *buf, char c, size_t n);
 void *memcpy(void *dst, const void *src, size_t n);