diff --git a/userspace/libc.h b/userspace/libc.h
index 166e51c..9ef9596 100644
--- a/userspace/libc.h
+++ b/userspace/libc.h
@@ -36,6 +36,10 @@ int putc(const int c);
 int vsnprintf(char *str, size_t size, const char *format, va_list ap) __attribute__ ((__format__ (printf, 3, 0)));
 int vprintf(const char *format, va_list ap) __attribute__ ((__format__ (printf, 1, 0)));
 int printf(const char *format, ...) __attribute__ ((__format__ (printf, 1, 2)));
+/* To keep in sync with PAGING_MEM_* */
+#define PROT_EXEC  (1<<3)
+#define PROT_READ  (1<<1)
+#define PROT_WRITE (1<<2)
 void *mmap(void *addr, size_t len, int prot, int flags, char *path);
 
 int asprintf(char **strp, const char *fmt, ...) __attribute__ ((__format__ (printf, 2, 3)));