diff --git a/kern/pmap.c b/kern/pmap.c
index a514b2a..d08a6f3 100644
--- a/kern/pmap.c
+++ b/kern/pmap.c
@@ -175,9 +175,7 @@ mem_init(void)
 	// Your code goes here:
 	boot_map_region(kern_pgdir,
 			UPAGES, ROUNDUP(pages_size, PGSIZE),
-			PADDR(pages), PTE_W);
-	kern_pgdir[PDX(UPAGES)] |= PTE_U | PTE_P;
-	kern_pgdir[PDX(UPAGES)] &= ~PTE_W;
+			PADDR(pages), PTE_U);
 
 	//////////////////////////////////////////////////////////////////////
 	// Use the physical memory that 'bootstack' refers to as the kernel
@@ -193,8 +191,6 @@ mem_init(void)
 	boot_map_region(kern_pgdir,
 			KSTACKTOP-KSTKSIZE, KSTKSIZE,
 			PADDR(bootstack), PTE_W);
-	kern_pgdir[PDX(KSTACKTOP-KSTKSIZE)] |= PTE_W | PTE_P;
-	kern_pgdir[PDX(KSTACKTOP-KSTKSIZE)] &= ~PTE_U;
 
 	//////////////////////////////////////////////////////////////////////
 	// Map all of physical memory at KERNBASE.
@@ -207,9 +203,6 @@ mem_init(void)
 	boot_map_region(kern_pgdir,
 			KERNBASE, 0x100000000 - KERNBASE,
 			0, PTE_W);
-	kern_pgdir[PDX(KERNBASE)] |= PTE_W | PTE_P;
-	kern_pgdir[PDX(KERNBASE)] &= ~PTE_U;
-
 
 	// Check that the initial page directory has been set up correctly.
 	check_kern_pgdir();