set only PG and WP in vminit; the rest don't seem to be needed and are confusing

main.c

@@ -41,7 +41,7 @@ void
 mainc(void)
 {
   cprintf("\ncpu%d: starting xv6\n\n", cpu->id);
-  kvmalloc();      // initialze the kernel page table
+  kvmalloc();      // initialize the kernel page table
   pinit();         // process table
   tvinit();        // trap vectors
   binit();         // buffer cache

user.h

@@ -21,6 +21,7 @@ int dup(int);
 int getpid();
 char* sbrk(int);
 int sleep(int);
+int uptime();
 
 // ulib.c
 int stat(char*, struct stat*);

vm.c

@@ -375,8 +375,9 @@ vminit(void)
 
   lcr3(PADDR(kpgdir));
   cr0 = rcr0();
-  cr0 |= CR0_PE|CR0_PG|CR0_AM|CR0_WP|CR0_NE|CR0_TS|CR0_EM|CR0_MP;
-  cr0 &= ~(CR0_TS|CR0_EM);
+  // cr0 |= CR0_PE|CR0_PG|CR0_AM|CR0_WP|CR0_NE|CR0_TS|CR0_EM|CR0_MP;
+  // cr0 &= ~(CR0_TS|CR0_EM);
+  cr0 |= CR0_PG | CR0_WP;
   lcr0(cr0);
 }