cp/include/mm.h

   1 /*
   2  * (C) Copyright 2007-2010  Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
   3  *
   4  * This file is released under the GPLv2.  See the COPYING file for more
   5  * details.
   6  */
   7
   8 #ifndef __MM_H
   9 #define __MM_H
  10
  11 extern u64 memsize;
  12
  13 extern const u8 zeropage[PAGE_SIZE];
  14
  15 /* Turn Low-address protection on */
  16 static inline void lap_on(void)
  17 {
  18         u64 cr0;
  19
  20         asm volatile(
  21                 "stctg  0,0,%0\n"       /* get cr0 */
  22                 "oi     %1,0x10\n"      /* enable */
  23                 "lctlg  0,0,%0\n"       /* reload cr0 */
  24         : /* output */
  25         : /* input */
  26           "m" (cr0),
  27           "m" (*(u64*) (((u8*)&cr0) + 4))
  28         );
  29 }
  30
  31 #endif