arch/x86/kernel/trampoline.c

   1 #include <linux/io.h>
   2
   3 #include <asm/trampoline.h>
   4 #include <asm/e820.h>
   5
   6 /* ready for x86_64 and x86 */
   7 unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
   8
   9 void __init reserve_trampoline_memory(void)
  10 {
  11 #ifdef CONFIG_X86_32
  12         /*
  13          * But first pinch a few for the stack/trampoline stuff
  14          * FIXME: Don't need the extra page at 4K, but need to fix
  15          * trampoline before removing it. (see the GDT stuff)
  16          */
  17         reserve_early(PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE");
  18 #endif
  19         /* Has to be in very low memory so we can execute real-mode AP code. */
  20         reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE,
  21                         "TRAMPOLINE");
  22 }
  23
  24 /*
  25  * Currently trivial. Write the real->protected mode
  26  * bootstrap into the page concerned. The caller
  27  * has made sure it's suitably aligned.
  28  */
  29 unsigned long setup_trampoline(void)
  30 {
  31         memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
  32         return virt_to_phys(trampoline_base);
  33 }