arch/x86/kernel/trampoline.c

   1 #include <linux/io.h>
   2
   3 #include <asm/trampoline.h>
   4 #include <asm/e820.h>
   5
   6 #if defined(CONFIG_X86_64) && defined(CONFIG_ACPI_SLEEP)
   7 #define __trampinit
   8 #define __trampinitdata
   9 #else
  10 #define __trampinit __cpuinit
  11 #define __trampinitdata __cpuinitdata
  12 #endif
  13
  14 /* ready for x86_64 and x86 */
  15 unsigned char *__trampinitdata trampoline_base;
  16
  17 void __init reserve_trampoline_memory(void)
  18 {
  19         unsigned long mem;
  20
  21         /* Has to be in very low memory so we can execute real-mode AP code. */
  22         mem = find_e820_area(0, 1<<20, TRAMPOLINE_SIZE, PAGE_SIZE);
  23         if (mem == -1L)
  24                 panic("Cannot allocate trampoline\n");
  25
  26         trampoline_base = __va(mem);
  27         reserve_early(mem, mem + TRAMPOLINE_SIZE, "TRAMPOLINE");
  28 }
  29
  30 /*
  31  * Currently trivial. Write the real->protected mode
  32  * bootstrap into the page concerned. The caller
  33  * has made sure it's suitably aligned.
  34  */
  35 unsigned long __trampinit setup_trampoline(void)
  36 {
  37         memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
  38         return virt_to_phys(trampoline_base);
  39 }