arch/x86/kernel/trampoline.c

   1 #include <linux/io.h>
   2
   3 #include <asm/trampoline.h>
   4 #include <asm/pgtable.h>
   5 #include <asm/e820.h>
   6
   7 #if defined(CONFIG_X86_64) && defined(CONFIG_ACPI_SLEEP)
   8 #define __trampinit
   9 #define __trampinitdata
  10 #else
  11 #define __trampinit __cpuinit
  12 #define __trampinitdata __cpuinitdata
  13 #endif
  14
  15 /* ready for x86_64 and x86 */
  16 unsigned char *__trampinitdata trampoline_base;
  17
  18 void __init reserve_trampoline_memory(void)
  19 {
  20         unsigned long mem;
  21
  22         /* Has to be in very low memory so we can execute real-mode AP code. */
  23         mem = find_e820_area(0, 1<<20, TRAMPOLINE_SIZE, PAGE_SIZE);
  24         if (mem == -1L)
  25                 panic("Cannot allocate trampoline\n");
  26
  27         trampoline_base = __va(mem);
  28         reserve_early(mem, mem + TRAMPOLINE_SIZE, "TRAMPOLINE");
  29 }
  30
  31 /*
  32  * Currently trivial. Write the real->protected mode
  33  * bootstrap into the page concerned. The caller
  34  * has made sure it's suitably aligned.
  35  */
  36 unsigned long __trampinit setup_trampoline(void)
  37 {
  38         memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
  39         return virt_to_phys(trampoline_base);
  40 }
  41
  42 void __init setup_trampoline_page_table(void)
  43 {
  44 #ifdef CONFIG_X86_32
  45         /* Copy kernel address range */
  46         clone_pgd_range(trampoline_pg_dir + KERNEL_PGD_BOUNDARY,
  47                         swapper_pg_dir + KERNEL_PGD_BOUNDARY,
  48                         KERNEL_PGD_PTRS);
  49
  50         /* Initialize low mappings */
  51         clone_pgd_range(trampoline_pg_dir,
  52                         swapper_pg_dir + KERNEL_PGD_BOUNDARY,
  53                         min_t(unsigned long, KERNEL_PGD_PTRS,
  54                               KERNEL_PGD_BOUNDARY));
  55 #endif
  56 }