arch/x86/kernel/efi_32.c

   1 /*
   2  * Extensible Firmware Interface
   3  *
   4  * Based on Extensible Firmware Interface Specification version 1.0
   5  *
   6  * Copyright (C) 1999 VA Linux Systems
   7  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   8  * Copyright (C) 1999-2002 Hewlett-Packard Co.
   9  *      David Mosberger-Tang <davidm@hpl.hp.com>
  10  *      Stephane Eranian <eranian@hpl.hp.com>
  11  *
  12  * All EFI Runtime Services are not implemented yet as EFI only
  13  * supports physical mode addressing on SoftSDV. This is to be fixed
  14  * in a future version.  --drummond 1999-07-20
  15  *
  16  * Implemented EFI runtime services and virtual mode calls.  --davidm
  17  *
  18  * Goutham Rao: <goutham.rao@intel.com>
  19  *      Skip non-WB memory and ignore empty memory ranges.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/types.h>
  24 #include <linux/ioport.h>
  25 #include <linux/efi.h>
  26
  27 #include <asm/io.h>
  28 #include <asm/page.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/tlbflush.h>
  31 <<<<<<< HEAD:arch/x86/kernel/efi_32.c
  32 =======
  33 #include <asm/efi.h>
  34 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/x86/kernel/efi_32.c
  35
  36 /*
  37  * To make EFI call EFI runtime service in physical addressing mode we need
  38  * prelog/epilog before/after the invocation to disable interrupt, to
  39  * claim EFI runtime service handler exclusively and to duplicate a memory in
  40  * low memory space say 0 - 3G.
  41  */
  42
  43 static unsigned long efi_rt_eflags;
  44 static pgd_t efi_bak_pg_dir_pointer[2];
  45
  46 void efi_call_phys_prelog(void)
  47 {
  48         unsigned long cr4;
  49         unsigned long temp;
  50         struct desc_ptr gdt_descr;
  51
  52         local_irq_save(efi_rt_eflags);
  53
  54         /*
  55          * If I don't have PSE, I should just duplicate two entries in page
  56          * directory. If I have PSE, I just need to duplicate one entry in
  57          * page directory.
  58          */
  59         cr4 = read_cr4();
  60
  61         if (cr4 & X86_CR4_PSE) {
  62                 efi_bak_pg_dir_pointer[0].pgd =
  63                     swapper_pg_dir[pgd_index(0)].pgd;
  64                 swapper_pg_dir[0].pgd =
  65                     swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
  66         } else {
  67                 efi_bak_pg_dir_pointer[0].pgd =
  68                     swapper_pg_dir[pgd_index(0)].pgd;
  69                 efi_bak_pg_dir_pointer[1].pgd =
  70                     swapper_pg_dir[pgd_index(0x400000)].pgd;
  71                 swapper_pg_dir[pgd_index(0)].pgd =
  72                     swapper_pg_dir[pgd_index(PAGE_OFFSET)].pgd;
  73                 temp = PAGE_OFFSET + 0x400000;
  74                 swapper_pg_dir[pgd_index(0x400000)].pgd =
  75                     swapper_pg_dir[pgd_index(temp)].pgd;
  76         }
  77
  78         /*
  79          * After the lock is released, the original page table is restored.
  80          */
  81         __flush_tlb_all();
  82
  83         gdt_descr.address = __pa(get_cpu_gdt_table(0));
  84         gdt_descr.size = GDT_SIZE - 1;
  85         load_gdt(&gdt_descr);
  86 }
  87
  88 void efi_call_phys_epilog(void)
  89 {
  90         unsigned long cr4;
  91         struct desc_ptr gdt_descr;
  92
  93         gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
  94         gdt_descr.size = GDT_SIZE - 1;
  95         load_gdt(&gdt_descr);
  96
  97         cr4 = read_cr4();
  98
  99         if (cr4 & X86_CR4_PSE) {
 100                 swapper_pg_dir[pgd_index(0)].pgd =
 101                     efi_bak_pg_dir_pointer[0].pgd;
 102         } else {
 103                 swapper_pg_dir[pgd_index(0)].pgd =
 104                     efi_bak_pg_dir_pointer[0].pgd;
 105                 swapper_pg_dir[pgd_index(0x400000)].pgd =
 106                     efi_bak_pg_dir_pointer[1].pgd;
 107         }
 108
 109         /*
 110          * After the lock is released, the original page table is restored.
 111          */
 112         __flush_tlb_all();
 113
 114         local_irq_restore(efi_rt_eflags);
 115 }