arch/x86/platform/efi/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/desc.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.h>
  31 #include <asm/tlbflush.h>
  32 #include <asm/efi.h>
  33
  34 /*
  35  * To make EFI call EFI runtime service in physical addressing mode we need
  36  * prolog/epilog before/after the invocation to claim the EFI runtime service
  37  * handler exclusively and to duplicate a memory mapping in low memory space,
  38  * say 0 - 3G.
  39  */
  40
  41 int __init efi_alloc_page_tables(void)
  42 {
  43         return 0;
  44 }
  45
  46 void efi_sync_low_kernel_mappings(void) {}
  47 void __init efi_dump_pagetable(void) {}
  48 int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages)
  49 {
  50         return 0;
  51 }
  52
  53 void __init efi_map_region(efi_memory_desc_t *md)
  54 {
  55         old_map_region(md);
  56 }
  57
  58 void __init efi_map_region_fixed(efi_memory_desc_t *md) {}
  59 void __init parse_efi_setup(u64 phys_addr, u32 data_len) {}
  60
  61 pgd_t * __init efi_call_phys_prolog(void)
  62 {
  63         struct desc_ptr gdt_descr;
  64         pgd_t *save_pgd;
  65
  66         /* Current pgd is swapper_pg_dir, we'll restore it later: */
  67         save_pgd = swapper_pg_dir;
  68         load_cr3(initial_page_table);
  69         __flush_tlb_all();
  70
  71         gdt_descr.address = __pa(get_cpu_gdt_table(0));
  72         gdt_descr.size = GDT_SIZE - 1;
  73         load_gdt(&gdt_descr);
  74
  75         return save_pgd;
  76 }
  77
  78 void __init efi_call_phys_epilog(pgd_t *save_pgd)
  79 {
  80         struct desc_ptr gdt_descr;
  81
  82         gdt_descr.address = (unsigned long)get_cpu_gdt_table(0);
  83         gdt_descr.size = GDT_SIZE - 1;
  84         load_gdt(&gdt_descr);
  85
  86         load_cr3(save_pgd);
  87         __flush_tlb_all();
  88 }
  89
  90 void __init efi_runtime_update_mappings(void)
  91 {
  92         if (__supported_pte_mask & _PAGE_NX)
  93                 runtime_code_page_mkexec();
  94 }