arch/x86/kernel/efi_64.c

   1 /*
   2  * x86_64 specific EFI support functions
   3  * Based on Extensible Firmware Interface Specification version 1.0
   4  *
   5  * Copyright (C) 2005-2008 Intel Co.
   6  *      Fenghua Yu <fenghua.yu@intel.com>
   7  *      Bibo Mao <bibo.mao@intel.com>
   8  *      Chandramouli Narayanan <mouli@linux.intel.com>
   9  *      Huang Ying <ying.huang@intel.com>
  10  *
  11  * Code to convert EFI to E820 map has been implemented in elilo bootloader
  12  * based on a EFI patch by Edgar Hucek. Based on the E820 map, the page table
  13  * is setup appropriately for EFI runtime code.
  14  * - mouli 06/14/2007.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/mm.h>
  21 #include <linux/types.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/ioport.h>
  25 #include <linux/module.h>
  26 #include <linux/efi.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/io.h>
  29 #include <linux/reboot.h>
  30
  31 #include <asm/setup.h>
  32 #include <asm/page.h>
  33 #include <asm/e820.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/tlbflush.h>
  36 #include <asm/proto.h>
  37 #include <asm/efi.h>
  38 #include <asm/cacheflush.h>
  39 #include <asm/fixmap.h>
  40
  41 static pgd_t save_pgd __initdata;
  42 static unsigned long efi_flags __initdata;
  43
  44 static void __init early_mapping_set_exec(unsigned long start,
  45                                           unsigned long end,
  46                                           int executable)
  47 {
  48         unsigned long num_pages;
  49
  50         start &= PMD_MASK;
  51         end = (end + PMD_SIZE - 1) & PMD_MASK;
  52         num_pages = (end - start) >> PAGE_SHIFT;
  53         if (executable)
  54                 set_memory_x((unsigned long)__va(start), num_pages);
  55         else
  56                 set_memory_nx((unsigned long)__va(start), num_pages);
  57 }
  58
  59 static void __init early_runtime_code_mapping_set_exec(int executable)
  60 {
  61         efi_memory_desc_t *md;
  62         void *p;
  63
  64         if (!(__supported_pte_mask & _PAGE_NX))
  65                 return;
  66
  67         /* Make EFI runtime service code area executable */
  68         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  69                 md = p;
  70                 if (md->type == EFI_RUNTIME_SERVICES_CODE) {
  71                         unsigned long end;
  72                         end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
  73                         early_mapping_set_exec(md->phys_addr, end, executable);
  74                 }
  75         }
  76 }
  77
  78 void __init efi_call_phys_prelog(void)
  79 {
  80         unsigned long vaddress;
  81
  82         early_runtime_code_mapping_set_exec(1);
  83         local_irq_save(efi_flags);
  84         vaddress = (unsigned long)__va(0x0UL);
  85         save_pgd = *pgd_offset_k(0x0UL);
  86         set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
  87         __flush_tlb_all();
  88 }
  89
  90 void __init efi_call_phys_epilog(void)
  91 {
  92         /*
  93          * After the lock is released, the original page table is restored.
  94          */
  95         set_pgd(pgd_offset_k(0x0UL), save_pgd);
  96         __flush_tlb_all();
  97         local_irq_restore(efi_flags);
  98         early_runtime_code_mapping_set_exec(0);
  99 }
 100
 101 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size)
 102 {
 103         unsigned long last_map_pfn;
 104
 105         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
 106         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size)
 107                 return NULL;
 108
 109         return (void __iomem *)__va(phys_addr);
 110 }