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
  40 static pgd_t save_pgd __initdata;
  41 static unsigned long efi_flags __initdata;
  42
  43 static void __init early_mapping_set_exec(unsigned long start,
  44                                           unsigned long end,
  45                                           int executable)
  46 {
  47         unsigned long num_pages;
  48
  49         start &= PMD_MASK;
  50         end = (end + PMD_SIZE - 1) & PMD_MASK;
  51         num_pages = (end - start) >> PAGE_SHIFT;
  52         if (executable)
  53                 set_memory_x((unsigned long)__va(start), num_pages);
  54         else
  55                 set_memory_nx((unsigned long)__va(start), num_pages);
  56 }
  57
  58 static void __init early_runtime_code_mapping_set_exec(int executable)
  59 {
  60         efi_memory_desc_t *md;
  61         void *p;
  62
  63         if (!(__supported_pte_mask & _PAGE_NX))
  64                 return;
  65
  66         /* Make EFI runtime service code area executable */
  67         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  68                 md = p;
  69                 if (md->type == EFI_RUNTIME_SERVICES_CODE) {
  70                         unsigned long end;
  71                         end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
  72                         early_mapping_set_exec(md->phys_addr, end, executable);
  73                 }
  74         }
  75 }
  76
  77 void __init efi_call_phys_prelog(void)
  78 {
  79         unsigned long vaddress;
  80
  81         early_runtime_code_mapping_set_exec(1);
  82         local_irq_save(efi_flags);
  83         vaddress = (unsigned long)__va(0x0UL);
  84         save_pgd = *pgd_offset_k(0x0UL);
  85         set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
  86         __flush_tlb_all();
  87 }
  88
  89 void __init efi_call_phys_epilog(void)
  90 {
  91         /*
  92          * After the lock is released, the original page table is restored.
  93          */
  94         set_pgd(pgd_offset_k(0x0UL), save_pgd);
  95         __flush_tlb_all();
  96         local_irq_restore(efi_flags);
  97         early_runtime_code_mapping_set_exec(0);
  98 }
  99
 100 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size)
 101 {
 102         static unsigned pages_mapped __initdata;
 103         unsigned i, pages;
 104         unsigned long offset;
 105
 106         pages = PFN_UP(phys_addr + size) - PFN_DOWN(phys_addr);
 107         offset = phys_addr & ~PAGE_MASK;
 108         phys_addr &= PAGE_MASK;
 109
 110         if (pages_mapped + pages > MAX_EFI_IO_PAGES)
 111                 return NULL;
 112
 113         for (i = 0; i < pages; i++) {
 114                 __set_fixmap(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
 115                              phys_addr, PAGE_KERNEL);
 116                 phys_addr += PAGE_SIZE;
 117                 pages_mapped++;
 118         }
 119
 120         return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE - \
 121                                              (pages_mapped - pages)) + offset;
 122 }