arch/x86/platform/efi/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_code_mapping_set_exec(int executable)
  45 {
  46         efi_memory_desc_t *md;
  47         void *p;
  48
  49         if (!(__supported_pte_mask & _PAGE_NX))
  50                 return;
  51
  52         /* Make EFI service code area executable */
  53         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  54                 md = p;
  55                 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
  56                     md->type == EFI_BOOT_SERVICES_CODE)
  57                         efi_set_executable(md, executable);
  58         }
  59 }
  60
  61 void __init efi_call_phys_prelog(void)
  62 {
  63         unsigned long vaddress;
  64
  65         early_code_mapping_set_exec(1);
  66         local_irq_save(efi_flags);
  67         vaddress = (unsigned long)__va(0x0UL);
  68         save_pgd = *pgd_offset_k(0x0UL);
  69         set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
  70         __flush_tlb_all();
  71 }
  72
  73 void __init efi_call_phys_epilog(void)
  74 {
  75         /*
  76          * After the lock is released, the original page table is restored.
  77          */
  78         set_pgd(pgd_offset_k(0x0UL), save_pgd);
  79         __flush_tlb_all();
  80         local_irq_restore(efi_flags);
  81         early_code_mapping_set_exec(0);
  82 }
  83
  84 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
  85                                  u32 type, u64 attribute)
  86 {
  87         unsigned long last_map_pfn;
  88
  89         if (type == EFI_MEMORY_MAPPED_IO)
  90                 return ioremap(phys_addr, size);
  91
  92         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
  93         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
  94                 unsigned long top = last_map_pfn << PAGE_SHIFT;
  95                 efi_ioremap(top, size - (top - phys_addr), type, attribute);
  96         }
  97
  98         if (!(attribute & EFI_MEMORY_WB))
  99                 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
 100
 101         return (void __iomem *)__va(phys_addr);
 102 }