LXR linux/arch/x86/kernel/efi

   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
  41static pgd_t save_pgd __initdata;
  42static unsigned long efi_flags __initdata;
  43
  44static 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
  59static 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
  78void __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
  90void __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
 101void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
 102                                 u32 type)
 103{
 104        unsigned long last_map_pfn;
 105
 106        if (type == EFI_MEMORY_MAPPED_IO)
 107                return ioremap(phys_addr, size);
 108
 109        last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
 110        if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size)
 111                return NULL;
 112
 113        return (void __iomem *)__va(phys_addr);
 114}
 115