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
  40static pgd_t save_pgd __initdata;
  41static unsigned long efi_flags __initdata;
  42
  43static 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
  58static 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
  77void __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
  89void __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
 100void __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}
 123