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/cacheflush.h>
  37 #include <asm/proto.h>
  38 #include <asm/efi.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         pte_t *kpte;
  48         int level;
  49
  50         while (start < end) {
  51                 kpte = lookup_address((unsigned long)__va(start), &level);
  52                 BUG_ON(!kpte);
  53                 if (executable)
  54                         set_pte(kpte, pte_mkexec(*kpte));
  55                 else
  56                         set_pte(kpte, __pte((pte_val(*kpte) | _PAGE_NX) & \
  57                                             __supported_pte_mask));
  58                 if (pte_huge(*kpte))
  59                         start = (start + PMD_SIZE) & PMD_MASK;
  60                 else
  61                         start = (start + PAGE_SIZE) & PAGE_MASK;
  62         }
  63 }
  64
  65 static void __init early_runtime_code_mapping_set_exec(int executable)
  66 {
  67         efi_memory_desc_t *md;
  68         void *p;
  69
  70         /* Make EFI runtime service code area executable */
  71         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  72                 md = p;
  73                 if (md->type == EFI_RUNTIME_SERVICES_CODE) {
  74                         unsigned long end;
  75                         end = md->phys_addr + (md->num_pages << PAGE_SHIFT);
  76                         early_mapping_set_exec(md->phys_addr, end, executable);
  77                 }
  78         }
  79 }
  80
  81 void __init efi_call_phys_prelog(void)
  82 {
  83         unsigned long vaddress;
  84
  85         local_irq_save(efi_flags);
  86         early_runtime_code_mapping_set_exec(1);
  87         vaddress = (unsigned long)__va(0x0UL);
  88         save_pgd = *pgd_offset_k(0x0UL);
  89         set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
  90         __flush_tlb_all();
  91 }
  92
  93 void __init efi_call_phys_epilog(void)
  94 {
  95         /*
  96          * After the lock is released, the original page table is restored.
  97          */
  98         set_pgd(pgd_offset_k(0x0UL), save_pgd);
  99         early_runtime_code_mapping_set_exec(0);
 100         __flush_tlb_all();
 101         local_irq_restore(efi_flags);
 102 }
 103
 104 /*
 105  * We need to map the EFI memory map again after init_memory_mapping().
 106  */
 107 void __init efi_map_memmap(void)
 108 {
 109         memmap.map = __va(memmap.phys_map);
 110         memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
 111 }
 112
 113 void __init efi_reserve_bootmem(void)
 114 {
 115         reserve_bootmem_generic((unsigned long)memmap.phys_map,
 116                                 memmap.nr_map * memmap.desc_size);
 117 }
 118
 119 void __init runtime_code_page_mkexec(void)
 120 {
 121         efi_memory_desc_t *md;
 122         void *p;
 123
 124         /* Make EFI runtime service code area executable */
 125         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 126                 md = p;
 127                 if (md->type == EFI_RUNTIME_SERVICES_CODE)
 128                         change_page_attr_addr(md->virt_addr,
 129                                               md->num_pages,
 130                                               PAGE_KERNEL_EXEC);
 131         }
 132         __flush_tlb_all();
 133 }
 134
 135 void __iomem * __init efi_ioremap(unsigned long offset,
 136                                   unsigned long size)
 137 {
 138         static unsigned pages_mapped;
 139         unsigned long last_addr;
 140         unsigned i, pages;
 141
 142         last_addr = offset + size - 1;
 143         offset &= PAGE_MASK;
 144         pages = (PAGE_ALIGN(last_addr) - offset) >> PAGE_SHIFT;
 145         if (pages_mapped + pages > MAX_EFI_IO_PAGES)
 146                 return NULL;
 147
 148         for (i = 0; i < pages; i++) {
 149                 set_fixmap_nocache(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
 150                                    offset);
 151                 offset += PAGE_SIZE;
 152                 pages_mapped++;
 153         }
 154
 155         return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE - \
 156                                              (pages_mapped - pages));
 157 }