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 int __init setup_noefi(char *arg)
  44 {
  45         efi_enabled = 0;
  46         return 0;
  47 }
  48 early_param("noefi", setup_noefi);
  49
  50 static void __init early_mapping_set_exec(unsigned long start,
  51                                           unsigned long end,
  52                                           int executable)
  53 {
  54         pte_t *kpte;
  55         int level;
  56
  57         while (start < end) {
  58                 kpte = lookup_address((unsigned long)__va(start), &level);
  59                 BUG_ON(!kpte);
  60                 if (executable)
  61                         set_pte(kpte, pte_mkexec(*kpte));
  62                 else
  63                         set_pte(kpte, __pte((pte_val(*kpte) | _PAGE_NX) & \
  64                                             __supported_pte_mask));
  65                 if (pte_huge(*kpte))
  66                         start = (start + PMD_SIZE) & PMD_MASK;
  67                 else
  68                         start = (start + PAGE_SIZE) & PAGE_MASK;
  69         }
  70 }
  71
  72 static void __init early_runtime_code_mapping_set_exec(int executable)
  73 {
  74         efi_memory_desc_t *md;
  75         void *p;
  76
  77         /* Make EFI runtime service code area executable */
  78         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  79                 md = p;
  80                 if (md->type == EFI_RUNTIME_SERVICES_CODE) {
  81                         unsigned long end;
  82                         end = md->phys_addr + (md->num_pages << PAGE_SHIFT);
  83                         early_mapping_set_exec(md->phys_addr, end, executable);
  84                 }
  85         }
  86 }
  87
  88 void __init efi_call_phys_prelog(void)
  89 {
  90         unsigned long vaddress;
  91
  92         local_irq_save(efi_flags);
  93         early_runtime_code_mapping_set_exec(1);
  94         vaddress = (unsigned long)__va(0x0UL);
  95         pgd_val(save_pgd) = pgd_val(*pgd_offset_k(0x0UL));
  96         set_pgd(pgd_offset_k(0x0UL), *pgd_offset_k(vaddress));
  97         __flush_tlb_all();
  98 }
  99
 100 void __init efi_call_phys_epilog(void)
 101 {
 102         /*
 103          * After the lock is released, the original page table is restored.
 104          */
 105         set_pgd(pgd_offset_k(0x0UL), save_pgd);
 106         early_runtime_code_mapping_set_exec(0);
 107         __flush_tlb_all();
 108         local_irq_restore(efi_flags);
 109 }
 110
 111 /*
 112  * We need to map the EFI memory map again after init_memory_mapping().
 113  */
 114 void __init efi_map_memmap(void)
 115 {
 116         memmap.map = __va(memmap.phys_map);
 117         memmap.map_end = memmap.map + (memmap.nr_map * memmap.desc_size);
 118 }
 119
 120 void __init efi_reserve_bootmem(void)
 121 {
 122         reserve_bootmem_generic((unsigned long)memmap.phys_map,
 123                                 memmap.nr_map * memmap.desc_size);
 124 }
 125
 126 void __init runtime_code_page_mkexec(void)
 127 {
 128         efi_memory_desc_t *md;
 129         void *p;
 130
 131         /* Make EFI runtime service code area executable */
 132         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 133                 md = p;
 134                 if (md->type == EFI_RUNTIME_SERVICES_CODE)
 135                         change_page_attr_addr(md->virt_addr,
 136                                               md->num_pages,
 137                                               PAGE_KERNEL_EXEC);
 138         }
 139         __flush_tlb_all();
 140 }
 141
 142 void __iomem * __init efi_ioremap(unsigned long offset,
 143                                   unsigned long size)
 144 {
 145         static unsigned pages_mapped;
 146         unsigned long last_addr;
 147         unsigned i, pages;
 148
 149         last_addr = offset + size - 1;
 150         offset &= PAGE_MASK;
 151         pages = (PAGE_ALIGN(last_addr) - offset) >> PAGE_SHIFT;
 152         if (pages_mapped + pages > MAX_EFI_IO_PAGES)
 153                 return NULL;
 154
 155         for (i = 0; i < pages; i++) {
 156                 set_fixmap_nocache(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
 157                                    offset);
 158                 offset += PAGE_SIZE;
 159                 pages_mapped++;
 160         }
 161
 162         return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE - \
 163                                              (pages_mapped - pages));
 164 }