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 #include <linux/slab.h>
  31
  32 #include <asm/setup.h>
  33 #include <asm/page.h>
  34 #include <asm/e820.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/tlbflush.h>
  37 #include <asm/proto.h>
  38 #include <asm/efi.h>
  39 #include <asm/cacheflush.h>
  40 #include <asm/fixmap.h>
  41
  42 static pgd_t *save_pgd __initdata;
  43 static unsigned long efi_flags __initdata;
  44
  45 static void __init early_code_mapping_set_exec(int executable)
  46 {
  47         efi_memory_desc_t *md;
  48         void *p;
  49
  50         if (!(__supported_pte_mask & _PAGE_NX))
  51                 return;
  52
  53         /* Make EFI service code area executable */
  54         for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
  55                 md = p;
  56                 if (md->type == EFI_RUNTIME_SERVICES_CODE ||
  57                     md->type == EFI_BOOT_SERVICES_CODE)
  58                         efi_set_executable(md, executable);
  59         }
  60 }
  61
  62 void __init efi_call_phys_prelog(void)
  63 {
  64         unsigned long vaddress;
  65         int pgd;
  66         int n_pgds;
  67
  68         early_code_mapping_set_exec(1);
  69         local_irq_save(efi_flags);
  70
  71         n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE);
  72         save_pgd = kmalloc(n_pgds * sizeof(pgd_t), GFP_KERNEL);
  73
  74         for (pgd = 0; pgd < n_pgds; pgd++) {
  75                 save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
  76                 vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
  77                 set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
  78         }
  79         __flush_tlb_all();
  80 }
  81
  82 void __init efi_call_phys_epilog(void)
  83 {
  84         /*
  85          * After the lock is released, the original page table is restored.
  86          */
  87         int pgd;
  88         int n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT) , PGDIR_SIZE);
  89         for (pgd = 0; pgd < n_pgds; pgd++)
  90                 set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), save_pgd[pgd]);
  91         kfree(save_pgd);
  92         __flush_tlb_all();
  93         local_irq_restore(efi_flags);
  94         early_code_mapping_set_exec(0);
  95 }
  96
  97 void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
  98                                  u32 type, u64 attribute)
  99 {
 100         unsigned long last_map_pfn;
 101
 102         if (type == EFI_MEMORY_MAPPED_IO)
 103                 return ioremap(phys_addr, size);
 104
 105         last_map_pfn = init_memory_mapping(phys_addr, phys_addr + size);
 106         if ((last_map_pfn << PAGE_SHIFT) < phys_addr + size) {
 107                 unsigned long top = last_map_pfn << PAGE_SHIFT;
 108                 efi_ioremap(top, size - (top - phys_addr), type, attribute);
 109         }
 110
 111         if (!(attribute & EFI_MEMORY_WB))
 112                 efi_memory_uc((u64)(unsigned long)__va(phys_addr), size);
 113
 114         return (void __iomem *)__va(phys_addr);
 115 }