LXR linux/arch/arm64/kernel/efi.c

   1/*
   2 * Extensible Firmware Interface
   3 *
   4 * Based on Extensible Firmware Interface Specification version 2.4
   5 *
   6 * Copyright (C) 2013, 2014 Linaro Ltd.
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 *
  12 */
  13
  14#include <linux/dmi.h>
  15#include <linux/efi.h>
  16#include <linux/init.h>
  17
  18#include <asm/efi.h>
  19
  20int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
  21{
  22        pteval_t prot_val;
  23
  24        /*
  25         * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
  26         * executable, everything else can be mapped with the XN bits
  27         * set.
  28         */
  29        if ((md->attribute & EFI_MEMORY_WB) == 0)
  30                prot_val = PROT_DEVICE_nGnRE;
  31        else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
  32                 !PAGE_ALIGNED(md->phys_addr))
  33                prot_val = pgprot_val(PAGE_KERNEL_EXEC);
  34        else
  35                prot_val = pgprot_val(PAGE_KERNEL);
  36
  37        create_pgd_mapping(mm, md->phys_addr, md->virt_addr,
  38                           md->num_pages << EFI_PAGE_SHIFT,
  39                           __pgprot(prot_val | PTE_NG));
  40        return 0;
  41}
  42
  43static int __init arm64_dmi_init(void)
  44{
  45        /*
  46         * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
  47         * be called early because dmi_id_init(), which is an arch_initcall
  48         * itself, depends on dmi_scan_machine() having been called already.
  49         */
  50        dmi_scan_machine();
  51        if (dmi_available)
  52                dmi_set_dump_stack_arch_desc();
  53        return 0;
  54}
  55core_initcall(arm64_dmi_init);
  56
  57/*
  58 * UpdateCapsule() depends on the system being shutdown via
  59 * ResetSystem().
  60 */
  61bool efi_poweroff_required(void)
  62{
  63        return efi_enabled(EFI_RUNTIME_SERVICES);
  64}
  65