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/*
* Extensible Firmware Interface
*
* Based on Extensible Firmware Interface Specification version 2.4
*
* Copyright (C) 2013, 2014 Linaro Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/dmi.h>
#include <linux/efi.h>
#include <linux/init.h>
#include <asm/efi.h>
/*
* Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
* executable, everything else can be mapped with the XN bits
* set. Also take the new (optional) RO/XP bits into account.
*/
static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
{
u64 attr = md->attribute;
u32 type = md->type;
if (type == EFI_MEMORY_MAPPED_IO)
return PROT_DEVICE_nGnRE;
if (WARN_ONCE(!PAGE_ALIGNED(md->phys_addr),
"UEFI Runtime regions are not aligned to 64 KB -- buggy firmware?"))
/*
* If the region is not aligned to the page size of the OS, we
* can not use strict permissions, since that would also affect
* the mapping attributes of the adjacent regions.
*/
return pgprot_val(PAGE_KERNEL_EXEC);
/* R-- */
if ((attr & (EFI_MEMORY_XP | EFI_MEMORY_RO)) ==
(EFI_MEMORY_XP | EFI_MEMORY_RO))
return pgprot_val(PAGE_KERNEL_RO);
/* R-X */
if (attr & EFI_MEMORY_RO)
return pgprot_val(PAGE_KERNEL_ROX);
/* RW- */
if (attr & EFI_MEMORY_XP || type != EFI_RUNTIME_SERVICES_CODE)
return pgprot_val(PAGE_KERNEL);
/* RWX */
return pgprot_val(PAGE_KERNEL_EXEC);
}
/* we will fill this structure from the stub, so don't put it in .bss */
struct screen_info screen_info __section(.data);
int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
{
pteval_t prot_val = create_mapping_protection(md);
create_pgd_mapping(mm, md->phys_addr, md->virt_addr,
md->num_pages << EFI_PAGE_SHIFT,
__pgprot(prot_val | PTE_NG), true);
return 0;
}
static int __init arm64_dmi_init(void)
{
/*
* On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
* be called early because dmi_id_init(), which is an arch_initcall
* itself, depends on dmi_scan_machine() having been called already.
*/
dmi_scan_machine();
if (dmi_available)
dmi_set_dump_stack_arch_desc();
return 0;
}
core_initcall(arm64_dmi_init);
/*
* UpdateCapsule() depends on the system being shutdown via
* ResetSystem().
*/
bool efi_poweroff_required(void)
{
return efi_enabled(EFI_RUNTIME_SERVICES);
}
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