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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/efi.h>
#include <linux/memblock.h>
#include <linux/mm_types.h>
#include <linux/preempt.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <asm/cacheflush.h>
#include <asm/efi.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
static pgd_t efi_pgd[PTRS_PER_PGD] __page_aligned_bss;
extern u64 efi_system_table;
static struct mm_struct efi_mm = {
.mm_rb = RB_ROOT,
.pgd = efi_pgd,
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),
.mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
.page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
.mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
};
static bool __init efi_virtmap_init(void)
{
efi_memory_desc_t *md;
init_new_context(NULL, &efi_mm);
for_each_efi_memory_desc(&memmap, md) {
pgprot_t prot;
if (!(md->attribute & EFI_MEMORY_RUNTIME))
continue;
if (md->virt_addr == 0)
return false;
pr_info(" EFI remap 0x%016llx => %p\n",
md->phys_addr, (void *)md->virt_addr);
/*
* Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
* executable, everything else can be mapped with the XN bits
* set.
*/
if ((md->attribute & EFI_MEMORY_WB) == 0)
prot = __pgprot(PROT_DEVICE_nGnRE);
else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
!PAGE_ALIGNED(md->phys_addr))
prot = PAGE_KERNEL_EXEC;
else
prot = PAGE_KERNEL;
create_pgd_mapping(&efi_mm, md->phys_addr, md->virt_addr,
md->num_pages << EFI_PAGE_SHIFT,
__pgprot(pgprot_val(prot) | PTE_NG));
}
return true;
}
/*
* Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
* non-early mapping of the UEFI system table and virtual mappings for all
* EFI_MEMORY_RUNTIME regions.
*/
static int __init arm64_enable_runtime_services(void)
{
u64 mapsize;
if (!efi_enabled(EFI_BOOT)) {
pr_info("EFI services will not be available.\n");
return 0;
}
if (efi_runtime_disabled()) {
pr_info("EFI runtime services will be disabled.\n");
return 0;
}
pr_info("Remapping and enabling EFI services.\n");
mapsize = memmap.map_end - memmap.map;
memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
mapsize);
if (!memmap.map) {
pr_err("Failed to remap EFI memory map\n");
return -ENOMEM;
}
memmap.map_end = memmap.map + mapsize;
efi.memmap = &memmap;
efi.systab = (__force void *)ioremap_cache(efi_system_table,
sizeof(efi_system_table_t));
if (!efi.systab) {
pr_err("Failed to remap EFI System Table\n");
return -ENOMEM;
}
set_bit(EFI_SYSTEM_TABLES, &efi.flags);
if (!efi_virtmap_init()) {
pr_err("No UEFI virtual mapping was installed -- runtime services will not be available\n");
return -ENOMEM;
}
/* Set up runtime services function pointers */
efi_native_runtime_setup();
set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
efi.runtime_version = efi.systab->hdr.revision;
return 0;
}
early_initcall(arm64_enable_runtime_services);
static void efi_set_pgd(struct mm_struct *mm)
{
switch_mm(NULL, mm, NULL);
}
void efi_virtmap_load(void)
{
preempt_disable();
efi_set_pgd(&efi_mm);
}
void efi_virtmap_unload(void)
{
efi_set_pgd(current->active_mm);
preempt_enable();
}
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