2 * Extensible Firmware Interface
4 * Based on Extensible Firmware Interface Specification version 2.4
6 * Copyright (C) 2013, 2014 Linaro Ltd.
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.
14 #include <linux/efi.h>
16 #include <linux/memblock.h>
17 #include <linux/mm_types.h>
18 #include <linux/preempt.h>
19 #include <linux/rbtree.h>
20 #include <linux/rwsem.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
25 #include <asm/cacheflush.h>
28 #include <asm/pgalloc.h>
29 #include <asm/pgtable.h>
31 extern u64 efi_system_table;
33 static struct mm_struct efi_mm = {
35 .mm_users = ATOMIC_INIT(2),
36 .mm_count = ATOMIC_INIT(1),
37 .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
38 .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
39 .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
42 static bool __init efi_virtmap_init(void)
44 efi_memory_desc_t *md;
47 efi_mm.pgd = pgd_alloc(&efi_mm);
48 init_new_context(NULL, &efi_mm);
51 for_each_efi_memory_desc(md) {
52 phys_addr_t phys = md->phys_addr;
55 if (!(md->attribute & EFI_MEMORY_RUNTIME))
57 if (md->virt_addr == 0)
60 ret = efi_create_mapping(&efi_mm, md);
62 pr_info(" EFI remap %pa => %p\n",
63 &phys, (void *)(unsigned long)md->virt_addr);
65 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
70 * If this entry covers the address of the UEFI system table,
71 * calculate and record its virtual address.
73 if (efi_system_table >= phys &&
74 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
75 efi.systab = (void *)(unsigned long)(efi_system_table -
76 phys + md->virt_addr);
81 pr_err("No virtual mapping found for the UEFI System Table\n");
85 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
92 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
93 * non-early mapping of the UEFI system table and virtual mappings for all
94 * EFI_MEMORY_RUNTIME regions.
96 static int __init arm_enable_runtime_services(void)
100 if (!efi_enabled(EFI_BOOT)) {
101 pr_info("EFI services will not be available.\n");
105 if (efi_runtime_disabled()) {
106 pr_info("EFI runtime services will be disabled.\n");
110 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
111 pr_info("EFI runtime services access via paravirt.\n");
115 pr_info("Remapping and enabling EFI services.\n");
117 mapsize = efi.memmap.map_end - efi.memmap.map;
119 efi.memmap.map = memremap(efi.memmap.phys_map, mapsize, MEMREMAP_WB);
120 if (!efi.memmap.map) {
121 pr_err("Failed to remap EFI memory map\n");
124 efi.memmap.map_end = efi.memmap.map + mapsize;
126 if (!efi_virtmap_init()) {
127 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
131 /* Set up runtime services function pointers */
132 efi_native_runtime_setup();
133 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
137 early_initcall(arm_enable_runtime_services);
139 void efi_virtmap_load(void)
142 efi_set_pgd(&efi_mm);
145 void efi_virtmap_unload(void)
147 efi_set_pgd(current->active_mm);