tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/efi.h>
15#include <linux/io.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>
24
25#include <asm/cacheflush.h>
26#include <asm/efi.h>
27#include <asm/mmu.h>
28#include <asm/pgalloc.h>
29#include <asm/pgtable.h>
30
31extern u64 efi_system_table;
32
33static struct mm_struct efi_mm = {
34 .mm_rb = RB_ROOT,
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),
40};
41
42#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
43#include <asm/ptdump.h>
44
45static struct ptdump_info efi_ptdump_info = {
46 .mm = &efi_mm,
47 .markers = (struct addr_marker[]){
48 { 0, "UEFI runtime start" },
49 { TASK_SIZE_64, "UEFI runtime end" }
50 },
51 .base_addr = 0,
52};
53
54static int __init ptdump_init(void)
55{
56 return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
57}
58device_initcall(ptdump_init);
59
60#endif
61
62static bool __init efi_virtmap_init(void)
63{
64 efi_memory_desc_t *md;
65 bool systab_found;
66
67 efi_mm.pgd = pgd_alloc(&efi_mm);
68 mm_init_cpumask(&efi_mm);
69 init_new_context(NULL, &efi_mm);
70
71 systab_found = false;
72 for_each_efi_memory_desc(md) {
73 phys_addr_t phys = md->phys_addr;
74 int ret;
75
76 if (!(md->attribute & EFI_MEMORY_RUNTIME))
77 continue;
78 if (md->virt_addr == 0)
79 return false;
80
81 ret = efi_create_mapping(&efi_mm, md);
82 if (!ret) {
83 pr_info(" EFI remap %pa => %p\n",
84 &phys, (void *)(unsigned long)md->virt_addr);
85 } else {
86 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
87 &phys, ret);
88 return false;
89 }
90 /*
91 * If this entry covers the address of the UEFI system table,
92 * calculate and record its virtual address.
93 */
94 if (efi_system_table >= phys &&
95 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
96 efi.systab = (void *)(unsigned long)(efi_system_table -
97 phys + md->virt_addr);
98 systab_found = true;
99 }
100 }
101 if (!systab_found) {
102 pr_err("No virtual mapping found for the UEFI System Table\n");
103 return false;
104 }
105
106 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
107 return false;
108
109 return true;
110}
111
112/*
113 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
114 * non-early mapping of the UEFI system table and virtual mappings for all
115 * EFI_MEMORY_RUNTIME regions.
116 */
117static int __init arm_enable_runtime_services(void)
118{
119 u64 mapsize;
120
121 if (!efi_enabled(EFI_BOOT)) {
122 pr_info("EFI services will not be available.\n");
123 return 0;
124 }
125
126 if (efi_runtime_disabled()) {
127 pr_info("EFI runtime services will be disabled.\n");
128 return 0;
129 }
130
131 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
132 pr_info("EFI runtime services access via paravirt.\n");
133 return 0;
134 }
135
136 pr_info("Remapping and enabling EFI services.\n");
137
138 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
139
140 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
141 pr_err("Failed to remap EFI memory map\n");
142 return -ENOMEM;
143 }
144
145 if (!efi_virtmap_init()) {
146 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
147 return -ENOMEM;
148 }
149
150 /* Set up runtime services function pointers */
151 efi_native_runtime_setup();
152 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
153
154 return 0;
155}
156early_initcall(arm_enable_runtime_services);
157
158void efi_virtmap_load(void)
159{
160 preempt_disable();
161 efi_set_pgd(&efi_mm);
162}
163
164void efi_virtmap_unload(void)
165{
166 efi_set_pgd(current->active_mm);
167 preempt_enable();
168}