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/io.h>
17 #include <linux/memblock.h>
18 #include <linux/mm_types.h>
19 #include <linux/preempt.h>
20 #include <linux/rbtree.h>
21 #include <linux/rwsem.h>
22 #include <linux/sched.h>
23 #include <linux/slab.h>
24 #include <linux/spinlock.h>
25
26 #include <asm/cacheflush.h>
27 #include <asm/efi.h>
28 #include <asm/mmu.h>
29 #include <asm/pgalloc.h>
30 #include <asm/pgtable.h>
31
32 extern u64 efi_system_table;
33
34 static struct mm_struct efi_mm = {
35 .mm_rb = RB_ROOT,
36 .mm_users = ATOMIC_INIT(2),
37 .mm_count = ATOMIC_INIT(1),
38 .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
39 .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
40 .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
41 };
42
43 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
44 #include <asm/ptdump.h>
45
46 static struct ptdump_info efi_ptdump_info = {
47 .mm = &efi_mm,
48 .markers = (struct addr_marker[]){
49 { 0, "UEFI runtime start" },
50 { TASK_SIZE_64, "UEFI runtime end" }
51 },
52 .base_addr = 0,
53 };
54
ptdump_init(void)55 static int __init ptdump_init(void)
56 {
57 if (!efi_enabled(EFI_RUNTIME_SERVICES))
58 return 0;
59
60 return ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
61 }
62 device_initcall(ptdump_init);
63
64 #endif
65
efi_virtmap_init(void)66 static bool __init efi_virtmap_init(void)
67 {
68 efi_memory_desc_t *md;
69 bool systab_found;
70
71 efi_mm.pgd = pgd_alloc(&efi_mm);
72 mm_init_cpumask(&efi_mm);
73 init_new_context(NULL, &efi_mm);
74
75 systab_found = false;
76 for_each_efi_memory_desc(md) {
77 phys_addr_t phys = md->phys_addr;
78 int ret;
79
80 if (!(md->attribute & EFI_MEMORY_RUNTIME))
81 continue;
82 if (md->virt_addr == 0)
83 return false;
84
85 ret = efi_create_mapping(&efi_mm, md);
86 if (!ret) {
87 pr_info(" EFI remap %pa => %p\n",
88 &phys, (void *)(unsigned long)md->virt_addr);
89 } else {
90 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
91 &phys, ret);
92 return false;
93 }
94 /*
95 * If this entry covers the address of the UEFI system table,
96 * calculate and record its virtual address.
97 */
98 if (efi_system_table >= phys &&
99 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
100 efi.systab = (void *)(unsigned long)(efi_system_table -
101 phys + md->virt_addr);
102 systab_found = true;
103 }
104 }
105 if (!systab_found) {
106 pr_err("No virtual mapping found for the UEFI System Table\n");
107 return false;
108 }
109
110 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
111 return false;
112
113 return true;
114 }
115
116 /*
117 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
118 * non-early mapping of the UEFI system table and virtual mappings for all
119 * EFI_MEMORY_RUNTIME regions.
120 */
arm_enable_runtime_services(void)121 static int __init arm_enable_runtime_services(void)
122 {
123 u64 mapsize;
124
125 if (!efi_enabled(EFI_BOOT)) {
126 pr_info("EFI services will not be available.\n");
127 return 0;
128 }
129
130 efi_memmap_unmap();
131
132 if (efi_runtime_disabled()) {
133 pr_info("EFI runtime services will be disabled.\n");
134 return 0;
135 }
136
137 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
138 pr_info("EFI runtime services access via paravirt.\n");
139 return 0;
140 }
141
142 pr_info("Remapping and enabling EFI services.\n");
143
144 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
145
146 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
147 pr_err("Failed to remap EFI memory map\n");
148 return -ENOMEM;
149 }
150
151 if (!efi_virtmap_init()) {
152 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
153 return -ENOMEM;
154 }
155
156 /* Set up runtime services function pointers */
157 efi_native_runtime_setup();
158 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
159
160 return 0;
161 }
162 early_initcall(arm_enable_runtime_services);
163
efi_virtmap_load(void)164 void efi_virtmap_load(void)
165 {
166 preempt_disable();
167 efi_set_pgd(&efi_mm);
168 }
169
efi_virtmap_unload(void)170 void efi_virtmap_unload(void)
171 {
172 efi_set_pgd(current->active_mm);
173 preempt_enable();
174 }
175
176
arm_dmi_init(void)177 static int __init arm_dmi_init(void)
178 {
179 /*
180 * On arm64/ARM, DMI depends on UEFI, and dmi_scan_machine() needs to
181 * be called early because dmi_id_init(), which is an arch_initcall
182 * itself, depends on dmi_scan_machine() having been called already.
183 */
184 dmi_scan_machine();
185 if (dmi_available)
186 dmi_set_dump_stack_arch_desc();
187 return 0;
188 }
189 core_initcall(arm_dmi_init);
190