1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Extensible Firmware Interface
4 *
5 * Based on Extensible Firmware Interface Specification version 2.4
6 *
7 * Copyright (C) 2013, 2014 Linaro Ltd.
8 */
9
10 #include <linux/dmi.h>
11 #include <linux/efi.h>
12 #include <linux/io.h>
13 #include <linux/memblock.h>
14 #include <linux/mm_types.h>
15 #include <linux/preempt.h>
16 #include <linux/rbtree.h>
17 #include <linux/rwsem.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21
22 #include <asm/cacheflush.h>
23 #include <asm/efi.h>
24 #include <asm/mmu.h>
25 #include <asm/pgalloc.h>
26 #include <asm/pgtable.h>
27
28 extern u64 efi_system_table;
29
30 #ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
31 #include <asm/ptdump.h>
32
33 static struct ptdump_info efi_ptdump_info = {
34 .mm = &efi_mm,
35 .markers = (struct addr_marker[]){
36 { 0, "UEFI runtime start" },
37 { DEFAULT_MAP_WINDOW_64, "UEFI runtime end" },
38 { -1, NULL }
39 },
40 .base_addr = 0,
41 };
42
ptdump_init(void)43 static int __init ptdump_init(void)
44 {
45 if (efi_enabled(EFI_RUNTIME_SERVICES))
46 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
47
48 return 0;
49 }
50 device_initcall(ptdump_init);
51
52 #endif
53
efi_virtmap_init(void)54 static bool __init efi_virtmap_init(void)
55 {
56 efi_memory_desc_t *md;
57 bool systab_found;
58
59 efi_mm.pgd = pgd_alloc(&efi_mm);
60 mm_init_cpumask(&efi_mm);
61 init_new_context(NULL, &efi_mm);
62
63 systab_found = false;
64 for_each_efi_memory_desc(md) {
65 phys_addr_t phys = md->phys_addr;
66 int ret;
67
68 if (!(md->attribute & EFI_MEMORY_RUNTIME))
69 continue;
70 if (md->virt_addr == 0)
71 return false;
72
73 ret = efi_create_mapping(&efi_mm, md);
74 if (ret) {
75 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
76 &phys, ret);
77 return false;
78 }
79 /*
80 * If this entry covers the address of the UEFI system table,
81 * calculate and record its virtual address.
82 */
83 if (efi_system_table >= phys &&
84 efi_system_table < phys + (md->num_pages * EFI_PAGE_SIZE)) {
85 efi.systab = (void *)(unsigned long)(efi_system_table -
86 phys + md->virt_addr);
87 systab_found = true;
88 }
89 }
90 if (!systab_found) {
91 pr_err("No virtual mapping found for the UEFI System Table\n");
92 return false;
93 }
94
95 if (efi_memattr_apply_permissions(&efi_mm, efi_set_mapping_permissions))
96 return false;
97
98 return true;
99 }
100
101 /*
102 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
103 * non-early mapping of the UEFI system table and virtual mappings for all
104 * EFI_MEMORY_RUNTIME regions.
105 */
arm_enable_runtime_services(void)106 static int __init arm_enable_runtime_services(void)
107 {
108 u64 mapsize;
109
110 if (!efi_enabled(EFI_BOOT)) {
111 pr_info("EFI services will not be available.\n");
112 return 0;
113 }
114
115 efi_memmap_unmap();
116
117 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
118
119 if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) {
120 pr_err("Failed to remap EFI memory map\n");
121 return 0;
122 }
123
124 if (efi_runtime_disabled()) {
125 pr_info("EFI runtime services will be disabled.\n");
126 return 0;
127 }
128
129 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
130 pr_info("EFI runtime services access via paravirt.\n");
131 return 0;
132 }
133
134 pr_info("Remapping and enabling EFI services.\n");
135
136 if (!efi_virtmap_init()) {
137 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
138 return -ENOMEM;
139 }
140
141 /* Set up runtime services function pointers */
142 efi_native_runtime_setup();
143 set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
144
145 return 0;
146 }
147 early_initcall(arm_enable_runtime_services);
148
efi_virtmap_load(void)149 void efi_virtmap_load(void)
150 {
151 preempt_disable();
152 efi_set_pgd(&efi_mm);
153 }
154
efi_virtmap_unload(void)155 void efi_virtmap_unload(void)
156 {
157 efi_set_pgd(current->active_mm);
158 preempt_enable();
159 }
160
161
arm_dmi_init(void)162 static int __init arm_dmi_init(void)
163 {
164 /*
165 * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to
166 * be called early because dmi_id_init(), which is an arch_initcall
167 * itself, depends on dmi_scan_machine() having been called already.
168 */
169 dmi_setup();
170 return 0;
171 }
172 core_initcall(arm_dmi_init);
173
