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/pgalloc.h>
16#include <linux/pgtable.h>
17#include <linux/preempt.h>
18#include <linux/rbtree.h>
19#include <linux/rwsem.h>
20#include <linux/sched.h>
21#include <linux/slab.h>
22#include <linux/spinlock.h>
23
24#include <asm/cacheflush.h>
25#include <asm/efi.h>
26#include <asm/mmu.h>
27
28#if defined(CONFIG_PTDUMP_DEBUGFS) || defined(CONFIG_ARM_PTDUMP_DEBUGFS)
29#include <asm/ptdump.h>
30
31static struct ptdump_info efi_ptdump_info = {
32 .mm = &efi_mm,
33 .markers = (struct addr_marker[]){
34 { 0, "UEFI runtime start" },
35 { EFI_RUNTIME_MAP_END, "UEFI runtime end" },
36 { -1, NULL }
37 },
38 .base_addr = 0,
39};
40
41static int __init ptdump_init(void)
42{
43 if (efi_enabled(EFI_RUNTIME_SERVICES))
44 ptdump_debugfs_register(&efi_ptdump_info, "efi_page_tables");
45
46 return 0;
47}
48device_initcall(ptdump_init);
49
50#endif
51
52static bool __init efi_virtmap_init(void)
53{
54 efi_memory_desc_t *md;
55
56 efi_mm.pgd = pgd_alloc(&efi_mm);
57 mm_init_cpumask(mm: &efi_mm);
58 init_new_context(NULL, mm: &efi_mm);
59
60 for_each_efi_memory_desc(md) {
61 phys_addr_t phys = md->phys_addr;
62 int ret;
63
64 if (!(md->attribute & EFI_MEMORY_RUNTIME))
65 continue;
66 if (md->virt_addr == U64_MAX)
67 return false;
68
69 ret = efi_create_mapping(&efi_mm, md);
70 if (ret) {
71 pr_warn(" EFI remap %pa: failed to create mapping (%d)\n",
72 &phys, ret);
73 return false;
74 }
75 }
76
77 if (efi_memattr_apply_permissions(mm: &efi_mm, fn: efi_set_mapping_permissions))
78 return false;
79
80 return true;
81}
82
83/*
84 * Enable the UEFI Runtime Services if all prerequisites are in place, i.e.,
85 * non-early mapping of the UEFI system table and virtual mappings for all
86 * EFI_MEMORY_RUNTIME regions.
87 */
88static int __init arm_enable_runtime_services(void)
89{
90 u64 mapsize;
91
92 if (!efi_enabled(EFI_BOOT)) {
93 pr_info("EFI services will not be available.\n");
94 return 0;
95 }
96
97 efi_memmap_unmap();
98
99 mapsize = efi.memmap.desc_size * efi.memmap.nr_map;
100
101 if (efi_memmap_init_late(addr: efi.memmap.phys_map, size: mapsize)) {
102 pr_err("Failed to remap EFI memory map\n");
103 return 0;
104 }
105
106 if (efi_soft_reserve_enabled()) {
107 efi_memory_desc_t *md;
108
109 for_each_efi_memory_desc(md) {
110 u64 md_size = md->num_pages << EFI_PAGE_SHIFT;
111 struct resource *res;
112
113 if (!(md->attribute & EFI_MEMORY_SP))
114 continue;
115
116 res = kzalloc(sizeof(*res), GFP_KERNEL);
117 if (WARN_ON(!res))
118 break;
119
120 res->start = md->phys_addr;
121 res->end = md->phys_addr + md_size - 1;
122 res->name = "Soft Reserved";
123 res->flags = IORESOURCE_MEM;
124 res->desc = IORES_DESC_SOFT_RESERVED;
125
126 insert_resource(parent: &iomem_resource, new: res);
127 }
128 }
129
130 if (efi_runtime_disabled()) {
131 pr_info("EFI runtime services will be disabled.\n");
132 return 0;
133 }
134
135 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
136 pr_info("EFI runtime services access via paravirt.\n");
137 return 0;
138 }
139
140 pr_info("Remapping and enabling EFI services.\n");
141
142 if (!efi_virtmap_init()) {
143 pr_err("UEFI virtual mapping missing or invalid -- runtime services will not be available\n");
144 return -ENOMEM;
145 }
146
147 /* Set up runtime services function pointers */
148 efi_native_runtime_setup();
149 set_bit(EFI_RUNTIME_SERVICES, addr: &efi.flags);
150
151 return 0;
152}
153early_initcall(arm_enable_runtime_services);
154
155void efi_virtmap_load(void)
156{
157 preempt_disable();
158 efi_set_pgd(&efi_mm);
159}
160
161void efi_virtmap_unload(void)
162{
163 efi_set_pgd(current->active_mm);
164 preempt_enable();
165}
166
167
168static int __init arm_dmi_init(void)
169{
170 /*
171 * On arm64/ARM, DMI depends on UEFI, and dmi_setup() needs to
172 * be called early because dmi_id_init(), which is an arch_initcall
173 * itself, depends on dmi_scan_machine() having been called already.
174 */
175 dmi_setup();
176 return 0;
177}
178core_initcall(arm_dmi_init);
179

source code of linux/drivers/firmware/efi/arm-runtime.c