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 - 2015 Linaro Ltd.
8 */
9
10 #define pr_fmt(fmt) "efi: " fmt
11
12 #include <linux/efi.h>
13 #include <linux/fwnode.h>
14 #include <linux/init.h>
15 #include <linux/memblock.h>
16 #include <linux/mm_types.h>
17 #include <linux/of.h>
18 #include <linux/of_address.h>
19 #include <linux/of_fdt.h>
20 #include <linux/platform_device.h>
21 #include <linux/screen_info.h>
22
23 #include <asm/efi.h>
24
25 unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
26
is_memory(efi_memory_desc_t * md)27 static int __init is_memory(efi_memory_desc_t *md)
28 {
29 if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
30 return 1;
31 return 0;
32 }
33
34 /*
35 * Translate a EFI virtual address into a physical address: this is necessary,
36 * as some data members of the EFI system table are virtually remapped after
37 * SetVirtualAddressMap() has been called.
38 */
efi_to_phys(unsigned long addr)39 static phys_addr_t __init efi_to_phys(unsigned long addr)
40 {
41 efi_memory_desc_t *md;
42
43 for_each_efi_memory_desc(md) {
44 if (!(md->attribute & EFI_MEMORY_RUNTIME))
45 continue;
46 if (md->virt_addr == 0)
47 /* no virtual mapping has been installed by the stub */
48 break;
49 if (md->virt_addr <= addr &&
50 (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
51 return md->phys_addr + addr - md->virt_addr;
52 }
53 return addr;
54 }
55
56 extern __weak const efi_config_table_type_t efi_arch_tables[];
57
init_screen_info(void)58 static void __init init_screen_info(void)
59 {
60 struct screen_info *si;
61
62 if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
63 si = early_memremap(screen_info_table, sizeof(*si));
64 if (!si) {
65 pr_err("Could not map screen_info config table\n");
66 return;
67 }
68 screen_info = *si;
69 memset(si, 0, sizeof(*si));
70 early_memunmap(si, sizeof(*si));
71
72 if (memblock_is_map_memory(screen_info.lfb_base))
73 memblock_mark_nomap(screen_info.lfb_base,
74 screen_info.lfb_size);
75
76 if (IS_ENABLED(CONFIG_EFI_EARLYCON))
77 efi_earlycon_reprobe();
78 }
79 }
80
uefi_init(u64 efi_system_table)81 static int __init uefi_init(u64 efi_system_table)
82 {
83 efi_config_table_t *config_tables;
84 efi_system_table_t *systab;
85 size_t table_size;
86 int retval;
87
88 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
89 if (systab == NULL) {
90 pr_warn("Unable to map EFI system table.\n");
91 return -ENOMEM;
92 }
93
94 set_bit(EFI_BOOT, &efi.flags);
95 if (IS_ENABLED(CONFIG_64BIT))
96 set_bit(EFI_64BIT, &efi.flags);
97
98 retval = efi_systab_check_header(&systab->hdr);
99 if (retval)
100 goto out;
101
102 efi.runtime = systab->runtime;
103 efi.runtime_version = systab->hdr.revision;
104
105 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
106
107 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
108 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
109 table_size);
110 if (config_tables == NULL) {
111 pr_warn("Unable to map EFI config table array.\n");
112 retval = -ENOMEM;
113 goto out;
114 }
115 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
116 efi_arch_tables);
117
118 early_memunmap(config_tables, table_size);
119 out:
120 early_memunmap(systab, sizeof(efi_system_table_t));
121 return retval;
122 }
123
124 /*
125 * Return true for regions that can be used as System RAM.
126 */
is_usable_memory(efi_memory_desc_t * md)127 static __init int is_usable_memory(efi_memory_desc_t *md)
128 {
129 switch (md->type) {
130 case EFI_LOADER_CODE:
131 case EFI_LOADER_DATA:
132 case EFI_ACPI_RECLAIM_MEMORY:
133 case EFI_BOOT_SERVICES_CODE:
134 case EFI_BOOT_SERVICES_DATA:
135 case EFI_CONVENTIONAL_MEMORY:
136 case EFI_PERSISTENT_MEMORY:
137 /*
138 * Special purpose memory is 'soft reserved', which means it
139 * is set aside initially, but can be hotplugged back in or
140 * be assigned to the dax driver after boot.
141 */
142 if (efi_soft_reserve_enabled() &&
143 (md->attribute & EFI_MEMORY_SP))
144 return false;
145
146 /*
147 * According to the spec, these regions are no longer reserved
148 * after calling ExitBootServices(). However, we can only use
149 * them as System RAM if they can be mapped writeback cacheable.
150 */
151 return (md->attribute & EFI_MEMORY_WB);
152 default:
153 break;
154 }
155 return false;
156 }
157
reserve_regions(void)158 static __init void reserve_regions(void)
159 {
160 efi_memory_desc_t *md;
161 u64 paddr, npages, size;
162
163 if (efi_enabled(EFI_DBG))
164 pr_info("Processing EFI memory map:\n");
165
166 /*
167 * Discard memblocks discovered so far: if there are any at this
168 * point, they originate from memory nodes in the DT, and UEFI
169 * uses its own memory map instead.
170 */
171 memblock_dump_all();
172 memblock_remove(0, PHYS_ADDR_MAX);
173
174 for_each_efi_memory_desc(md) {
175 paddr = md->phys_addr;
176 npages = md->num_pages;
177
178 if (efi_enabled(EFI_DBG)) {
179 char buf[64];
180
181 pr_info(" 0x%012llx-0x%012llx %s\n",
182 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
183 efi_md_typeattr_format(buf, sizeof(buf), md));
184 }
185
186 memrange_efi_to_native(&paddr, &npages);
187 size = npages << PAGE_SHIFT;
188
189 if (is_memory(md)) {
190 early_init_dt_add_memory_arch(paddr, size);
191
192 if (!is_usable_memory(md))
193 memblock_mark_nomap(paddr, size);
194
195 /* keep ACPI reclaim memory intact for kexec etc. */
196 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
197 memblock_reserve(paddr, size);
198 }
199 }
200 }
201
efi_init(void)202 void __init efi_init(void)
203 {
204 struct efi_memory_map_data data;
205 u64 efi_system_table;
206
207 /* Grab UEFI information placed in FDT by stub */
208 efi_system_table = efi_get_fdt_params(&data);
209 if (!efi_system_table)
210 return;
211
212 if (efi_memmap_init_early(&data) < 0) {
213 /*
214 * If we are booting via UEFI, the UEFI memory map is the only
215 * description of memory we have, so there is little point in
216 * proceeding if we cannot access it.
217 */
218 panic("Unable to map EFI memory map.\n");
219 }
220
221 WARN(efi.memmap.desc_version != 1,
222 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
223 efi.memmap.desc_version);
224
225 if (uefi_init(efi_system_table) < 0) {
226 efi_memmap_unmap();
227 return;
228 }
229
230 reserve_regions();
231 /*
232 * For memblock manipulation, the cap should come after the memblock_add().
233 * And now, memblock is fully populated, it is time to do capping.
234 */
235 early_init_dt_check_for_usable_mem_range();
236 efi_find_mirror();
237 efi_esrt_init();
238 efi_mokvar_table_init();
239
240 memblock_reserve(data.phys_map & PAGE_MASK,
241 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
242
243 init_screen_info();
244 }
245