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/init.h>
14 #include <linux/memblock.h>
15 #include <linux/mm_types.h>
16 #include <linux/of.h>
17 #include <linux/of_fdt.h>
18 #include <linux/platform_device.h>
19 #include <linux/screen_info.h>
20
21 #include <asm/efi.h>
22
23 u64 efi_system_table;
24
is_memory(efi_memory_desc_t * md)25 static int __init is_memory(efi_memory_desc_t *md)
26 {
27 if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
28 return 1;
29 return 0;
30 }
31
32 /*
33 * Translate a EFI virtual address into a physical address: this is necessary,
34 * as some data members of the EFI system table are virtually remapped after
35 * SetVirtualAddressMap() has been called.
36 */
efi_to_phys(unsigned long addr)37 static phys_addr_t efi_to_phys(unsigned long addr)
38 {
39 efi_memory_desc_t *md;
40
41 for_each_efi_memory_desc(md) {
42 if (!(md->attribute & EFI_MEMORY_RUNTIME))
43 continue;
44 if (md->virt_addr == 0)
45 /* no virtual mapping has been installed by the stub */
46 break;
47 if (md->virt_addr <= addr &&
48 (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
49 return md->phys_addr + addr - md->virt_addr;
50 }
51 return addr;
52 }
53
54 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
55
56 static __initdata efi_config_table_type_t arch_tables[] = {
57 {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
58 {NULL_GUID, NULL, NULL}
59 };
60
init_screen_info(void)61 static void __init init_screen_info(void)
62 {
63 struct screen_info *si;
64
65 if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
66 si = early_memremap_ro(screen_info_table, sizeof(*si));
67 if (!si) {
68 pr_err("Could not map screen_info config table\n");
69 return;
70 }
71 screen_info = *si;
72 early_memunmap(si, sizeof(*si));
73
74 /* dummycon on ARM needs non-zero values for columns/lines */
75 screen_info.orig_video_cols = 80;
76 screen_info.orig_video_lines = 25;
77 }
78
79 if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
80 memblock_is_map_memory(screen_info.lfb_base))
81 memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
82 }
83
uefi_init(void)84 static int __init uefi_init(void)
85 {
86 efi_char16_t *c16;
87 void *config_tables;
88 size_t table_size;
89 char vendor[100] = "unknown";
90 int i, retval;
91
92 efi.systab = early_memremap_ro(efi_system_table,
93 sizeof(efi_system_table_t));
94 if (efi.systab == NULL) {
95 pr_warn("Unable to map EFI system table.\n");
96 return -ENOMEM;
97 }
98
99 set_bit(EFI_BOOT, &efi.flags);
100 if (IS_ENABLED(CONFIG_64BIT))
101 set_bit(EFI_64BIT, &efi.flags);
102
103 /*
104 * Verify the EFI Table
105 */
106 if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
107 pr_err("System table signature incorrect\n");
108 retval = -EINVAL;
109 goto out;
110 }
111 if ((efi.systab->hdr.revision >> 16) < 2)
112 pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
113 efi.systab->hdr.revision >> 16,
114 efi.systab->hdr.revision & 0xffff);
115
116 efi.runtime_version = efi.systab->hdr.revision;
117
118 /* Show what we know for posterity */
119 c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
120 sizeof(vendor) * sizeof(efi_char16_t));
121 if (c16) {
122 for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
123 vendor[i] = c16[i];
124 vendor[i] = '\0';
125 early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
126 }
127
128 pr_info("EFI v%u.%.02u by %s\n",
129 efi.systab->hdr.revision >> 16,
130 efi.systab->hdr.revision & 0xffff, vendor);
131
132 table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
133 config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
134 table_size);
135 if (config_tables == NULL) {
136 pr_warn("Unable to map EFI config table array.\n");
137 retval = -ENOMEM;
138 goto out;
139 }
140 retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
141 sizeof(efi_config_table_t),
142 arch_tables);
143
144 if (!retval)
145 efi.config_table = (unsigned long)efi.systab->tables;
146
147 early_memunmap(config_tables, table_size);
148 out:
149 early_memunmap(efi.systab, sizeof(efi_system_table_t));
150 return retval;
151 }
152
153 /*
154 * Return true for regions that can be used as System RAM.
155 */
is_usable_memory(efi_memory_desc_t * md)156 static __init int is_usable_memory(efi_memory_desc_t *md)
157 {
158 switch (md->type) {
159 case EFI_LOADER_CODE:
160 case EFI_LOADER_DATA:
161 case EFI_ACPI_RECLAIM_MEMORY:
162 case EFI_BOOT_SERVICES_CODE:
163 case EFI_BOOT_SERVICES_DATA:
164 case EFI_CONVENTIONAL_MEMORY:
165 case EFI_PERSISTENT_MEMORY:
166 /*
167 * According to the spec, these regions are no longer reserved
168 * after calling ExitBootServices(). However, we can only use
169 * them as System RAM if they can be mapped writeback cacheable.
170 */
171 return (md->attribute & EFI_MEMORY_WB);
172 default:
173 break;
174 }
175 return false;
176 }
177
reserve_regions(void)178 static __init void reserve_regions(void)
179 {
180 efi_memory_desc_t *md;
181 u64 paddr, npages, size;
182
183 if (efi_enabled(EFI_DBG))
184 pr_info("Processing EFI memory map:\n");
185
186 /*
187 * Discard memblocks discovered so far: if there are any at this
188 * point, they originate from memory nodes in the DT, and UEFI
189 * uses its own memory map instead.
190 */
191 memblock_dump_all();
192 memblock_remove(0, PHYS_ADDR_MAX);
193
194 for_each_efi_memory_desc(md) {
195 paddr = md->phys_addr;
196 npages = md->num_pages;
197
198 if (efi_enabled(EFI_DBG)) {
199 char buf[64];
200
201 pr_info(" 0x%012llx-0x%012llx %s\n",
202 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
203 efi_md_typeattr_format(buf, sizeof(buf), md));
204 }
205
206 memrange_efi_to_native(&paddr, &npages);
207 size = npages << PAGE_SHIFT;
208
209 if (is_memory(md)) {
210 early_init_dt_add_memory_arch(paddr, size);
211
212 if (!is_usable_memory(md))
213 memblock_mark_nomap(paddr, size);
214
215 /* keep ACPI reclaim memory intact for kexec etc. */
216 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
217 memblock_reserve(paddr, size);
218 }
219 }
220 }
221
efi_init(void)222 void __init efi_init(void)
223 {
224 struct efi_memory_map_data data;
225 struct efi_fdt_params params;
226
227 /* Grab UEFI information placed in FDT by stub */
228 if (!efi_get_fdt_params(¶ms))
229 return;
230
231 efi_system_table = params.system_table;
232
233 data.desc_version = params.desc_ver;
234 data.desc_size = params.desc_size;
235 data.size = params.mmap_size;
236 data.phys_map = params.mmap;
237
238 if (efi_memmap_init_early(&data) < 0) {
239 /*
240 * If we are booting via UEFI, the UEFI memory map is the only
241 * description of memory we have, so there is little point in
242 * proceeding if we cannot access it.
243 */
244 panic("Unable to map EFI memory map.\n");
245 }
246
247 WARN(efi.memmap.desc_version != 1,
248 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
249 efi.memmap.desc_version);
250
251 if (uefi_init() < 0) {
252 efi_memmap_unmap();
253 return;
254 }
255
256 reserve_regions();
257 efi_esrt_init();
258
259 memblock_reserve(params.mmap & PAGE_MASK,
260 PAGE_ALIGN(params.mmap_size +
261 (params.mmap & ~PAGE_MASK)));
262
263 init_screen_info();
264
265 /* ARM does not permit early mappings to persist across paging_init() */
266 if (IS_ENABLED(CONFIG_ARM))
267 efi_memmap_unmap();
268 }
269
register_gop_device(void)270 static int __init register_gop_device(void)
271 {
272 void *pd;
273
274 if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
275 return 0;
276
277 pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
278 &screen_info, sizeof(screen_info));
279 return PTR_ERR_OR_ZERO(pd);
280 }
281 subsys_initcall(register_gop_device);
282