1 /*
2 * Extensible Firmware Interface
3 *
4 * Based on Extensible Firmware Interface Specification version 2.4
5 *
6 * Copyright (C) 2013 - 2015 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 #define pr_fmt(fmt) "efi: " fmt
15
16 #include <linux/efi.h>
17 #include <linux/init.h>
18 #include <linux/memblock.h>
19 #include <linux/mm_types.h>
20 #include <linux/of.h>
21 #include <linux/of_fdt.h>
22 #include <linux/platform_device.h>
23 #include <linux/screen_info.h>
24
25 #include <asm/efi.h>
26
27 u64 efi_system_table;
28
is_memory(efi_memory_desc_t * md)29 static int __init is_memory(efi_memory_desc_t *md)
30 {
31 if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
32 return 1;
33 return 0;
34 }
35
36 /*
37 * Translate a EFI virtual address into a physical address: this is necessary,
38 * as some data members of the EFI system table are virtually remapped after
39 * SetVirtualAddressMap() has been called.
40 */
efi_to_phys(unsigned long addr)41 static phys_addr_t efi_to_phys(unsigned long addr)
42 {
43 efi_memory_desc_t *md;
44
45 for_each_efi_memory_desc(md) {
46 if (!(md->attribute & EFI_MEMORY_RUNTIME))
47 continue;
48 if (md->virt_addr == 0)
49 /* no virtual mapping has been installed by the stub */
50 break;
51 if (md->virt_addr <= addr &&
52 (addr - md->virt_addr) < (md->num_pages << EFI_PAGE_SHIFT))
53 return md->phys_addr + addr - md->virt_addr;
54 }
55 return addr;
56 }
57
58 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
59
60 static __initdata efi_config_table_type_t arch_tables[] = {
61 {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
62 {NULL_GUID, NULL, NULL}
63 };
64
init_screen_info(void)65 static void __init init_screen_info(void)
66 {
67 struct screen_info *si;
68
69 if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
70 si = early_memremap_ro(screen_info_table, sizeof(*si));
71 if (!si) {
72 pr_err("Could not map screen_info config table\n");
73 return;
74 }
75 screen_info = *si;
76 early_memunmap(si, sizeof(*si));
77
78 /* dummycon on ARM needs non-zero values for columns/lines */
79 screen_info.orig_video_cols = 80;
80 screen_info.orig_video_lines = 25;
81 }
82
83 if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
84 memblock_is_map_memory(screen_info.lfb_base))
85 memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
86 }
87
uefi_init(void)88 static int __init uefi_init(void)
89 {
90 efi_char16_t *c16;
91 void *config_tables;
92 size_t table_size;
93 char vendor[100] = "unknown";
94 int i, retval;
95
96 efi.systab = early_memremap_ro(efi_system_table,
97 sizeof(efi_system_table_t));
98 if (efi.systab == NULL) {
99 pr_warn("Unable to map EFI system table.\n");
100 return -ENOMEM;
101 }
102
103 set_bit(EFI_BOOT, &efi.flags);
104 if (IS_ENABLED(CONFIG_64BIT))
105 set_bit(EFI_64BIT, &efi.flags);
106
107 /*
108 * Verify the EFI Table
109 */
110 if (efi.systab->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
111 pr_err("System table signature incorrect\n");
112 retval = -EINVAL;
113 goto out;
114 }
115 if ((efi.systab->hdr.revision >> 16) < 2)
116 pr_warn("Warning: EFI system table version %d.%02d, expected 2.00 or greater\n",
117 efi.systab->hdr.revision >> 16,
118 efi.systab->hdr.revision & 0xffff);
119
120 efi.runtime_version = efi.systab->hdr.revision;
121
122 /* Show what we know for posterity */
123 c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor),
124 sizeof(vendor) * sizeof(efi_char16_t));
125 if (c16) {
126 for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
127 vendor[i] = c16[i];
128 vendor[i] = '\0';
129 early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
130 }
131
132 pr_info("EFI v%u.%.02u by %s\n",
133 efi.systab->hdr.revision >> 16,
134 efi.systab->hdr.revision & 0xffff, vendor);
135
136 table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables;
137 config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables),
138 table_size);
139 if (config_tables == NULL) {
140 pr_warn("Unable to map EFI config table array.\n");
141 retval = -ENOMEM;
142 goto out;
143 }
144 retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
145 sizeof(efi_config_table_t),
146 arch_tables);
147
148 if (!retval)
149 efi.config_table = (unsigned long)efi.systab->tables;
150
151 early_memunmap(config_tables, table_size);
152 out:
153 early_memunmap(efi.systab, sizeof(efi_system_table_t));
154 return retval;
155 }
156
157 /*
158 * Return true for regions that can be used as System RAM.
159 */
is_usable_memory(efi_memory_desc_t * md)160 static __init int is_usable_memory(efi_memory_desc_t *md)
161 {
162 switch (md->type) {
163 case EFI_LOADER_CODE:
164 case EFI_LOADER_DATA:
165 case EFI_ACPI_RECLAIM_MEMORY:
166 case EFI_BOOT_SERVICES_CODE:
167 case EFI_BOOT_SERVICES_DATA:
168 case EFI_CONVENTIONAL_MEMORY:
169 case EFI_PERSISTENT_MEMORY:
170 /*
171 * According to the spec, these regions are no longer reserved
172 * after calling ExitBootServices(). However, we can only use
173 * them as System RAM if they can be mapped writeback cacheable.
174 */
175 return (md->attribute & EFI_MEMORY_WB);
176 default:
177 break;
178 }
179 return false;
180 }
181
reserve_regions(void)182 static __init void reserve_regions(void)
183 {
184 efi_memory_desc_t *md;
185 u64 paddr, npages, size;
186
187 if (efi_enabled(EFI_DBG))
188 pr_info("Processing EFI memory map:\n");
189
190 /*
191 * Discard memblocks discovered so far: if there are any at this
192 * point, they originate from memory nodes in the DT, and UEFI
193 * uses its own memory map instead.
194 */
195 memblock_dump_all();
196 memblock_remove(0, PHYS_ADDR_MAX);
197
198 for_each_efi_memory_desc(md) {
199 paddr = md->phys_addr;
200 npages = md->num_pages;
201
202 if (efi_enabled(EFI_DBG)) {
203 char buf[64];
204
205 pr_info(" 0x%012llx-0x%012llx %s\n",
206 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
207 efi_md_typeattr_format(buf, sizeof(buf), md));
208 }
209
210 memrange_efi_to_native(&paddr, &npages);
211 size = npages << PAGE_SHIFT;
212
213 if (is_memory(md)) {
214 early_init_dt_add_memory_arch(paddr, size);
215
216 if (!is_usable_memory(md))
217 memblock_mark_nomap(paddr, size);
218
219 /* keep ACPI reclaim memory intact for kexec etc. */
220 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
221 memblock_reserve(paddr, size);
222 }
223 }
224 }
225
efi_init(void)226 void __init efi_init(void)
227 {
228 struct efi_memory_map_data data;
229 struct efi_fdt_params params;
230
231 /* Grab UEFI information placed in FDT by stub */
232 if (!efi_get_fdt_params(¶ms))
233 return;
234
235 efi_system_table = params.system_table;
236
237 data.desc_version = params.desc_ver;
238 data.desc_size = params.desc_size;
239 data.size = params.mmap_size;
240 data.phys_map = params.mmap;
241
242 if (efi_memmap_init_early(&data) < 0) {
243 /*
244 * If we are booting via UEFI, the UEFI memory map is the only
245 * description of memory we have, so there is little point in
246 * proceeding if we cannot access it.
247 */
248 panic("Unable to map EFI memory map.\n");
249 }
250
251 WARN(efi.memmap.desc_version != 1,
252 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
253 efi.memmap.desc_version);
254
255 if (uefi_init() < 0) {
256 efi_memmap_unmap();
257 return;
258 }
259
260 reserve_regions();
261 efi_esrt_init();
262
263 memblock_reserve(params.mmap & PAGE_MASK,
264 PAGE_ALIGN(params.mmap_size +
265 (params.mmap & ~PAGE_MASK)));
266
267 init_screen_info();
268
269 /* ARM does not permit early mappings to persist across paging_init() */
270 if (IS_ENABLED(CONFIG_ARM))
271 efi_memmap_unmap();
272 }
273
register_gop_device(void)274 static int __init register_gop_device(void)
275 {
276 void *pd;
277
278 if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
279 return 0;
280
281 pd = platform_device_register_data(NULL, "efi-framebuffer", 0,
282 &screen_info, sizeof(screen_info));
283 return PTR_ERR_OR_ZERO(pd);
284 }
285 subsys_initcall(register_gop_device);
286