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
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 __init 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 extern __weak const efi_config_table_type_t efi_arch_tables[];
55
init_screen_info(void)56 static void __init init_screen_info(void)
57 {
58 if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
59 memblock_is_map_memory(screen_info.lfb_base))
60 memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
61 }
62
uefi_init(u64 efi_system_table)63 static int __init uefi_init(u64 efi_system_table)
64 {
65 efi_config_table_t *config_tables;
66 efi_system_table_t *systab;
67 size_t table_size;
68 int retval;
69
70 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
71 if (systab == NULL) {
72 pr_warn("Unable to map EFI system table.\n");
73 return -ENOMEM;
74 }
75
76 set_bit(EFI_BOOT, &efi.flags);
77 if (IS_ENABLED(CONFIG_64BIT))
78 set_bit(EFI_64BIT, &efi.flags);
79
80 retval = efi_systab_check_header(&systab->hdr, 2);
81 if (retval)
82 goto out;
83
84 efi.runtime = systab->runtime;
85 efi.runtime_version = systab->hdr.revision;
86
87 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
88
89 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
90 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
91 table_size);
92 if (config_tables == NULL) {
93 pr_warn("Unable to map EFI config table array.\n");
94 retval = -ENOMEM;
95 goto out;
96 }
97 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
98 efi_arch_tables);
99
100 early_memunmap(config_tables, table_size);
101 out:
102 early_memunmap(systab, sizeof(efi_system_table_t));
103 return retval;
104 }
105
106 /*
107 * Return true for regions that can be used as System RAM.
108 */
is_usable_memory(efi_memory_desc_t * md)109 static __init int is_usable_memory(efi_memory_desc_t *md)
110 {
111 switch (md->type) {
112 case EFI_LOADER_CODE:
113 case EFI_LOADER_DATA:
114 case EFI_ACPI_RECLAIM_MEMORY:
115 case EFI_BOOT_SERVICES_CODE:
116 case EFI_BOOT_SERVICES_DATA:
117 case EFI_CONVENTIONAL_MEMORY:
118 case EFI_PERSISTENT_MEMORY:
119 /*
120 * Special purpose memory is 'soft reserved', which means it
121 * is set aside initially, but can be hotplugged back in or
122 * be assigned to the dax driver after boot.
123 */
124 if (efi_soft_reserve_enabled() &&
125 (md->attribute & EFI_MEMORY_SP))
126 return false;
127
128 /*
129 * According to the spec, these regions are no longer reserved
130 * after calling ExitBootServices(). However, we can only use
131 * them as System RAM if they can be mapped writeback cacheable.
132 */
133 return (md->attribute & EFI_MEMORY_WB);
134 default:
135 break;
136 }
137 return false;
138 }
139
reserve_regions(void)140 static __init void reserve_regions(void)
141 {
142 efi_memory_desc_t *md;
143 u64 paddr, npages, size;
144
145 if (efi_enabled(EFI_DBG))
146 pr_info("Processing EFI memory map:\n");
147
148 /*
149 * Discard memblocks discovered so far: if there are any at this
150 * point, they originate from memory nodes in the DT, and UEFI
151 * uses its own memory map instead.
152 */
153 memblock_dump_all();
154 memblock_remove(0, PHYS_ADDR_MAX);
155
156 for_each_efi_memory_desc(md) {
157 paddr = md->phys_addr;
158 npages = md->num_pages;
159
160 if (efi_enabled(EFI_DBG)) {
161 char buf[64];
162
163 pr_info(" 0x%012llx-0x%012llx %s\n",
164 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
165 efi_md_typeattr_format(buf, sizeof(buf), md));
166 }
167
168 memrange_efi_to_native(&paddr, &npages);
169 size = npages << PAGE_SHIFT;
170
171 if (is_memory(md)) {
172 early_init_dt_add_memory_arch(paddr, size);
173
174 if (!is_usable_memory(md))
175 memblock_mark_nomap(paddr, size);
176
177 /* keep ACPI reclaim memory intact for kexec etc. */
178 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
179 memblock_reserve(paddr, size);
180 }
181 }
182 }
183
efi_init(void)184 void __init efi_init(void)
185 {
186 struct efi_memory_map_data data;
187 u64 efi_system_table;
188
189 /* Grab UEFI information placed in FDT by stub */
190 efi_system_table = efi_get_fdt_params(&data);
191 if (!efi_system_table)
192 return;
193
194 if (efi_memmap_init_early(&data) < 0) {
195 /*
196 * If we are booting via UEFI, the UEFI memory map is the only
197 * description of memory we have, so there is little point in
198 * proceeding if we cannot access it.
199 */
200 panic("Unable to map EFI memory map.\n");
201 }
202
203 WARN(efi.memmap.desc_version != 1,
204 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
205 efi.memmap.desc_version);
206
207 if (uefi_init(efi_system_table) < 0) {
208 efi_memmap_unmap();
209 return;
210 }
211
212 reserve_regions();
213 /*
214 * For memblock manipulation, the cap should come after the memblock_add().
215 * And now, memblock is fully populated, it is time to do capping.
216 */
217 early_init_dt_check_for_usable_mem_range();
218 efi_find_mirror();
219 efi_esrt_init();
220 efi_mokvar_table_init();
221
222 memblock_reserve(data.phys_map & PAGE_MASK,
223 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
224
225 init_screen_info();
226 }
227