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 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
55 static __initdata unsigned long cpu_state_table = EFI_INVALID_TABLE_ADDR;
56
57 static const efi_config_table_type_t arch_tables[] __initconst = {
58 {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, &screen_info_table},
59 {LINUX_EFI_ARM_CPU_STATE_TABLE_GUID, &cpu_state_table},
60 {}
61 };
62
init_screen_info(void)63 static void __init init_screen_info(void)
64 {
65 struct screen_info *si;
66
67 if (IS_ENABLED(CONFIG_ARM) &&
68 screen_info_table != EFI_INVALID_TABLE_ADDR) {
69 si = early_memremap_ro(screen_info_table, sizeof(*si));
70 if (!si) {
71 pr_err("Could not map screen_info config table\n");
72 return;
73 }
74 screen_info = *si;
75 early_memunmap(si, sizeof(*si));
76
77 /* dummycon on ARM needs non-zero values for columns/lines */
78 screen_info.orig_video_cols = 80;
79 screen_info.orig_video_lines = 25;
80 }
81
82 if (screen_info.orig_video_isVGA == VIDEO_TYPE_EFI &&
83 memblock_is_map_memory(screen_info.lfb_base))
84 memblock_mark_nomap(screen_info.lfb_base, screen_info.lfb_size);
85 }
86
uefi_init(u64 efi_system_table)87 static int __init uefi_init(u64 efi_system_table)
88 {
89 efi_config_table_t *config_tables;
90 efi_system_table_t *systab;
91 size_t table_size;
92 int retval;
93
94 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
95 if (systab == NULL) {
96 pr_warn("Unable to map EFI system table.\n");
97 return -ENOMEM;
98 }
99
100 set_bit(EFI_BOOT, &efi.flags);
101 if (IS_ENABLED(CONFIG_64BIT))
102 set_bit(EFI_64BIT, &efi.flags);
103
104 retval = efi_systab_check_header(&systab->hdr, 2);
105 if (retval)
106 goto out;
107
108 efi.runtime = systab->runtime;
109 efi.runtime_version = systab->hdr.revision;
110
111 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
112
113 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
114 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
115 table_size);
116 if (config_tables == NULL) {
117 pr_warn("Unable to map EFI config table array.\n");
118 retval = -ENOMEM;
119 goto out;
120 }
121 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
122 IS_ENABLED(CONFIG_ARM) ? arch_tables
123 : NULL);
124
125 early_memunmap(config_tables, table_size);
126 out:
127 early_memunmap(systab, sizeof(efi_system_table_t));
128 return retval;
129 }
130
131 /*
132 * Return true for regions that can be used as System RAM.
133 */
is_usable_memory(efi_memory_desc_t * md)134 static __init int is_usable_memory(efi_memory_desc_t *md)
135 {
136 switch (md->type) {
137 case EFI_LOADER_CODE:
138 case EFI_LOADER_DATA:
139 case EFI_ACPI_RECLAIM_MEMORY:
140 case EFI_BOOT_SERVICES_CODE:
141 case EFI_BOOT_SERVICES_DATA:
142 case EFI_CONVENTIONAL_MEMORY:
143 case EFI_PERSISTENT_MEMORY:
144 /*
145 * According to the spec, these regions are no longer reserved
146 * after calling ExitBootServices(). However, we can only use
147 * them as System RAM if they can be mapped writeback cacheable.
148 */
149 return (md->attribute & EFI_MEMORY_WB);
150 default:
151 break;
152 }
153 return false;
154 }
155
reserve_regions(void)156 static __init void reserve_regions(void)
157 {
158 efi_memory_desc_t *md;
159 u64 paddr, npages, size;
160
161 if (efi_enabled(EFI_DBG))
162 pr_info("Processing EFI memory map:\n");
163
164 /*
165 * Discard memblocks discovered so far: if there are any at this
166 * point, they originate from memory nodes in the DT, and UEFI
167 * uses its own memory map instead.
168 */
169 memblock_dump_all();
170 memblock_remove(0, PHYS_ADDR_MAX);
171
172 for_each_efi_memory_desc(md) {
173 paddr = md->phys_addr;
174 npages = md->num_pages;
175
176 if (efi_enabled(EFI_DBG)) {
177 char buf[64];
178
179 pr_info(" 0x%012llx-0x%012llx %s\n",
180 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
181 efi_md_typeattr_format(buf, sizeof(buf), md));
182 }
183
184 memrange_efi_to_native(&paddr, &npages);
185 size = npages << PAGE_SHIFT;
186
187 if (is_memory(md)) {
188 /*
189 * Special purpose memory is 'soft reserved', which
190 * means it is set aside initially. Don't add a memblock
191 * for it now so that it can be hotplugged back in or
192 * be assigned to the dax driver after boot.
193 */
194 if (efi_soft_reserve_enabled() &&
195 (md->attribute & EFI_MEMORY_SP))
196 continue;
197
198 early_init_dt_add_memory_arch(paddr, size);
199
200 if (!is_usable_memory(md))
201 memblock_mark_nomap(paddr, size);
202
203 /* keep ACPI reclaim memory intact for kexec etc. */
204 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
205 memblock_reserve(paddr, size);
206 }
207 }
208 }
209
efi_init(void)210 void __init efi_init(void)
211 {
212 struct efi_memory_map_data data;
213 u64 efi_system_table;
214
215 /* Grab UEFI information placed in FDT by stub */
216 efi_system_table = efi_get_fdt_params(&data);
217 if (!efi_system_table)
218 return;
219
220 if (efi_memmap_init_early(&data) < 0) {
221 /*
222 * If we are booting via UEFI, the UEFI memory map is the only
223 * description of memory we have, so there is little point in
224 * proceeding if we cannot access it.
225 */
226 panic("Unable to map EFI memory map.\n");
227 }
228
229 WARN(efi.memmap.desc_version != 1,
230 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
231 efi.memmap.desc_version);
232
233 if (uefi_init(efi_system_table) < 0) {
234 efi_memmap_unmap();
235 return;
236 }
237
238 reserve_regions();
239 /*
240 * For memblock manipulation, the cap should come after the memblock_add().
241 * And now, memblock is fully populated, it is time to do capping.
242 */
243 early_init_dt_check_for_usable_mem_range();
244 efi_esrt_init();
245 efi_mokvar_table_init();
246
247 memblock_reserve(data.phys_map & PAGE_MASK,
248 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
249
250 init_screen_info();
251
252 #ifdef CONFIG_ARM
253 /* ARM does not permit early mappings to persist across paging_init() */
254 efi_memmap_unmap();
255
256 if (cpu_state_table != EFI_INVALID_TABLE_ADDR) {
257 struct efi_arm_entry_state *state;
258 bool dump_state = true;
259
260 state = early_memremap_ro(cpu_state_table,
261 sizeof(struct efi_arm_entry_state));
262 if (state == NULL) {
263 pr_warn("Unable to map CPU entry state table.\n");
264 return;
265 }
266
267 if ((state->sctlr_before_ebs & 1) == 0)
268 pr_warn(FW_BUG "EFI stub was entered with MMU and Dcache disabled, please fix your firmware!\n");
269 else if ((state->sctlr_after_ebs & 1) == 0)
270 pr_warn(FW_BUG "ExitBootServices() returned with MMU and Dcache disabled, please fix your firmware!\n");
271 else
272 dump_state = false;
273
274 if (dump_state || efi_enabled(EFI_DBG)) {
275 pr_info("CPSR at EFI stub entry : 0x%08x\n", state->cpsr_before_ebs);
276 pr_info("SCTLR at EFI stub entry : 0x%08x\n", state->sctlr_before_ebs);
277 pr_info("CPSR after ExitBootServices() : 0x%08x\n", state->cpsr_after_ebs);
278 pr_info("SCTLR after ExitBootServices(): 0x%08x\n", state->sctlr_after_ebs);
279 }
280 early_memunmap(state, sizeof(struct efi_arm_entry_state));
281 }
282 #endif
283 }
284