1 // SPDX-License-Identifier: GPL-2.0
3 * Extensible Firmware Interface
5 * Based on Extensible Firmware Interface Specification version 2.4
7 * Copyright (C) 2013 - 2015 Linaro Ltd.
10 #define pr_fmt(fmt) "efi: " fmt
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>
18 #include <linux/of_address.h>
19 #include <linux/of_fdt.h>
20 #include <linux/platform_device.h>
21 #include <linux/screen_info.h>
25 unsigned long __initdata screen_info_table = EFI_INVALID_TABLE_ADDR;
27 static int __init is_memory(efi_memory_desc_t *md)
29 if (md->attribute & (EFI_MEMORY_WB|EFI_MEMORY_WT|EFI_MEMORY_WC))
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.
39 static phys_addr_t __init efi_to_phys(unsigned long addr)
41 efi_memory_desc_t *md;
43 for_each_efi_memory_desc(md) {
44 if (!(md->attribute & EFI_MEMORY_RUNTIME))
46 if (md->virt_addr == 0)
47 /* no virtual mapping has been installed by the stub */
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;
56 extern __weak const efi_config_table_type_t efi_arch_tables[];
59 * x86 defines its own screen_info and uses it even without EFI,
60 * everything else can get it from here.
62 #if !defined(CONFIG_X86) && (defined(CONFIG_SYSFB) || defined(CONFIG_EFI_EARLYCON))
63 struct screen_info screen_info __section(".data");
64 EXPORT_SYMBOL_GPL(screen_info);
67 static void __init init_screen_info(void)
69 struct screen_info *si;
71 if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
72 si = early_memremap(screen_info_table, sizeof(*si));
74 pr_err("Could not map screen_info config table\n");
78 memset(si, 0, sizeof(*si));
79 early_memunmap(si, sizeof(*si));
81 if (memblock_is_map_memory(screen_info.lfb_base))
82 memblock_mark_nomap(screen_info.lfb_base,
83 screen_info.lfb_size);
85 if (IS_ENABLED(CONFIG_EFI_EARLYCON))
86 efi_earlycon_reprobe();
90 static int __init uefi_init(u64 efi_system_table)
92 efi_config_table_t *config_tables;
93 efi_system_table_t *systab;
97 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
99 pr_warn("Unable to map EFI system table.\n");
103 set_bit(EFI_BOOT, &efi.flags);
104 if (IS_ENABLED(CONFIG_64BIT))
105 set_bit(EFI_64BIT, &efi.flags);
107 retval = efi_systab_check_header(&systab->hdr);
111 efi.runtime = systab->runtime;
112 efi.runtime_version = systab->hdr.revision;
114 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
116 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
117 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
119 if (config_tables == NULL) {
120 pr_warn("Unable to map EFI config table array.\n");
124 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
127 early_memunmap(config_tables, table_size);
129 early_memunmap(systab, sizeof(efi_system_table_t));
134 * Return true for regions that can be used as System RAM.
136 static __init int is_usable_memory(efi_memory_desc_t *md)
139 case EFI_LOADER_CODE:
140 case EFI_LOADER_DATA:
141 case EFI_ACPI_RECLAIM_MEMORY:
142 case EFI_BOOT_SERVICES_CODE:
143 case EFI_BOOT_SERVICES_DATA:
144 case EFI_CONVENTIONAL_MEMORY:
145 case EFI_PERSISTENT_MEMORY:
147 * Special purpose memory is 'soft reserved', which means it
148 * is set aside initially, but can be hotplugged back in or
149 * be assigned to the dax driver after boot.
151 if (efi_soft_reserve_enabled() &&
152 (md->attribute & EFI_MEMORY_SP))
156 * According to the spec, these regions are no longer reserved
157 * after calling ExitBootServices(). However, we can only use
158 * them as System RAM if they can be mapped writeback cacheable.
160 return (md->attribute & EFI_MEMORY_WB);
167 static __init void reserve_regions(void)
169 efi_memory_desc_t *md;
170 u64 paddr, npages, size;
172 if (efi_enabled(EFI_DBG))
173 pr_info("Processing EFI memory map:\n");
176 * Discard memblocks discovered so far: if there are any at this
177 * point, they originate from memory nodes in the DT, and UEFI
178 * uses its own memory map instead.
181 memblock_remove(0, PHYS_ADDR_MAX);
183 for_each_efi_memory_desc(md) {
184 paddr = md->phys_addr;
185 npages = md->num_pages;
187 if (efi_enabled(EFI_DBG)) {
190 pr_info(" 0x%012llx-0x%012llx %s\n",
191 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
192 efi_md_typeattr_format(buf, sizeof(buf), md));
195 memrange_efi_to_native(&paddr, &npages);
196 size = npages << PAGE_SHIFT;
199 early_init_dt_add_memory_arch(paddr, size);
201 if (!is_usable_memory(md))
202 memblock_mark_nomap(paddr, size);
204 /* keep ACPI reclaim memory intact for kexec etc. */
205 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
206 memblock_reserve(paddr, size);
211 void __init efi_init(void)
213 struct efi_memory_map_data data;
214 u64 efi_system_table;
216 /* Grab UEFI information placed in FDT by stub */
217 efi_system_table = efi_get_fdt_params(&data);
218 if (!efi_system_table)
221 if (efi_memmap_init_early(&data) < 0) {
223 * If we are booting via UEFI, the UEFI memory map is the only
224 * description of memory we have, so there is little point in
225 * proceeding if we cannot access it.
227 panic("Unable to map EFI memory map.\n");
230 WARN(efi.memmap.desc_version != 1,
231 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
232 efi.memmap.desc_version);
234 if (uefi_init(efi_system_table) < 0) {
241 * For memblock manipulation, the cap should come after the memblock_add().
242 * And now, memblock is fully populated, it is time to do capping.
244 early_init_dt_check_for_usable_mem_range();
247 efi_mokvar_table_init();
249 memblock_reserve(data.phys_map & PAGE_MASK,
250 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));
252 if (IS_ENABLED(CONFIG_X86) ||
253 IS_ENABLED(CONFIG_SYSFB) ||
254 IS_ENABLED(CONFIG_EFI_EARLYCON))