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[];
58 static void __init init_screen_info(void)
60 struct screen_info *si;
62 if (screen_info_table != EFI_INVALID_TABLE_ADDR) {
63 si = early_memremap(screen_info_table, sizeof(*si));
65 pr_err("Could not map screen_info config table\n");
69 memset(si, 0, sizeof(*si));
70 early_memunmap(si, sizeof(*si));
72 if (memblock_is_map_memory(screen_info.lfb_base))
73 memblock_mark_nomap(screen_info.lfb_base,
74 screen_info.lfb_size);
76 if (IS_ENABLED(CONFIG_EFI_EARLYCON))
77 efi_earlycon_reprobe();
81 static int __init uefi_init(u64 efi_system_table)
83 efi_config_table_t *config_tables;
84 efi_system_table_t *systab;
88 systab = early_memremap_ro(efi_system_table, sizeof(efi_system_table_t));
90 pr_warn("Unable to map EFI system table.\n");
94 set_bit(EFI_BOOT, &efi.flags);
95 if (IS_ENABLED(CONFIG_64BIT))
96 set_bit(EFI_64BIT, &efi.flags);
98 retval = efi_systab_check_header(&systab->hdr);
102 efi.runtime = systab->runtime;
103 efi.runtime_version = systab->hdr.revision;
105 efi_systab_report_header(&systab->hdr, efi_to_phys(systab->fw_vendor));
107 table_size = sizeof(efi_config_table_t) * systab->nr_tables;
108 config_tables = early_memremap_ro(efi_to_phys(systab->tables),
110 if (config_tables == NULL) {
111 pr_warn("Unable to map EFI config table array.\n");
115 retval = efi_config_parse_tables(config_tables, systab->nr_tables,
118 early_memunmap(config_tables, table_size);
120 early_memunmap(systab, sizeof(efi_system_table_t));
125 * Return true for regions that can be used as System RAM.
127 static __init int is_usable_memory(efi_memory_desc_t *md)
130 case EFI_LOADER_CODE:
131 case EFI_LOADER_DATA:
132 case EFI_ACPI_RECLAIM_MEMORY:
133 case EFI_BOOT_SERVICES_CODE:
134 case EFI_BOOT_SERVICES_DATA:
135 case EFI_CONVENTIONAL_MEMORY:
136 case EFI_PERSISTENT_MEMORY:
138 * Special purpose memory is 'soft reserved', which means it
139 * is set aside initially, but can be hotplugged back in or
140 * be assigned to the dax driver after boot.
142 if (efi_soft_reserve_enabled() &&
143 (md->attribute & EFI_MEMORY_SP))
147 * According to the spec, these regions are no longer reserved
148 * after calling ExitBootServices(). However, we can only use
149 * them as System RAM if they can be mapped writeback cacheable.
151 return (md->attribute & EFI_MEMORY_WB);
158 static __init void reserve_regions(void)
160 efi_memory_desc_t *md;
161 u64 paddr, npages, size;
163 if (efi_enabled(EFI_DBG))
164 pr_info("Processing EFI memory map:\n");
167 * Discard memblocks discovered so far: if there are any at this
168 * point, they originate from memory nodes in the DT, and UEFI
169 * uses its own memory map instead.
172 memblock_remove(0, PHYS_ADDR_MAX);
174 for_each_efi_memory_desc(md) {
175 paddr = md->phys_addr;
176 npages = md->num_pages;
178 if (efi_enabled(EFI_DBG)) {
181 pr_info(" 0x%012llx-0x%012llx %s\n",
182 paddr, paddr + (npages << EFI_PAGE_SHIFT) - 1,
183 efi_md_typeattr_format(buf, sizeof(buf), md));
186 memrange_efi_to_native(&paddr, &npages);
187 size = npages << PAGE_SHIFT;
190 early_init_dt_add_memory_arch(paddr, size);
192 if (!is_usable_memory(md))
193 memblock_mark_nomap(paddr, size);
195 /* keep ACPI reclaim memory intact for kexec etc. */
196 if (md->type == EFI_ACPI_RECLAIM_MEMORY)
197 memblock_reserve(paddr, size);
202 void __init efi_init(void)
204 struct efi_memory_map_data data;
205 u64 efi_system_table;
207 /* Grab UEFI information placed in FDT by stub */
208 efi_system_table = efi_get_fdt_params(&data);
209 if (!efi_system_table)
212 if (efi_memmap_init_early(&data) < 0) {
214 * If we are booting via UEFI, the UEFI memory map is the only
215 * description of memory we have, so there is little point in
216 * proceeding if we cannot access it.
218 panic("Unable to map EFI memory map.\n");
221 WARN(efi.memmap.desc_version != 1,
222 "Unexpected EFI_MEMORY_DESCRIPTOR version %ld",
223 efi.memmap.desc_version);
225 if (uefi_init(efi_system_table) < 0) {
232 * For memblock manipulation, the cap should come after the memblock_add().
233 * And now, memblock is fully populated, it is time to do capping.
235 early_init_dt_check_for_usable_mem_range();
238 efi_mokvar_table_init();
240 memblock_reserve(data.phys_map & PAGE_MASK,
241 PAGE_ALIGN(data.size + (data.phys_map & ~PAGE_MASK)));