1 // SPDX-License-Identifier: GPL-2.0-only
3 * efi.c - EFI subsystem
5 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
6 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
7 * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
9 * This code registers /sys/firmware/efi{,/efivars} when EFI is supported,
10 * allowing the efivarfs to be mounted or the efivars module to be loaded.
11 * The existance of /sys/firmware/efi may also be used by userspace to
12 * determine that the system supports EFI.
15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 #include <linux/kobject.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/device.h>
21 #include <linux/efi.h>
23 #include <linux/of_fdt.h>
25 #include <linux/kexec.h>
26 #include <linux/platform_device.h>
27 #include <linux/random.h>
28 #include <linux/reboot.h>
29 #include <linux/slab.h>
30 #include <linux/acpi.h>
31 #include <linux/ucs2_string.h>
32 #include <linux/memblock.h>
33 #include <linux/security.h>
35 #include <asm/early_ioremap.h>
37 struct efi __read_mostly efi = {
38 .acpi = EFI_INVALID_TABLE_ADDR,
39 .acpi20 = EFI_INVALID_TABLE_ADDR,
40 .smbios = EFI_INVALID_TABLE_ADDR,
41 .smbios3 = EFI_INVALID_TABLE_ADDR,
42 .fw_vendor = EFI_INVALID_TABLE_ADDR,
43 .runtime = EFI_INVALID_TABLE_ADDR,
44 .config_table = EFI_INVALID_TABLE_ADDR,
45 .esrt = EFI_INVALID_TABLE_ADDR,
46 .mem_attr_table = EFI_INVALID_TABLE_ADDR,
47 .tpm_log = EFI_INVALID_TABLE_ADDR,
48 .tpm_final_log = EFI_INVALID_TABLE_ADDR,
49 .mem_reserve = EFI_INVALID_TABLE_ADDR,
53 static unsigned long __ro_after_init rng_seed = EFI_INVALID_TABLE_ADDR;
55 struct mm_struct efi_mm = {
57 .mm_users = ATOMIC_INIT(2),
58 .mm_count = ATOMIC_INIT(1),
59 .mmap_sem = __RWSEM_INITIALIZER(efi_mm.mmap_sem),
60 .page_table_lock = __SPIN_LOCK_UNLOCKED(efi_mm.page_table_lock),
61 .mmlist = LIST_HEAD_INIT(efi_mm.mmlist),
62 .cpu_bitmap = { [BITS_TO_LONGS(NR_CPUS)] = 0},
65 struct workqueue_struct *efi_rts_wq;
67 static bool disable_runtime;
68 static int __init setup_noefi(char *arg)
70 disable_runtime = true;
73 early_param("noefi", setup_noefi);
75 bool efi_runtime_disabled(void)
77 return disable_runtime;
80 bool __pure __efi_soft_reserve_enabled(void)
82 return !efi_enabled(EFI_MEM_NO_SOFT_RESERVE);
85 static int __init parse_efi_cmdline(char *str)
88 pr_warn("need at least one option\n");
92 if (parse_option_str(str, "debug"))
93 set_bit(EFI_DBG, &efi.flags);
95 if (parse_option_str(str, "noruntime"))
96 disable_runtime = true;
98 if (parse_option_str(str, "nosoftreserve"))
99 set_bit(EFI_MEM_NO_SOFT_RESERVE, &efi.flags);
103 early_param("efi", parse_efi_cmdline);
105 struct kobject *efi_kobj;
108 * Let's not leave out systab information that snuck into
110 * Note, do not add more fields in systab sysfs file as it breaks sysfs
111 * one value per file rule!
113 static ssize_t systab_show(struct kobject *kobj,
114 struct kobj_attribute *attr, char *buf)
121 if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
122 str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
123 if (efi.acpi != EFI_INVALID_TABLE_ADDR)
124 str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
126 * If both SMBIOS and SMBIOS3 entry points are implemented, the
127 * SMBIOS3 entry point shall be preferred, so we list it first to
128 * let applications stop parsing after the first match.
130 if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
131 str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
132 if (efi.smbios != EFI_INVALID_TABLE_ADDR)
133 str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
135 if (IS_ENABLED(CONFIG_IA64) || IS_ENABLED(CONFIG_X86)) {
136 extern char *efi_systab_show_arch(char *str);
138 str = efi_systab_show_arch(str);
144 static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400);
146 #define EFI_FIELD(var) efi.var
148 #define EFI_ATTR_SHOW(name) \
149 static ssize_t name##_show(struct kobject *kobj, \
150 struct kobj_attribute *attr, char *buf) \
152 return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
155 EFI_ATTR_SHOW(fw_vendor);
156 EFI_ATTR_SHOW(runtime);
157 EFI_ATTR_SHOW(config_table);
159 static ssize_t fw_platform_size_show(struct kobject *kobj,
160 struct kobj_attribute *attr, char *buf)
162 return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
165 static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);
166 static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);
167 static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);
168 static struct kobj_attribute efi_attr_fw_platform_size =
169 __ATTR_RO(fw_platform_size);
171 static struct attribute *efi_subsys_attrs[] = {
172 &efi_attr_systab.attr,
173 &efi_attr_fw_vendor.attr,
174 &efi_attr_runtime.attr,
175 &efi_attr_config_table.attr,
176 &efi_attr_fw_platform_size.attr,
180 static umode_t efi_attr_is_visible(struct kobject *kobj,
181 struct attribute *attr, int n)
183 if (attr == &efi_attr_fw_vendor.attr) {
184 if (efi_enabled(EFI_PARAVIRT) ||
185 efi.fw_vendor == EFI_INVALID_TABLE_ADDR)
187 } else if (attr == &efi_attr_runtime.attr) {
188 if (efi.runtime == EFI_INVALID_TABLE_ADDR)
190 } else if (attr == &efi_attr_config_table.attr) {
191 if (efi.config_table == EFI_INVALID_TABLE_ADDR)
198 static const struct attribute_group efi_subsys_attr_group = {
199 .attrs = efi_subsys_attrs,
200 .is_visible = efi_attr_is_visible,
203 static struct efivars generic_efivars;
204 static struct efivar_operations generic_ops;
206 static int generic_ops_register(void)
208 generic_ops.get_variable = efi.get_variable;
209 generic_ops.set_variable = efi.set_variable;
210 generic_ops.set_variable_nonblocking = efi.set_variable_nonblocking;
211 generic_ops.get_next_variable = efi.get_next_variable;
212 generic_ops.query_variable_store = efi_query_variable_store;
214 return efivars_register(&generic_efivars, &generic_ops, efi_kobj);
217 static void generic_ops_unregister(void)
219 efivars_unregister(&generic_efivars);
222 #if IS_ENABLED(CONFIG_ACPI)
223 #define EFIVAR_SSDT_NAME_MAX 16
224 static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata;
225 static int __init efivar_ssdt_setup(char *str)
227 int ret = security_locked_down(LOCKDOWN_ACPI_TABLES);
232 if (strlen(str) < sizeof(efivar_ssdt))
233 memcpy(efivar_ssdt, str, strlen(str));
235 pr_warn("efivar_ssdt: name too long: %s\n", str);
238 __setup("efivar_ssdt=", efivar_ssdt_setup);
240 static __init int efivar_ssdt_iter(efi_char16_t *name, efi_guid_t vendor,
241 unsigned long name_size, void *data)
243 struct efivar_entry *entry;
244 struct list_head *list = data;
245 char utf8_name[EFIVAR_SSDT_NAME_MAX];
246 int limit = min_t(unsigned long, EFIVAR_SSDT_NAME_MAX, name_size);
248 ucs2_as_utf8(utf8_name, name, limit - 1);
249 if (strncmp(utf8_name, efivar_ssdt, limit) != 0)
252 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
256 memcpy(entry->var.VariableName, name, name_size);
257 memcpy(&entry->var.VendorGuid, &vendor, sizeof(efi_guid_t));
259 efivar_entry_add(entry, list);
264 static __init int efivar_ssdt_load(void)
267 struct efivar_entry *entry, *aux;
275 ret = efivar_init(efivar_ssdt_iter, &entries, true, &entries);
277 list_for_each_entry_safe(entry, aux, &entries, list) {
278 pr_info("loading SSDT from variable %s-%pUl\n", efivar_ssdt,
279 &entry->var.VendorGuid);
281 list_del(&entry->list);
283 ret = efivar_entry_size(entry, &size);
285 pr_err("failed to get var size\n");
289 data = kmalloc(size, GFP_KERNEL);
295 ret = efivar_entry_get(entry, NULL, &size, data);
297 pr_err("failed to get var data\n");
301 ret = acpi_load_table(data, NULL);
303 pr_err("failed to load table: %d\n", ret);
319 static inline int efivar_ssdt_load(void) { return 0; }
323 * We register the efi subsystem with the firmware subsystem and the
324 * efivars subsystem with the efi subsystem, if the system was booted with
327 static int __init efisubsys_init(void)
331 if (!efi_enabled(EFI_BOOT))
335 * Since we process only one efi_runtime_service() at a time, an
336 * ordered workqueue (which creates only one execution context)
337 * should suffice all our needs.
339 efi_rts_wq = alloc_ordered_workqueue("efi_rts_wq", 0);
341 pr_err("Creating efi_rts_wq failed, EFI runtime services disabled.\n");
342 clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
346 /* We register the efi directory at /sys/firmware/efi */
347 efi_kobj = kobject_create_and_add("efi", firmware_kobj);
349 pr_err("efi: Firmware registration failed.\n");
353 error = generic_ops_register();
357 if (efi_enabled(EFI_RUNTIME_SERVICES))
360 error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group);
362 pr_err("efi: Sysfs attribute export failed with error %d.\n",
367 error = efi_runtime_map_init(efi_kobj);
369 goto err_remove_group;
371 /* and the standard mountpoint for efivarfs */
372 error = sysfs_create_mount_point(efi_kobj, "efivars");
374 pr_err("efivars: Subsystem registration failed.\n");
375 goto err_remove_group;
381 sysfs_remove_group(efi_kobj, &efi_subsys_attr_group);
383 generic_ops_unregister();
385 kobject_put(efi_kobj);
389 subsys_initcall(efisubsys_init);
392 * Find the efi memory descriptor for a given physical address. Given a
393 * physical address, determine if it exists within an EFI Memory Map entry,
394 * and if so, populate the supplied memory descriptor with the appropriate
397 int efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md)
399 efi_memory_desc_t *md;
401 if (!efi_enabled(EFI_MEMMAP)) {
402 pr_err_once("EFI_MEMMAP is not enabled.\n");
407 pr_err_once("out_md is null.\n");
411 for_each_efi_memory_desc(md) {
415 size = md->num_pages << EFI_PAGE_SHIFT;
416 end = md->phys_addr + size;
417 if (phys_addr >= md->phys_addr && phys_addr < end) {
418 memcpy(out_md, md, sizeof(*out_md));
426 * Calculate the highest address of an efi memory descriptor.
428 u64 __init efi_mem_desc_end(efi_memory_desc_t *md)
430 u64 size = md->num_pages << EFI_PAGE_SHIFT;
431 u64 end = md->phys_addr + size;
435 void __init __weak efi_arch_mem_reserve(phys_addr_t addr, u64 size) {}
438 * efi_mem_reserve - Reserve an EFI memory region
439 * @addr: Physical address to reserve
440 * @size: Size of reservation
442 * Mark a region as reserved from general kernel allocation and
443 * prevent it being released by efi_free_boot_services().
445 * This function should be called drivers once they've parsed EFI
446 * configuration tables to figure out where their data lives, e.g.
449 void __init efi_mem_reserve(phys_addr_t addr, u64 size)
451 if (!memblock_is_region_reserved(addr, size))
452 memblock_reserve(addr, size);
455 * Some architectures (x86) reserve all boot services ranges
456 * until efi_free_boot_services() because of buggy firmware
457 * implementations. This means the above memblock_reserve() is
458 * superfluous on x86 and instead what it needs to do is
459 * ensure the @start, @size is not freed.
461 efi_arch_mem_reserve(addr, size);
464 static __initdata efi_config_table_type_t common_tables[] = {
465 {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
466 {ACPI_TABLE_GUID, "ACPI", &efi.acpi},
467 {SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
468 {SMBIOS3_TABLE_GUID, "SMBIOS 3.0", &efi.smbios3},
469 {EFI_SYSTEM_RESOURCE_TABLE_GUID, "ESRT", &efi.esrt},
470 {EFI_MEMORY_ATTRIBUTES_TABLE_GUID, "MEMATTR", &efi.mem_attr_table},
471 {LINUX_EFI_RANDOM_SEED_TABLE_GUID, "RNG", &rng_seed},
472 {LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log},
473 {LINUX_EFI_TPM_FINAL_LOG_GUID, "TPMFinalLog", &efi.tpm_final_log},
474 {LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &efi.mem_reserve},
475 #ifdef CONFIG_EFI_RCI2_TABLE
476 {DELLEMC_EFI_RCI2_TABLE_GUID, NULL, &rci2_table_phys},
478 {NULL_GUID, NULL, NULL},
481 static __init int match_config_table(efi_guid_t *guid,
483 efi_config_table_type_t *table_types)
488 for (i = 0; efi_guidcmp(table_types[i].guid, NULL_GUID); i++) {
489 if (!efi_guidcmp(*guid, table_types[i].guid)) {
490 *(table_types[i].ptr) = table;
491 if (table_types[i].name)
492 pr_cont(" %s=0x%lx ",
493 table_types[i].name, table);
502 int __init efi_config_parse_tables(void *config_tables, int count, int sz,
503 efi_config_table_type_t *arch_tables)
508 tablep = config_tables;
510 for (i = 0; i < count; i++) {
514 if (efi_enabled(EFI_64BIT)) {
516 guid = ((efi_config_table_64_t *)tablep)->guid;
517 table64 = ((efi_config_table_64_t *)tablep)->table;
522 pr_err("Table located above 4GB, disabling EFI.\n");
527 guid = ((efi_config_table_32_t *)tablep)->guid;
528 table = ((efi_config_table_32_t *)tablep)->table;
531 if (!match_config_table(&guid, table, common_tables))
532 match_config_table(&guid, table, arch_tables);
537 set_bit(EFI_CONFIG_TABLES, &efi.flags);
539 if (rng_seed != EFI_INVALID_TABLE_ADDR) {
540 struct linux_efi_random_seed *seed;
543 seed = early_memremap(rng_seed, sizeof(*seed));
546 early_memunmap(seed, sizeof(*seed));
548 pr_err("Could not map UEFI random seed!\n");
551 seed = early_memremap(rng_seed, sizeof(*seed) + size);
553 pr_notice("seeding entropy pool\n");
554 add_bootloader_randomness(seed->bits, seed->size);
555 early_memunmap(seed, sizeof(*seed) + size);
557 pr_err("Could not map UEFI random seed!\n");
562 if (efi_enabled(EFI_MEMMAP))
565 efi_tpm_eventlog_init();
567 if (efi.mem_reserve != EFI_INVALID_TABLE_ADDR) {
568 unsigned long prsv = efi.mem_reserve;
571 struct linux_efi_memreserve *rsv;
576 * Just map a full page: that is what we will get
577 * anyway, and it permits us to map the entire entry
578 * before knowing its size.
580 p = early_memremap(ALIGN_DOWN(prsv, PAGE_SIZE),
583 pr_err("Could not map UEFI memreserve entry!\n");
587 rsv = (void *)(p + prsv % PAGE_SIZE);
589 /* reserve the entry itself */
590 memblock_reserve(prsv, EFI_MEMRESERVE_SIZE(rsv->size));
592 for (i = 0; i < atomic_read(&rsv->count); i++) {
593 memblock_reserve(rsv->entry[i].base,
598 early_memunmap(p, PAGE_SIZE);
605 int __init efi_config_init(efi_config_table_type_t *arch_tables)
610 if (efi.systab->nr_tables == 0)
613 if (efi_enabled(EFI_64BIT))
614 sz = sizeof(efi_config_table_64_t);
616 sz = sizeof(efi_config_table_32_t);
619 * Let's see what config tables the firmware passed to us.
621 config_tables = early_memremap(efi.systab->tables,
622 efi.systab->nr_tables * sz);
623 if (config_tables == NULL) {
624 pr_err("Could not map Configuration table!\n");
628 ret = efi_config_parse_tables(config_tables, efi.systab->nr_tables, sz,
631 early_memunmap(config_tables, efi.systab->nr_tables * sz);
635 #ifdef CONFIG_EFI_VARS_MODULE
636 static int __init efi_load_efivars(void)
638 struct platform_device *pdev;
640 if (!efi_enabled(EFI_RUNTIME_SERVICES))
643 pdev = platform_device_register_simple("efivars", 0, NULL, 0);
644 return PTR_ERR_OR_ZERO(pdev);
646 device_initcall(efi_load_efivars);
649 #ifdef CONFIG_EFI_PARAMS_FROM_FDT
651 #define UEFI_PARAM(name, prop, field) \
655 offsetof(struct efi_fdt_params, field), \
656 sizeof_field(struct efi_fdt_params, field) \
661 const char propname[32];
666 static __initdata struct params fdt_params[] = {
667 UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
668 UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
669 UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
670 UEFI_PARAM("MemMap Desc. Size", "linux,uefi-mmap-desc-size", desc_size),
671 UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", desc_ver)
674 static __initdata struct params xen_fdt_params[] = {
675 UEFI_PARAM("System Table", "xen,uefi-system-table", system_table),
676 UEFI_PARAM("MemMap Address", "xen,uefi-mmap-start", mmap),
677 UEFI_PARAM("MemMap Size", "xen,uefi-mmap-size", mmap_size),
678 UEFI_PARAM("MemMap Desc. Size", "xen,uefi-mmap-desc-size", desc_size),
679 UEFI_PARAM("MemMap Desc. Version", "xen,uefi-mmap-desc-ver", desc_ver)
682 #define EFI_FDT_PARAMS_SIZE ARRAY_SIZE(fdt_params)
684 static __initdata struct {
687 struct params *params;
689 { "hypervisor", "uefi", xen_fdt_params },
690 { "chosen", NULL, fdt_params },
699 static int __init __find_uefi_params(unsigned long node,
700 struct param_info *info,
701 struct params *params)
708 for (i = 0; i < EFI_FDT_PARAMS_SIZE; i++) {
709 prop = of_get_flat_dt_prop(node, params[i].propname, &len);
711 info->missing = params[i].name;
715 dest = info->params + params[i].offset;
718 val = of_read_number(prop, len / sizeof(u32));
720 if (params[i].size == sizeof(u32))
725 if (efi_enabled(EFI_DBG))
726 pr_info(" %s: 0x%0*llx\n", params[i].name,
727 params[i].size * 2, val);
733 static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
734 int depth, void *data)
736 struct param_info *info = data;
739 for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
740 const char *subnode = dt_params[i].subnode;
742 if (depth != 1 || strcmp(uname, dt_params[i].uname) != 0) {
743 info->missing = dt_params[i].params[0].name;
748 int err = of_get_flat_dt_subnode_by_name(node, subnode);
756 return __find_uefi_params(node, info, dt_params[i].params);
762 int __init efi_get_fdt_params(struct efi_fdt_params *params)
764 struct param_info info;
767 pr_info("Getting EFI parameters from FDT:\n");
770 info.params = params;
772 ret = of_scan_flat_dt(fdt_find_uefi_params, &info);
774 pr_info("UEFI not found.\n");
776 pr_err("Can't find '%s' in device tree!\n",
781 #endif /* CONFIG_EFI_PARAMS_FROM_FDT */
783 static __initdata char memory_type_name[][20] = {
791 "Conventional Memory",
793 "ACPI Reclaim Memory",
801 char * __init efi_md_typeattr_format(char *buf, size_t size,
802 const efi_memory_desc_t *md)
809 if (md->type >= ARRAY_SIZE(memory_type_name))
810 type_len = snprintf(pos, size, "[type=%u", md->type);
812 type_len = snprintf(pos, size, "[%-*s",
813 (int)(sizeof(memory_type_name[0]) - 1),
814 memory_type_name[md->type]);
815 if (type_len >= size)
821 attr = md->attribute;
822 if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT |
823 EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_RO |
824 EFI_MEMORY_WP | EFI_MEMORY_RP | EFI_MEMORY_XP |
825 EFI_MEMORY_NV | EFI_MEMORY_SP |
826 EFI_MEMORY_RUNTIME | EFI_MEMORY_MORE_RELIABLE))
827 snprintf(pos, size, "|attr=0x%016llx]",
828 (unsigned long long)attr);
831 "|%3s|%2s|%2s|%2s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]",
832 attr & EFI_MEMORY_RUNTIME ? "RUN" : "",
833 attr & EFI_MEMORY_MORE_RELIABLE ? "MR" : "",
834 attr & EFI_MEMORY_SP ? "SP" : "",
835 attr & EFI_MEMORY_NV ? "NV" : "",
836 attr & EFI_MEMORY_XP ? "XP" : "",
837 attr & EFI_MEMORY_RP ? "RP" : "",
838 attr & EFI_MEMORY_WP ? "WP" : "",
839 attr & EFI_MEMORY_RO ? "RO" : "",
840 attr & EFI_MEMORY_UCE ? "UCE" : "",
841 attr & EFI_MEMORY_WB ? "WB" : "",
842 attr & EFI_MEMORY_WT ? "WT" : "",
843 attr & EFI_MEMORY_WC ? "WC" : "",
844 attr & EFI_MEMORY_UC ? "UC" : "");
849 * IA64 has a funky EFI memory map that doesn't work the same way as
850 * other architectures.
854 * efi_mem_attributes - lookup memmap attributes for physical address
855 * @phys_addr: the physical address to lookup
857 * Search in the EFI memory map for the region covering
858 * @phys_addr. Returns the EFI memory attributes if the region
859 * was found in the memory map, 0 otherwise.
861 u64 efi_mem_attributes(unsigned long phys_addr)
863 efi_memory_desc_t *md;
865 if (!efi_enabled(EFI_MEMMAP))
868 for_each_efi_memory_desc(md) {
869 if ((md->phys_addr <= phys_addr) &&
870 (phys_addr < (md->phys_addr +
871 (md->num_pages << EFI_PAGE_SHIFT))))
872 return md->attribute;
878 * efi_mem_type - lookup memmap type for physical address
879 * @phys_addr: the physical address to lookup
881 * Search in the EFI memory map for the region covering @phys_addr.
882 * Returns the EFI memory type if the region was found in the memory
883 * map, -EINVAL otherwise.
885 int efi_mem_type(unsigned long phys_addr)
887 const efi_memory_desc_t *md;
889 if (!efi_enabled(EFI_MEMMAP))
892 for_each_efi_memory_desc(md) {
893 if ((md->phys_addr <= phys_addr) &&
894 (phys_addr < (md->phys_addr +
895 (md->num_pages << EFI_PAGE_SHIFT))))
902 int efi_status_to_err(efi_status_t status)
910 case EFI_INVALID_PARAMETER:
913 case EFI_OUT_OF_RESOURCES:
916 case EFI_DEVICE_ERROR:
919 case EFI_WRITE_PROTECTED:
922 case EFI_SECURITY_VIOLATION:
938 static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock);
939 static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init;
941 static int __init efi_memreserve_map_root(void)
943 if (efi.mem_reserve == EFI_INVALID_TABLE_ADDR)
946 efi_memreserve_root = memremap(efi.mem_reserve,
947 sizeof(*efi_memreserve_root),
949 if (WARN_ON_ONCE(!efi_memreserve_root))
954 static int efi_mem_reserve_iomem(phys_addr_t addr, u64 size)
956 struct resource *res, *parent;
958 res = kzalloc(sizeof(struct resource), GFP_ATOMIC);
962 res->name = "reserved";
963 res->flags = IORESOURCE_MEM;
965 res->end = addr + size - 1;
967 /* we expect a conflict with a 'System RAM' region */
968 parent = request_resource_conflict(&iomem_resource, res);
969 return parent ? request_resource(parent, res) : 0;
972 int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
974 struct linux_efi_memreserve *rsv;
978 if (efi_memreserve_root == (void *)ULONG_MAX)
981 if (!efi_memreserve_root) {
982 rc = efi_memreserve_map_root();
987 /* first try to find a slot in an existing linked list entry */
988 for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
989 rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB);
990 index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
991 if (index < rsv->size) {
992 rsv->entry[index].base = addr;
993 rsv->entry[index].size = size;
996 return efi_mem_reserve_iomem(addr, size);
1001 /* no slot found - allocate a new linked list entry */
1002 rsv = (struct linux_efi_memreserve *)__get_free_page(GFP_ATOMIC);
1006 rc = efi_mem_reserve_iomem(__pa(rsv), SZ_4K);
1008 free_page((unsigned long)rsv);
1013 * The memremap() call above assumes that a linux_efi_memreserve entry
1014 * never crosses a page boundary, so let's ensure that this remains true
1015 * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by
1016 * using SZ_4K explicitly in the size calculation below.
1018 rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K);
1019 atomic_set(&rsv->count, 1);
1020 rsv->entry[0].base = addr;
1021 rsv->entry[0].size = size;
1023 spin_lock(&efi_mem_reserve_persistent_lock);
1024 rsv->next = efi_memreserve_root->next;
1025 efi_memreserve_root->next = __pa(rsv);
1026 spin_unlock(&efi_mem_reserve_persistent_lock);
1028 return efi_mem_reserve_iomem(addr, size);
1031 static int __init efi_memreserve_root_init(void)
1033 if (efi_memreserve_root)
1035 if (efi_memreserve_map_root())
1036 efi_memreserve_root = (void *)ULONG_MAX;
1039 early_initcall(efi_memreserve_root_init);
1042 static int update_efi_random_seed(struct notifier_block *nb,
1043 unsigned long code, void *unused)
1045 struct linux_efi_random_seed *seed;
1048 if (!kexec_in_progress)
1051 seed = memremap(rng_seed, sizeof(*seed), MEMREMAP_WB);
1053 size = min(seed->size, EFI_RANDOM_SEED_SIZE);
1056 pr_err("Could not map UEFI random seed!\n");
1059 seed = memremap(rng_seed, sizeof(*seed) + size, MEMREMAP_WB);
1062 get_random_bytes(seed->bits, seed->size);
1065 pr_err("Could not map UEFI random seed!\n");
1071 static struct notifier_block efi_random_seed_nb = {
1072 .notifier_call = update_efi_random_seed,
1075 static int __init register_update_efi_random_seed(void)
1077 if (rng_seed == EFI_INVALID_TABLE_ADDR)
1079 return register_reboot_notifier(&efi_random_seed_nb);
1081 late_initcall(register_update_efi_random_seed);