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1// SPDX-License-Identifier: GPL-2.0+2/*3 * esrt.c4 *5 * This module exports EFI System Resource Table (ESRT) entries into userspace6 * through the sysfs file system. The ESRT provides a read-only catalog of7 * system components for which the system accepts firmware upgrades via UEFI's8 * "Capsule Update" feature. This module allows userland utilities to evaluate9 * what firmware updates can be applied to this system, and potentially arrange10 * for those updates to occur.11 *12 * Data is currently found below /sys/firmware/efi/esrt/...13 */14#define pr_fmt(fmt) "esrt: " fmt15 16#include <linux/capability.h>17#include <linux/device.h>18#include <linux/efi.h>19#include <linux/init.h>20#include <linux/io.h>21#include <linux/kernel.h>22#include <linux/kobject.h>23#include <linux/list.h>24#include <linux/memblock.h>25#include <linux/slab.h>26#include <linux/types.h>27 28#include <asm/io.h>29#include <asm/early_ioremap.h>30 31struct efi_system_resource_entry_v1 {32 efi_guid_t fw_class;33 u32 fw_type;34 u32 fw_version;35 u32 lowest_supported_fw_version;36 u32 capsule_flags;37 u32 last_attempt_version;38 u32 last_attempt_status;39};40 41/*42 * _count and _version are what they seem like. _max is actually just43 * accounting info for the firmware when creating the table; it should never44 * have been exposed to us. To wit, the spec says:45 * The maximum number of resource array entries that can be within the46 * table without reallocating the table, must not be zero.47 * Since there's no guidance about what that means in terms of memory layout,48 * it means nothing to us.49 */50struct efi_system_resource_table {51 u32 fw_resource_count;52 u32 fw_resource_count_max;53 u64 fw_resource_version;54 u8 entries[];55};56 57static phys_addr_t esrt_data;58static size_t esrt_data_size;59 60static struct efi_system_resource_table *esrt;61 62struct esre_entry {63 union {64 struct efi_system_resource_entry_v1 *esre1;65 } esre;66 67 struct kobject kobj;68 struct list_head list;69};70 71/* global list of esre_entry. */72static LIST_HEAD(entry_list);73 74/* entry attribute */75struct esre_attribute {76 struct attribute attr;77 ssize_t (*show)(struct esre_entry *entry, char *buf);78 ssize_t (*store)(struct esre_entry *entry,79 const char *buf, size_t count);80};81 82static struct esre_entry *to_entry(struct kobject *kobj)83{84 return container_of(kobj, struct esre_entry, kobj);85}86 87static struct esre_attribute *to_attr(struct attribute *attr)88{89 return container_of(attr, struct esre_attribute, attr);90}91 92static ssize_t esre_attr_show(struct kobject *kobj,93 struct attribute *_attr, char *buf)94{95 struct esre_entry *entry = to_entry(kobj);96 struct esre_attribute *attr = to_attr(_attr);97 98 return attr->show(entry, buf);99}100 101static const struct sysfs_ops esre_attr_ops = {102 .show = esre_attr_show,103};104 105/* Generic ESRT Entry ("ESRE") support. */106static ssize_t fw_class_show(struct esre_entry *entry, char *buf)107{108 char *str = buf;109 110 efi_guid_to_str(&entry->esre.esre1->fw_class, str);111 str += strlen(str);112 str += sprintf(str, "\n");113 114 return str - buf;115}116 117static struct esre_attribute esre_fw_class = __ATTR_RO_MODE(fw_class, 0400);118 119#define esre_attr_decl(name, size, fmt) \120static ssize_t name##_show(struct esre_entry *entry, char *buf) \121{ \122 return sprintf(buf, fmt "\n", \123 le##size##_to_cpu(entry->esre.esre1->name)); \124} \125\126static struct esre_attribute esre_##name = __ATTR_RO_MODE(name, 0400)127 128esre_attr_decl(fw_type, 32, "%u");129esre_attr_decl(fw_version, 32, "%u");130esre_attr_decl(lowest_supported_fw_version, 32, "%u");131esre_attr_decl(capsule_flags, 32, "0x%x");132esre_attr_decl(last_attempt_version, 32, "%u");133esre_attr_decl(last_attempt_status, 32, "%u");134 135static struct attribute *esre1_attrs[] = {136 &esre_fw_class.attr,137 &esre_fw_type.attr,138 &esre_fw_version.attr,139 &esre_lowest_supported_fw_version.attr,140 &esre_capsule_flags.attr,141 &esre_last_attempt_version.attr,142 &esre_last_attempt_status.attr,143 NULL144};145ATTRIBUTE_GROUPS(esre1);146 147static void esre_release(struct kobject *kobj)148{149 struct esre_entry *entry = to_entry(kobj);150 151 list_del(&entry->list);152 kfree(entry);153}154 155static const struct kobj_type esre1_ktype = {156 .release = esre_release,157 .sysfs_ops = &esre_attr_ops,158 .default_groups = esre1_groups,159};160 161 162static struct kobject *esrt_kobj;163static struct kset *esrt_kset;164 165static int esre_create_sysfs_entry(void *esre, int entry_num)166{167 struct esre_entry *entry;168 169 entry = kzalloc(sizeof(*entry), GFP_KERNEL);170 if (!entry)171 return -ENOMEM;172 173 entry->kobj.kset = esrt_kset;174 175 if (esrt->fw_resource_version == 1) {176 int rc = 0;177 178 entry->esre.esre1 = esre;179 rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,180 "entry%d", entry_num);181 if (rc) {182 kobject_put(&entry->kobj);183 return rc;184 }185 }186 187 list_add_tail(&entry->list, &entry_list);188 return 0;189}190 191/* support for displaying ESRT fields at the top level */192#define esrt_attr_decl(name, size, fmt) \193static ssize_t name##_show(struct kobject *kobj, \194 struct kobj_attribute *attr, char *buf)\195{ \196 return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \197} \198\199static struct kobj_attribute esrt_##name = __ATTR_RO_MODE(name, 0400)200 201esrt_attr_decl(fw_resource_count, 32, "%u");202esrt_attr_decl(fw_resource_count_max, 32, "%u");203esrt_attr_decl(fw_resource_version, 64, "%llu");204 205static struct attribute *esrt_attrs[] = {206 &esrt_fw_resource_count.attr,207 &esrt_fw_resource_count_max.attr,208 &esrt_fw_resource_version.attr,209 NULL,210};211 212static inline int esrt_table_exists(void)213{214 if (!efi_enabled(EFI_CONFIG_TABLES))215 return 0;216 if (efi.esrt == EFI_INVALID_TABLE_ADDR)217 return 0;218 return 1;219}220 221static umode_t esrt_attr_is_visible(struct kobject *kobj,222 struct attribute *attr, int n)223{224 if (!esrt_table_exists())225 return 0;226 return attr->mode;227}228 229static const struct attribute_group esrt_attr_group = {230 .attrs = esrt_attrs,231 .is_visible = esrt_attr_is_visible,232};233 234/*235 * remap the table, validate it, mark it reserved and unmap it.236 */237void __init efi_esrt_init(void)238{239 void *va;240 struct efi_system_resource_table tmpesrt;241 size_t size, max, entry_size, entries_size;242 efi_memory_desc_t md;243 int rc;244 phys_addr_t end;245 246 if (!efi_enabled(EFI_MEMMAP) && !efi_enabled(EFI_PARAVIRT))247 return;248 249 pr_debug("esrt-init: loading.\n");250 if (!esrt_table_exists())251 return;252 253 rc = efi_mem_desc_lookup(efi.esrt, &md);254 if (rc < 0 ||255 (!(md.attribute & EFI_MEMORY_RUNTIME) &&256 md.type != EFI_BOOT_SERVICES_DATA &&257 md.type != EFI_RUNTIME_SERVICES_DATA &&258 md.type != EFI_ACPI_RECLAIM_MEMORY &&259 md.type != EFI_ACPI_MEMORY_NVS)) {260 pr_warn("ESRT header is not in the memory map.\n");261 return;262 }263 264 max = efi_mem_desc_end(&md) - efi.esrt;265 size = sizeof(*esrt);266 267 if (max < size) {268 pr_err("ESRT header doesn't fit on single memory map entry. (size: %zu max: %zu)\n",269 size, max);270 return;271 }272 273 va = early_memremap(efi.esrt, size);274 if (!va) {275 pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,276 size);277 return;278 }279 280 memcpy(&tmpesrt, va, sizeof(tmpesrt));281 early_memunmap(va, size);282 283 if (tmpesrt.fw_resource_version != 1) {284 pr_err("Unsupported ESRT version %lld.\n",285 tmpesrt.fw_resource_version);286 return;287 }288 289 entry_size = sizeof(struct efi_system_resource_entry_v1);290 if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {291 pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",292 max - size, entry_size);293 return;294 }295 296 /*297 * The format doesn't really give us any boundary to test here,298 * so I'm making up 128 as the max number of individually updatable299 * components we support.300 * 128 should be pretty excessive, but there's still some chance301 * somebody will do that someday and we'll need to raise this.302 */303 if (tmpesrt.fw_resource_count > 128) {304 pr_err("ESRT says fw_resource_count has very large value %d.\n",305 tmpesrt.fw_resource_count);306 return;307 }308 309 /*310 * We know it can't be larger than N * sizeof() here, and N is limited311 * by the previous test to a small number, so there's no overflow.312 */313 entries_size = tmpesrt.fw_resource_count * entry_size;314 if (max < size + entries_size) {315 pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",316 size, max);317 return;318 }319 320 size += entries_size;321 322 esrt_data = (phys_addr_t)efi.esrt;323 esrt_data_size = size;324 325 end = esrt_data + size;326 pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);327 if (md.type == EFI_BOOT_SERVICES_DATA)328 efi_mem_reserve(esrt_data, esrt_data_size);329 330 pr_debug("esrt-init: loaded.\n");331}332 333static int __init register_entries(void)334{335 struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries;336 int i, rc;337 338 if (!esrt_table_exists())339 return 0;340 341 for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {342 void *esre = NULL;343 if (esrt->fw_resource_version == 1) {344 esre = &v1_entries[i];345 } else {346 pr_err("Unsupported ESRT version %lld.\n",347 esrt->fw_resource_version);348 return -EINVAL;349 }350 351 rc = esre_create_sysfs_entry(esre, i);352 if (rc < 0) {353 pr_err("ESRT entry creation failed with error %d.\n",354 rc);355 return rc;356 }357 }358 return 0;359}360 361static void cleanup_entry_list(void)362{363 struct esre_entry *entry, *next;364 365 list_for_each_entry_safe(entry, next, &entry_list, list) {366 kobject_put(&entry->kobj);367 }368}369 370static int __init esrt_sysfs_init(void)371{372 int error;373 374 pr_debug("esrt-sysfs: loading.\n");375 if (!esrt_data || !esrt_data_size)376 return -ENOSYS;377 378 esrt = memremap(esrt_data, esrt_data_size, MEMREMAP_WB);379 if (!esrt) {380 pr_err("memremap(%pa, %zu) failed.\n", &esrt_data,381 esrt_data_size);382 return -ENOMEM;383 }384 385 esrt_kobj = kobject_create_and_add("esrt", efi_kobj);386 if (!esrt_kobj) {387 pr_err("Firmware table registration failed.\n");388 error = -ENOMEM;389 goto err;390 }391 392 error = sysfs_create_group(esrt_kobj, &esrt_attr_group);393 if (error) {394 pr_err("Sysfs attribute export failed with error %d.\n",395 error);396 goto err_remove_esrt;397 }398 399 esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj);400 if (!esrt_kset) {401 pr_err("kset creation failed.\n");402 error = -ENOMEM;403 goto err_remove_group;404 }405 406 error = register_entries();407 if (error)408 goto err_cleanup_list;409 410 pr_debug("esrt-sysfs: loaded.\n");411 412 return 0;413err_cleanup_list:414 cleanup_entry_list();415 kset_unregister(esrt_kset);416err_remove_group:417 sysfs_remove_group(esrt_kobj, &esrt_attr_group);418err_remove_esrt:419 kobject_put(esrt_kobj);420err:421 memunmap(esrt);422 esrt = NULL;423 return error;424}425device_initcall(esrt_sysfs_init);426 427/*428MODULE_AUTHOR("Peter Jones <pjones@redhat.com>");429MODULE_DESCRIPTION("EFI System Resource Table support");430MODULE_LICENSE("GPL");431*/432