4 * This module exports EFI System Resource Table (ESRT) entries into userspace
5 * through the sysfs file system. The ESRT provides a read-only catalog of
6 * system components for which the system accepts firmware upgrades via UEFI's
7 * "Capsule Update" feature. This module allows userland utilities to evaluate
8 * what firmware updates can be applied to this system, and potentially arrange
9 * for those updates to occur.
11 * Data is currently found below /sys/firmware/efi/esrt/...
13 #define pr_fmt(fmt) "esrt: " fmt
15 #include <linux/capability.h>
16 #include <linux/device.h>
17 #include <linux/efi.h>
18 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/kobject.h>
22 #include <linux/list.h>
23 #include <linux/memblock.h>
24 #include <linux/slab.h>
25 #include <linux/types.h>
28 #include <asm/early_ioremap.h>
30 struct efi_system_resource_entry_v1 {
34 u32 lowest_supported_fw_version;
36 u32 last_attempt_version;
37 u32 last_attempt_status;
41 * _count and _version are what they seem like. _max is actually just
42 * accounting info for the firmware when creating the table; it should never
43 * have been exposed to us. To wit, the spec says:
44 * The maximum number of resource array entries that can be within the
45 * table without reallocating the table, must not be zero.
46 * Since there's no guidance about what that means in terms of memory layout,
47 * it means nothing to us.
49 struct efi_system_resource_table {
50 u32 fw_resource_count;
51 u32 fw_resource_count_max;
52 u64 fw_resource_version;
56 static phys_addr_t esrt_data;
57 static size_t esrt_data_size;
59 static struct efi_system_resource_table *esrt;
63 struct efi_system_resource_entry_v1 *esre1;
67 struct list_head list;
70 /* global list of esre_entry. */
71 static LIST_HEAD(entry_list);
74 struct esre_attribute {
75 struct attribute attr;
76 ssize_t (*show)(struct esre_entry *entry, char *buf);
77 ssize_t (*store)(struct esre_entry *entry,
78 const char *buf, size_t count);
81 static struct esre_entry *to_entry(struct kobject *kobj)
83 return container_of(kobj, struct esre_entry, kobj);
86 static struct esre_attribute *to_attr(struct attribute *attr)
88 return container_of(attr, struct esre_attribute, attr);
91 static ssize_t esre_attr_show(struct kobject *kobj,
92 struct attribute *_attr, char *buf)
94 struct esre_entry *entry = to_entry(kobj);
95 struct esre_attribute *attr = to_attr(_attr);
97 /* Don't tell normal users what firmware versions we've got... */
98 if (!capable(CAP_SYS_ADMIN))
101 return attr->show(entry, buf);
104 static const struct sysfs_ops esre_attr_ops = {
105 .show = esre_attr_show,
108 /* Generic ESRT Entry ("ESRE") support. */
109 static ssize_t esre_fw_class_show(struct esre_entry *entry, char *buf)
113 efi_guid_to_str(&entry->esre.esre1->fw_class, str);
115 str += sprintf(str, "\n");
120 static struct esre_attribute esre_fw_class = __ATTR(fw_class, 0400,
121 esre_fw_class_show, NULL);
123 #define esre_attr_decl(name, size, fmt) \
124 static ssize_t esre_##name##_show(struct esre_entry *entry, char *buf) \
126 return sprintf(buf, fmt "\n", \
127 le##size##_to_cpu(entry->esre.esre1->name)); \
130 static struct esre_attribute esre_##name = __ATTR(name, 0400, \
131 esre_##name##_show, NULL)
133 esre_attr_decl(fw_type, 32, "%u");
134 esre_attr_decl(fw_version, 32, "%u");
135 esre_attr_decl(lowest_supported_fw_version, 32, "%u");
136 esre_attr_decl(capsule_flags, 32, "0x%x");
137 esre_attr_decl(last_attempt_version, 32, "%u");
138 esre_attr_decl(last_attempt_status, 32, "%u");
140 static struct attribute *esre1_attrs[] = {
143 &esre_fw_version.attr,
144 &esre_lowest_supported_fw_version.attr,
145 &esre_capsule_flags.attr,
146 &esre_last_attempt_version.attr,
147 &esre_last_attempt_status.attr,
150 static void esre_release(struct kobject *kobj)
152 struct esre_entry *entry = to_entry(kobj);
154 list_del(&entry->list);
158 static struct kobj_type esre1_ktype = {
159 .release = esre_release,
160 .sysfs_ops = &esre_attr_ops,
161 .default_attrs = esre1_attrs,
165 static struct kobject *esrt_kobj;
166 static struct kset *esrt_kset;
168 static int esre_create_sysfs_entry(void *esre, int entry_num)
170 struct esre_entry *entry;
172 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
176 entry->kobj.kset = esrt_kset;
178 if (esrt->fw_resource_version == 1) {
181 entry->esre.esre1 = esre;
182 rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,
183 "entry%d", entry_num);
190 list_add_tail(&entry->list, &entry_list);
194 /* support for displaying ESRT fields at the top level */
195 #define esrt_attr_decl(name, size, fmt) \
196 static ssize_t esrt_##name##_show(struct kobject *kobj, \
197 struct kobj_attribute *attr, char *buf)\
199 return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \
202 static struct kobj_attribute esrt_##name = __ATTR(name, 0400, \
203 esrt_##name##_show, NULL)
205 esrt_attr_decl(fw_resource_count, 32, "%u");
206 esrt_attr_decl(fw_resource_count_max, 32, "%u");
207 esrt_attr_decl(fw_resource_version, 64, "%llu");
209 static struct attribute *esrt_attrs[] = {
210 &esrt_fw_resource_count.attr,
211 &esrt_fw_resource_count_max.attr,
212 &esrt_fw_resource_version.attr,
216 static inline int esrt_table_exists(void)
218 if (!efi_enabled(EFI_CONFIG_TABLES))
220 if (efi.esrt == EFI_INVALID_TABLE_ADDR)
225 static umode_t esrt_attr_is_visible(struct kobject *kobj,
226 struct attribute *attr, int n)
228 if (!esrt_table_exists())
233 static struct attribute_group esrt_attr_group = {
235 .is_visible = esrt_attr_is_visible,
239 * remap the table, validate it, mark it reserved and unmap it.
241 void __init efi_esrt_init(void)
244 struct efi_system_resource_table tmpesrt;
245 struct efi_system_resource_entry_v1 *v1_entries;
246 size_t size, max, entry_size, entries_size;
247 efi_memory_desc_t md;
251 pr_debug("esrt-init: loading.\n");
252 if (!esrt_table_exists())
255 rc = efi_mem_desc_lookup(efi.esrt, &md);
257 pr_err("ESRT header is not in the memory map.\n");
261 max = efi_mem_desc_end(&md);
262 if (max < efi.esrt) {
263 pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n",
264 (void *)efi.esrt, (void *)max);
268 size = sizeof(*esrt);
272 pr_err("ESRT header doesn't fit on single memory map entry. (size: %zu max: %zu)\n",
277 va = early_memremap(efi.esrt, size);
279 pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
284 memcpy(&tmpesrt, va, sizeof(tmpesrt));
286 if (tmpesrt.fw_resource_version == 1) {
287 entry_size = sizeof (*v1_entries);
289 pr_err("Unsupported ESRT version %lld.\n",
290 tmpesrt.fw_resource_version);
294 if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
295 pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
296 max - size, entry_size);
301 * The format doesn't really give us any boundary to test here,
302 * so I'm making up 128 as the max number of individually updatable
303 * components we support.
304 * 128 should be pretty excessive, but there's still some chance
305 * somebody will do that someday and we'll need to raise this.
307 if (tmpesrt.fw_resource_count > 128) {
308 pr_err("ESRT says fw_resource_count has very large value %d.\n",
309 tmpesrt.fw_resource_count);
314 * We know it can't be larger than N * sizeof() here, and N is limited
315 * by the previous test to a small number, so there's no overflow.
317 entries_size = tmpesrt.fw_resource_count * entry_size;
318 if (max < size + entries_size) {
319 pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
324 /* remap it with our (plausible) new pages */
325 early_memunmap(va, size);
326 size += entries_size;
327 va = early_memremap(efi.esrt, size);
329 pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
334 esrt_data = (phys_addr_t)efi.esrt;
335 esrt_data_size = size;
337 end = esrt_data + size;
338 pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
339 efi_mem_reserve(esrt_data, esrt_data_size);
341 pr_debug("esrt-init: loaded.\n");
343 early_memunmap(va, size);
346 static int __init register_entries(void)
348 struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries;
351 if (!esrt_table_exists())
354 for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {
356 if (esrt->fw_resource_version == 1) {
357 esre = &v1_entries[i];
359 pr_err("Unsupported ESRT version %lld.\n",
360 esrt->fw_resource_version);
364 rc = esre_create_sysfs_entry(esre, i);
366 pr_err("ESRT entry creation failed with error %d.\n",
374 static void cleanup_entry_list(void)
376 struct esre_entry *entry, *next;
378 list_for_each_entry_safe(entry, next, &entry_list, list) {
379 kobject_put(&entry->kobj);
383 static int __init esrt_sysfs_init(void)
387 pr_debug("esrt-sysfs: loading.\n");
388 if (!esrt_data || !esrt_data_size)
391 esrt = memremap(esrt_data, esrt_data_size, MEMREMAP_WB);
393 pr_err("memremap(%pa, %zu) failed.\n", &esrt_data,
398 esrt_kobj = kobject_create_and_add("esrt", efi_kobj);
400 pr_err("Firmware table registration failed.\n");
405 error = sysfs_create_group(esrt_kobj, &esrt_attr_group);
407 pr_err("Sysfs attribute export failed with error %d.\n",
409 goto err_remove_esrt;
412 esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj);
414 pr_err("kset creation failed.\n");
416 goto err_remove_group;
419 error = register_entries();
421 goto err_cleanup_list;
423 pr_debug("esrt-sysfs: loaded.\n");
427 cleanup_entry_list();
428 kset_unregister(esrt_kset);
430 sysfs_remove_group(esrt_kobj, &esrt_attr_group);
432 kobject_put(esrt_kobj);
438 device_initcall(esrt_sysfs_init);
441 MODULE_AUTHOR("Peter Jones <pjones@redhat.com>");
442 MODULE_DESCRIPTION("EFI System Resource Table support");
443 MODULE_LICENSE("GPL");