aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/firmware/efi/esrt.c
blob: 2f6204b2fdd38a66db2ed4bfb1e0c2066d44d12c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
/*
 * esrt.c
 *
 * This module exports EFI System Resource Table (ESRT) entries into userspace
 * through the sysfs file system. The ESRT provides a read-only catalog of
 * system components for which the system accepts firmware upgrades via UEFI's
 * "Capsule Update" feature. This module allows userland utilities to evaluate
 * what firmware updates can be applied to this system, and potentially arrange
 * for those updates to occur.
 *
 * Data is currently found below /sys/firmware/efi/esrt/...
 */
#define pr_fmt(fmt) "esrt: " fmt

#include <linux/capability.h>
#include <linux/device.h>
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/list.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <asm/io.h>
#include <asm/early_ioremap.h>

struct efi_system_resource_entry_v1 {
	efi_guid_t	fw_class;
	u32		fw_type;
	u32		fw_version;
	u32		lowest_supported_fw_version;
	u32		capsule_flags;
	u32		last_attempt_version;
	u32		last_attempt_status;
};

/*
 * _count and _version are what they seem like.  _max is actually just
 * accounting info for the firmware when creating the table; it should never
 * have been exposed to us.  To wit, the spec says:
 * The maximum number of resource array entries that can be within the
 * table without reallocating the table, must not be zero.
 * Since there's no guidance about what that means in terms of memory layout,
 * it means nothing to us.
 */
struct efi_system_resource_table {
	u32	fw_resource_count;
	u32	fw_resource_count_max;
	u64	fw_resource_version;
	u8	entries[];
};

static phys_addr_t esrt_data;
static size_t esrt_data_size;

static struct efi_system_resource_table *esrt;

struct esre_entry {
	union {
		struct efi_system_resource_entry_v1 *esre1;
	} esre;

	struct kobject kobj;
	struct list_head list;
};

/* global list of esre_entry. */
static LIST_HEAD(entry_list);

/* entry attribute */
struct esre_attribute {
	struct attribute attr;
	ssize_t (*show)(struct esre_entry *entry, char *buf);
	ssize_t (*store)(struct esre_entry *entry,
			 const char *buf, size_t count);
};

static struct esre_entry *to_entry(struct kobject *kobj)
{
	return container_of(kobj, struct esre_entry, kobj);
}

static struct esre_attribute *to_attr(struct attribute *attr)
{
	return container_of(attr, struct esre_attribute, attr);
}

static ssize_t esre_attr_show(struct kobject *kobj,
			      struct attribute *_attr, char *buf)
{
	struct esre_entry *entry = to_entry(kobj);
	struct esre_attribute *attr = to_attr(_attr);

	/* Don't tell normal users what firmware versions we've got... */
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	return attr->show(entry, buf);
}

static const struct sysfs_ops esre_attr_ops = {
	.show = esre_attr_show,
};

/* Generic ESRT Entry ("ESRE") support. */
static ssize_t fw_class_show(struct esre_entry *entry, char *buf)
{
	char *str = buf;

	efi_guid_to_str(&entry->esre.esre1->fw_class, str);
	str += strlen(str);
	str += sprintf(str, "\n");

	return str - buf;
}

static struct esre_attribute esre_fw_class = __ATTR_RO_MODE(fw_class, 0400);

#define esre_attr_decl(name, size, fmt) \
static ssize_t name##_show(struct esre_entry *entry, char *buf) \
{ \
	return sprintf(buf, fmt "\n", \
		       le##size##_to_cpu(entry->esre.esre1->name)); \
} \
\
static struct esre_attribute esre_##name = __ATTR_RO_MODE(name, 0400)

esre_attr_decl(fw_type, 32, "%u");
esre_attr_decl(fw_version, 32, "%u");
esre_attr_decl(lowest_supported_fw_version, 32, "%u");
esre_attr_decl(capsule_flags, 32, "0x%x");
esre_attr_decl(last_attempt_version, 32, "%u");
esre_attr_decl(last_attempt_status, 32, "%u");

static struct attribute *esre1_attrs[] = {
	&esre_fw_class.attr,
	&esre_fw_type.attr,
	&esre_fw_version.attr,
	&esre_lowest_supported_fw_version.attr,
	&esre_capsule_flags.attr,
	&esre_last_attempt_version.attr,
	&esre_last_attempt_status.attr,
	NULL
};
static void esre_release(struct kobject *kobj)
{
	struct esre_entry *entry = to_entry(kobj);

	list_del(&entry->list);
	kfree(entry);
}

static struct kobj_type esre1_ktype = {
	.release = esre_release,
	.sysfs_ops = &esre_attr_ops,
	.default_attrs = esre1_attrs,
};


static struct kobject *esrt_kobj;
static struct kset *esrt_kset;

static int esre_create_sysfs_entry(void *esre, int entry_num)
{
	struct esre_entry *entry;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return -ENOMEM;

	entry->kobj.kset = esrt_kset;

	if (esrt->fw_resource_version == 1) {
		int rc = 0;

		entry->esre.esre1 = esre;
		rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,
					  "entry%d", entry_num);
		if (rc) {
			kobject_put(&entry->kobj);
			return rc;
		}
	}

	list_add_tail(&entry->list, &entry_list);
	return 0;
}

/* support for displaying ESRT fields at the top level */
#define esrt_attr_decl(name, size, fmt) \
static ssize_t name##_show(struct kobject *kobj, \
				  struct kobj_attribute *attr, char *buf)\
{ \
	return sprintf(buf, fmt "\n", le##size##_to_cpu(esrt->name)); \
} \
\
static struct kobj_attribute esrt_##name = __ATTR_RO_MODE(name, 0400)

esrt_attr_decl(fw_resource_count, 32, "%u");
esrt_attr_decl(fw_resource_count_max, 32, "%u");
esrt_attr_decl(fw_resource_version, 64, "%llu");

static struct attribute *esrt_attrs[] = {
	&esrt_fw_resource_count.attr,
	&esrt_fw_resource_count_max.attr,
	&esrt_fw_resource_version.attr,
	NULL,
};

static inline int esrt_table_exists(void)
{
	if (!efi_enabled(EFI_CONFIG_TABLES))
		return 0;
	if (efi.esrt == EFI_INVALID_TABLE_ADDR)
		return 0;
	return 1;
}

static umode_t esrt_attr_is_visible(struct kobject *kobj,
				    struct attribute *attr, int n)
{
	if (!esrt_table_exists())
		return 0;
	return attr->mode;
}

static const struct attribute_group esrt_attr_group = {
	.attrs = esrt_attrs,
	.is_visible = esrt_attr_is_visible,
};

/*
 * remap the table, validate it, mark it reserved and unmap it.
 */
void __init efi_esrt_init(void)
{
	void *va;
	struct efi_system_resource_table tmpesrt;
	struct efi_system_resource_entry_v1 *v1_entries;
	size_t size, max, entry_size, entries_size;
	efi_memory_desc_t md;
	int rc;
	phys_addr_t end;

	pr_debug("esrt-init: loading.\n");
	if (!esrt_table_exists())
		return;

	rc = efi_mem_desc_lookup(efi.esrt, &md);
	if (rc < 0 ||
	    (!(md.attribute & EFI_MEMORY_RUNTIME) &&
	     md.type != EFI_BOOT_SERVICES_DATA &&
	     md.type != EFI_RUNTIME_SERVICES_DATA)) {
		pr_warn("ESRT header is not in the memory map.\n");
		return;
	}

	max = efi_mem_desc_end(&md);
	if (max < efi.esrt) {
		pr_err("EFI memory descriptor is invalid. (esrt: %p max: %p)\n",
		       (void *)efi.esrt, (void *)max);
		return;
	}

	size = sizeof(*esrt);
	max -= efi.esrt;

	if (max < size) {
		pr_err("ESRT header doesn't fit on single memory map entry. (size: %zu max: %zu)\n",
		       size, max);
		return;
	}

	va = early_memremap(efi.esrt, size);
	if (!va) {
		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,
		       size);
		return;
	}

	memcpy(&tmpesrt, va, sizeof(tmpesrt));
	early_memunmap(va, size);

	if (tmpesrt.fw_resource_version == 1) {
		entry_size = sizeof (*v1_entries);
	} else {
		pr_err("Unsupported ESRT version %lld.\n",
		       tmpesrt.fw_resource_version);
		return;
	}

	if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {
		pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",
		       max - size, entry_size);
		return;
	}

	/*
	 * The format doesn't really give us any boundary to test here,
	 * so I'm making up 128 as the max number of individually updatable
	 * components we support.
	 * 128 should be pretty excessive, but there's still some chance
	 * somebody will do that someday and we'll need to raise this.
	 */
	if (tmpesrt.fw_resource_count > 128) {
		pr_err("ESRT says fw_resource_count has very large value %d.\n",
		       tmpesrt.fw_resource_count);
		return;
	}

	/*
	 * We know it can't be larger than N * sizeof() here, and N is limited
	 * by the previous test to a small number, so there's no overflow.
	 */
	entries_size = tmpesrt.fw_resource_count * entry_size;
	if (max < size + entries_size) {
		pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",
		       size, max);
		return;
	}

	size += entries_size;

	esrt_data = (phys_addr_t)efi.esrt;
	esrt_data_size = size;

	end = esrt_data + size;
	pr_info("Reserving ESRT space from %pa to %pa.\n", &esrt_data, &end);
	if (md.type == EFI_BOOT_SERVICES_DATA)
		efi_mem_reserve(esrt_data, esrt_data_size);

	pr_debug("esrt-init: loaded.\n");
}

static int __init register_entries(void)
{
	struct efi_system_resource_entry_v1 *v1_entries = (void *)esrt->entries;
	int i, rc;

	if (!esrt_table_exists())
		return 0;

	for (i = 0; i < le32_to_cpu(esrt->fw_resource_count); i++) {
		void *esre = NULL;
		if (esrt->fw_resource_version == 1) {
			esre = &v1_entries[i];
		} else {
			pr_err("Unsupported ESRT version %lld.\n",
			       esrt->fw_resource_version);
			return -EINVAL;
		}

		rc = esre_create_sysfs_entry(esre, i);
		if (rc < 0) {
			pr_err("ESRT entry creation failed with error %d.\n",
			       rc);
			return rc;
		}
	}
	return 0;
}

static void cleanup_entry_list(void)
{
	struct esre_entry *entry, *next;

	list_for_each_entry_safe(entry, next, &entry_list, list) {
		kobject_put(&entry->kobj);
	}
}

static int __init esrt_sysfs_init(void)
{
	int error;

	pr_debug("esrt-sysfs: loading.\n");
	if (!esrt_data || !esrt_data_size)
		return -ENOSYS;

	esrt = memremap(esrt_data, esrt_data_size, MEMREMAP_WB);
	if (!esrt) {
		pr_err("memremap(%pa, %zu) failed.\n", &esrt_data,
		       esrt_data_size);
		return -ENOMEM;
	}

	esrt_kobj = kobject_create_and_add("esrt", efi_kobj);
	if (!esrt_kobj) {
		pr_err("Firmware table registration failed.\n");
		error = -ENOMEM;
		goto err;
	}

	error = sysfs_create_group(esrt_kobj, &esrt_attr_group);
	if (error) {
		pr_err("Sysfs attribute export failed with error %d.\n",
		       error);
		goto err_remove_esrt;
	}

	esrt_kset = kset_create_and_add("entries", NULL, esrt_kobj);
	if (!esrt_kset) {
		pr_err("kset creation failed.\n");
		error = -ENOMEM;
		goto err_remove_group;
	}

	error = register_entries();
	if (error)
		goto err_cleanup_list;

	pr_debug("esrt-sysfs: loaded.\n");

	return 0;
err_cleanup_list:
	cleanup_entry_list();
	kset_unregister(esrt_kset);
err_remove_group:
	sysfs_remove_group(esrt_kobj, &esrt_attr_group);
err_remove_esrt:
	kobject_put(esrt_kobj);
err:
	memunmap(esrt);
	esrt = NULL;
	return error;
}
device_initcall(esrt_sysfs_init);

/*
MODULE_AUTHOR("Peter Jones <pjones@redhat.com>");
MODULE_DESCRIPTION("EFI System Resource Table support");
MODULE_LICENSE("GPL");
*/