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1/*
2 * dmi-sysfs.c
3 *
4 * This module exports the DMI tables read-only to userspace through the
5 * sysfs file system.
6 *
7 * Data is currently found below
8 * /sys/firmware/dmi/...
9 *
10 * DMI attributes are presented in attribute files with names
11 * formatted using %d-%d, so that the first integer indicates the
12 * structure type (0-255), and the second field is the instance of that
13 * entry.
14 *
15 * Copyright 2011 Google, Inc.
16 */
17
18#include <linux/kernel.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/types.h>
22#include <linux/kobject.h>
23#include <linux/dmi.h>
24#include <linux/capability.h>
25#include <linux/slab.h>
26#include <linux/list.h>
27#include <linux/io.h>
28
29#define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
30 the top entry type is only 8 bits */
31
32struct dmi_sysfs_entry {
33 struct dmi_header dh;
34 struct kobject kobj;
35 int instance;
36 int position;
37 struct list_head list;
38 struct kobject *child;
39};
40
41/*
42 * Global list of dmi_sysfs_entry. Even though this should only be
43 * manipulated at setup and teardown, the lazy nature of the kobject
44 * system means we get lazy removes.
45 */
46static LIST_HEAD(entry_list);
47static DEFINE_SPINLOCK(entry_list_lock);
48
49/* dmi_sysfs_attribute - Top level attribute. used by all entries. */
50struct dmi_sysfs_attribute {
51 struct attribute attr;
52 ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
53};
54
55#define DMI_SYSFS_ATTR(_entry, _name) \
56struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
57 .attr = {.name = __stringify(_name), .mode = 0400}, \
58 .show = dmi_sysfs_##_entry##_##_name, \
59}
60
61/*
62 * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
63 * mapped in. Use in conjunction with dmi_sysfs_specialize_attr_ops.
64 */
65struct dmi_sysfs_mapped_attribute {
66 struct attribute attr;
67 ssize_t (*show)(struct dmi_sysfs_entry *entry,
68 const struct dmi_header *dh,
69 char *buf);
70};
71
72#define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
73struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
74 .attr = {.name = __stringify(_name), .mode = 0400}, \
75 .show = dmi_sysfs_##_entry##_##_name, \
76}
77
78/*************************************************
79 * Generic DMI entry support.
80 *************************************************/
81static void dmi_entry_free(struct kobject *kobj)
82{
83 kfree(kobj);
84}
85
86static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
87{
88 return container_of(kobj, struct dmi_sysfs_entry, kobj);
89}
90
91static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
92{
93 return container_of(attr, struct dmi_sysfs_attribute, attr);
94}
95
96static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
97 struct attribute *_attr, char *buf)
98{
99 struct dmi_sysfs_entry *entry = to_entry(kobj);
100 struct dmi_sysfs_attribute *attr = to_attr(_attr);
101
102 /* DMI stuff is only ever admin visible */
103 if (!capable(CAP_SYS_ADMIN))
104 return -EACCES;
105
106 return attr->show(entry, buf);
107}
108
109static const struct sysfs_ops dmi_sysfs_attr_ops = {
110 .show = dmi_sysfs_attr_show,
111};
112
113typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
114 const struct dmi_header *dh, void *);
115
116struct find_dmi_data {
117 struct dmi_sysfs_entry *entry;
118 dmi_callback callback;
119 void *private;
120 int instance_countdown;
121 ssize_t ret;
122};
123
124static void find_dmi_entry_helper(const struct dmi_header *dh,
125 void *_data)
126{
127 struct find_dmi_data *data = _data;
128 struct dmi_sysfs_entry *entry = data->entry;
129
130 /* Is this the entry we want? */
131 if (dh->type != entry->dh.type)
132 return;
133
134 if (data->instance_countdown != 0) {
135 /* try the next instance? */
136 data->instance_countdown--;
137 return;
138 }
139
140 /*
141 * Don't ever revisit the instance. Short circuit later
142 * instances by letting the instance_countdown run negative
143 */
144 data->instance_countdown--;
145
146 /* Found the entry */
147 data->ret = data->callback(entry, dh, data->private);
148}
149
150/* State for passing the read parameters through dmi_find_entry() */
151struct dmi_read_state {
152 char *buf;
153 loff_t pos;
154 size_t count;
155};
156
157static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
158 dmi_callback callback, void *private)
159{
160 struct find_dmi_data data = {
161 .entry = entry,
162 .callback = callback,
163 .private = private,
164 .instance_countdown = entry->instance,
165 .ret = -EIO, /* To signal the entry disappeared */
166 };
167 int ret;
168
169 ret = dmi_walk(find_dmi_entry_helper, &data);
170 /* This shouldn't happen, but just in case. */
171 if (ret)
172 return -EINVAL;
173 return data.ret;
174}
175
176/*
177 * Calculate and return the byte length of the dmi entry identified by
178 * dh. This includes both the formatted portion as well as the
179 * unformatted string space, including the two trailing nul characters.
180 */
181static size_t dmi_entry_length(const struct dmi_header *dh)
182{
183 const char *p = (const char *)dh;
184
185 p += dh->length;
186
187 while (p[0] || p[1])
188 p++;
189
190 return 2 + p - (const char *)dh;
191}
192
193/*************************************************
194 * Support bits for specialized DMI entry support
195 *************************************************/
196struct dmi_entry_attr_show_data {
197 struct attribute *attr;
198 char *buf;
199};
200
201static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
202 const struct dmi_header *dh,
203 void *_data)
204{
205 struct dmi_entry_attr_show_data *data = _data;
206 struct dmi_sysfs_mapped_attribute *attr;
207
208 attr = container_of(data->attr,
209 struct dmi_sysfs_mapped_attribute, attr);
210 return attr->show(entry, dh, data->buf);
211}
212
213static ssize_t dmi_entry_attr_show(struct kobject *kobj,
214 struct attribute *attr,
215 char *buf)
216{
217 struct dmi_entry_attr_show_data data = {
218 .attr = attr,
219 .buf = buf,
220 };
221 /* Find the entry according to our parent and call the
222 * normalized show method hanging off of the attribute */
223 return find_dmi_entry(to_entry(kobj->parent),
224 dmi_entry_attr_show_helper, &data);
225}
226
227static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
228 .show = dmi_entry_attr_show,
229};
230
231/*************************************************
232 * Specialized DMI entry support.
233 *************************************************/
234
235/*** Type 15 - System Event Table ***/
236
237#define DMI_SEL_ACCESS_METHOD_IO8 0x00
238#define DMI_SEL_ACCESS_METHOD_IO2x8 0x01
239#define DMI_SEL_ACCESS_METHOD_IO16 0x02
240#define DMI_SEL_ACCESS_METHOD_PHYS32 0x03
241#define DMI_SEL_ACCESS_METHOD_GPNV 0x04
242
243struct dmi_system_event_log {
244 struct dmi_header header;
245 u16 area_length;
246 u16 header_start_offset;
247 u16 data_start_offset;
248 u8 access_method;
249 u8 status;
250 u32 change_token;
251 union {
252 struct {
253 u16 index_addr;
254 u16 data_addr;
255 } io;
256 u32 phys_addr32;
257 u16 gpnv_handle;
258 u32 access_method_address;
259 };
260 u8 header_format;
261 u8 type_descriptors_supported_count;
262 u8 per_log_type_descriptor_length;
263 u8 supported_log_type_descriptos[0];
264} __packed;
265
266#define DMI_SYSFS_SEL_FIELD(_field) \
267static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
268 const struct dmi_header *dh, \
269 char *buf) \
270{ \
271 struct dmi_system_event_log sel; \
272 if (sizeof(sel) > dmi_entry_length(dh)) \
273 return -EIO; \
274 memcpy(&sel, dh, sizeof(sel)); \
275 return sprintf(buf, "%u\n", sel._field); \
276} \
277static DMI_SYSFS_MAPPED_ATTR(sel, _field)
278
279DMI_SYSFS_SEL_FIELD(area_length);
280DMI_SYSFS_SEL_FIELD(header_start_offset);
281DMI_SYSFS_SEL_FIELD(data_start_offset);
282DMI_SYSFS_SEL_FIELD(access_method);
283DMI_SYSFS_SEL_FIELD(status);
284DMI_SYSFS_SEL_FIELD(change_token);
285DMI_SYSFS_SEL_FIELD(access_method_address);
286DMI_SYSFS_SEL_FIELD(header_format);
287DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
288DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
289
290static struct attribute *dmi_sysfs_sel_attrs[] = {
291 &dmi_sysfs_attr_sel_area_length.attr,
292 &dmi_sysfs_attr_sel_header_start_offset.attr,
293 &dmi_sysfs_attr_sel_data_start_offset.attr,
294 &dmi_sysfs_attr_sel_access_method.attr,
295 &dmi_sysfs_attr_sel_status.attr,
296 &dmi_sysfs_attr_sel_change_token.attr,
297 &dmi_sysfs_attr_sel_access_method_address.attr,
298 &dmi_sysfs_attr_sel_header_format.attr,
299 &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
300 &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
301 NULL,
302};
303
304
305static struct kobj_type dmi_system_event_log_ktype = {
306 .release = dmi_entry_free,
307 .sysfs_ops = &dmi_sysfs_specialize_attr_ops,
308 .default_attrs = dmi_sysfs_sel_attrs,
309};
310
311typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
312 loff_t offset);
313
314static DEFINE_MUTEX(io_port_lock);
315
316static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
317 loff_t offset)
318{
319 u8 ret;
320
321 mutex_lock(&io_port_lock);
322 outb((u8)offset, sel->io.index_addr);
323 ret = inb(sel->io.data_addr);
324 mutex_unlock(&io_port_lock);
325 return ret;
326}
327
328static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
329 loff_t offset)
330{
331 u8 ret;
332
333 mutex_lock(&io_port_lock);
334 outb((u8)offset, sel->io.index_addr);
335 outb((u8)(offset >> 8), sel->io.index_addr + 1);
336 ret = inb(sel->io.data_addr);
337 mutex_unlock(&io_port_lock);
338 return ret;
339}
340
341static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
342 loff_t offset)
343{
344 u8 ret;
345
346 mutex_lock(&io_port_lock);
347 outw((u16)offset, sel->io.index_addr);
348 ret = inb(sel->io.data_addr);
349 mutex_unlock(&io_port_lock);
350 return ret;
351}
352
353static sel_io_reader sel_io_readers[] = {
354 [DMI_SEL_ACCESS_METHOD_IO8] = read_sel_8bit_indexed_io,
355 [DMI_SEL_ACCESS_METHOD_IO2x8] = read_sel_2x8bit_indexed_io,
356 [DMI_SEL_ACCESS_METHOD_IO16] = read_sel_16bit_indexed_io,
357};
358
359static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
360 const struct dmi_system_event_log *sel,
361 char *buf, loff_t pos, size_t count)
362{
363 ssize_t wrote = 0;
364
365 sel_io_reader io_reader = sel_io_readers[sel->access_method];
366
367 while (count && pos < sel->area_length) {
368 count--;
369 *(buf++) = io_reader(sel, pos++);
370 wrote++;
371 }
372
373 return wrote;
374}
375
376static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
377 const struct dmi_system_event_log *sel,
378 char *buf, loff_t pos, size_t count)
379{
380 u8 __iomem *mapped;
381 ssize_t wrote = 0;
382
383 mapped = ioremap(sel->access_method_address, sel->area_length);
384 if (!mapped)
385 return -EIO;
386
387 while (count && pos < sel->area_length) {
388 count--;
389 *(buf++) = readb(mapped + pos++);
390 wrote++;
391 }
392
393 iounmap(mapped);
394 return wrote;
395}
396
397static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
398 const struct dmi_header *dh,
399 void *_state)
400{
401 struct dmi_read_state *state = _state;
402 struct dmi_system_event_log sel;
403
404 if (sizeof(sel) > dmi_entry_length(dh))
405 return -EIO;
406
407 memcpy(&sel, dh, sizeof(sel));
408
409 switch (sel.access_method) {
410 case DMI_SEL_ACCESS_METHOD_IO8:
411 case DMI_SEL_ACCESS_METHOD_IO2x8:
412 case DMI_SEL_ACCESS_METHOD_IO16:
413 return dmi_sel_raw_read_io(entry, &sel, state->buf,
414 state->pos, state->count);
415 case DMI_SEL_ACCESS_METHOD_PHYS32:
416 return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
417 state->pos, state->count);
418 case DMI_SEL_ACCESS_METHOD_GPNV:
419 pr_info("dmi-sysfs: GPNV support missing.\n");
420 return -EIO;
421 default:
422 pr_info("dmi-sysfs: Unknown access method %02x\n",
423 sel.access_method);
424 return -EIO;
425 }
426}
427
428static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
429 struct bin_attribute *bin_attr,
430 char *buf, loff_t pos, size_t count)
431{
432 struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
433 struct dmi_read_state state = {
434 .buf = buf,
435 .pos = pos,
436 .count = count,
437 };
438
439 return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
440}
441
442static struct bin_attribute dmi_sel_raw_attr = {
443 .attr = {.name = "raw_event_log", .mode = 0400},
444 .read = dmi_sel_raw_read,
445};
446
447static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
448{
449 int ret;
450
451 entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
452 if (!entry->child)
453 return -ENOMEM;
454 ret = kobject_init_and_add(entry->child,
455 &dmi_system_event_log_ktype,
456 &entry->kobj,
457 "system_event_log");
458 if (ret)
459 goto out_free;
460
461 ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
462 if (ret)
463 goto out_del;
464
465 return 0;
466
467out_del:
468 kobject_del(entry->child);
469out_free:
470 kfree(entry->child);
471 return ret;
472}
473
474/*************************************************
475 * Generic DMI entry support.
476 *************************************************/
477
478static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
479{
480 return sprintf(buf, "%d\n", entry->dh.length);
481}
482
483static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
484{
485 return sprintf(buf, "%d\n", entry->dh.handle);
486}
487
488static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
489{
490 return sprintf(buf, "%d\n", entry->dh.type);
491}
492
493static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
494 char *buf)
495{
496 return sprintf(buf, "%d\n", entry->instance);
497}
498
499static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
500 char *buf)
501{
502 return sprintf(buf, "%d\n", entry->position);
503}
504
505static DMI_SYSFS_ATTR(entry, length);
506static DMI_SYSFS_ATTR(entry, handle);
507static DMI_SYSFS_ATTR(entry, type);
508static DMI_SYSFS_ATTR(entry, instance);
509static DMI_SYSFS_ATTR(entry, position);
510
511static struct attribute *dmi_sysfs_entry_attrs[] = {
512 &dmi_sysfs_attr_entry_length.attr,
513 &dmi_sysfs_attr_entry_handle.attr,
514 &dmi_sysfs_attr_entry_type.attr,
515 &dmi_sysfs_attr_entry_instance.attr,
516 &dmi_sysfs_attr_entry_position.attr,
517 NULL,
518};
519
520static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
521 const struct dmi_header *dh,
522 void *_state)
523{
524 struct dmi_read_state *state = _state;
525 size_t entry_length;
526
527 entry_length = dmi_entry_length(dh);
528
529 return memory_read_from_buffer(state->buf, state->count,
530 &state->pos, dh, entry_length);
531}
532
533static ssize_t dmi_entry_raw_read(struct file *filp,
534 struct kobject *kobj,
535 struct bin_attribute *bin_attr,
536 char *buf, loff_t pos, size_t count)
537{
538 struct dmi_sysfs_entry *entry = to_entry(kobj);
539 struct dmi_read_state state = {
540 .buf = buf,
541 .pos = pos,
542 .count = count,
543 };
544
545 return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
546}
547
548static const struct bin_attribute dmi_entry_raw_attr = {
549 .attr = {.name = "raw", .mode = 0400},
550 .read = dmi_entry_raw_read,
551};
552
553static void dmi_sysfs_entry_release(struct kobject *kobj)
554{
555 struct dmi_sysfs_entry *entry = to_entry(kobj);
556 sysfs_remove_bin_file(&entry->kobj, &dmi_entry_raw_attr);
557 spin_lock(&entry_list_lock);
558 list_del(&entry->list);
559 spin_unlock(&entry_list_lock);
560 kfree(entry);
561}
562
563static struct kobj_type dmi_sysfs_entry_ktype = {
564 .release = dmi_sysfs_entry_release,
565 .sysfs_ops = &dmi_sysfs_attr_ops,
566 .default_attrs = dmi_sysfs_entry_attrs,
567};
568
569static struct kobject *dmi_kobj;
570static struct kset *dmi_kset;
571
572/* Global count of all instances seen. Only for setup */
573static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
574
575/* Global positional count of all entries seen. Only for setup */
576static int __initdata position_count;
577
578static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
579 void *_ret)
580{
581 struct dmi_sysfs_entry *entry;
582 int *ret = _ret;
583
584 /* If a previous entry saw an error, short circuit */
585 if (*ret)
586 return;
587
588 /* Allocate and register a new entry into the entries set */
589 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
590 if (!entry) {
591 *ret = -ENOMEM;
592 return;
593 }
594
595 /* Set the key */
596 memcpy(&entry->dh, dh, sizeof(*dh));
597 entry->instance = instance_counts[dh->type]++;
598 entry->position = position_count++;
599
600 entry->kobj.kset = dmi_kset;
601 *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
602 "%d-%d", dh->type, entry->instance);
603
604 if (*ret) {
605 kfree(entry);
606 return;
607 }
608
609 /* Thread on the global list for cleanup */
610 spin_lock(&entry_list_lock);
611 list_add_tail(&entry->list, &entry_list);
612 spin_unlock(&entry_list_lock);
613
614 /* Handle specializations by type */
615 switch (dh->type) {
616 case DMI_ENTRY_SYSTEM_EVENT_LOG:
617 *ret = dmi_system_event_log(entry);
618 break;
619 default:
620 /* No specialization */
621 break;
622 }
623 if (*ret)
624 goto out_err;
625
626 /* Create the raw binary file to access the entry */
627 *ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
628 if (*ret)
629 goto out_err;
630
631 return;
632out_err:
633 kobject_put(entry->child);
634 kobject_put(&entry->kobj);
635 return;
636}
637
638static void cleanup_entry_list(void)
639{
640 struct dmi_sysfs_entry *entry, *next;
641
642 /* No locks, we are on our way out */
643 list_for_each_entry_safe(entry, next, &entry_list, list) {
644 kobject_put(entry->child);
645 kobject_put(&entry->kobj);
646 }
647}
648
649static int __init dmi_sysfs_init(void)
650{
651 int error = -ENOMEM;
652 int val;
653
654 /* Set up our directory */
655 dmi_kobj = kobject_create_and_add("dmi", firmware_kobj);
656 if (!dmi_kobj)
657 goto err;
658
659 dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
660 if (!dmi_kset)
661 goto err;
662
663 val = 0;
664 error = dmi_walk(dmi_sysfs_register_handle, &val);
665 if (error)
666 goto err;
667 if (val) {
668 error = val;
669 goto err;
670 }
671
672 pr_debug("dmi-sysfs: loaded.\n");
673
674 return 0;
675err:
676 cleanup_entry_list();
677 kset_unregister(dmi_kset);
678 kobject_put(dmi_kobj);
679 return error;
680}
681
682/* clean up everything. */
683static void __exit dmi_sysfs_exit(void)
684{
685 pr_debug("dmi-sysfs: unloading.\n");
686 cleanup_entry_list();
687 kset_unregister(dmi_kset);
688 kobject_put(dmi_kobj);
689}
690
691module_init(dmi_sysfs_init);
692module_exit(dmi_sysfs_exit);
693
694MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
695MODULE_DESCRIPTION("DMI sysfs support");
696MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * dmi-sysfs.c
4 *
5 * This module exports the DMI tables read-only to userspace through the
6 * sysfs file system.
7 *
8 * Data is currently found below
9 * /sys/firmware/dmi/...
10 *
11 * DMI attributes are presented in attribute files with names
12 * formatted using %d-%d, so that the first integer indicates the
13 * structure type (0-255), and the second field is the instance of that
14 * entry.
15 *
16 * Copyright 2011 Google, Inc.
17 */
18
19#include <linux/kernel.h>
20#include <linux/init.h>
21#include <linux/module.h>
22#include <linux/types.h>
23#include <linux/kobject.h>
24#include <linux/dmi.h>
25#include <linux/capability.h>
26#include <linux/slab.h>
27#include <linux/list.h>
28#include <linux/io.h>
29#include <asm/dmi.h>
30
31#define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
32 the top entry type is only 8 bits */
33
34struct dmi_sysfs_entry {
35 struct dmi_header dh;
36 struct kobject kobj;
37 int instance;
38 int position;
39 struct list_head list;
40 struct kobject *child;
41};
42
43/*
44 * Global list of dmi_sysfs_entry. Even though this should only be
45 * manipulated at setup and teardown, the lazy nature of the kobject
46 * system means we get lazy removes.
47 */
48static LIST_HEAD(entry_list);
49static DEFINE_SPINLOCK(entry_list_lock);
50
51/* dmi_sysfs_attribute - Top level attribute. used by all entries. */
52struct dmi_sysfs_attribute {
53 struct attribute attr;
54 ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
55};
56
57#define DMI_SYSFS_ATTR(_entry, _name) \
58struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
59 .attr = {.name = __stringify(_name), .mode = 0400}, \
60 .show = dmi_sysfs_##_entry##_##_name, \
61}
62
63/*
64 * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
65 * mapped in. Use in conjunction with dmi_sysfs_specialize_attr_ops.
66 */
67struct dmi_sysfs_mapped_attribute {
68 struct attribute attr;
69 ssize_t (*show)(struct dmi_sysfs_entry *entry,
70 const struct dmi_header *dh,
71 char *buf);
72};
73
74#define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
75struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
76 .attr = {.name = __stringify(_name), .mode = 0400}, \
77 .show = dmi_sysfs_##_entry##_##_name, \
78}
79
80/*************************************************
81 * Generic DMI entry support.
82 *************************************************/
83static void dmi_entry_free(struct kobject *kobj)
84{
85 kfree(kobj);
86}
87
88static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
89{
90 return container_of(kobj, struct dmi_sysfs_entry, kobj);
91}
92
93static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
94{
95 return container_of(attr, struct dmi_sysfs_attribute, attr);
96}
97
98static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
99 struct attribute *_attr, char *buf)
100{
101 struct dmi_sysfs_entry *entry = to_entry(kobj);
102 struct dmi_sysfs_attribute *attr = to_attr(_attr);
103
104 /* DMI stuff is only ever admin visible */
105 if (!capable(CAP_SYS_ADMIN))
106 return -EACCES;
107
108 return attr->show(entry, buf);
109}
110
111static const struct sysfs_ops dmi_sysfs_attr_ops = {
112 .show = dmi_sysfs_attr_show,
113};
114
115typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
116 const struct dmi_header *dh, void *);
117
118struct find_dmi_data {
119 struct dmi_sysfs_entry *entry;
120 dmi_callback callback;
121 void *private;
122 int instance_countdown;
123 ssize_t ret;
124};
125
126static void find_dmi_entry_helper(const struct dmi_header *dh,
127 void *_data)
128{
129 struct find_dmi_data *data = _data;
130 struct dmi_sysfs_entry *entry = data->entry;
131
132 /* Is this the entry we want? */
133 if (dh->type != entry->dh.type)
134 return;
135
136 if (data->instance_countdown != 0) {
137 /* try the next instance? */
138 data->instance_countdown--;
139 return;
140 }
141
142 /*
143 * Don't ever revisit the instance. Short circuit later
144 * instances by letting the instance_countdown run negative
145 */
146 data->instance_countdown--;
147
148 /* Found the entry */
149 data->ret = data->callback(entry, dh, data->private);
150}
151
152/* State for passing the read parameters through dmi_find_entry() */
153struct dmi_read_state {
154 char *buf;
155 loff_t pos;
156 size_t count;
157};
158
159static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
160 dmi_callback callback, void *private)
161{
162 struct find_dmi_data data = {
163 .entry = entry,
164 .callback = callback,
165 .private = private,
166 .instance_countdown = entry->instance,
167 .ret = -EIO, /* To signal the entry disappeared */
168 };
169 int ret;
170
171 ret = dmi_walk(find_dmi_entry_helper, &data);
172 /* This shouldn't happen, but just in case. */
173 if (ret)
174 return -EINVAL;
175 return data.ret;
176}
177
178/*
179 * Calculate and return the byte length of the dmi entry identified by
180 * dh. This includes both the formatted portion as well as the
181 * unformatted string space, including the two trailing nul characters.
182 */
183static size_t dmi_entry_length(const struct dmi_header *dh)
184{
185 const char *p = (const char *)dh;
186
187 p += dh->length;
188
189 while (p[0] || p[1])
190 p++;
191
192 return 2 + p - (const char *)dh;
193}
194
195/*************************************************
196 * Support bits for specialized DMI entry support
197 *************************************************/
198struct dmi_entry_attr_show_data {
199 struct attribute *attr;
200 char *buf;
201};
202
203static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
204 const struct dmi_header *dh,
205 void *_data)
206{
207 struct dmi_entry_attr_show_data *data = _data;
208 struct dmi_sysfs_mapped_attribute *attr;
209
210 attr = container_of(data->attr,
211 struct dmi_sysfs_mapped_attribute, attr);
212 return attr->show(entry, dh, data->buf);
213}
214
215static ssize_t dmi_entry_attr_show(struct kobject *kobj,
216 struct attribute *attr,
217 char *buf)
218{
219 struct dmi_entry_attr_show_data data = {
220 .attr = attr,
221 .buf = buf,
222 };
223 /* Find the entry according to our parent and call the
224 * normalized show method hanging off of the attribute */
225 return find_dmi_entry(to_entry(kobj->parent),
226 dmi_entry_attr_show_helper, &data);
227}
228
229static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
230 .show = dmi_entry_attr_show,
231};
232
233/*************************************************
234 * Specialized DMI entry support.
235 *************************************************/
236
237/*** Type 15 - System Event Table ***/
238
239#define DMI_SEL_ACCESS_METHOD_IO8 0x00
240#define DMI_SEL_ACCESS_METHOD_IO2x8 0x01
241#define DMI_SEL_ACCESS_METHOD_IO16 0x02
242#define DMI_SEL_ACCESS_METHOD_PHYS32 0x03
243#define DMI_SEL_ACCESS_METHOD_GPNV 0x04
244
245struct dmi_system_event_log {
246 struct dmi_header header;
247 u16 area_length;
248 u16 header_start_offset;
249 u16 data_start_offset;
250 u8 access_method;
251 u8 status;
252 u32 change_token;
253 union {
254 struct {
255 u16 index_addr;
256 u16 data_addr;
257 } io;
258 u32 phys_addr32;
259 u16 gpnv_handle;
260 u32 access_method_address;
261 };
262 u8 header_format;
263 u8 type_descriptors_supported_count;
264 u8 per_log_type_descriptor_length;
265 u8 supported_log_type_descriptos[];
266} __packed;
267
268#define DMI_SYSFS_SEL_FIELD(_field) \
269static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
270 const struct dmi_header *dh, \
271 char *buf) \
272{ \
273 struct dmi_system_event_log sel; \
274 if (sizeof(sel) > dmi_entry_length(dh)) \
275 return -EIO; \
276 memcpy(&sel, dh, sizeof(sel)); \
277 return sprintf(buf, "%u\n", sel._field); \
278} \
279static DMI_SYSFS_MAPPED_ATTR(sel, _field)
280
281DMI_SYSFS_SEL_FIELD(area_length);
282DMI_SYSFS_SEL_FIELD(header_start_offset);
283DMI_SYSFS_SEL_FIELD(data_start_offset);
284DMI_SYSFS_SEL_FIELD(access_method);
285DMI_SYSFS_SEL_FIELD(status);
286DMI_SYSFS_SEL_FIELD(change_token);
287DMI_SYSFS_SEL_FIELD(access_method_address);
288DMI_SYSFS_SEL_FIELD(header_format);
289DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
290DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);
291
292static struct attribute *dmi_sysfs_sel_attrs[] = {
293 &dmi_sysfs_attr_sel_area_length.attr,
294 &dmi_sysfs_attr_sel_header_start_offset.attr,
295 &dmi_sysfs_attr_sel_data_start_offset.attr,
296 &dmi_sysfs_attr_sel_access_method.attr,
297 &dmi_sysfs_attr_sel_status.attr,
298 &dmi_sysfs_attr_sel_change_token.attr,
299 &dmi_sysfs_attr_sel_access_method_address.attr,
300 &dmi_sysfs_attr_sel_header_format.attr,
301 &dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
302 &dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
303 NULL,
304};
305ATTRIBUTE_GROUPS(dmi_sysfs_sel);
306
307static struct kobj_type dmi_system_event_log_ktype = {
308 .release = dmi_entry_free,
309 .sysfs_ops = &dmi_sysfs_specialize_attr_ops,
310 .default_groups = dmi_sysfs_sel_groups,
311};
312
313typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
314 loff_t offset);
315
316static DEFINE_MUTEX(io_port_lock);
317
318static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
319 loff_t offset)
320{
321 u8 ret;
322
323 mutex_lock(&io_port_lock);
324 outb((u8)offset, sel->io.index_addr);
325 ret = inb(sel->io.data_addr);
326 mutex_unlock(&io_port_lock);
327 return ret;
328}
329
330static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
331 loff_t offset)
332{
333 u8 ret;
334
335 mutex_lock(&io_port_lock);
336 outb((u8)offset, sel->io.index_addr);
337 outb((u8)(offset >> 8), sel->io.index_addr + 1);
338 ret = inb(sel->io.data_addr);
339 mutex_unlock(&io_port_lock);
340 return ret;
341}
342
343static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
344 loff_t offset)
345{
346 u8 ret;
347
348 mutex_lock(&io_port_lock);
349 outw((u16)offset, sel->io.index_addr);
350 ret = inb(sel->io.data_addr);
351 mutex_unlock(&io_port_lock);
352 return ret;
353}
354
355static sel_io_reader sel_io_readers[] = {
356 [DMI_SEL_ACCESS_METHOD_IO8] = read_sel_8bit_indexed_io,
357 [DMI_SEL_ACCESS_METHOD_IO2x8] = read_sel_2x8bit_indexed_io,
358 [DMI_SEL_ACCESS_METHOD_IO16] = read_sel_16bit_indexed_io,
359};
360
361static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
362 const struct dmi_system_event_log *sel,
363 char *buf, loff_t pos, size_t count)
364{
365 ssize_t wrote = 0;
366
367 sel_io_reader io_reader = sel_io_readers[sel->access_method];
368
369 while (count && pos < sel->area_length) {
370 count--;
371 *(buf++) = io_reader(sel, pos++);
372 wrote++;
373 }
374
375 return wrote;
376}
377
378static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
379 const struct dmi_system_event_log *sel,
380 char *buf, loff_t pos, size_t count)
381{
382 u8 __iomem *mapped;
383 ssize_t wrote = 0;
384
385 mapped = dmi_remap(sel->access_method_address, sel->area_length);
386 if (!mapped)
387 return -EIO;
388
389 while (count && pos < sel->area_length) {
390 count--;
391 *(buf++) = readb(mapped + pos++);
392 wrote++;
393 }
394
395 dmi_unmap(mapped);
396 return wrote;
397}
398
399static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
400 const struct dmi_header *dh,
401 void *_state)
402{
403 struct dmi_read_state *state = _state;
404 struct dmi_system_event_log sel;
405
406 if (sizeof(sel) > dmi_entry_length(dh))
407 return -EIO;
408
409 memcpy(&sel, dh, sizeof(sel));
410
411 switch (sel.access_method) {
412 case DMI_SEL_ACCESS_METHOD_IO8:
413 case DMI_SEL_ACCESS_METHOD_IO2x8:
414 case DMI_SEL_ACCESS_METHOD_IO16:
415 return dmi_sel_raw_read_io(entry, &sel, state->buf,
416 state->pos, state->count);
417 case DMI_SEL_ACCESS_METHOD_PHYS32:
418 return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
419 state->pos, state->count);
420 case DMI_SEL_ACCESS_METHOD_GPNV:
421 pr_info("dmi-sysfs: GPNV support missing.\n");
422 return -EIO;
423 default:
424 pr_info("dmi-sysfs: Unknown access method %02x\n",
425 sel.access_method);
426 return -EIO;
427 }
428}
429
430static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
431 struct bin_attribute *bin_attr,
432 char *buf, loff_t pos, size_t count)
433{
434 struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
435 struct dmi_read_state state = {
436 .buf = buf,
437 .pos = pos,
438 .count = count,
439 };
440
441 return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
442}
443
444static struct bin_attribute dmi_sel_raw_attr = {
445 .attr = {.name = "raw_event_log", .mode = 0400},
446 .read = dmi_sel_raw_read,
447};
448
449static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
450{
451 int ret;
452
453 entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
454 if (!entry->child)
455 return -ENOMEM;
456 ret = kobject_init_and_add(entry->child,
457 &dmi_system_event_log_ktype,
458 &entry->kobj,
459 "system_event_log");
460 if (ret)
461 goto out_free;
462
463 ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
464 if (ret)
465 goto out_del;
466
467 return 0;
468
469out_del:
470 kobject_del(entry->child);
471out_free:
472 kfree(entry->child);
473 return ret;
474}
475
476/*************************************************
477 * Generic DMI entry support.
478 *************************************************/
479
480static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
481{
482 return sprintf(buf, "%d\n", entry->dh.length);
483}
484
485static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
486{
487 return sprintf(buf, "%d\n", entry->dh.handle);
488}
489
490static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
491{
492 return sprintf(buf, "%d\n", entry->dh.type);
493}
494
495static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
496 char *buf)
497{
498 return sprintf(buf, "%d\n", entry->instance);
499}
500
501static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
502 char *buf)
503{
504 return sprintf(buf, "%d\n", entry->position);
505}
506
507static DMI_SYSFS_ATTR(entry, length);
508static DMI_SYSFS_ATTR(entry, handle);
509static DMI_SYSFS_ATTR(entry, type);
510static DMI_SYSFS_ATTR(entry, instance);
511static DMI_SYSFS_ATTR(entry, position);
512
513static struct attribute *dmi_sysfs_entry_attrs[] = {
514 &dmi_sysfs_attr_entry_length.attr,
515 &dmi_sysfs_attr_entry_handle.attr,
516 &dmi_sysfs_attr_entry_type.attr,
517 &dmi_sysfs_attr_entry_instance.attr,
518 &dmi_sysfs_attr_entry_position.attr,
519 NULL,
520};
521ATTRIBUTE_GROUPS(dmi_sysfs_entry);
522
523static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
524 const struct dmi_header *dh,
525 void *_state)
526{
527 struct dmi_read_state *state = _state;
528 size_t entry_length;
529
530 entry_length = dmi_entry_length(dh);
531
532 return memory_read_from_buffer(state->buf, state->count,
533 &state->pos, dh, entry_length);
534}
535
536static ssize_t dmi_entry_raw_read(struct file *filp,
537 struct kobject *kobj,
538 struct bin_attribute *bin_attr,
539 char *buf, loff_t pos, size_t count)
540{
541 struct dmi_sysfs_entry *entry = to_entry(kobj);
542 struct dmi_read_state state = {
543 .buf = buf,
544 .pos = pos,
545 .count = count,
546 };
547
548 return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
549}
550
551static const struct bin_attribute dmi_entry_raw_attr = {
552 .attr = {.name = "raw", .mode = 0400},
553 .read = dmi_entry_raw_read,
554};
555
556static void dmi_sysfs_entry_release(struct kobject *kobj)
557{
558 struct dmi_sysfs_entry *entry = to_entry(kobj);
559
560 spin_lock(&entry_list_lock);
561 list_del(&entry->list);
562 spin_unlock(&entry_list_lock);
563 kfree(entry);
564}
565
566static struct kobj_type dmi_sysfs_entry_ktype = {
567 .release = dmi_sysfs_entry_release,
568 .sysfs_ops = &dmi_sysfs_attr_ops,
569 .default_groups = dmi_sysfs_entry_groups,
570};
571
572static struct kset *dmi_kset;
573
574/* Global count of all instances seen. Only for setup */
575static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];
576
577/* Global positional count of all entries seen. Only for setup */
578static int __initdata position_count;
579
580static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
581 void *_ret)
582{
583 struct dmi_sysfs_entry *entry;
584 int *ret = _ret;
585
586 /* If a previous entry saw an error, short circuit */
587 if (*ret)
588 return;
589
590 /* Allocate and register a new entry into the entries set */
591 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
592 if (!entry) {
593 *ret = -ENOMEM;
594 return;
595 }
596
597 /* Set the key */
598 memcpy(&entry->dh, dh, sizeof(*dh));
599 entry->instance = instance_counts[dh->type]++;
600 entry->position = position_count++;
601
602 entry->kobj.kset = dmi_kset;
603 *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
604 "%d-%d", dh->type, entry->instance);
605
606 if (*ret) {
607 kobject_put(&entry->kobj);
608 return;
609 }
610
611 /* Thread on the global list for cleanup */
612 spin_lock(&entry_list_lock);
613 list_add_tail(&entry->list, &entry_list);
614 spin_unlock(&entry_list_lock);
615
616 /* Handle specializations by type */
617 switch (dh->type) {
618 case DMI_ENTRY_SYSTEM_EVENT_LOG:
619 *ret = dmi_system_event_log(entry);
620 break;
621 default:
622 /* No specialization */
623 break;
624 }
625 if (*ret)
626 goto out_err;
627
628 /* Create the raw binary file to access the entry */
629 *ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
630 if (*ret)
631 goto out_err;
632
633 return;
634out_err:
635 kobject_put(entry->child);
636 kobject_put(&entry->kobj);
637 return;
638}
639
640static void cleanup_entry_list(void)
641{
642 struct dmi_sysfs_entry *entry, *next;
643
644 /* No locks, we are on our way out */
645 list_for_each_entry_safe(entry, next, &entry_list, list) {
646 kobject_put(entry->child);
647 kobject_put(&entry->kobj);
648 }
649}
650
651static int __init dmi_sysfs_init(void)
652{
653 int error;
654 int val;
655
656 if (!dmi_kobj) {
657 pr_debug("dmi-sysfs: dmi entry is absent.\n");
658 error = -ENODATA;
659 goto err;
660 }
661
662 dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
663 if (!dmi_kset) {
664 error = -ENOMEM;
665 goto err;
666 }
667
668 val = 0;
669 error = dmi_walk(dmi_sysfs_register_handle, &val);
670 if (error)
671 goto err;
672 if (val) {
673 error = val;
674 goto err;
675 }
676
677 pr_debug("dmi-sysfs: loaded.\n");
678
679 return 0;
680err:
681 cleanup_entry_list();
682 kset_unregister(dmi_kset);
683 return error;
684}
685
686/* clean up everything. */
687static void __exit dmi_sysfs_exit(void)
688{
689 pr_debug("dmi-sysfs: unloading.\n");
690 cleanup_entry_list();
691 kset_unregister(dmi_kset);
692}
693
694module_init(dmi_sysfs_init);
695module_exit(dmi_sysfs_exit);
696
697MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
698MODULE_DESCRIPTION("DMI sysfs support");
699MODULE_LICENSE("GPL");