xref: /openbmc/linux/drivers/firmware/dmi_scan.c (revision 78700c0a)
1 #include <linux/types.h>
2 #include <linux/string.h>
3 #include <linux/init.h>
4 #include <linux/module.h>
5 #include <linux/ctype.h>
6 #include <linux/dmi.h>
7 #include <linux/efi.h>
8 #include <linux/bootmem.h>
9 #include <linux/random.h>
10 #include <asm/dmi.h>
11 #include <asm/unaligned.h>
12 
13 struct kobject *dmi_kobj;
14 EXPORT_SYMBOL_GPL(dmi_kobj);
15 
16 /*
17  * DMI stands for "Desktop Management Interface".  It is part
18  * of and an antecedent to, SMBIOS, which stands for System
19  * Management BIOS.  See further: http://www.dmtf.org/standards
20  */
21 static const char dmi_empty_string[] = "        ";
22 
23 static u32 dmi_ver __initdata;
24 static u32 dmi_len;
25 static u16 dmi_num;
26 static u8 smbios_entry_point[32];
27 static int smbios_entry_point_size;
28 
29 /*
30  * Catch too early calls to dmi_check_system():
31  */
32 static int dmi_initialized;
33 
34 /* DMI system identification string used during boot */
35 static char dmi_ids_string[128] __initdata;
36 
37 static struct dmi_memdev_info {
38 	const char *device;
39 	const char *bank;
40 	u16 handle;
41 } *dmi_memdev;
42 static int dmi_memdev_nr;
43 
44 static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
45 {
46 	const u8 *bp = ((u8 *) dm) + dm->length;
47 
48 	if (s) {
49 		s--;
50 		while (s > 0 && *bp) {
51 			bp += strlen(bp) + 1;
52 			s--;
53 		}
54 
55 		if (*bp != 0) {
56 			size_t len = strlen(bp)+1;
57 			size_t cmp_len = len > 8 ? 8 : len;
58 
59 			if (!memcmp(bp, dmi_empty_string, cmp_len))
60 				return dmi_empty_string;
61 			return bp;
62 		}
63 	}
64 
65 	return "";
66 }
67 
68 static const char * __init dmi_string(const struct dmi_header *dm, u8 s)
69 {
70 	const char *bp = dmi_string_nosave(dm, s);
71 	char *str;
72 	size_t len;
73 
74 	if (bp == dmi_empty_string)
75 		return dmi_empty_string;
76 
77 	len = strlen(bp) + 1;
78 	str = dmi_alloc(len);
79 	if (str != NULL)
80 		strcpy(str, bp);
81 
82 	return str;
83 }
84 
85 /*
86  *	We have to be cautious here. We have seen BIOSes with DMI pointers
87  *	pointing to completely the wrong place for example
88  */
89 static void dmi_decode_table(u8 *buf,
90 			     void (*decode)(const struct dmi_header *, void *),
91 			     void *private_data)
92 {
93 	u8 *data = buf;
94 	int i = 0;
95 
96 	/*
97 	 * Stop when we have seen all the items the table claimed to have
98 	 * (SMBIOS < 3.0 only) OR we reach an end-of-table marker (SMBIOS
99 	 * >= 3.0 only) OR we run off the end of the table (should never
100 	 * happen but sometimes does on bogus implementations.)
101 	 */
102 	while ((!dmi_num || i < dmi_num) &&
103 	       (data - buf + sizeof(struct dmi_header)) <= dmi_len) {
104 		const struct dmi_header *dm = (const struct dmi_header *)data;
105 
106 		/*
107 		 *  We want to know the total length (formatted area and
108 		 *  strings) before decoding to make sure we won't run off the
109 		 *  table in dmi_decode or dmi_string
110 		 */
111 		data += dm->length;
112 		while ((data - buf < dmi_len - 1) && (data[0] || data[1]))
113 			data++;
114 		if (data - buf < dmi_len - 1)
115 			decode(dm, private_data);
116 
117 		data += 2;
118 		i++;
119 
120 		/*
121 		 * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
122 		 * For tables behind a 64-bit entry point, we have no item
123 		 * count and no exact table length, so stop on end-of-table
124 		 * marker. For tables behind a 32-bit entry point, we have
125 		 * seen OEM structures behind the end-of-table marker on
126 		 * some systems, so don't trust it.
127 		 */
128 		if (!dmi_num && dm->type == DMI_ENTRY_END_OF_TABLE)
129 			break;
130 	}
131 
132 	/* Trim DMI table length if needed */
133 	if (dmi_len > data - buf)
134 		dmi_len = data - buf;
135 }
136 
137 static phys_addr_t dmi_base;
138 
139 static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
140 		void *))
141 {
142 	u8 *buf;
143 	u32 orig_dmi_len = dmi_len;
144 
145 	buf = dmi_early_remap(dmi_base, orig_dmi_len);
146 	if (buf == NULL)
147 		return -1;
148 
149 	dmi_decode_table(buf, decode, NULL);
150 
151 	add_device_randomness(buf, dmi_len);
152 
153 	dmi_early_unmap(buf, orig_dmi_len);
154 	return 0;
155 }
156 
157 static int __init dmi_checksum(const u8 *buf, u8 len)
158 {
159 	u8 sum = 0;
160 	int a;
161 
162 	for (a = 0; a < len; a++)
163 		sum += buf[a];
164 
165 	return sum == 0;
166 }
167 
168 static const char *dmi_ident[DMI_STRING_MAX];
169 static LIST_HEAD(dmi_devices);
170 int dmi_available;
171 
172 /*
173  *	Save a DMI string
174  */
175 static void __init dmi_save_ident(const struct dmi_header *dm, int slot,
176 		int string)
177 {
178 	const char *d = (const char *) dm;
179 	const char *p;
180 
181 	if (dmi_ident[slot])
182 		return;
183 
184 	p = dmi_string(dm, d[string]);
185 	if (p == NULL)
186 		return;
187 
188 	dmi_ident[slot] = p;
189 }
190 
191 static void __init dmi_save_uuid(const struct dmi_header *dm, int slot,
192 		int index)
193 {
194 	const u8 *d = (u8 *) dm + index;
195 	char *s;
196 	int is_ff = 1, is_00 = 1, i;
197 
198 	if (dmi_ident[slot])
199 		return;
200 
201 	for (i = 0; i < 16 && (is_ff || is_00); i++) {
202 		if (d[i] != 0x00)
203 			is_00 = 0;
204 		if (d[i] != 0xFF)
205 			is_ff = 0;
206 	}
207 
208 	if (is_ff || is_00)
209 		return;
210 
211 	s = dmi_alloc(16*2+4+1);
212 	if (!s)
213 		return;
214 
215 	/*
216 	 * As of version 2.6 of the SMBIOS specification, the first 3 fields of
217 	 * the UUID are supposed to be little-endian encoded.  The specification
218 	 * says that this is the defacto standard.
219 	 */
220 	if (dmi_ver >= 0x020600)
221 		sprintf(s, "%pUL", d);
222 	else
223 		sprintf(s, "%pUB", d);
224 
225 	dmi_ident[slot] = s;
226 }
227 
228 static void __init dmi_save_type(const struct dmi_header *dm, int slot,
229 		int index)
230 {
231 	const u8 *d = (u8 *) dm + index;
232 	char *s;
233 
234 	if (dmi_ident[slot])
235 		return;
236 
237 	s = dmi_alloc(4);
238 	if (!s)
239 		return;
240 
241 	sprintf(s, "%u", *d & 0x7F);
242 	dmi_ident[slot] = s;
243 }
244 
245 static void __init dmi_save_one_device(int type, const char *name)
246 {
247 	struct dmi_device *dev;
248 
249 	/* No duplicate device */
250 	if (dmi_find_device(type, name, NULL))
251 		return;
252 
253 	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
254 	if (!dev)
255 		return;
256 
257 	dev->type = type;
258 	strcpy((char *)(dev + 1), name);
259 	dev->name = (char *)(dev + 1);
260 	dev->device_data = NULL;
261 	list_add(&dev->list, &dmi_devices);
262 }
263 
264 static void __init dmi_save_devices(const struct dmi_header *dm)
265 {
266 	int i, count = (dm->length - sizeof(struct dmi_header)) / 2;
267 
268 	for (i = 0; i < count; i++) {
269 		const char *d = (char *)(dm + 1) + (i * 2);
270 
271 		/* Skip disabled device */
272 		if ((*d & 0x80) == 0)
273 			continue;
274 
275 		dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
276 	}
277 }
278 
279 static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
280 {
281 	int i, count = *(u8 *)(dm + 1);
282 	struct dmi_device *dev;
283 
284 	for (i = 1; i <= count; i++) {
285 		const char *devname = dmi_string(dm, i);
286 
287 		if (devname == dmi_empty_string)
288 			continue;
289 
290 		dev = dmi_alloc(sizeof(*dev));
291 		if (!dev)
292 			break;
293 
294 		dev->type = DMI_DEV_TYPE_OEM_STRING;
295 		dev->name = devname;
296 		dev->device_data = NULL;
297 
298 		list_add(&dev->list, &dmi_devices);
299 	}
300 }
301 
302 static void __init dmi_save_ipmi_device(const struct dmi_header *dm)
303 {
304 	struct dmi_device *dev;
305 	void *data;
306 
307 	data = dmi_alloc(dm->length);
308 	if (data == NULL)
309 		return;
310 
311 	memcpy(data, dm, dm->length);
312 
313 	dev = dmi_alloc(sizeof(*dev));
314 	if (!dev)
315 		return;
316 
317 	dev->type = DMI_DEV_TYPE_IPMI;
318 	dev->name = "IPMI controller";
319 	dev->device_data = data;
320 
321 	list_add_tail(&dev->list, &dmi_devices);
322 }
323 
324 static void __init dmi_save_dev_pciaddr(int instance, int segment, int bus,
325 					int devfn, const char *name, int type)
326 {
327 	struct dmi_dev_onboard *dev;
328 
329 	/* Ignore invalid values */
330 	if (type == DMI_DEV_TYPE_DEV_SLOT &&
331 	    segment == 0xFFFF && bus == 0xFF && devfn == 0xFF)
332 		return;
333 
334 	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
335 	if (!dev)
336 		return;
337 
338 	dev->instance = instance;
339 	dev->segment = segment;
340 	dev->bus = bus;
341 	dev->devfn = devfn;
342 
343 	strcpy((char *)&dev[1], name);
344 	dev->dev.type = type;
345 	dev->dev.name = (char *)&dev[1];
346 	dev->dev.device_data = dev;
347 
348 	list_add(&dev->dev.list, &dmi_devices);
349 }
350 
351 static void __init dmi_save_extended_devices(const struct dmi_header *dm)
352 {
353 	const char *name;
354 	const u8 *d = (u8 *)dm;
355 
356 	/* Skip disabled device */
357 	if ((d[0x5] & 0x80) == 0)
358 		return;
359 
360 	name = dmi_string_nosave(dm, d[0x4]);
361 	dmi_save_dev_pciaddr(d[0x6], *(u16 *)(d + 0x7), d[0x9], d[0xA], name,
362 			     DMI_DEV_TYPE_DEV_ONBOARD);
363 	dmi_save_one_device(d[0x5] & 0x7f, name);
364 }
365 
366 static void __init dmi_save_system_slot(const struct dmi_header *dm)
367 {
368 	const u8 *d = (u8 *)dm;
369 
370 	/* Need SMBIOS 2.6+ structure */
371 	if (dm->length < 0x11)
372 		return;
373 	dmi_save_dev_pciaddr(*(u16 *)(d + 0x9), *(u16 *)(d + 0xD), d[0xF],
374 			     d[0x10], dmi_string_nosave(dm, d[0x4]),
375 			     DMI_DEV_TYPE_DEV_SLOT);
376 }
377 
378 static void __init count_mem_devices(const struct dmi_header *dm, void *v)
379 {
380 	if (dm->type != DMI_ENTRY_MEM_DEVICE)
381 		return;
382 	dmi_memdev_nr++;
383 }
384 
385 static void __init save_mem_devices(const struct dmi_header *dm, void *v)
386 {
387 	const char *d = (const char *)dm;
388 	static int nr;
389 
390 	if (dm->type != DMI_ENTRY_MEM_DEVICE)
391 		return;
392 	if (nr >= dmi_memdev_nr) {
393 		pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");
394 		return;
395 	}
396 	dmi_memdev[nr].handle = get_unaligned(&dm->handle);
397 	dmi_memdev[nr].device = dmi_string(dm, d[0x10]);
398 	dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
399 	nr++;
400 }
401 
402 void __init dmi_memdev_walk(void)
403 {
404 	if (!dmi_available)
405 		return;
406 
407 	if (dmi_walk_early(count_mem_devices) == 0 && dmi_memdev_nr) {
408 		dmi_memdev = dmi_alloc(sizeof(*dmi_memdev) * dmi_memdev_nr);
409 		if (dmi_memdev)
410 			dmi_walk_early(save_mem_devices);
411 	}
412 }
413 
414 /*
415  *	Process a DMI table entry. Right now all we care about are the BIOS
416  *	and machine entries. For 2.5 we should pull the smbus controller info
417  *	out of here.
418  */
419 static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
420 {
421 	switch (dm->type) {
422 	case 0:		/* BIOS Information */
423 		dmi_save_ident(dm, DMI_BIOS_VENDOR, 4);
424 		dmi_save_ident(dm, DMI_BIOS_VERSION, 5);
425 		dmi_save_ident(dm, DMI_BIOS_DATE, 8);
426 		break;
427 	case 1:		/* System Information */
428 		dmi_save_ident(dm, DMI_SYS_VENDOR, 4);
429 		dmi_save_ident(dm, DMI_PRODUCT_NAME, 5);
430 		dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
431 		dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
432 		dmi_save_uuid(dm, DMI_PRODUCT_UUID, 8);
433 		break;
434 	case 2:		/* Base Board Information */
435 		dmi_save_ident(dm, DMI_BOARD_VENDOR, 4);
436 		dmi_save_ident(dm, DMI_BOARD_NAME, 5);
437 		dmi_save_ident(dm, DMI_BOARD_VERSION, 6);
438 		dmi_save_ident(dm, DMI_BOARD_SERIAL, 7);
439 		dmi_save_ident(dm, DMI_BOARD_ASSET_TAG, 8);
440 		break;
441 	case 3:		/* Chassis Information */
442 		dmi_save_ident(dm, DMI_CHASSIS_VENDOR, 4);
443 		dmi_save_type(dm, DMI_CHASSIS_TYPE, 5);
444 		dmi_save_ident(dm, DMI_CHASSIS_VERSION, 6);
445 		dmi_save_ident(dm, DMI_CHASSIS_SERIAL, 7);
446 		dmi_save_ident(dm, DMI_CHASSIS_ASSET_TAG, 8);
447 		break;
448 	case 9:		/* System Slots */
449 		dmi_save_system_slot(dm);
450 		break;
451 	case 10:	/* Onboard Devices Information */
452 		dmi_save_devices(dm);
453 		break;
454 	case 11:	/* OEM Strings */
455 		dmi_save_oem_strings_devices(dm);
456 		break;
457 	case 38:	/* IPMI Device Information */
458 		dmi_save_ipmi_device(dm);
459 		break;
460 	case 41:	/* Onboard Devices Extended Information */
461 		dmi_save_extended_devices(dm);
462 	}
463 }
464 
465 static int __init print_filtered(char *buf, size_t len, const char *info)
466 {
467 	int c = 0;
468 	const char *p;
469 
470 	if (!info)
471 		return c;
472 
473 	for (p = info; *p; p++)
474 		if (isprint(*p))
475 			c += scnprintf(buf + c, len - c, "%c", *p);
476 		else
477 			c += scnprintf(buf + c, len - c, "\\x%02x", *p & 0xff);
478 	return c;
479 }
480 
481 static void __init dmi_format_ids(char *buf, size_t len)
482 {
483 	int c = 0;
484 	const char *board;	/* Board Name is optional */
485 
486 	c += print_filtered(buf + c, len - c,
487 			    dmi_get_system_info(DMI_SYS_VENDOR));
488 	c += scnprintf(buf + c, len - c, " ");
489 	c += print_filtered(buf + c, len - c,
490 			    dmi_get_system_info(DMI_PRODUCT_NAME));
491 
492 	board = dmi_get_system_info(DMI_BOARD_NAME);
493 	if (board) {
494 		c += scnprintf(buf + c, len - c, "/");
495 		c += print_filtered(buf + c, len - c, board);
496 	}
497 	c += scnprintf(buf + c, len - c, ", BIOS ");
498 	c += print_filtered(buf + c, len - c,
499 			    dmi_get_system_info(DMI_BIOS_VERSION));
500 	c += scnprintf(buf + c, len - c, " ");
501 	c += print_filtered(buf + c, len - c,
502 			    dmi_get_system_info(DMI_BIOS_DATE));
503 }
504 
505 /*
506  * Check for DMI/SMBIOS headers in the system firmware image.  Any
507  * SMBIOS header must start 16 bytes before the DMI header, so take a
508  * 32 byte buffer and check for DMI at offset 16 and SMBIOS at offset
509  * 0.  If the DMI header is present, set dmi_ver accordingly (SMBIOS
510  * takes precedence) and return 0.  Otherwise return 1.
511  */
512 static int __init dmi_present(const u8 *buf)
513 {
514 	u32 smbios_ver;
515 
516 	if (memcmp(buf, "_SM_", 4) == 0 &&
517 	    buf[5] < 32 && dmi_checksum(buf, buf[5])) {
518 		smbios_ver = get_unaligned_be16(buf + 6);
519 		smbios_entry_point_size = buf[5];
520 		memcpy(smbios_entry_point, buf, smbios_entry_point_size);
521 
522 		/* Some BIOS report weird SMBIOS version, fix that up */
523 		switch (smbios_ver) {
524 		case 0x021F:
525 		case 0x0221:
526 			pr_debug("SMBIOS version fixup (2.%d->2.%d)\n",
527 				 smbios_ver & 0xFF, 3);
528 			smbios_ver = 0x0203;
529 			break;
530 		case 0x0233:
531 			pr_debug("SMBIOS version fixup (2.%d->2.%d)\n", 51, 6);
532 			smbios_ver = 0x0206;
533 			break;
534 		}
535 	} else {
536 		smbios_ver = 0;
537 	}
538 
539 	buf += 16;
540 
541 	if (memcmp(buf, "_DMI_", 5) == 0 && dmi_checksum(buf, 15)) {
542 		if (smbios_ver)
543 			dmi_ver = smbios_ver;
544 		else
545 			dmi_ver = (buf[14] & 0xF0) << 4 | (buf[14] & 0x0F);
546 		dmi_ver <<= 8;
547 		dmi_num = get_unaligned_le16(buf + 12);
548 		dmi_len = get_unaligned_le16(buf + 6);
549 		dmi_base = get_unaligned_le32(buf + 8);
550 
551 		if (dmi_walk_early(dmi_decode) == 0) {
552 			if (smbios_ver) {
553 				pr_info("SMBIOS %d.%d present.\n",
554 					dmi_ver >> 16, (dmi_ver >> 8) & 0xFF);
555 			} else {
556 				smbios_entry_point_size = 15;
557 				memcpy(smbios_entry_point, buf,
558 				       smbios_entry_point_size);
559 				pr_info("Legacy DMI %d.%d present.\n",
560 					dmi_ver >> 16, (dmi_ver >> 8) & 0xFF);
561 			}
562 			dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
563 			printk(KERN_DEBUG "DMI: %s\n", dmi_ids_string);
564 			return 0;
565 		}
566 	}
567 
568 	return 1;
569 }
570 
571 /*
572  * Check for the SMBIOS 3.0 64-bit entry point signature. Unlike the legacy
573  * 32-bit entry point, there is no embedded DMI header (_DMI_) in here.
574  */
575 static int __init dmi_smbios3_present(const u8 *buf)
576 {
577 	if (memcmp(buf, "_SM3_", 5) == 0 &&
578 	    buf[6] < 32 && dmi_checksum(buf, buf[6])) {
579 		dmi_ver = get_unaligned_be32(buf + 6) & 0xFFFFFF;
580 		dmi_num = 0;			/* No longer specified */
581 		dmi_len = get_unaligned_le32(buf + 12);
582 		dmi_base = get_unaligned_le64(buf + 16);
583 		smbios_entry_point_size = buf[6];
584 		memcpy(smbios_entry_point, buf, smbios_entry_point_size);
585 
586 		if (dmi_walk_early(dmi_decode) == 0) {
587 			pr_info("SMBIOS %d.%d.%d present.\n",
588 				dmi_ver >> 16, (dmi_ver >> 8) & 0xFF,
589 				dmi_ver & 0xFF);
590 			dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
591 			pr_debug("DMI: %s\n", dmi_ids_string);
592 			return 0;
593 		}
594 	}
595 	return 1;
596 }
597 
598 void __init dmi_scan_machine(void)
599 {
600 	char __iomem *p, *q;
601 	char buf[32];
602 
603 	if (efi_enabled(EFI_CONFIG_TABLES)) {
604 		/*
605 		 * According to the DMTF SMBIOS reference spec v3.0.0, it is
606 		 * allowed to define both the 64-bit entry point (smbios3) and
607 		 * the 32-bit entry point (smbios), in which case they should
608 		 * either both point to the same SMBIOS structure table, or the
609 		 * table pointed to by the 64-bit entry point should contain a
610 		 * superset of the table contents pointed to by the 32-bit entry
611 		 * point (section 5.2)
612 		 * This implies that the 64-bit entry point should have
613 		 * precedence if it is defined and supported by the OS. If we
614 		 * have the 64-bit entry point, but fail to decode it, fall
615 		 * back to the legacy one (if available)
616 		 */
617 		if (efi.smbios3 != EFI_INVALID_TABLE_ADDR) {
618 			p = dmi_early_remap(efi.smbios3, 32);
619 			if (p == NULL)
620 				goto error;
621 			memcpy_fromio(buf, p, 32);
622 			dmi_early_unmap(p, 32);
623 
624 			if (!dmi_smbios3_present(buf)) {
625 				dmi_available = 1;
626 				goto out;
627 			}
628 		}
629 		if (efi.smbios == EFI_INVALID_TABLE_ADDR)
630 			goto error;
631 
632 		/* This is called as a core_initcall() because it isn't
633 		 * needed during early boot.  This also means we can
634 		 * iounmap the space when we're done with it.
635 		 */
636 		p = dmi_early_remap(efi.smbios, 32);
637 		if (p == NULL)
638 			goto error;
639 		memcpy_fromio(buf, p, 32);
640 		dmi_early_unmap(p, 32);
641 
642 		if (!dmi_present(buf)) {
643 			dmi_available = 1;
644 			goto out;
645 		}
646 	} else if (IS_ENABLED(CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK)) {
647 		p = dmi_early_remap(0xF0000, 0x10000);
648 		if (p == NULL)
649 			goto error;
650 
651 		/*
652 		 * Iterate over all possible DMI header addresses q.
653 		 * Maintain the 32 bytes around q in buf.  On the
654 		 * first iteration, substitute zero for the
655 		 * out-of-range bytes so there is no chance of falsely
656 		 * detecting an SMBIOS header.
657 		 */
658 		memset(buf, 0, 16);
659 		for (q = p; q < p + 0x10000; q += 16) {
660 			memcpy_fromio(buf + 16, q, 16);
661 			if (!dmi_smbios3_present(buf) || !dmi_present(buf)) {
662 				dmi_available = 1;
663 				dmi_early_unmap(p, 0x10000);
664 				goto out;
665 			}
666 			memcpy(buf, buf + 16, 16);
667 		}
668 		dmi_early_unmap(p, 0x10000);
669 	}
670  error:
671 	pr_info("DMI not present or invalid.\n");
672  out:
673 	dmi_initialized = 1;
674 }
675 
676 static ssize_t raw_table_read(struct file *file, struct kobject *kobj,
677 			      struct bin_attribute *attr, char *buf,
678 			      loff_t pos, size_t count)
679 {
680 	memcpy(buf, attr->private + pos, count);
681 	return count;
682 }
683 
684 static BIN_ATTR(smbios_entry_point, S_IRUSR, raw_table_read, NULL, 0);
685 static BIN_ATTR(DMI, S_IRUSR, raw_table_read, NULL, 0);
686 
687 static int __init dmi_init(void)
688 {
689 	struct kobject *tables_kobj;
690 	u8 *dmi_table;
691 	int ret = -ENOMEM;
692 
693 	if (!dmi_available) {
694 		ret = -ENODATA;
695 		goto err;
696 	}
697 
698 	/*
699 	 * Set up dmi directory at /sys/firmware/dmi. This entry should stay
700 	 * even after farther error, as it can be used by other modules like
701 	 * dmi-sysfs.
702 	 */
703 	dmi_kobj = kobject_create_and_add("dmi", firmware_kobj);
704 	if (!dmi_kobj)
705 		goto err;
706 
707 	tables_kobj = kobject_create_and_add("tables", dmi_kobj);
708 	if (!tables_kobj)
709 		goto err;
710 
711 	dmi_table = dmi_remap(dmi_base, dmi_len);
712 	if (!dmi_table)
713 		goto err_tables;
714 
715 	bin_attr_smbios_entry_point.size = smbios_entry_point_size;
716 	bin_attr_smbios_entry_point.private = smbios_entry_point;
717 	ret = sysfs_create_bin_file(tables_kobj, &bin_attr_smbios_entry_point);
718 	if (ret)
719 		goto err_unmap;
720 
721 	bin_attr_DMI.size = dmi_len;
722 	bin_attr_DMI.private = dmi_table;
723 	ret = sysfs_create_bin_file(tables_kobj, &bin_attr_DMI);
724 	if (!ret)
725 		return 0;
726 
727 	sysfs_remove_bin_file(tables_kobj,
728 			      &bin_attr_smbios_entry_point);
729  err_unmap:
730 	dmi_unmap(dmi_table);
731  err_tables:
732 	kobject_del(tables_kobj);
733 	kobject_put(tables_kobj);
734  err:
735 	pr_err("dmi: Firmware registration failed.\n");
736 
737 	return ret;
738 }
739 subsys_initcall(dmi_init);
740 
741 /**
742  * dmi_set_dump_stack_arch_desc - set arch description for dump_stack()
743  *
744  * Invoke dump_stack_set_arch_desc() with DMI system information so that
745  * DMI identifiers are printed out on task dumps.  Arch boot code should
746  * call this function after dmi_scan_machine() if it wants to print out DMI
747  * identifiers on task dumps.
748  */
749 void __init dmi_set_dump_stack_arch_desc(void)
750 {
751 	dump_stack_set_arch_desc("%s", dmi_ids_string);
752 }
753 
754 /**
755  *	dmi_matches - check if dmi_system_id structure matches system DMI data
756  *	@dmi: pointer to the dmi_system_id structure to check
757  */
758 static bool dmi_matches(const struct dmi_system_id *dmi)
759 {
760 	int i;
761 
762 	WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");
763 
764 	for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
765 		int s = dmi->matches[i].slot;
766 		if (s == DMI_NONE)
767 			break;
768 		if (dmi_ident[s]) {
769 			if (!dmi->matches[i].exact_match &&
770 			    strstr(dmi_ident[s], dmi->matches[i].substr))
771 				continue;
772 			else if (dmi->matches[i].exact_match &&
773 				 !strcmp(dmi_ident[s], dmi->matches[i].substr))
774 				continue;
775 		}
776 
777 		/* No match */
778 		return false;
779 	}
780 	return true;
781 }
782 
783 /**
784  *	dmi_is_end_of_table - check for end-of-table marker
785  *	@dmi: pointer to the dmi_system_id structure to check
786  */
787 static bool dmi_is_end_of_table(const struct dmi_system_id *dmi)
788 {
789 	return dmi->matches[0].slot == DMI_NONE;
790 }
791 
792 /**
793  *	dmi_check_system - check system DMI data
794  *	@list: array of dmi_system_id structures to match against
795  *		All non-null elements of the list must match
796  *		their slot's (field index's) data (i.e., each
797  *		list string must be a substring of the specified
798  *		DMI slot's string data) to be considered a
799  *		successful match.
800  *
801  *	Walk the blacklist table running matching functions until someone
802  *	returns non zero or we hit the end. Callback function is called for
803  *	each successful match. Returns the number of matches.
804  */
805 int dmi_check_system(const struct dmi_system_id *list)
806 {
807 	int count = 0;
808 	const struct dmi_system_id *d;
809 
810 	for (d = list; !dmi_is_end_of_table(d); d++)
811 		if (dmi_matches(d)) {
812 			count++;
813 			if (d->callback && d->callback(d))
814 				break;
815 		}
816 
817 	return count;
818 }
819 EXPORT_SYMBOL(dmi_check_system);
820 
821 /**
822  *	dmi_first_match - find dmi_system_id structure matching system DMI data
823  *	@list: array of dmi_system_id structures to match against
824  *		All non-null elements of the list must match
825  *		their slot's (field index's) data (i.e., each
826  *		list string must be a substring of the specified
827  *		DMI slot's string data) to be considered a
828  *		successful match.
829  *
830  *	Walk the blacklist table until the first match is found.  Return the
831  *	pointer to the matching entry or NULL if there's no match.
832  */
833 const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
834 {
835 	const struct dmi_system_id *d;
836 
837 	for (d = list; !dmi_is_end_of_table(d); d++)
838 		if (dmi_matches(d))
839 			return d;
840 
841 	return NULL;
842 }
843 EXPORT_SYMBOL(dmi_first_match);
844 
845 /**
846  *	dmi_get_system_info - return DMI data value
847  *	@field: data index (see enum dmi_field)
848  *
849  *	Returns one DMI data value, can be used to perform
850  *	complex DMI data checks.
851  */
852 const char *dmi_get_system_info(int field)
853 {
854 	return dmi_ident[field];
855 }
856 EXPORT_SYMBOL(dmi_get_system_info);
857 
858 /**
859  * dmi_name_in_serial - Check if string is in the DMI product serial information
860  * @str: string to check for
861  */
862 int dmi_name_in_serial(const char *str)
863 {
864 	int f = DMI_PRODUCT_SERIAL;
865 	if (dmi_ident[f] && strstr(dmi_ident[f], str))
866 		return 1;
867 	return 0;
868 }
869 
870 /**
871  *	dmi_name_in_vendors - Check if string is in the DMI system or board vendor name
872  *	@str: Case sensitive Name
873  */
874 int dmi_name_in_vendors(const char *str)
875 {
876 	static int fields[] = { DMI_SYS_VENDOR, DMI_BOARD_VENDOR, DMI_NONE };
877 	int i;
878 	for (i = 0; fields[i] != DMI_NONE; i++) {
879 		int f = fields[i];
880 		if (dmi_ident[f] && strstr(dmi_ident[f], str))
881 			return 1;
882 	}
883 	return 0;
884 }
885 EXPORT_SYMBOL(dmi_name_in_vendors);
886 
887 /**
888  *	dmi_find_device - find onboard device by type/name
889  *	@type: device type or %DMI_DEV_TYPE_ANY to match all device types
890  *	@name: device name string or %NULL to match all
891  *	@from: previous device found in search, or %NULL for new search.
892  *
893  *	Iterates through the list of known onboard devices. If a device is
894  *	found with a matching @type and @name, a pointer to its device
895  *	structure is returned.  Otherwise, %NULL is returned.
896  *	A new search is initiated by passing %NULL as the @from argument.
897  *	If @from is not %NULL, searches continue from next device.
898  */
899 const struct dmi_device *dmi_find_device(int type, const char *name,
900 				    const struct dmi_device *from)
901 {
902 	const struct list_head *head = from ? &from->list : &dmi_devices;
903 	struct list_head *d;
904 
905 	for (d = head->next; d != &dmi_devices; d = d->next) {
906 		const struct dmi_device *dev =
907 			list_entry(d, struct dmi_device, list);
908 
909 		if (((type == DMI_DEV_TYPE_ANY) || (dev->type == type)) &&
910 		    ((name == NULL) || (strcmp(dev->name, name) == 0)))
911 			return dev;
912 	}
913 
914 	return NULL;
915 }
916 EXPORT_SYMBOL(dmi_find_device);
917 
918 /**
919  *	dmi_get_date - parse a DMI date
920  *	@field:	data index (see enum dmi_field)
921  *	@yearp: optional out parameter for the year
922  *	@monthp: optional out parameter for the month
923  *	@dayp: optional out parameter for the day
924  *
925  *	The date field is assumed to be in the form resembling
926  *	[mm[/dd]]/yy[yy] and the result is stored in the out
927  *	parameters any or all of which can be omitted.
928  *
929  *	If the field doesn't exist, all out parameters are set to zero
930  *	and false is returned.  Otherwise, true is returned with any
931  *	invalid part of date set to zero.
932  *
933  *	On return, year, month and day are guaranteed to be in the
934  *	range of [0,9999], [0,12] and [0,31] respectively.
935  */
936 bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
937 {
938 	int year = 0, month = 0, day = 0;
939 	bool exists;
940 	const char *s, *y;
941 	char *e;
942 
943 	s = dmi_get_system_info(field);
944 	exists = s;
945 	if (!exists)
946 		goto out;
947 
948 	/*
949 	 * Determine year first.  We assume the date string resembles
950 	 * mm/dd/yy[yy] but the original code extracted only the year
951 	 * from the end.  Keep the behavior in the spirit of no
952 	 * surprises.
953 	 */
954 	y = strrchr(s, '/');
955 	if (!y)
956 		goto out;
957 
958 	y++;
959 	year = simple_strtoul(y, &e, 10);
960 	if (y != e && year < 100) {	/* 2-digit year */
961 		year += 1900;
962 		if (year < 1996)	/* no dates < spec 1.0 */
963 			year += 100;
964 	}
965 	if (year > 9999)		/* year should fit in %04d */
966 		year = 0;
967 
968 	/* parse the mm and dd */
969 	month = simple_strtoul(s, &e, 10);
970 	if (s == e || *e != '/' || !month || month > 12) {
971 		month = 0;
972 		goto out;
973 	}
974 
975 	s = e + 1;
976 	day = simple_strtoul(s, &e, 10);
977 	if (s == y || s == e || *e != '/' || day > 31)
978 		day = 0;
979 out:
980 	if (yearp)
981 		*yearp = year;
982 	if (monthp)
983 		*monthp = month;
984 	if (dayp)
985 		*dayp = day;
986 	return exists;
987 }
988 EXPORT_SYMBOL(dmi_get_date);
989 
990 /**
991  *	dmi_walk - Walk the DMI table and get called back for every record
992  *	@decode: Callback function
993  *	@private_data: Private data to be passed to the callback function
994  *
995  *	Returns -1 when the DMI table can't be reached, 0 on success.
996  */
997 int dmi_walk(void (*decode)(const struct dmi_header *, void *),
998 	     void *private_data)
999 {
1000 	u8 *buf;
1001 
1002 	if (!dmi_available)
1003 		return -1;
1004 
1005 	buf = dmi_remap(dmi_base, dmi_len);
1006 	if (buf == NULL)
1007 		return -1;
1008 
1009 	dmi_decode_table(buf, decode, private_data);
1010 
1011 	dmi_unmap(buf);
1012 	return 0;
1013 }
1014 EXPORT_SYMBOL_GPL(dmi_walk);
1015 
1016 /**
1017  * dmi_match - compare a string to the dmi field (if exists)
1018  * @f: DMI field identifier
1019  * @str: string to compare the DMI field to
1020  *
1021  * Returns true if the requested field equals to the str (including NULL).
1022  */
1023 bool dmi_match(enum dmi_field f, const char *str)
1024 {
1025 	const char *info = dmi_get_system_info(f);
1026 
1027 	if (info == NULL || str == NULL)
1028 		return info == str;
1029 
1030 	return !strcmp(info, str);
1031 }
1032 EXPORT_SYMBOL_GPL(dmi_match);
1033 
1034 void dmi_memdev_name(u16 handle, const char **bank, const char **device)
1035 {
1036 	int n;
1037 
1038 	if (dmi_memdev == NULL)
1039 		return;
1040 
1041 	for (n = 0; n < dmi_memdev_nr; n++) {
1042 		if (handle == dmi_memdev[n].handle) {
1043 			*bank = dmi_memdev[n].bank;
1044 			*device = dmi_memdev[n].device;
1045 			break;
1046 		}
1047 	}
1048 }
1049 EXPORT_SYMBOL_GPL(dmi_memdev_name);
1050