xref: /linux/drivers/firmware/dmi_scan.c (revision e3e29f990cc77c5b23280c77275812a3f010cc41)
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 /*
14  * DMI stands for "Desktop Management Interface".  It is part
15  * of and an antecedent to, SMBIOS, which stands for System
16  * Management BIOS.  See further: http://www.dmtf.org/standards
17  */
18 static const char dmi_empty_string[] = "        ";
19 
20 static u16 __initdata dmi_ver;
21 /*
22  * Catch too early calls to dmi_check_system():
23  */
24 static int dmi_initialized;
25 
26 /* DMI system identification string used during boot */
27 static char dmi_ids_string[128] __initdata;
28 
29 static struct dmi_memdev_info {
30 	const char *device;
31 	const char *bank;
32 	u16 handle;
33 } *dmi_memdev;
34 static int dmi_memdev_nr;
35 
36 static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
37 {
38 	const u8 *bp = ((u8 *) dm) + dm->length;
39 
40 	if (s) {
41 		s--;
42 		while (s > 0 && *bp) {
43 			bp += strlen(bp) + 1;
44 			s--;
45 		}
46 
47 		if (*bp != 0) {
48 			size_t len = strlen(bp)+1;
49 			size_t cmp_len = len > 8 ? 8 : len;
50 
51 			if (!memcmp(bp, dmi_empty_string, cmp_len))
52 				return dmi_empty_string;
53 			return bp;
54 		}
55 	}
56 
57 	return "";
58 }
59 
60 static const char * __init dmi_string(const struct dmi_header *dm, u8 s)
61 {
62 	const char *bp = dmi_string_nosave(dm, s);
63 	char *str;
64 	size_t len;
65 
66 	if (bp == dmi_empty_string)
67 		return dmi_empty_string;
68 
69 	len = strlen(bp) + 1;
70 	str = dmi_alloc(len);
71 	if (str != NULL)
72 		strcpy(str, bp);
73 
74 	return str;
75 }
76 
77 /*
78  *	We have to be cautious here. We have seen BIOSes with DMI pointers
79  *	pointing to completely the wrong place for example
80  */
81 static void dmi_table(u8 *buf, u32 len, int num,
82 		      void (*decode)(const struct dmi_header *, void *),
83 		      void *private_data)
84 {
85 	u8 *data = buf;
86 	int i = 0;
87 
88 	/*
89 	 * Stop when we have seen all the items the table claimed to have
90 	 * (SMBIOS < 3.0 only) OR we reach an end-of-table marker OR we run
91 	 * off the end of the table (should never happen but sometimes does
92 	 * on bogus implementations.)
93 	 */
94 	while ((!num || i < num) &&
95 	       (data - buf + sizeof(struct dmi_header)) <= len) {
96 		const struct dmi_header *dm = (const struct dmi_header *)data;
97 
98 		/*
99 		 *  We want to know the total length (formatted area and
100 		 *  strings) before decoding to make sure we won't run off the
101 		 *  table in dmi_decode or dmi_string
102 		 */
103 		data += dm->length;
104 		while ((data - buf < len - 1) && (data[0] || data[1]))
105 			data++;
106 		if (data - buf < len - 1)
107 			decode(dm, private_data);
108 
109 		/*
110 		 * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
111 		 */
112 		if (dm->type == DMI_ENTRY_END_OF_TABLE)
113 			break;
114 
115 		data += 2;
116 		i++;
117 	}
118 }
119 
120 static phys_addr_t dmi_base;
121 static u32 dmi_len;
122 static u16 dmi_num;
123 
124 static int __init dmi_walk_early(void (*decode)(const struct dmi_header *,
125 		void *))
126 {
127 	u8 *buf;
128 
129 	buf = dmi_early_remap(dmi_base, dmi_len);
130 	if (buf == NULL)
131 		return -1;
132 
133 	dmi_table(buf, dmi_len, dmi_num, decode, NULL);
134 
135 	add_device_randomness(buf, dmi_len);
136 
137 	dmi_early_unmap(buf, dmi_len);
138 	return 0;
139 }
140 
141 static int __init dmi_checksum(const u8 *buf, u8 len)
142 {
143 	u8 sum = 0;
144 	int a;
145 
146 	for (a = 0; a < len; a++)
147 		sum += buf[a];
148 
149 	return sum == 0;
150 }
151 
152 static const char *dmi_ident[DMI_STRING_MAX];
153 static LIST_HEAD(dmi_devices);
154 int dmi_available;
155 
156 /*
157  *	Save a DMI string
158  */
159 static void __init dmi_save_ident(const struct dmi_header *dm, int slot,
160 		int string)
161 {
162 	const char *d = (const char *) dm;
163 	const char *p;
164 
165 	if (dmi_ident[slot])
166 		return;
167 
168 	p = dmi_string(dm, d[string]);
169 	if (p == NULL)
170 		return;
171 
172 	dmi_ident[slot] = p;
173 }
174 
175 static void __init dmi_save_uuid(const struct dmi_header *dm, int slot,
176 		int index)
177 {
178 	const u8 *d = (u8 *) dm + index;
179 	char *s;
180 	int is_ff = 1, is_00 = 1, i;
181 
182 	if (dmi_ident[slot])
183 		return;
184 
185 	for (i = 0; i < 16 && (is_ff || is_00); i++) {
186 		if (d[i] != 0x00)
187 			is_00 = 0;
188 		if (d[i] != 0xFF)
189 			is_ff = 0;
190 	}
191 
192 	if (is_ff || is_00)
193 		return;
194 
195 	s = dmi_alloc(16*2+4+1);
196 	if (!s)
197 		return;
198 
199 	/*
200 	 * As of version 2.6 of the SMBIOS specification, the first 3 fields of
201 	 * the UUID are supposed to be little-endian encoded.  The specification
202 	 * says that this is the defacto standard.
203 	 */
204 	if (dmi_ver >= 0x0206)
205 		sprintf(s, "%pUL", d);
206 	else
207 		sprintf(s, "%pUB", d);
208 
209 	dmi_ident[slot] = s;
210 }
211 
212 static void __init dmi_save_type(const struct dmi_header *dm, int slot,
213 		int index)
214 {
215 	const u8 *d = (u8 *) dm + index;
216 	char *s;
217 
218 	if (dmi_ident[slot])
219 		return;
220 
221 	s = dmi_alloc(4);
222 	if (!s)
223 		return;
224 
225 	sprintf(s, "%u", *d & 0x7F);
226 	dmi_ident[slot] = s;
227 }
228 
229 static void __init dmi_save_one_device(int type, const char *name)
230 {
231 	struct dmi_device *dev;
232 
233 	/* No duplicate device */
234 	if (dmi_find_device(type, name, NULL))
235 		return;
236 
237 	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
238 	if (!dev)
239 		return;
240 
241 	dev->type = type;
242 	strcpy((char *)(dev + 1), name);
243 	dev->name = (char *)(dev + 1);
244 	dev->device_data = NULL;
245 	list_add(&dev->list, &dmi_devices);
246 }
247 
248 static void __init dmi_save_devices(const struct dmi_header *dm)
249 {
250 	int i, count = (dm->length - sizeof(struct dmi_header)) / 2;
251 
252 	for (i = 0; i < count; i++) {
253 		const char *d = (char *)(dm + 1) + (i * 2);
254 
255 		/* Skip disabled device */
256 		if ((*d & 0x80) == 0)
257 			continue;
258 
259 		dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
260 	}
261 }
262 
263 static void __init dmi_save_oem_strings_devices(const struct dmi_header *dm)
264 {
265 	int i, count = *(u8 *)(dm + 1);
266 	struct dmi_device *dev;
267 
268 	for (i = 1; i <= count; i++) {
269 		const char *devname = dmi_string(dm, i);
270 
271 		if (devname == dmi_empty_string)
272 			continue;
273 
274 		dev = dmi_alloc(sizeof(*dev));
275 		if (!dev)
276 			break;
277 
278 		dev->type = DMI_DEV_TYPE_OEM_STRING;
279 		dev->name = devname;
280 		dev->device_data = NULL;
281 
282 		list_add(&dev->list, &dmi_devices);
283 	}
284 }
285 
286 static void __init dmi_save_ipmi_device(const struct dmi_header *dm)
287 {
288 	struct dmi_device *dev;
289 	void *data;
290 
291 	data = dmi_alloc(dm->length);
292 	if (data == NULL)
293 		return;
294 
295 	memcpy(data, dm, dm->length);
296 
297 	dev = dmi_alloc(sizeof(*dev));
298 	if (!dev)
299 		return;
300 
301 	dev->type = DMI_DEV_TYPE_IPMI;
302 	dev->name = "IPMI controller";
303 	dev->device_data = data;
304 
305 	list_add_tail(&dev->list, &dmi_devices);
306 }
307 
308 static void __init dmi_save_dev_onboard(int instance, int segment, int bus,
309 					int devfn, const char *name)
310 {
311 	struct dmi_dev_onboard *onboard_dev;
312 
313 	onboard_dev = dmi_alloc(sizeof(*onboard_dev) + strlen(name) + 1);
314 	if (!onboard_dev)
315 		return;
316 
317 	onboard_dev->instance = instance;
318 	onboard_dev->segment = segment;
319 	onboard_dev->bus = bus;
320 	onboard_dev->devfn = devfn;
321 
322 	strcpy((char *)&onboard_dev[1], name);
323 	onboard_dev->dev.type = DMI_DEV_TYPE_DEV_ONBOARD;
324 	onboard_dev->dev.name = (char *)&onboard_dev[1];
325 	onboard_dev->dev.device_data = onboard_dev;
326 
327 	list_add(&onboard_dev->dev.list, &dmi_devices);
328 }
329 
330 static void __init dmi_save_extended_devices(const struct dmi_header *dm)
331 {
332 	const u8 *d = (u8 *) dm + 5;
333 
334 	/* Skip disabled device */
335 	if ((*d & 0x80) == 0)
336 		return;
337 
338 	dmi_save_dev_onboard(*(d+1), *(u16 *)(d+2), *(d+4), *(d+5),
339 			     dmi_string_nosave(dm, *(d-1)));
340 	dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
341 }
342 
343 static void __init count_mem_devices(const struct dmi_header *dm, void *v)
344 {
345 	if (dm->type != DMI_ENTRY_MEM_DEVICE)
346 		return;
347 	dmi_memdev_nr++;
348 }
349 
350 static void __init save_mem_devices(const struct dmi_header *dm, void *v)
351 {
352 	const char *d = (const char *)dm;
353 	static int nr;
354 
355 	if (dm->type != DMI_ENTRY_MEM_DEVICE)
356 		return;
357 	if (nr >= dmi_memdev_nr) {
358 		pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");
359 		return;
360 	}
361 	dmi_memdev[nr].handle = get_unaligned(&dm->handle);
362 	dmi_memdev[nr].device = dmi_string(dm, d[0x10]);
363 	dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
364 	nr++;
365 }
366 
367 void __init dmi_memdev_walk(void)
368 {
369 	if (!dmi_available)
370 		return;
371 
372 	if (dmi_walk_early(count_mem_devices) == 0 && dmi_memdev_nr) {
373 		dmi_memdev = dmi_alloc(sizeof(*dmi_memdev) * dmi_memdev_nr);
374 		if (dmi_memdev)
375 			dmi_walk_early(save_mem_devices);
376 	}
377 }
378 
379 /*
380  *	Process a DMI table entry. Right now all we care about are the BIOS
381  *	and machine entries. For 2.5 we should pull the smbus controller info
382  *	out of here.
383  */
384 static void __init dmi_decode(const struct dmi_header *dm, void *dummy)
385 {
386 	switch (dm->type) {
387 	case 0:		/* BIOS Information */
388 		dmi_save_ident(dm, DMI_BIOS_VENDOR, 4);
389 		dmi_save_ident(dm, DMI_BIOS_VERSION, 5);
390 		dmi_save_ident(dm, DMI_BIOS_DATE, 8);
391 		break;
392 	case 1:		/* System Information */
393 		dmi_save_ident(dm, DMI_SYS_VENDOR, 4);
394 		dmi_save_ident(dm, DMI_PRODUCT_NAME, 5);
395 		dmi_save_ident(dm, DMI_PRODUCT_VERSION, 6);
396 		dmi_save_ident(dm, DMI_PRODUCT_SERIAL, 7);
397 		dmi_save_uuid(dm, DMI_PRODUCT_UUID, 8);
398 		break;
399 	case 2:		/* Base Board Information */
400 		dmi_save_ident(dm, DMI_BOARD_VENDOR, 4);
401 		dmi_save_ident(dm, DMI_BOARD_NAME, 5);
402 		dmi_save_ident(dm, DMI_BOARD_VERSION, 6);
403 		dmi_save_ident(dm, DMI_BOARD_SERIAL, 7);
404 		dmi_save_ident(dm, DMI_BOARD_ASSET_TAG, 8);
405 		break;
406 	case 3:		/* Chassis Information */
407 		dmi_save_ident(dm, DMI_CHASSIS_VENDOR, 4);
408 		dmi_save_type(dm, DMI_CHASSIS_TYPE, 5);
409 		dmi_save_ident(dm, DMI_CHASSIS_VERSION, 6);
410 		dmi_save_ident(dm, DMI_CHASSIS_SERIAL, 7);
411 		dmi_save_ident(dm, DMI_CHASSIS_ASSET_TAG, 8);
412 		break;
413 	case 10:	/* Onboard Devices Information */
414 		dmi_save_devices(dm);
415 		break;
416 	case 11:	/* OEM Strings */
417 		dmi_save_oem_strings_devices(dm);
418 		break;
419 	case 38:	/* IPMI Device Information */
420 		dmi_save_ipmi_device(dm);
421 		break;
422 	case 41:	/* Onboard Devices Extended Information */
423 		dmi_save_extended_devices(dm);
424 	}
425 }
426 
427 static int __init print_filtered(char *buf, size_t len, const char *info)
428 {
429 	int c = 0;
430 	const char *p;
431 
432 	if (!info)
433 		return c;
434 
435 	for (p = info; *p; p++)
436 		if (isprint(*p))
437 			c += scnprintf(buf + c, len - c, "%c", *p);
438 		else
439 			c += scnprintf(buf + c, len - c, "\\x%02x", *p & 0xff);
440 	return c;
441 }
442 
443 static void __init dmi_format_ids(char *buf, size_t len)
444 {
445 	int c = 0;
446 	const char *board;	/* Board Name is optional */
447 
448 	c += print_filtered(buf + c, len - c,
449 			    dmi_get_system_info(DMI_SYS_VENDOR));
450 	c += scnprintf(buf + c, len - c, " ");
451 	c += print_filtered(buf + c, len - c,
452 			    dmi_get_system_info(DMI_PRODUCT_NAME));
453 
454 	board = dmi_get_system_info(DMI_BOARD_NAME);
455 	if (board) {
456 		c += scnprintf(buf + c, len - c, "/");
457 		c += print_filtered(buf + c, len - c, board);
458 	}
459 	c += scnprintf(buf + c, len - c, ", BIOS ");
460 	c += print_filtered(buf + c, len - c,
461 			    dmi_get_system_info(DMI_BIOS_VERSION));
462 	c += scnprintf(buf + c, len - c, " ");
463 	c += print_filtered(buf + c, len - c,
464 			    dmi_get_system_info(DMI_BIOS_DATE));
465 }
466 
467 /*
468  * Check for DMI/SMBIOS headers in the system firmware image.  Any
469  * SMBIOS header must start 16 bytes before the DMI header, so take a
470  * 32 byte buffer and check for DMI at offset 16 and SMBIOS at offset
471  * 0.  If the DMI header is present, set dmi_ver accordingly (SMBIOS
472  * takes precedence) and return 0.  Otherwise return 1.
473  */
474 static int __init dmi_present(const u8 *buf)
475 {
476 	int smbios_ver;
477 
478 	if (memcmp(buf, "_SM_", 4) == 0 &&
479 	    buf[5] < 32 && dmi_checksum(buf, buf[5])) {
480 		smbios_ver = get_unaligned_be16(buf + 6);
481 
482 		/* Some BIOS report weird SMBIOS version, fix that up */
483 		switch (smbios_ver) {
484 		case 0x021F:
485 		case 0x0221:
486 			pr_debug("SMBIOS version fixup(2.%d->2.%d)\n",
487 				 smbios_ver & 0xFF, 3);
488 			smbios_ver = 0x0203;
489 			break;
490 		case 0x0233:
491 			pr_debug("SMBIOS version fixup(2.%d->2.%d)\n", 51, 6);
492 			smbios_ver = 0x0206;
493 			break;
494 		}
495 	} else {
496 		smbios_ver = 0;
497 	}
498 
499 	buf += 16;
500 
501 	if (memcmp(buf, "_DMI_", 5) == 0 && dmi_checksum(buf, 15)) {
502 		dmi_num = get_unaligned_le16(buf + 12);
503 		dmi_len = get_unaligned_le16(buf + 6);
504 		dmi_base = get_unaligned_le32(buf + 8);
505 
506 		if (dmi_walk_early(dmi_decode) == 0) {
507 			if (smbios_ver) {
508 				dmi_ver = smbios_ver;
509 				pr_info("SMBIOS %d.%d present.\n",
510 				       dmi_ver >> 8, dmi_ver & 0xFF);
511 			} else {
512 				dmi_ver = (buf[14] & 0xF0) << 4 |
513 					   (buf[14] & 0x0F);
514 				pr_info("Legacy DMI %d.%d present.\n",
515 				       dmi_ver >> 8, dmi_ver & 0xFF);
516 			}
517 			dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
518 			printk(KERN_DEBUG "DMI: %s\n", dmi_ids_string);
519 			return 0;
520 		}
521 	}
522 
523 	return 1;
524 }
525 
526 /*
527  * Check for the SMBIOS 3.0 64-bit entry point signature. Unlike the legacy
528  * 32-bit entry point, there is no embedded DMI header (_DMI_) in here.
529  */
530 static int __init dmi_smbios3_present(const u8 *buf)
531 {
532 	if (memcmp(buf, "_SM3_", 5) == 0 &&
533 	    buf[6] < 32 && dmi_checksum(buf, buf[6])) {
534 		dmi_ver = get_unaligned_be16(buf + 7);
535 		dmi_num = 0;			/* No longer specified */
536 		dmi_len = get_unaligned_le32(buf + 12);
537 		dmi_base = get_unaligned_le64(buf + 16);
538 
539 		if (dmi_walk_early(dmi_decode) == 0) {
540 			pr_info("SMBIOS %d.%d present.\n",
541 				dmi_ver >> 8, dmi_ver & 0xFF);
542 			dmi_format_ids(dmi_ids_string, sizeof(dmi_ids_string));
543 			pr_debug("DMI: %s\n", dmi_ids_string);
544 			return 0;
545 		}
546 	}
547 	return 1;
548 }
549 
550 void __init dmi_scan_machine(void)
551 {
552 	char __iomem *p, *q;
553 	char buf[32];
554 
555 	if (efi_enabled(EFI_CONFIG_TABLES)) {
556 		/*
557 		 * According to the DMTF SMBIOS reference spec v3.0.0, it is
558 		 * allowed to define both the 64-bit entry point (smbios3) and
559 		 * the 32-bit entry point (smbios), in which case they should
560 		 * either both point to the same SMBIOS structure table, or the
561 		 * table pointed to by the 64-bit entry point should contain a
562 		 * superset of the table contents pointed to by the 32-bit entry
563 		 * point (section 5.2)
564 		 * This implies that the 64-bit entry point should have
565 		 * precedence if it is defined and supported by the OS. If we
566 		 * have the 64-bit entry point, but fail to decode it, fall
567 		 * back to the legacy one (if available)
568 		 */
569 		if (efi.smbios3 != EFI_INVALID_TABLE_ADDR) {
570 			p = dmi_early_remap(efi.smbios3, 32);
571 			if (p == NULL)
572 				goto error;
573 			memcpy_fromio(buf, p, 32);
574 			dmi_early_unmap(p, 32);
575 
576 			if (!dmi_smbios3_present(buf)) {
577 				dmi_available = 1;
578 				goto out;
579 			}
580 		}
581 		if (efi.smbios == EFI_INVALID_TABLE_ADDR)
582 			goto error;
583 
584 		/* This is called as a core_initcall() because it isn't
585 		 * needed during early boot.  This also means we can
586 		 * iounmap the space when we're done with it.
587 		 */
588 		p = dmi_early_remap(efi.smbios, 32);
589 		if (p == NULL)
590 			goto error;
591 		memcpy_fromio(buf, p, 32);
592 		dmi_early_unmap(p, 32);
593 
594 		if (!dmi_present(buf)) {
595 			dmi_available = 1;
596 			goto out;
597 		}
598 	} else if (IS_ENABLED(CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK)) {
599 		p = dmi_early_remap(0xF0000, 0x10000);
600 		if (p == NULL)
601 			goto error;
602 
603 		/*
604 		 * Iterate over all possible DMI header addresses q.
605 		 * Maintain the 32 bytes around q in buf.  On the
606 		 * first iteration, substitute zero for the
607 		 * out-of-range bytes so there is no chance of falsely
608 		 * detecting an SMBIOS header.
609 		 */
610 		memset(buf, 0, 16);
611 		for (q = p; q < p + 0x10000; q += 16) {
612 			memcpy_fromio(buf + 16, q, 16);
613 			if (!dmi_smbios3_present(buf) || !dmi_present(buf)) {
614 				dmi_available = 1;
615 				dmi_early_unmap(p, 0x10000);
616 				goto out;
617 			}
618 			memcpy(buf, buf + 16, 16);
619 		}
620 		dmi_early_unmap(p, 0x10000);
621 	}
622  error:
623 	pr_info("DMI not present or invalid.\n");
624  out:
625 	dmi_initialized = 1;
626 }
627 
628 /**
629  * dmi_set_dump_stack_arch_desc - set arch description for dump_stack()
630  *
631  * Invoke dump_stack_set_arch_desc() with DMI system information so that
632  * DMI identifiers are printed out on task dumps.  Arch boot code should
633  * call this function after dmi_scan_machine() if it wants to print out DMI
634  * identifiers on task dumps.
635  */
636 void __init dmi_set_dump_stack_arch_desc(void)
637 {
638 	dump_stack_set_arch_desc("%s", dmi_ids_string);
639 }
640 
641 /**
642  *	dmi_matches - check if dmi_system_id structure matches system DMI data
643  *	@dmi: pointer to the dmi_system_id structure to check
644  */
645 static bool dmi_matches(const struct dmi_system_id *dmi)
646 {
647 	int i;
648 
649 	WARN(!dmi_initialized, KERN_ERR "dmi check: not initialized yet.\n");
650 
651 	for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
652 		int s = dmi->matches[i].slot;
653 		if (s == DMI_NONE)
654 			break;
655 		if (dmi_ident[s]) {
656 			if (!dmi->matches[i].exact_match &&
657 			    strstr(dmi_ident[s], dmi->matches[i].substr))
658 				continue;
659 			else if (dmi->matches[i].exact_match &&
660 				 !strcmp(dmi_ident[s], dmi->matches[i].substr))
661 				continue;
662 		}
663 
664 		/* No match */
665 		return false;
666 	}
667 	return true;
668 }
669 
670 /**
671  *	dmi_is_end_of_table - check for end-of-table marker
672  *	@dmi: pointer to the dmi_system_id structure to check
673  */
674 static bool dmi_is_end_of_table(const struct dmi_system_id *dmi)
675 {
676 	return dmi->matches[0].slot == DMI_NONE;
677 }
678 
679 /**
680  *	dmi_check_system - check system DMI data
681  *	@list: array of dmi_system_id structures to match against
682  *		All non-null elements of the list must match
683  *		their slot's (field index's) data (i.e., each
684  *		list string must be a substring of the specified
685  *		DMI slot's string data) to be considered a
686  *		successful match.
687  *
688  *	Walk the blacklist table running matching functions until someone
689  *	returns non zero or we hit the end. Callback function is called for
690  *	each successful match. Returns the number of matches.
691  */
692 int dmi_check_system(const struct dmi_system_id *list)
693 {
694 	int count = 0;
695 	const struct dmi_system_id *d;
696 
697 	for (d = list; !dmi_is_end_of_table(d); d++)
698 		if (dmi_matches(d)) {
699 			count++;
700 			if (d->callback && d->callback(d))
701 				break;
702 		}
703 
704 	return count;
705 }
706 EXPORT_SYMBOL(dmi_check_system);
707 
708 /**
709  *	dmi_first_match - find dmi_system_id structure matching system DMI data
710  *	@list: array of dmi_system_id structures to match against
711  *		All non-null elements of the list must match
712  *		their slot's (field index's) data (i.e., each
713  *		list string must be a substring of the specified
714  *		DMI slot's string data) to be considered a
715  *		successful match.
716  *
717  *	Walk the blacklist table until the first match is found.  Return the
718  *	pointer to the matching entry or NULL if there's no match.
719  */
720 const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
721 {
722 	const struct dmi_system_id *d;
723 
724 	for (d = list; !dmi_is_end_of_table(d); d++)
725 		if (dmi_matches(d))
726 			return d;
727 
728 	return NULL;
729 }
730 EXPORT_SYMBOL(dmi_first_match);
731 
732 /**
733  *	dmi_get_system_info - return DMI data value
734  *	@field: data index (see enum dmi_field)
735  *
736  *	Returns one DMI data value, can be used to perform
737  *	complex DMI data checks.
738  */
739 const char *dmi_get_system_info(int field)
740 {
741 	return dmi_ident[field];
742 }
743 EXPORT_SYMBOL(dmi_get_system_info);
744 
745 /**
746  * dmi_name_in_serial - Check if string is in the DMI product serial information
747  * @str: string to check for
748  */
749 int dmi_name_in_serial(const char *str)
750 {
751 	int f = DMI_PRODUCT_SERIAL;
752 	if (dmi_ident[f] && strstr(dmi_ident[f], str))
753 		return 1;
754 	return 0;
755 }
756 
757 /**
758  *	dmi_name_in_vendors - Check if string is in the DMI system or board vendor name
759  *	@str: Case sensitive Name
760  */
761 int dmi_name_in_vendors(const char *str)
762 {
763 	static int fields[] = { DMI_SYS_VENDOR, DMI_BOARD_VENDOR, DMI_NONE };
764 	int i;
765 	for (i = 0; fields[i] != DMI_NONE; i++) {
766 		int f = fields[i];
767 		if (dmi_ident[f] && strstr(dmi_ident[f], str))
768 			return 1;
769 	}
770 	return 0;
771 }
772 EXPORT_SYMBOL(dmi_name_in_vendors);
773 
774 /**
775  *	dmi_find_device - find onboard device by type/name
776  *	@type: device type or %DMI_DEV_TYPE_ANY to match all device types
777  *	@name: device name string or %NULL to match all
778  *	@from: previous device found in search, or %NULL for new search.
779  *
780  *	Iterates through the list of known onboard devices. If a device is
781  *	found with a matching @vendor and @device, a pointer to its device
782  *	structure is returned.  Otherwise, %NULL is returned.
783  *	A new search is initiated by passing %NULL as the @from argument.
784  *	If @from is not %NULL, searches continue from next device.
785  */
786 const struct dmi_device *dmi_find_device(int type, const char *name,
787 				    const struct dmi_device *from)
788 {
789 	const struct list_head *head = from ? &from->list : &dmi_devices;
790 	struct list_head *d;
791 
792 	for (d = head->next; d != &dmi_devices; d = d->next) {
793 		const struct dmi_device *dev =
794 			list_entry(d, struct dmi_device, list);
795 
796 		if (((type == DMI_DEV_TYPE_ANY) || (dev->type == type)) &&
797 		    ((name == NULL) || (strcmp(dev->name, name) == 0)))
798 			return dev;
799 	}
800 
801 	return NULL;
802 }
803 EXPORT_SYMBOL(dmi_find_device);
804 
805 /**
806  *	dmi_get_date - parse a DMI date
807  *	@field:	data index (see enum dmi_field)
808  *	@yearp: optional out parameter for the year
809  *	@monthp: optional out parameter for the month
810  *	@dayp: optional out parameter for the day
811  *
812  *	The date field is assumed to be in the form resembling
813  *	[mm[/dd]]/yy[yy] and the result is stored in the out
814  *	parameters any or all of which can be omitted.
815  *
816  *	If the field doesn't exist, all out parameters are set to zero
817  *	and false is returned.  Otherwise, true is returned with any
818  *	invalid part of date set to zero.
819  *
820  *	On return, year, month and day are guaranteed to be in the
821  *	range of [0,9999], [0,12] and [0,31] respectively.
822  */
823 bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
824 {
825 	int year = 0, month = 0, day = 0;
826 	bool exists;
827 	const char *s, *y;
828 	char *e;
829 
830 	s = dmi_get_system_info(field);
831 	exists = s;
832 	if (!exists)
833 		goto out;
834 
835 	/*
836 	 * Determine year first.  We assume the date string resembles
837 	 * mm/dd/yy[yy] but the original code extracted only the year
838 	 * from the end.  Keep the behavior in the spirit of no
839 	 * surprises.
840 	 */
841 	y = strrchr(s, '/');
842 	if (!y)
843 		goto out;
844 
845 	y++;
846 	year = simple_strtoul(y, &e, 10);
847 	if (y != e && year < 100) {	/* 2-digit year */
848 		year += 1900;
849 		if (year < 1996)	/* no dates < spec 1.0 */
850 			year += 100;
851 	}
852 	if (year > 9999)		/* year should fit in %04d */
853 		year = 0;
854 
855 	/* parse the mm and dd */
856 	month = simple_strtoul(s, &e, 10);
857 	if (s == e || *e != '/' || !month || month > 12) {
858 		month = 0;
859 		goto out;
860 	}
861 
862 	s = e + 1;
863 	day = simple_strtoul(s, &e, 10);
864 	if (s == y || s == e || *e != '/' || day > 31)
865 		day = 0;
866 out:
867 	if (yearp)
868 		*yearp = year;
869 	if (monthp)
870 		*monthp = month;
871 	if (dayp)
872 		*dayp = day;
873 	return exists;
874 }
875 EXPORT_SYMBOL(dmi_get_date);
876 
877 /**
878  *	dmi_walk - Walk the DMI table and get called back for every record
879  *	@decode: Callback function
880  *	@private_data: Private data to be passed to the callback function
881  *
882  *	Returns -1 when the DMI table can't be reached, 0 on success.
883  */
884 int dmi_walk(void (*decode)(const struct dmi_header *, void *),
885 	     void *private_data)
886 {
887 	u8 *buf;
888 
889 	if (!dmi_available)
890 		return -1;
891 
892 	buf = dmi_remap(dmi_base, dmi_len);
893 	if (buf == NULL)
894 		return -1;
895 
896 	dmi_table(buf, dmi_len, dmi_num, decode, private_data);
897 
898 	dmi_unmap(buf);
899 	return 0;
900 }
901 EXPORT_SYMBOL_GPL(dmi_walk);
902 
903 /**
904  * dmi_match - compare a string to the dmi field (if exists)
905  * @f: DMI field identifier
906  * @str: string to compare the DMI field to
907  *
908  * Returns true if the requested field equals to the str (including NULL).
909  */
910 bool dmi_match(enum dmi_field f, const char *str)
911 {
912 	const char *info = dmi_get_system_info(f);
913 
914 	if (info == NULL || str == NULL)
915 		return info == str;
916 
917 	return !strcmp(info, str);
918 }
919 EXPORT_SYMBOL_GPL(dmi_match);
920 
921 void dmi_memdev_name(u16 handle, const char **bank, const char **device)
922 {
923 	int n;
924 
925 	if (dmi_memdev == NULL)
926 		return;
927 
928 	for (n = 0; n < dmi_memdev_nr; n++) {
929 		if (handle == dmi_memdev[n].handle) {
930 			*bank = dmi_memdev[n].bank;
931 			*device = dmi_memdev[n].device;
932 			break;
933 		}
934 	}
935 }
936 EXPORT_SYMBOL_GPL(dmi_memdev_name);
937