xref: /openbmc/linux/arch/x86/kernel/cpu/microcode/intel.c (revision 6b5fc336)
1 /*
2  * Intel CPU Microcode Update Driver for Linux
3  *
4  * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
5  *		 2006 Shaohua Li <shaohua.li@intel.com>
6  *
7  * Intel CPU microcode early update for Linux
8  *
9  * Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
10  *		      H Peter Anvin" <hpa@zytor.com>
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License
14  * as published by the Free Software Foundation; either version
15  * 2 of the License, or (at your option) any later version.
16  */
17 
18 /*
19  * This needs to be before all headers so that pr_debug in printk.h doesn't turn
20  * printk calls into no_printk().
21  *
22  *#define DEBUG
23  */
24 #define pr_fmt(fmt) "microcode: " fmt
25 
26 #include <linux/earlycpio.h>
27 #include <linux/firmware.h>
28 #include <linux/uaccess.h>
29 #include <linux/vmalloc.h>
30 #include <linux/initrd.h>
31 #include <linux/kernel.h>
32 #include <linux/slab.h>
33 #include <linux/cpu.h>
34 #include <linux/mm.h>
35 
36 #include <asm/microcode_intel.h>
37 #include <asm/processor.h>
38 #include <asm/tlbflush.h>
39 #include <asm/setup.h>
40 #include <asm/msr.h>
41 
42 static const char ucode_path[] = "kernel/x86/microcode/GenuineIntel.bin";
43 
44 /* Current microcode patch used in early patching on the APs. */
45 static struct microcode_intel *intel_ucode_patch;
46 
47 static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
48 					unsigned int s2, unsigned int p2)
49 {
50 	if (s1 != s2)
51 		return false;
52 
53 	/* Processor flags are either both 0 ... */
54 	if (!p1 && !p2)
55 		return true;
56 
57 	/* ... or they intersect. */
58 	return p1 & p2;
59 }
60 
61 /*
62  * Returns 1 if update has been found, 0 otherwise.
63  */
64 static int find_matching_signature(void *mc, unsigned int csig, int cpf)
65 {
66 	struct microcode_header_intel *mc_hdr = mc;
67 	struct extended_sigtable *ext_hdr;
68 	struct extended_signature *ext_sig;
69 	int i;
70 
71 	if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
72 		return 1;
73 
74 	/* Look for ext. headers: */
75 	if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)
76 		return 0;
77 
78 	ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
79 	ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;
80 
81 	for (i = 0; i < ext_hdr->count; i++) {
82 		if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
83 			return 1;
84 		ext_sig++;
85 	}
86 	return 0;
87 }
88 
89 /*
90  * Returns 1 if update has been found, 0 otherwise.
91  */
92 static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
93 {
94 	struct microcode_header_intel *mc_hdr = mc;
95 
96 	if (mc_hdr->rev <= new_rev)
97 		return 0;
98 
99 	return find_matching_signature(mc, csig, cpf);
100 }
101 
102 /*
103  * Given CPU signature and a microcode patch, this function finds if the
104  * microcode patch has matching family and model with the CPU.
105  *
106  * %true - if there's a match
107  * %false - otherwise
108  */
109 static bool microcode_matches(struct microcode_header_intel *mc_header,
110 			      unsigned long sig)
111 {
112 	unsigned long total_size = get_totalsize(mc_header);
113 	unsigned long data_size = get_datasize(mc_header);
114 	struct extended_sigtable *ext_header;
115 	unsigned int fam_ucode, model_ucode;
116 	struct extended_signature *ext_sig;
117 	unsigned int fam, model;
118 	int ext_sigcount, i;
119 
120 	fam   = x86_family(sig);
121 	model = x86_model(sig);
122 
123 	fam_ucode   = x86_family(mc_header->sig);
124 	model_ucode = x86_model(mc_header->sig);
125 
126 	if (fam == fam_ucode && model == model_ucode)
127 		return true;
128 
129 	/* Look for ext. headers: */
130 	if (total_size <= data_size + MC_HEADER_SIZE)
131 		return false;
132 
133 	ext_header   = (void *) mc_header + data_size + MC_HEADER_SIZE;
134 	ext_sig      = (void *)ext_header + EXT_HEADER_SIZE;
135 	ext_sigcount = ext_header->count;
136 
137 	for (i = 0; i < ext_sigcount; i++) {
138 		fam_ucode   = x86_family(ext_sig->sig);
139 		model_ucode = x86_model(ext_sig->sig);
140 
141 		if (fam == fam_ucode && model == model_ucode)
142 			return true;
143 
144 		ext_sig++;
145 	}
146 	return false;
147 }
148 
149 static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
150 {
151 	struct ucode_patch *p;
152 
153 	p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
154 	if (!p)
155 		return ERR_PTR(-ENOMEM);
156 
157 	p->data = kmemdup(data, size, GFP_KERNEL);
158 	if (!p->data) {
159 		kfree(p);
160 		return ERR_PTR(-ENOMEM);
161 	}
162 
163 	return p;
164 }
165 
166 static void save_microcode_patch(void *data, unsigned int size)
167 {
168 	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
169 	struct ucode_patch *iter, *tmp, *p = NULL;
170 	bool prev_found = false;
171 	unsigned int sig, pf;
172 
173 	mc_hdr = (struct microcode_header_intel *)data;
174 
175 	list_for_each_entry_safe(iter, tmp, &microcode_cache, plist) {
176 		mc_saved_hdr = (struct microcode_header_intel *)iter->data;
177 		sig	     = mc_saved_hdr->sig;
178 		pf	     = mc_saved_hdr->pf;
179 
180 		if (find_matching_signature(data, sig, pf)) {
181 			prev_found = true;
182 
183 			if (mc_hdr->rev <= mc_saved_hdr->rev)
184 				continue;
185 
186 			p = __alloc_microcode_buf(data, size);
187 			if (IS_ERR(p))
188 				pr_err("Error allocating buffer %p\n", data);
189 			else
190 				list_replace(&iter->plist, &p->plist);
191 		}
192 	}
193 
194 	/*
195 	 * There weren't any previous patches found in the list cache; save the
196 	 * newly found.
197 	 */
198 	if (!prev_found) {
199 		p = __alloc_microcode_buf(data, size);
200 		if (IS_ERR(p))
201 			pr_err("Error allocating buffer for %p\n", data);
202 		else
203 			list_add_tail(&p->plist, &microcode_cache);
204 	}
205 
206 	/*
207 	 * Save for early loading. On 32-bit, that needs to be a physical
208 	 * address as the APs are running from physical addresses, before
209 	 * paging has been enabled.
210 	 */
211 	if (p) {
212 		if (IS_ENABLED(CONFIG_X86_32))
213 			intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
214 		else
215 			intel_ucode_patch = p->data;
216 	}
217 }
218 
219 static int microcode_sanity_check(void *mc, int print_err)
220 {
221 	unsigned long total_size, data_size, ext_table_size;
222 	struct microcode_header_intel *mc_header = mc;
223 	struct extended_sigtable *ext_header = NULL;
224 	u32 sum, orig_sum, ext_sigcount = 0, i;
225 	struct extended_signature *ext_sig;
226 
227 	total_size = get_totalsize(mc_header);
228 	data_size = get_datasize(mc_header);
229 
230 	if (data_size + MC_HEADER_SIZE > total_size) {
231 		if (print_err)
232 			pr_err("Error: bad microcode data file size.\n");
233 		return -EINVAL;
234 	}
235 
236 	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
237 		if (print_err)
238 			pr_err("Error: invalid/unknown microcode update format.\n");
239 		return -EINVAL;
240 	}
241 
242 	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
243 	if (ext_table_size) {
244 		u32 ext_table_sum = 0;
245 		u32 *ext_tablep;
246 
247 		if ((ext_table_size < EXT_HEADER_SIZE)
248 		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
249 			if (print_err)
250 				pr_err("Error: truncated extended signature table.\n");
251 			return -EINVAL;
252 		}
253 
254 		ext_header = mc + MC_HEADER_SIZE + data_size;
255 		if (ext_table_size != exttable_size(ext_header)) {
256 			if (print_err)
257 				pr_err("Error: extended signature table size mismatch.\n");
258 			return -EFAULT;
259 		}
260 
261 		ext_sigcount = ext_header->count;
262 
263 		/*
264 		 * Check extended table checksum: the sum of all dwords that
265 		 * comprise a valid table must be 0.
266 		 */
267 		ext_tablep = (u32 *)ext_header;
268 
269 		i = ext_table_size / sizeof(u32);
270 		while (i--)
271 			ext_table_sum += ext_tablep[i];
272 
273 		if (ext_table_sum) {
274 			if (print_err)
275 				pr_warn("Bad extended signature table checksum, aborting.\n");
276 			return -EINVAL;
277 		}
278 	}
279 
280 	/*
281 	 * Calculate the checksum of update data and header. The checksum of
282 	 * valid update data and header including the extended signature table
283 	 * must be 0.
284 	 */
285 	orig_sum = 0;
286 	i = (MC_HEADER_SIZE + data_size) / sizeof(u32);
287 	while (i--)
288 		orig_sum += ((u32 *)mc)[i];
289 
290 	if (orig_sum) {
291 		if (print_err)
292 			pr_err("Bad microcode data checksum, aborting.\n");
293 		return -EINVAL;
294 	}
295 
296 	if (!ext_table_size)
297 		return 0;
298 
299 	/*
300 	 * Check extended signature checksum: 0 => valid.
301 	 */
302 	for (i = 0; i < ext_sigcount; i++) {
303 		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
304 			  EXT_SIGNATURE_SIZE * i;
305 
306 		sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -
307 		      (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
308 		if (sum) {
309 			if (print_err)
310 				pr_err("Bad extended signature checksum, aborting.\n");
311 			return -EINVAL;
312 		}
313 	}
314 	return 0;
315 }
316 
317 /*
318  * Get microcode matching with BSP's model. Only CPUs with the same model as
319  * BSP can stay in the platform.
320  */
321 static struct microcode_intel *
322 scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
323 {
324 	struct microcode_header_intel *mc_header;
325 	struct microcode_intel *patch = NULL;
326 	unsigned int mc_size;
327 
328 	while (size) {
329 		if (size < sizeof(struct microcode_header_intel))
330 			break;
331 
332 		mc_header = (struct microcode_header_intel *)data;
333 
334 		mc_size = get_totalsize(mc_header);
335 		if (!mc_size ||
336 		    mc_size > size ||
337 		    microcode_sanity_check(data, 0) < 0)
338 			break;
339 
340 		size -= mc_size;
341 
342 		if (!microcode_matches(mc_header, uci->cpu_sig.sig)) {
343 			data += mc_size;
344 			continue;
345 		}
346 
347 		if (save) {
348 			save_microcode_patch(data, mc_size);
349 			goto next;
350 		}
351 
352 
353 		if (!patch) {
354 			if (!has_newer_microcode(data,
355 						 uci->cpu_sig.sig,
356 						 uci->cpu_sig.pf,
357 						 uci->cpu_sig.rev))
358 				goto next;
359 
360 		} else {
361 			struct microcode_header_intel *phdr = &patch->hdr;
362 
363 			if (!has_newer_microcode(data,
364 						 phdr->sig,
365 						 phdr->pf,
366 						 phdr->rev))
367 				goto next;
368 		}
369 
370 		/* We have a newer patch, save it. */
371 		patch = data;
372 
373 next:
374 		data += mc_size;
375 	}
376 
377 	if (size)
378 		return NULL;
379 
380 	return patch;
381 }
382 
383 static int collect_cpu_info_early(struct ucode_cpu_info *uci)
384 {
385 	unsigned int val[2];
386 	unsigned int family, model;
387 	struct cpu_signature csig = { 0 };
388 	unsigned int eax, ebx, ecx, edx;
389 
390 	memset(uci, 0, sizeof(*uci));
391 
392 	eax = 0x00000001;
393 	ecx = 0;
394 	native_cpuid(&eax, &ebx, &ecx, &edx);
395 	csig.sig = eax;
396 
397 	family = x86_family(eax);
398 	model  = x86_model(eax);
399 
400 	if ((model >= 5) || (family > 6)) {
401 		/* get processor flags from MSR 0x17 */
402 		native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
403 		csig.pf = 1 << ((val[1] >> 18) & 7);
404 	}
405 
406 	csig.rev = intel_get_microcode_revision();
407 
408 	uci->cpu_sig = csig;
409 	uci->valid = 1;
410 
411 	return 0;
412 }
413 
414 static void show_saved_mc(void)
415 {
416 #ifdef DEBUG
417 	int i = 0, j;
418 	unsigned int sig, pf, rev, total_size, data_size, date;
419 	struct ucode_cpu_info uci;
420 	struct ucode_patch *p;
421 
422 	if (list_empty(&microcode_cache)) {
423 		pr_debug("no microcode data saved.\n");
424 		return;
425 	}
426 
427 	collect_cpu_info_early(&uci);
428 
429 	sig	= uci.cpu_sig.sig;
430 	pf	= uci.cpu_sig.pf;
431 	rev	= uci.cpu_sig.rev;
432 	pr_debug("CPU: sig=0x%x, pf=0x%x, rev=0x%x\n", sig, pf, rev);
433 
434 	list_for_each_entry(p, &microcode_cache, plist) {
435 		struct microcode_header_intel *mc_saved_header;
436 		struct extended_sigtable *ext_header;
437 		struct extended_signature *ext_sig;
438 		int ext_sigcount;
439 
440 		mc_saved_header = (struct microcode_header_intel *)p->data;
441 
442 		sig	= mc_saved_header->sig;
443 		pf	= mc_saved_header->pf;
444 		rev	= mc_saved_header->rev;
445 		date	= mc_saved_header->date;
446 
447 		total_size	= get_totalsize(mc_saved_header);
448 		data_size	= get_datasize(mc_saved_header);
449 
450 		pr_debug("mc_saved[%d]: sig=0x%x, pf=0x%x, rev=0x%x, total size=0x%x, date = %04x-%02x-%02x\n",
451 			 i++, sig, pf, rev, total_size,
452 			 date & 0xffff,
453 			 date >> 24,
454 			 (date >> 16) & 0xff);
455 
456 		/* Look for ext. headers: */
457 		if (total_size <= data_size + MC_HEADER_SIZE)
458 			continue;
459 
460 		ext_header = (void *)mc_saved_header + data_size + MC_HEADER_SIZE;
461 		ext_sigcount = ext_header->count;
462 		ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
463 
464 		for (j = 0; j < ext_sigcount; j++) {
465 			sig = ext_sig->sig;
466 			pf = ext_sig->pf;
467 
468 			pr_debug("\tExtended[%d]: sig=0x%x, pf=0x%x\n",
469 				 j, sig, pf);
470 
471 			ext_sig++;
472 		}
473 	}
474 #endif
475 }
476 
477 /*
478  * Save this microcode patch. It will be loaded early when a CPU is
479  * hot-added or resumes.
480  */
481 static void save_mc_for_early(u8 *mc, unsigned int size)
482 {
483 #ifdef CONFIG_HOTPLUG_CPU
484 	/* Synchronization during CPU hotplug. */
485 	static DEFINE_MUTEX(x86_cpu_microcode_mutex);
486 
487 	mutex_lock(&x86_cpu_microcode_mutex);
488 
489 	save_microcode_patch(mc, size);
490 	show_saved_mc();
491 
492 	mutex_unlock(&x86_cpu_microcode_mutex);
493 #endif
494 }
495 
496 static bool load_builtin_intel_microcode(struct cpio_data *cp)
497 {
498 	unsigned int eax = 1, ebx, ecx = 0, edx;
499 	char name[30];
500 
501 	if (IS_ENABLED(CONFIG_X86_32))
502 		return false;
503 
504 	native_cpuid(&eax, &ebx, &ecx, &edx);
505 
506 	sprintf(name, "intel-ucode/%02x-%02x-%02x",
507 		      x86_family(eax), x86_model(eax), x86_stepping(eax));
508 
509 	return get_builtin_firmware(cp, name);
510 }
511 
512 /*
513  * Print ucode update info.
514  */
515 static void
516 print_ucode_info(struct ucode_cpu_info *uci, unsigned int date)
517 {
518 	pr_info_once("microcode updated early to revision 0x%x, date = %04x-%02x-%02x\n",
519 		     uci->cpu_sig.rev,
520 		     date & 0xffff,
521 		     date >> 24,
522 		     (date >> 16) & 0xff);
523 }
524 
525 #ifdef CONFIG_X86_32
526 
527 static int delay_ucode_info;
528 static int current_mc_date;
529 
530 /*
531  * Print early updated ucode info after printk works. This is delayed info dump.
532  */
533 void show_ucode_info_early(void)
534 {
535 	struct ucode_cpu_info uci;
536 
537 	if (delay_ucode_info) {
538 		collect_cpu_info_early(&uci);
539 		print_ucode_info(&uci, current_mc_date);
540 		delay_ucode_info = 0;
541 	}
542 }
543 
544 /*
545  * At this point, we can not call printk() yet. Delay printing microcode info in
546  * show_ucode_info_early() until printk() works.
547  */
548 static void print_ucode(struct ucode_cpu_info *uci)
549 {
550 	struct microcode_intel *mc;
551 	int *delay_ucode_info_p;
552 	int *current_mc_date_p;
553 
554 	mc = uci->mc;
555 	if (!mc)
556 		return;
557 
558 	delay_ucode_info_p = (int *)__pa_nodebug(&delay_ucode_info);
559 	current_mc_date_p = (int *)__pa_nodebug(&current_mc_date);
560 
561 	*delay_ucode_info_p = 1;
562 	*current_mc_date_p = mc->hdr.date;
563 }
564 #else
565 
566 /*
567  * Flush global tlb. We only do this in x86_64 where paging has been enabled
568  * already and PGE should be enabled as well.
569  */
570 static inline void flush_tlb_early(void)
571 {
572 	__native_flush_tlb_global_irq_disabled();
573 }
574 
575 static inline void print_ucode(struct ucode_cpu_info *uci)
576 {
577 	struct microcode_intel *mc;
578 
579 	mc = uci->mc;
580 	if (!mc)
581 		return;
582 
583 	print_ucode_info(uci, mc->hdr.date);
584 }
585 #endif
586 
587 static int apply_microcode_early(struct ucode_cpu_info *uci, bool early)
588 {
589 	struct microcode_intel *mc;
590 	u32 rev;
591 
592 	mc = uci->mc;
593 	if (!mc)
594 		return 0;
595 
596 	/* write microcode via MSR 0x79 */
597 	native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
598 
599 	rev = intel_get_microcode_revision();
600 	if (rev != mc->hdr.rev)
601 		return -1;
602 
603 #ifdef CONFIG_X86_64
604 	/* Flush global tlb. This is precaution. */
605 	flush_tlb_early();
606 #endif
607 	uci->cpu_sig.rev = rev;
608 
609 	if (early)
610 		print_ucode(uci);
611 	else
612 		print_ucode_info(uci, mc->hdr.date);
613 
614 	return 0;
615 }
616 
617 int __init save_microcode_in_initrd_intel(void)
618 {
619 	struct ucode_cpu_info uci;
620 	struct cpio_data cp;
621 
622 	/*
623 	 * initrd is going away, clear patch ptr. We will scan the microcode one
624 	 * last time before jettisoning and save a patch, if found. Then we will
625 	 * update that pointer too, with a stable patch address to use when
626 	 * resuming the cores.
627 	 */
628 	intel_ucode_patch = NULL;
629 
630 	if (!load_builtin_intel_microcode(&cp))
631 		cp = find_microcode_in_initrd(ucode_path, false);
632 
633 	if (!(cp.data && cp.size))
634 		return 0;
635 
636 	collect_cpu_info_early(&uci);
637 
638 	scan_microcode(cp.data, cp.size, &uci, true);
639 
640 	show_saved_mc();
641 
642 	return 0;
643 }
644 
645 /*
646  * @res_patch, output: a pointer to the patch we found.
647  */
648 static struct microcode_intel *__load_ucode_intel(struct ucode_cpu_info *uci)
649 {
650 	static const char *path;
651 	struct cpio_data cp;
652 	bool use_pa;
653 
654 	if (IS_ENABLED(CONFIG_X86_32)) {
655 		path	  = (const char *)__pa_nodebug(ucode_path);
656 		use_pa	  = true;
657 	} else {
658 		path	  = ucode_path;
659 		use_pa	  = false;
660 	}
661 
662 	/* try built-in microcode first */
663 	if (!load_builtin_intel_microcode(&cp))
664 		cp = find_microcode_in_initrd(path, use_pa);
665 
666 	if (!(cp.data && cp.size))
667 		return NULL;
668 
669 	collect_cpu_info_early(uci);
670 
671 	return scan_microcode(cp.data, cp.size, uci, false);
672 }
673 
674 void __init load_ucode_intel_bsp(void)
675 {
676 	struct microcode_intel *patch;
677 	struct ucode_cpu_info uci;
678 
679 	patch = __load_ucode_intel(&uci);
680 	if (!patch)
681 		return;
682 
683 	uci.mc = patch;
684 
685 	apply_microcode_early(&uci, true);
686 }
687 
688 void load_ucode_intel_ap(void)
689 {
690 	struct microcode_intel *patch, **iup;
691 	struct ucode_cpu_info uci;
692 
693 	if (IS_ENABLED(CONFIG_X86_32))
694 		iup = (struct microcode_intel **) __pa_nodebug(&intel_ucode_patch);
695 	else
696 		iup = &intel_ucode_patch;
697 
698 reget:
699 	if (!*iup) {
700 		patch = __load_ucode_intel(&uci);
701 		if (!patch)
702 			return;
703 
704 		*iup = patch;
705 	}
706 
707 	uci.mc = *iup;
708 
709 	if (apply_microcode_early(&uci, true)) {
710 		/* Mixed-silicon system? Try to refetch the proper patch: */
711 		*iup = NULL;
712 
713 		goto reget;
714 	}
715 }
716 
717 static struct microcode_intel *find_patch(struct ucode_cpu_info *uci)
718 {
719 	struct microcode_header_intel *phdr;
720 	struct ucode_patch *iter, *tmp;
721 
722 	list_for_each_entry_safe(iter, tmp, &microcode_cache, plist) {
723 
724 		phdr = (struct microcode_header_intel *)iter->data;
725 
726 		if (phdr->rev <= uci->cpu_sig.rev)
727 			continue;
728 
729 		if (!find_matching_signature(phdr,
730 					     uci->cpu_sig.sig,
731 					     uci->cpu_sig.pf))
732 			continue;
733 
734 		return iter->data;
735 	}
736 	return NULL;
737 }
738 
739 void reload_ucode_intel(void)
740 {
741 	struct microcode_intel *p;
742 	struct ucode_cpu_info uci;
743 
744 	collect_cpu_info_early(&uci);
745 
746 	p = find_patch(&uci);
747 	if (!p)
748 		return;
749 
750 	uci.mc = p;
751 
752 	apply_microcode_early(&uci, false);
753 }
754 
755 static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
756 {
757 	static struct cpu_signature prev;
758 	struct cpuinfo_x86 *c = &cpu_data(cpu_num);
759 	unsigned int val[2];
760 
761 	memset(csig, 0, sizeof(*csig));
762 
763 	csig->sig = cpuid_eax(0x00000001);
764 
765 	if ((c->x86_model >= 5) || (c->x86 > 6)) {
766 		/* get processor flags from MSR 0x17 */
767 		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
768 		csig->pf = 1 << ((val[1] >> 18) & 7);
769 	}
770 
771 	csig->rev = c->microcode;
772 
773 	/* No extra locking on prev, races are harmless. */
774 	if (csig->sig != prev.sig || csig->pf != prev.pf || csig->rev != prev.rev) {
775 		pr_info("sig=0x%x, pf=0x%x, revision=0x%x\n",
776 			csig->sig, csig->pf, csig->rev);
777 		prev = *csig;
778 	}
779 
780 	return 0;
781 }
782 
783 static int apply_microcode_intel(int cpu)
784 {
785 	struct microcode_intel *mc;
786 	struct ucode_cpu_info *uci;
787 	struct cpuinfo_x86 *c;
788 	static int prev_rev;
789 	u32 rev;
790 
791 	/* We should bind the task to the CPU */
792 	if (WARN_ON(raw_smp_processor_id() != cpu))
793 		return -1;
794 
795 	uci = ucode_cpu_info + cpu;
796 	mc = uci->mc;
797 	if (!mc) {
798 		/* Look for a newer patch in our cache: */
799 		mc = find_patch(uci);
800 		if (!mc)
801 			return 0;
802 	}
803 
804 	/* write microcode via MSR 0x79 */
805 	wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
806 
807 	rev = intel_get_microcode_revision();
808 
809 	if (rev != mc->hdr.rev) {
810 		pr_err("CPU%d update to revision 0x%x failed\n",
811 		       cpu, mc->hdr.rev);
812 		return -1;
813 	}
814 
815 	if (rev != prev_rev) {
816 		pr_info("updated to revision 0x%x, date = %04x-%02x-%02x\n",
817 			rev,
818 			mc->hdr.date & 0xffff,
819 			mc->hdr.date >> 24,
820 			(mc->hdr.date >> 16) & 0xff);
821 		prev_rev = rev;
822 	}
823 
824 	c = &cpu_data(cpu);
825 
826 	uci->cpu_sig.rev = rev;
827 	c->microcode = rev;
828 
829 	return 0;
830 }
831 
832 static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
833 				int (*get_ucode_data)(void *, const void *, size_t))
834 {
835 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
836 	u8 *ucode_ptr = data, *new_mc = NULL, *mc = NULL;
837 	int new_rev = uci->cpu_sig.rev;
838 	unsigned int leftover = size;
839 	unsigned int curr_mc_size = 0, new_mc_size = 0;
840 	unsigned int csig, cpf;
841 
842 	while (leftover) {
843 		struct microcode_header_intel mc_header;
844 		unsigned int mc_size;
845 
846 		if (leftover < sizeof(mc_header)) {
847 			pr_err("error! Truncated header in microcode data file\n");
848 			break;
849 		}
850 
851 		if (get_ucode_data(&mc_header, ucode_ptr, sizeof(mc_header)))
852 			break;
853 
854 		mc_size = get_totalsize(&mc_header);
855 		if (!mc_size || mc_size > leftover) {
856 			pr_err("error! Bad data in microcode data file\n");
857 			break;
858 		}
859 
860 		/* For performance reasons, reuse mc area when possible */
861 		if (!mc || mc_size > curr_mc_size) {
862 			vfree(mc);
863 			mc = vmalloc(mc_size);
864 			if (!mc)
865 				break;
866 			curr_mc_size = mc_size;
867 		}
868 
869 		if (get_ucode_data(mc, ucode_ptr, mc_size) ||
870 		    microcode_sanity_check(mc, 1) < 0) {
871 			break;
872 		}
873 
874 		csig = uci->cpu_sig.sig;
875 		cpf = uci->cpu_sig.pf;
876 		if (has_newer_microcode(mc, csig, cpf, new_rev)) {
877 			vfree(new_mc);
878 			new_rev = mc_header.rev;
879 			new_mc  = mc;
880 			new_mc_size = mc_size;
881 			mc = NULL;	/* trigger new vmalloc */
882 		}
883 
884 		ucode_ptr += mc_size;
885 		leftover  -= mc_size;
886 	}
887 
888 	vfree(mc);
889 
890 	if (leftover) {
891 		vfree(new_mc);
892 		return UCODE_ERROR;
893 	}
894 
895 	if (!new_mc)
896 		return UCODE_NFOUND;
897 
898 	vfree(uci->mc);
899 	uci->mc = (struct microcode_intel *)new_mc;
900 
901 	/*
902 	 * If early loading microcode is supported, save this mc into
903 	 * permanent memory. So it will be loaded early when a CPU is hot added
904 	 * or resumes.
905 	 */
906 	save_mc_for_early(new_mc, new_mc_size);
907 
908 	pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n",
909 		 cpu, new_rev, uci->cpu_sig.rev);
910 
911 	return UCODE_OK;
912 }
913 
914 static int get_ucode_fw(void *to, const void *from, size_t n)
915 {
916 	memcpy(to, from, n);
917 	return 0;
918 }
919 
920 static enum ucode_state request_microcode_fw(int cpu, struct device *device,
921 					     bool refresh_fw)
922 {
923 	char name[30];
924 	struct cpuinfo_x86 *c = &cpu_data(cpu);
925 	const struct firmware *firmware;
926 	enum ucode_state ret;
927 
928 	sprintf(name, "intel-ucode/%02x-%02x-%02x",
929 		c->x86, c->x86_model, c->x86_mask);
930 
931 	if (request_firmware_direct(&firmware, name, device)) {
932 		pr_debug("data file %s load failed\n", name);
933 		return UCODE_NFOUND;
934 	}
935 
936 	ret = generic_load_microcode(cpu, (void *)firmware->data,
937 				     firmware->size, &get_ucode_fw);
938 
939 	release_firmware(firmware);
940 
941 	return ret;
942 }
943 
944 static int get_ucode_user(void *to, const void *from, size_t n)
945 {
946 	return copy_from_user(to, from, n);
947 }
948 
949 static enum ucode_state
950 request_microcode_user(int cpu, const void __user *buf, size_t size)
951 {
952 	return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
953 }
954 
955 static struct microcode_ops microcode_intel_ops = {
956 	.request_microcode_user		  = request_microcode_user,
957 	.request_microcode_fw             = request_microcode_fw,
958 	.collect_cpu_info                 = collect_cpu_info,
959 	.apply_microcode                  = apply_microcode_intel,
960 };
961 
962 struct microcode_ops * __init init_intel_microcode(void)
963 {
964 	struct cpuinfo_x86 *c = &boot_cpu_data;
965 
966 	if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
967 	    cpu_has(c, X86_FEATURE_IA64)) {
968 		pr_err("Intel CPU family 0x%x not supported\n", c->x86);
969 		return NULL;
970 	}
971 
972 	return &microcode_intel_ops;
973 }
974