1/*
  2 * 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 *	      2013-2016	Borislav Petkov <bp@alien8.de>
  7 *
  8 * X86 CPU microcode early update for Linux:
  9 *
 10 *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
 11 *			   H Peter Anvin" <hpa@zytor.com>
 12 *		  (C) 2015 Borislav Petkov <bp@alien8.de>
 13 *
 14 * This driver allows to upgrade microcode on x86 processors.
 15 *
 16 * This program is free software; you can redistribute it and/or
 17 * modify it under the terms of the GNU General Public License
 18 * as published by the Free Software Foundation; either version
 19 * 2 of the License, or (at your option) any later version.
 20 */
 21
 22#define pr_fmt(fmt) "microcode: " fmt
 23
 24#include <linux/platform_device.h>
 25#include <linux/stop_machine.h>
 26#include <linux/syscore_ops.h>
 27#include <linux/miscdevice.h>
 28#include <linux/capability.h>
 29#include <linux/firmware.h>
 30#include <linux/kernel.h>
 31#include <linux/delay.h>
 32#include <linux/mutex.h>
 33#include <linux/cpu.h>
 34#include <linux/nmi.h>
 35#include <linux/fs.h>
 36#include <linux/mm.h>
 37
 38#include <asm/microcode_intel.h>
 39#include <asm/cpu_device_id.h>
 40#include <asm/microcode_amd.h>
 41#include <asm/perf_event.h>
 42#include <asm/microcode.h>
 43#include <asm/processor.h>
 44#include <asm/cmdline.h>
 45#include <asm/setup.h>
 46
 47#define DRIVER_VERSION	"2.2"
 48
 49static struct microcode_ops	*microcode_ops;
 50static bool dis_ucode_ldr = true;
 51
 52bool initrd_gone;
 53
 54LIST_HEAD(microcode_cache);
 55
 56/*
 57 * Synchronization.
 58 *
 59 * All non cpu-hotplug-callback call sites use:
 60 *
 61 * - microcode_mutex to synchronize with each other;
 62 * - get/put_online_cpus() to synchronize with
 63 *   the cpu-hotplug-callback call sites.
 64 *
 65 * We guarantee that only a single cpu is being
 66 * updated at any particular moment of time.
 67 */
 68static DEFINE_MUTEX(microcode_mutex);
 69
 70/*
 71 * Serialize late loading so that CPUs get updated one-by-one.
 72 */
 73static DEFINE_SPINLOCK(update_lock);
 74
 75struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
 76
 77struct cpu_info_ctx {
 78	struct cpu_signature	*cpu_sig;
 79	int			err;
 80};
 81
 82/*
 83 * Those patch levels cannot be updated to newer ones and thus should be final.
 84 */
 85static u32 final_levels[] = {
 86	0x01000098,
 87	0x0100009f,
 88	0x010000af,
 89	0, /* T-101 terminator */
 90};
 91
 92/*
 93 * Check the current patch level on this CPU.
 94 *
 95 * Returns:
 96 *  - true: if update should stop
 97 *  - false: otherwise
 98 */
 99static bool amd_check_current_patch_level(void)
100{
101	u32 lvl, dummy, i;
102	u32 *levels;
103
104	native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
105
106	if (IS_ENABLED(CONFIG_X86_32))
107		levels = (u32 *)__pa_nodebug(&final_levels);
108	else
109		levels = final_levels;
110
111	for (i = 0; levels[i]; i++) {
112		if (lvl == levels[i])
113			return true;
114	}
115	return false;
116}
117
118static bool __init check_loader_disabled_bsp(void)
119{
120	static const char *__dis_opt_str = "dis_ucode_ldr";
121
122#ifdef CONFIG_X86_32
123	const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
124	const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
125	bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
126
127#else /* CONFIG_X86_64 */
128	const char *cmdline = boot_command_line;
129	const char *option  = __dis_opt_str;
130	bool *res = &dis_ucode_ldr;
131#endif
132
133	/*
134	 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
135	 * completely accurate as xen pv guests don't see that CPUID bit set but
136	 * that's good enough as they don't land on the BSP path anyway.
137	 */
138	if (native_cpuid_ecx(1) & BIT(31))
139		return *res;
140
141	if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
142		if (amd_check_current_patch_level())
143			return *res;
144	}
145
146	if (cmdline_find_option_bool(cmdline, option) <= 0)
147		*res = false;
148
149	return *res;
150}
151
152extern struct builtin_fw __start_builtin_fw[];
153extern struct builtin_fw __end_builtin_fw[];
154
155bool get_builtin_firmware(struct cpio_data *cd, const char *name)
156{
157#ifdef CONFIG_FW_LOADER
158	struct builtin_fw *b_fw;
159
160	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
161		if (!strcmp(name, b_fw->name)) {
162			cd->size = b_fw->size;
163			cd->data = b_fw->data;
164			return true;
165		}
166	}
167#endif
168	return false;
169}
170
171void __init load_ucode_bsp(void)
172{
173	unsigned int cpuid_1_eax;
174	bool intel = true;
175
176	if (!have_cpuid_p())
177		return;
178
179	cpuid_1_eax = native_cpuid_eax(1);
180
181	switch (x86_cpuid_vendor()) {
182	case X86_VENDOR_INTEL:
183		if (x86_family(cpuid_1_eax) < 6)
184			return;
185		break;
186
187	case X86_VENDOR_AMD:
188		if (x86_family(cpuid_1_eax) < 0x10)
189			return;
190		intel = false;
191		break;
192
193	default:
194		return;
195	}
196
197	if (check_loader_disabled_bsp())
198		return;
199
200	if (intel)
201		load_ucode_intel_bsp();
202	else
203		load_ucode_amd_bsp(cpuid_1_eax);
204}
205
206static bool check_loader_disabled_ap(void)
207{
208#ifdef CONFIG_X86_32
209	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
210#else
211	return dis_ucode_ldr;
212#endif
213}
214
215void load_ucode_ap(void)
216{
217	unsigned int cpuid_1_eax;
218
219	if (check_loader_disabled_ap())
220		return;
221
222	cpuid_1_eax = native_cpuid_eax(1);
223
224	switch (x86_cpuid_vendor()) {
225	case X86_VENDOR_INTEL:
226		if (x86_family(cpuid_1_eax) >= 6)
227			load_ucode_intel_ap();
228		break;
229	case X86_VENDOR_AMD:
230		if (x86_family(cpuid_1_eax) >= 0x10)
231			load_ucode_amd_ap(cpuid_1_eax);
232		break;
233	default:
234		break;
235	}
236}
237
238static int __init save_microcode_in_initrd(void)
239{
240	struct cpuinfo_x86 *c = &boot_cpu_data;
241	int ret = -EINVAL;
242
243	switch (c->x86_vendor) {
244	case X86_VENDOR_INTEL:
245		if (c->x86 >= 6)
246			ret = save_microcode_in_initrd_intel();
247		break;
248	case X86_VENDOR_AMD:
249		if (c->x86 >= 0x10)
250			ret = save_microcode_in_initrd_amd(cpuid_eax(1));
251		break;
252	default:
253		break;
254	}
255
256	initrd_gone = true;
257
258	return ret;
259}
260
261struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
262{
263#ifdef CONFIG_BLK_DEV_INITRD
264	unsigned long start = 0;
265	size_t size;
266
267#ifdef CONFIG_X86_32
268	struct boot_params *params;
269
270	if (use_pa)
271		params = (struct boot_params *)__pa_nodebug(&boot_params);
272	else
273		params = &boot_params;
274
275	size = params->hdr.ramdisk_size;
276
277	/*
278	 * Set start only if we have an initrd image. We cannot use initrd_start
279	 * because it is not set that early yet.
280	 */
281	if (size)
282		start = params->hdr.ramdisk_image;
283
284# else /* CONFIG_X86_64 */
285	size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
286	size |= boot_params.hdr.ramdisk_size;
287
288	if (size) {
289		start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
290		start |= boot_params.hdr.ramdisk_image;
291
292		start += PAGE_OFFSET;
293	}
294# endif
295
296	/*
297	 * Fixup the start address: after reserve_initrd() runs, initrd_start
298	 * has the virtual address of the beginning of the initrd. It also
299	 * possibly relocates the ramdisk. In either case, initrd_start contains
300	 * the updated address so use that instead.
301	 *
302	 * initrd_gone is for the hotplug case where we've thrown out initrd
303	 * already.
304	 */
305	if (!use_pa) {
306		if (initrd_gone)
307			return (struct cpio_data){ NULL, 0, "" };
308		if (initrd_start)
309			start = initrd_start;
310	} else {
311		/*
312		 * The picture with physical addresses is a bit different: we
313		 * need to get the *physical* address to which the ramdisk was
314		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
315		 * since we're running from physical addresses, we need to access
316		 * relocated_ramdisk through its *physical* address too.
317		 */
318		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
319		if (*rr)
320			start = *rr;
321	}
322
323	return find_cpio_data(path, (void *)start, size, NULL);
324#else /* !CONFIG_BLK_DEV_INITRD */
325	return (struct cpio_data){ NULL, 0, "" };
326#endif
327}
328
329void reload_early_microcode(void)
330{
331	int vendor, family;
332
333	vendor = x86_cpuid_vendor();
334	family = x86_cpuid_family();
335
336	switch (vendor) {
337	case X86_VENDOR_INTEL:
338		if (family >= 6)
339			reload_ucode_intel();
340		break;
341	case X86_VENDOR_AMD:
342		if (family >= 0x10)
343			reload_ucode_amd();
344		break;
345	default:
346		break;
347	}
348}
349
350static void collect_cpu_info_local(void *arg)
351{
352	struct cpu_info_ctx *ctx = arg;
353
354	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
355						   ctx->cpu_sig);
356}
357
358static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
359{
360	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
361	int ret;
362
363	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
364	if (!ret)
365		ret = ctx.err;
366
367	return ret;
368}
369
370static int collect_cpu_info(int cpu)
371{
372	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
373	int ret;
374
375	memset(uci, 0, sizeof(*uci));
376
377	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
378	if (!ret)
379		uci->valid = 1;
380
381	return ret;
382}
383
384static void apply_microcode_local(void *arg)
385{
386	enum ucode_state *err = arg;
387
388	*err = microcode_ops->apply_microcode(smp_processor_id());
389}
390
391static int apply_microcode_on_target(int cpu)
392{
393	enum ucode_state err;
394	int ret;
395
396	ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
397	if (!ret) {
398		if (err == UCODE_ERROR)
399			ret = 1;
400	}
401	return ret;
402}
403
404#ifdef CONFIG_MICROCODE_OLD_INTERFACE
405static int do_microcode_update(const void __user *buf, size_t size)
406{
407	int error = 0;
408	int cpu;
409
410	for_each_online_cpu(cpu) {
411		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
412		enum ucode_state ustate;
413
414		if (!uci->valid)
415			continue;
416
417		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
418		if (ustate == UCODE_ERROR) {
419			error = -1;
420			break;
421		} else if (ustate == UCODE_OK)
422			apply_microcode_on_target(cpu);
423	}
424
425	return error;
426}
427
428static int microcode_open(struct inode *inode, struct file *file)
429{
430	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
431}
432
433static ssize_t microcode_write(struct file *file, const char __user *buf,
434			       size_t len, loff_t *ppos)
435{
436	ssize_t ret = -EINVAL;
437
438	if ((len >> PAGE_SHIFT) > totalram_pages) {
439		pr_err("too much data (max %ld pages)\n", totalram_pages);
440		return ret;
441	}
442
443	get_online_cpus();
444	mutex_lock(&microcode_mutex);
445
446	if (do_microcode_update(buf, len) == 0)
447		ret = (ssize_t)len;
448
449	if (ret > 0)
450		perf_check_microcode();
451
452	mutex_unlock(&microcode_mutex);
453	put_online_cpus();
454
455	return ret;
456}
457
458static const struct file_operations microcode_fops = {
459	.owner			= THIS_MODULE,
460	.write			= microcode_write,
461	.open			= microcode_open,
462	.llseek		= no_llseek,
463};
464
465static struct miscdevice microcode_dev = {
466	.minor			= MICROCODE_MINOR,
467	.name			= "microcode",
468	.nodename		= "cpu/microcode",
469	.fops			= &microcode_fops,
470};
471
472static int __init microcode_dev_init(void)
473{
474	int error;
475
476	error = misc_register(&microcode_dev);
477	if (error) {
478		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
479		return error;
480	}
481
482	return 0;
483}
484
485static void __exit microcode_dev_exit(void)
486{
487	misc_deregister(&microcode_dev);
488}
489#else
490#define microcode_dev_init()	0
491#define microcode_dev_exit()	do { } while (0)
492#endif
493
494/* fake device for request_firmware */
495static struct platform_device	*microcode_pdev;
496
 
497/*
498 * Late loading dance. Why the heavy-handed stomp_machine effort?
499 *
500 * - HT siblings must be idle and not execute other code while the other sibling
501 *   is loading microcode in order to avoid any negative interactions caused by
502 *   the loading.
503 *
504 * - In addition, microcode update on the cores must be serialized until this
505 *   requirement can be relaxed in the future. Right now, this is conservative
506 *   and good.
507 */
508#define SPINUNIT 100 /* 100 nsec */
509
510static int check_online_cpus(void)
511{
512	if (num_online_cpus() == num_present_cpus())
513		return 0;
514
515	pr_err("Not all CPUs online, aborting microcode update.\n");
 
 
 
 
 
 
 
 
 
516
517	return -EINVAL;
518}
519
520static atomic_t late_cpus_in;
521static atomic_t late_cpus_out;
522
523static int __wait_for_cpus(atomic_t *t, long long timeout)
524{
525	int all_cpus = num_online_cpus();
526
527	atomic_inc(t);
528
529	while (atomic_read(t) < all_cpus) {
530		if (timeout < SPINUNIT) {
531			pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
532				all_cpus - atomic_read(t));
533			return 1;
534		}
535
536		ndelay(SPINUNIT);
537		timeout -= SPINUNIT;
538
539		touch_nmi_watchdog();
540	}
541	return 0;
542}
543
544/*
545 * Returns:
546 * < 0 - on error
547 *   0 - no update done
548 *   1 - microcode was updated
549 */
550static int __reload_late(void *info)
551{
552	int cpu = smp_processor_id();
553	enum ucode_state err;
554	int ret = 0;
555
556	/*
557	 * Wait for all CPUs to arrive. A load will not be attempted unless all
558	 * CPUs show up.
559	 * */
560	if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
561		return -1;
562
563	spin_lock(&update_lock);
564	apply_microcode_local(&err);
565	spin_unlock(&update_lock);
566
567	/* siblings return UCODE_OK because their engine got updated already */
568	if (err > UCODE_NFOUND) {
569		pr_warn("Error reloading microcode on CPU %d\n", cpu);
 
 
 
 
 
 
 
 
 
570		ret = -1;
571	} else if (err == UCODE_UPDATED || err == UCODE_OK) {
572		ret = 1;
573	}
574
 
 
 
 
575	/*
576	 * Increase the wait timeout to a safe value here since we're
577	 * serializing the microcode update and that could take a while on a
578	 * large number of CPUs. And that is fine as the *actual* timeout will
579	 * be determined by the last CPU finished updating and thus cut short.
580	 */
581	if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC * num_online_cpus()))
582		panic("Timeout during microcode update!\n");
583
584	return ret;
585}
586
587/*
588 * Reload microcode late on all CPUs. Wait for a sec until they
589 * all gather together.
590 */
591static int microcode_reload_late(void)
592{
593	int ret;
 
 
 
594
595	atomic_set(&late_cpus_in,  0);
596	atomic_set(&late_cpus_out, 0);
597
598	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
599	if (ret > 0)
600		microcode_check();
601
 
 
 
602	return ret;
603}
604
605static ssize_t reload_store(struct device *dev,
606			    struct device_attribute *attr,
607			    const char *buf, size_t size)
608{
609	enum ucode_state tmp_ret = UCODE_OK;
610	int bsp = boot_cpu_data.cpu_index;
611	unsigned long val;
612	ssize_t ret = 0;
613
614	ret = kstrtoul(buf, 0, &val);
615	if (ret)
616		return ret;
617
618	if (val != 1)
619		return size;
620
621	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
622	if (tmp_ret != UCODE_NEW)
623		return size;
624
625	get_online_cpus();
626
627	ret = check_online_cpus();
628	if (ret)
629		goto put;
630
 
 
 
 
631	mutex_lock(&microcode_mutex);
632	ret = microcode_reload_late();
633	mutex_unlock(&microcode_mutex);
634
635put:
636	put_online_cpus();
637
638	if (ret >= 0)
639		ret = size;
640
 
 
641	return ret;
642}
643
 
 
 
644static ssize_t version_show(struct device *dev,
645			struct device_attribute *attr, char *buf)
646{
647	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
648
649	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
650}
651
652static ssize_t pf_show(struct device *dev,
653			struct device_attribute *attr, char *buf)
654{
655	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
656
657	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
658}
659
660static DEVICE_ATTR_WO(reload);
661static DEVICE_ATTR(version, 0400, version_show, NULL);
662static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
663
664static struct attribute *mc_default_attrs[] = {
665	&dev_attr_version.attr,
666	&dev_attr_processor_flags.attr,
667	NULL
668};
669
670static const struct attribute_group mc_attr_group = {
671	.attrs			= mc_default_attrs,
672	.name			= "microcode",
673};
674
675static void microcode_fini_cpu(int cpu)
676{
677	if (microcode_ops->microcode_fini_cpu)
678		microcode_ops->microcode_fini_cpu(cpu);
679}
680
681static enum ucode_state microcode_resume_cpu(int cpu)
682{
683	if (apply_microcode_on_target(cpu))
684		return UCODE_ERROR;
685
686	pr_debug("CPU%d updated upon resume\n", cpu);
687
688	return UCODE_OK;
689}
690
691static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
692{
693	enum ucode_state ustate;
694	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
695
696	if (uci->valid)
697		return UCODE_OK;
698
699	if (collect_cpu_info(cpu))
700		return UCODE_ERROR;
701
702	/* --dimm. Trigger a delayed update? */
703	if (system_state != SYSTEM_RUNNING)
704		return UCODE_NFOUND;
705
706	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
707	if (ustate == UCODE_NEW) {
708		pr_debug("CPU%d updated upon init\n", cpu);
709		apply_microcode_on_target(cpu);
710	}
711
712	return ustate;
713}
714
715static enum ucode_state microcode_update_cpu(int cpu)
716{
717	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
718
719	/* Refresh CPU microcode revision after resume. */
720	collect_cpu_info(cpu);
721
722	if (uci->valid)
723		return microcode_resume_cpu(cpu);
724
725	return microcode_init_cpu(cpu, false);
726}
727
728static int mc_device_add(struct device *dev, struct subsys_interface *sif)
729{
730	int err, cpu = dev->id;
731
732	if (!cpu_online(cpu))
733		return 0;
734
735	pr_debug("CPU%d added\n", cpu);
736
737	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
738	if (err)
739		return err;
740
741	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
742		return -EINVAL;
743
744	return err;
745}
746
747static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
748{
749	int cpu = dev->id;
750
751	if (!cpu_online(cpu))
752		return;
753
754	pr_debug("CPU%d removed\n", cpu);
755	microcode_fini_cpu(cpu);
756	sysfs_remove_group(&dev->kobj, &mc_attr_group);
757}
758
759static struct subsys_interface mc_cpu_interface = {
760	.name			= "microcode",
761	.subsys			= &cpu_subsys,
762	.add_dev		= mc_device_add,
763	.remove_dev		= mc_device_remove,
764};
765
766/**
767 * mc_bp_resume - Update boot CPU microcode during resume.
768 */
769static void mc_bp_resume(void)
770{
771	int cpu = smp_processor_id();
772	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
773
774	if (uci->valid && uci->mc)
775		microcode_ops->apply_microcode(cpu);
776	else if (!uci->mc)
777		reload_early_microcode();
778}
779
780static struct syscore_ops mc_syscore_ops = {
781	.resume			= mc_bp_resume,
782};
783
784static int mc_cpu_online(unsigned int cpu)
785{
786	struct device *dev;
787
788	dev = get_cpu_device(cpu);
789	microcode_update_cpu(cpu);
790	pr_debug("CPU%d added\n", cpu);
 
 
 
 
 
791
792	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
793		pr_err("Failed to create group for CPU%d\n", cpu);
794	return 0;
795}
796
797static int mc_cpu_down_prep(unsigned int cpu)
798{
799	struct device *dev;
800
801	dev = get_cpu_device(cpu);
 
 
 
802	/* Suspend is in progress, only remove the interface */
803	sysfs_remove_group(&dev->kobj, &mc_attr_group);
804	pr_debug("CPU%d removed\n", cpu);
805
806	return 0;
807}
808
 
 
 
 
 
 
 
 
 
 
 
 
 
 
809static struct attribute *cpu_root_microcode_attrs[] = {
 
810	&dev_attr_reload.attr,
 
811	NULL
812};
813
814static const struct attribute_group cpu_root_microcode_group = {
815	.name  = "microcode",
816	.attrs = cpu_root_microcode_attrs,
817};
818
819int __init microcode_init(void)
820{
821	struct cpuinfo_x86 *c = &boot_cpu_data;
822	int error;
823
824	if (dis_ucode_ldr)
825		return -EINVAL;
826
827	if (c->x86_vendor == X86_VENDOR_INTEL)
828		microcode_ops = init_intel_microcode();
829	else if (c->x86_vendor == X86_VENDOR_AMD)
830		microcode_ops = init_amd_microcode();
831	else
832		pr_err("no support for this CPU vendor\n");
833
834	if (!microcode_ops)
835		return -ENODEV;
836
837	microcode_pdev = platform_device_register_simple("microcode", -1,
838							 NULL, 0);
839	if (IS_ERR(microcode_pdev))
840		return PTR_ERR(microcode_pdev);
841
842	get_online_cpus();
843	mutex_lock(&microcode_mutex);
844
845	error = subsys_interface_register(&mc_cpu_interface);
846	if (!error)
847		perf_check_microcode();
848	mutex_unlock(&microcode_mutex);
849	put_online_cpus();
850
851	if (error)
852		goto out_pdev;
853
854	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
855				   &cpu_root_microcode_group);
856
857	if (error) {
858		pr_err("Error creating microcode group!\n");
859		goto out_driver;
860	}
861
862	error = microcode_dev_init();
863	if (error)
864		goto out_ucode_group;
865
866	register_syscore_ops(&mc_syscore_ops);
 
 
867	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
868				  mc_cpu_online, mc_cpu_down_prep);
869
870	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
871
872	return 0;
873
874 out_ucode_group:
875	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
876			   &cpu_root_microcode_group);
877
878 out_driver:
879	get_online_cpus();
880	mutex_lock(&microcode_mutex);
881
882	subsys_interface_unregister(&mc_cpu_interface);
883
884	mutex_unlock(&microcode_mutex);
885	put_online_cpus();
886
887 out_pdev:
888	platform_device_unregister(microcode_pdev);
889	return error;
890
891}
892fs_initcall(save_microcode_in_initrd);
893late_initcall(microcode_init);