summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/microcode/core.c
blob: 319dd65f98a25530d3a55cb6ea1cf61f6c2004bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
/*
 * CPU Microcode Update Driver for Linux
 *
 * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
 *	      2006	Shaohua Li <shaohua.li@intel.com>
 *	      2013-2016	Borislav Petkov <bp@alien8.de>
 *
 * X86 CPU microcode early update for Linux:
 *
 *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
 *			   H Peter Anvin" <hpa@zytor.com>
 *		  (C) 2015 Borislav Petkov <bp@alien8.de>
 *
 * This driver allows to upgrade microcode on x86 processors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#define pr_fmt(fmt) "microcode: " fmt

#include <linux/platform_device.h>
#include <linux/syscore_ops.h>
#include <linux/miscdevice.h>
#include <linux/capability.h>
#include <linux/firmware.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/mm.h>

#include <asm/microcode_intel.h>
#include <asm/cpu_device_id.h>
#include <asm/microcode_amd.h>
#include <asm/perf_event.h>
#include <asm/microcode.h>
#include <asm/processor.h>
#include <asm/cmdline.h>
#include <asm/setup.h>

#define DRIVER_VERSION	"2.2"

static struct microcode_ops	*microcode_ops;
static bool dis_ucode_ldr = true;

bool initrd_gone;

LIST_HEAD(microcode_cache);

/*
 * Synchronization.
 *
 * All non cpu-hotplug-callback call sites use:
 *
 * - microcode_mutex to synchronize with each other;
 * - get/put_online_cpus() to synchronize with
 *   the cpu-hotplug-callback call sites.
 *
 * We guarantee that only a single cpu is being
 * updated at any particular moment of time.
 */
static DEFINE_MUTEX(microcode_mutex);

struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];

struct cpu_info_ctx {
	struct cpu_signature	*cpu_sig;
	int			err;
};

/*
 * Those patch levels cannot be updated to newer ones and thus should be final.
 */
static u32 final_levels[] = {
	0x01000098,
	0x0100009f,
	0x010000af,
	0, /* T-101 terminator */
};

/*
 * Check the current patch level on this CPU.
 *
 * Returns:
 *  - true: if update should stop
 *  - false: otherwise
 */
static bool amd_check_current_patch_level(void)
{
	u32 lvl, dummy, i;
	u32 *levels;

	native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);

	if (IS_ENABLED(CONFIG_X86_32))
		levels = (u32 *)__pa_nodebug(&final_levels);
	else
		levels = final_levels;

	for (i = 0; levels[i]; i++) {
		if (lvl == levels[i])
			return true;
	}
	return false;
}

static bool __init check_loader_disabled_bsp(void)
{
	static const char *__dis_opt_str = "dis_ucode_ldr";

#ifdef CONFIG_X86_32
	const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
	const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
	bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);

#else /* CONFIG_X86_64 */
	const char *cmdline = boot_command_line;
	const char *option  = __dis_opt_str;
	bool *res = &dis_ucode_ldr;
#endif

	/*
	 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
	 * completely accurate as xen pv guests don't see that CPUID bit set but
	 * that's good enough as they don't land on the BSP path anyway.
	 */
	if (native_cpuid_ecx(1) & BIT(31))
		return *res;

	if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
		if (amd_check_current_patch_level())
			return *res;
	}

	if (cmdline_find_option_bool(cmdline, option) <= 0)
		*res = false;

	return *res;
}

extern struct builtin_fw __start_builtin_fw[];
extern struct builtin_fw __end_builtin_fw[];

bool get_builtin_firmware(struct cpio_data *cd, const char *name)
{
#ifdef CONFIG_FW_LOADER
	struct builtin_fw *b_fw;

	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
		if (!strcmp(name, b_fw->name)) {
			cd->size = b_fw->size;
			cd->data = b_fw->data;
			return true;
		}
	}
#endif
	return false;
}

void __init load_ucode_bsp(void)
{
	unsigned int cpuid_1_eax;
	bool intel = true;

	if (!have_cpuid_p())
		return;

	cpuid_1_eax = native_cpuid_eax(1);

	switch (x86_cpuid_vendor()) {
	case X86_VENDOR_INTEL:
		if (x86_family(cpuid_1_eax) < 6)
			return;
		break;

	case X86_VENDOR_AMD:
		if (x86_family(cpuid_1_eax) < 0x10)
			return;
		intel = false;
		break;

	default:
		return;
	}

	if (check_loader_disabled_bsp())
		return;

	if (intel)
		load_ucode_intel_bsp();
	else
		load_ucode_amd_bsp(cpuid_1_eax);
}

static bool check_loader_disabled_ap(void)
{
#ifdef CONFIG_X86_32
	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
#else
	return dis_ucode_ldr;
#endif
}

void load_ucode_ap(void)
{
	unsigned int cpuid_1_eax;

	if (check_loader_disabled_ap())
		return;

	cpuid_1_eax = native_cpuid_eax(1);

	switch (x86_cpuid_vendor()) {
	case X86_VENDOR_INTEL:
		if (x86_family(cpuid_1_eax) >= 6)
			load_ucode_intel_ap();
		break;
	case X86_VENDOR_AMD:
		if (x86_family(cpuid_1_eax) >= 0x10)
			load_ucode_amd_ap(cpuid_1_eax);
		break;
	default:
		break;
	}
}

static int __init save_microcode_in_initrd(void)
{
	struct cpuinfo_x86 *c = &boot_cpu_data;
	int ret = -EINVAL;

	switch (c->x86_vendor) {
	case X86_VENDOR_INTEL:
		if (c->x86 >= 6)
			ret = save_microcode_in_initrd_intel();
		break;
	case X86_VENDOR_AMD:
		if (c->x86 >= 0x10)
			ret = save_microcode_in_initrd_amd(cpuid_eax(1));
		break;
	default:
		break;
	}

	initrd_gone = true;

	return ret;
}

struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
{
#ifdef CONFIG_BLK_DEV_INITRD
	unsigned long start = 0;
	size_t size;

#ifdef CONFIG_X86_32
	struct boot_params *params;

	if (use_pa)
		params = (struct boot_params *)__pa_nodebug(&boot_params);
	else
		params = &boot_params;

	size = params->hdr.ramdisk_size;

	/*
	 * Set start only if we have an initrd image. We cannot use initrd_start
	 * because it is not set that early yet.
	 */
	if (size)
		start = params->hdr.ramdisk_image;

# else /* CONFIG_X86_64 */
	size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
	size |= boot_params.hdr.ramdisk_size;

	if (size) {
		start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
		start |= boot_params.hdr.ramdisk_image;

		start += PAGE_OFFSET;
	}
# endif

	/*
	 * Fixup the start address: after reserve_initrd() runs, initrd_start
	 * has the virtual address of the beginning of the initrd. It also
	 * possibly relocates the ramdisk. In either case, initrd_start contains
	 * the updated address so use that instead.
	 *
	 * initrd_gone is for the hotplug case where we've thrown out initrd
	 * already.
	 */
	if (!use_pa) {
		if (initrd_gone)
			return (struct cpio_data){ NULL, 0, "" };
		if (initrd_start)
			start = initrd_start;
	} else {
		/*
		 * The picture with physical addresses is a bit different: we
		 * need to get the *physical* address to which the ramdisk was
		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
		 * since we're running from physical addresses, we need to access
		 * relocated_ramdisk through its *physical* address too.
		 */
		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
		if (*rr)
			start = *rr;
	}

	return find_cpio_data(path, (void *)start, size, NULL);
#else /* !CONFIG_BLK_DEV_INITRD */
	return (struct cpio_data){ NULL, 0, "" };
#endif
}

void reload_early_microcode(void)
{
	int vendor, family;

	vendor = x86_cpuid_vendor();
	family = x86_cpuid_family();

	switch (vendor) {
	case X86_VENDOR_INTEL:
		if (family >= 6)
			reload_ucode_intel();
		break;
	case X86_VENDOR_AMD:
		if (family >= 0x10)
			reload_ucode_amd();
		break;
	default:
		break;
	}
}

static void collect_cpu_info_local(void *arg)
{
	struct cpu_info_ctx *ctx = arg;

	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
						   ctx->cpu_sig);
}

static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
{
	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
	int ret;

	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
	if (!ret)
		ret = ctx.err;

	return ret;
}

static int collect_cpu_info(int cpu)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	int ret;

	memset(uci, 0, sizeof(*uci));

	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
	if (!ret)
		uci->valid = 1;

	return ret;
}

struct apply_microcode_ctx {
	int err;
};

static void apply_microcode_local(void *arg)
{
	struct apply_microcode_ctx *ctx = arg;

	ctx->err = microcode_ops->apply_microcode(smp_processor_id());
}

static int apply_microcode_on_target(int cpu)
{
	struct apply_microcode_ctx ctx = { .err = 0 };
	int ret;

	ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
	if (!ret)
		ret = ctx.err;

	return ret;
}

#ifdef CONFIG_MICROCODE_OLD_INTERFACE
static int do_microcode_update(const void __user *buf, size_t size)
{
	int error = 0;
	int cpu;

	for_each_online_cpu(cpu) {
		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
		enum ucode_state ustate;

		if (!uci->valid)
			continue;

		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
		if (ustate == UCODE_ERROR) {
			error = -1;
			break;
		} else if (ustate == UCODE_OK)
			apply_microcode_on_target(cpu);
	}

	return error;
}

static int microcode_open(struct inode *inode, struct file *file)
{
	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
}

static ssize_t microcode_write(struct file *file, const char __user *buf,
			       size_t len, loff_t *ppos)
{
	ssize_t ret = -EINVAL;

	if ((len >> PAGE_SHIFT) > totalram_pages) {
		pr_err("too much data (max %ld pages)\n", totalram_pages);
		return ret;
	}

	get_online_cpus();
	mutex_lock(&microcode_mutex);

	if (do_microcode_update(buf, len) == 0)
		ret = (ssize_t)len;

	if (ret > 0)
		perf_check_microcode();

	mutex_unlock(&microcode_mutex);
	put_online_cpus();

	return ret;
}

static const struct file_operations microcode_fops = {
	.owner			= THIS_MODULE,
	.write			= microcode_write,
	.open			= microcode_open,
	.llseek		= no_llseek,
};

static struct miscdevice microcode_dev = {
	.minor			= MICROCODE_MINOR,
	.name			= "microcode",
	.nodename		= "cpu/microcode",
	.fops			= &microcode_fops,
};

static int __init microcode_dev_init(void)
{
	int error;

	error = misc_register(&microcode_dev);
	if (error) {
		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
		return error;
	}

	return 0;
}

static void __exit microcode_dev_exit(void)
{
	misc_deregister(&microcode_dev);
}
#else
#define microcode_dev_init()	0
#define microcode_dev_exit()	do { } while (0)
#endif

/* fake device for request_firmware */
static struct platform_device	*microcode_pdev;

static int reload_for_cpu(int cpu)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	enum ucode_state ustate;
	int err = 0;

	if (!uci->valid)
		return err;

	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
	if (ustate == UCODE_OK)
		apply_microcode_on_target(cpu);
	else
		if (ustate == UCODE_ERROR)
			err = -EINVAL;
	return err;
}

static ssize_t reload_store(struct device *dev,
			    struct device_attribute *attr,
			    const char *buf, size_t size)
{
	unsigned long val;
	int cpu;
	ssize_t ret = 0, tmp_ret;

	ret = kstrtoul(buf, 0, &val);
	if (ret)
		return ret;

	if (val != 1)
		return size;

	get_online_cpus();
	mutex_lock(&microcode_mutex);
	for_each_online_cpu(cpu) {
		tmp_ret = reload_for_cpu(cpu);
		if (tmp_ret != 0)
			pr_warn("Error reloading microcode on CPU %d\n", cpu);

		/* save retval of the first encountered reload error */
		if (!ret)
			ret = tmp_ret;
	}
	if (!ret)
		perf_check_microcode();
	mutex_unlock(&microcode_mutex);
	put_online_cpus();

	if (!ret)
		ret = size;

	return ret;
}

static ssize_t version_show(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
}

static ssize_t pf_show(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
}

static DEVICE_ATTR_WO(reload);
static DEVICE_ATTR(version, 0400, version_show, NULL);
static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);

static struct attribute *mc_default_attrs[] = {
	&dev_attr_version.attr,
	&dev_attr_processor_flags.attr,
	NULL
};

static const struct attribute_group mc_attr_group = {
	.attrs			= mc_default_attrs,
	.name			= "microcode",
};

static void microcode_fini_cpu(int cpu)
{
	if (microcode_ops->microcode_fini_cpu)
		microcode_ops->microcode_fini_cpu(cpu);
}

static enum ucode_state microcode_resume_cpu(int cpu)
{
	if (apply_microcode_on_target(cpu))
		return UCODE_ERROR;

	pr_debug("CPU%d updated upon resume\n", cpu);

	return UCODE_OK;
}

static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
{
	enum ucode_state ustate;
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	if (uci->valid)
		return UCODE_OK;

	if (collect_cpu_info(cpu))
		return UCODE_ERROR;

	/* --dimm. Trigger a delayed update? */
	if (system_state != SYSTEM_RUNNING)
		return UCODE_NFOUND;

	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
						     refresh_fw);

	if (ustate == UCODE_OK) {
		pr_debug("CPU%d updated upon init\n", cpu);
		apply_microcode_on_target(cpu);
	}

	return ustate;
}

static enum ucode_state microcode_update_cpu(int cpu)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	/* Refresh CPU microcode revision after resume. */
	collect_cpu_info(cpu);

	if (uci->valid)
		return microcode_resume_cpu(cpu);

	return microcode_init_cpu(cpu, false);
}

static int mc_device_add(struct device *dev, struct subsys_interface *sif)
{
	int err, cpu = dev->id;

	if (!cpu_online(cpu))
		return 0;

	pr_debug("CPU%d added\n", cpu);

	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
	if (err)
		return err;

	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
		return -EINVAL;

	return err;
}

static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
{
	int cpu = dev->id;

	if (!cpu_online(cpu))
		return;

	pr_debug("CPU%d removed\n", cpu);
	microcode_fini_cpu(cpu);
	sysfs_remove_group(&dev->kobj, &mc_attr_group);
}

static struct subsys_interface mc_cpu_interface = {
	.name			= "microcode",
	.subsys			= &cpu_subsys,
	.add_dev		= mc_device_add,
	.remove_dev		= mc_device_remove,
};

/**
 * mc_bp_resume - Update boot CPU microcode during resume.
 */
static void mc_bp_resume(void)
{
	int cpu = smp_processor_id();
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	if (uci->valid && uci->mc)
		microcode_ops->apply_microcode(cpu);
	else if (!uci->mc)
		reload_early_microcode();
}

static struct syscore_ops mc_syscore_ops = {
	.resume			= mc_bp_resume,
};

static int mc_cpu_online(unsigned int cpu)
{
	struct device *dev;

	dev = get_cpu_device(cpu);
	microcode_update_cpu(cpu);
	pr_debug("CPU%d added\n", cpu);

	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
		pr_err("Failed to create group for CPU%d\n", cpu);
	return 0;
}

static int mc_cpu_down_prep(unsigned int cpu)
{
	struct device *dev;

	dev = get_cpu_device(cpu);
	/* Suspend is in progress, only remove the interface */
	sysfs_remove_group(&dev->kobj, &mc_attr_group);
	pr_debug("CPU%d removed\n", cpu);

	return 0;
}

static struct attribute *cpu_root_microcode_attrs[] = {
	&dev_attr_reload.attr,
	NULL
};

static const struct attribute_group cpu_root_microcode_group = {
	.name  = "microcode",
	.attrs = cpu_root_microcode_attrs,
};

int __init microcode_init(void)
{
	struct cpuinfo_x86 *c = &boot_cpu_data;
	int error;

	if (dis_ucode_ldr)
		return -EINVAL;

	if (c->x86_vendor == X86_VENDOR_INTEL)
		microcode_ops = init_intel_microcode();
	else if (c->x86_vendor == X86_VENDOR_AMD)
		microcode_ops = init_amd_microcode();
	else
		pr_err("no support for this CPU vendor\n");

	if (!microcode_ops)
		return -ENODEV;

	microcode_pdev = platform_device_register_simple("microcode", -1,
							 NULL, 0);
	if (IS_ERR(microcode_pdev))
		return PTR_ERR(microcode_pdev);

	get_online_cpus();
	mutex_lock(&microcode_mutex);

	error = subsys_interface_register(&mc_cpu_interface);
	if (!error)
		perf_check_microcode();
	mutex_unlock(&microcode_mutex);
	put_online_cpus();

	if (error)
		goto out_pdev;

	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
				   &cpu_root_microcode_group);

	if (error) {
		pr_err("Error creating microcode group!\n");
		goto out_driver;
	}

	error = microcode_dev_init();
	if (error)
		goto out_ucode_group;

	register_syscore_ops(&mc_syscore_ops);
	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
				  mc_cpu_online, mc_cpu_down_prep);

	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);

	return 0;

 out_ucode_group:
	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
			   &cpu_root_microcode_group);

 out_driver:
	get_online_cpus();
	mutex_lock(&microcode_mutex);

	subsys_interface_unregister(&mc_cpu_interface);

	mutex_unlock(&microcode_mutex);
	put_online_cpus();

 out_pdev:
	platform_device_unregister(microcode_pdev);
	return error;

}
fs_initcall(save_microcode_in_initrd);
late_initcall(microcode_init);
OpenPOWER on IntegriCloud