1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * CPU Microcode Update Driver for Linux
4 *
5 * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
6 * 2006 Shaohua Li <shaohua.li@intel.com>
7 * 2013-2016 Borislav Petkov <bp@alien8.de>
8 *
9 * X86 CPU microcode early update for Linux:
10 *
11 * Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
12 * H Peter Anvin" <hpa@zytor.com>
13 * (C) 2015 Borislav Petkov <bp@alien8.de>
14 *
15 * This driver allows to upgrade microcode on x86 processors.
16 */
17
18 #define pr_fmt(fmt) "microcode: " fmt
19
20 #include <linux/platform_device.h>
21 #include <linux/stop_machine.h>
22 #include <linux/syscore_ops.h>
23 #include <linux/miscdevice.h>
24 #include <linux/capability.h>
25 #include <linux/firmware.h>
26 #include <linux/kernel.h>
27 #include <linux/delay.h>
28 #include <linux/mutex.h>
29 #include <linux/cpu.h>
30 #include <linux/nmi.h>
31 #include <linux/fs.h>
32 #include <linux/mm.h>
33
34 #include <asm/microcode_intel.h>
35 #include <asm/cpu_device_id.h>
36 #include <asm/microcode_amd.h>
37 #include <asm/perf_event.h>
38 #include <asm/microcode.h>
39 #include <asm/processor.h>
40 #include <asm/cmdline.h>
41 #include <asm/setup.h>
42
43 #define DRIVER_VERSION "2.2"
44
45 static struct microcode_ops *microcode_ops;
46 static bool dis_ucode_ldr = true;
47
48 bool initrd_gone;
49
50 LIST_HEAD(microcode_cache);
51
52 /*
53 * Synchronization.
54 *
55 * All non cpu-hotplug-callback call sites use:
56 *
57 * - microcode_mutex to synchronize with each other;
58 * - cpus_read_lock/unlock() to synchronize with
59 * the cpu-hotplug-callback call sites.
60 *
61 * We guarantee that only a single cpu is being
62 * updated at any particular moment of time.
63 */
64 static DEFINE_MUTEX(microcode_mutex);
65
66 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
67
68 struct cpu_info_ctx {
69 struct cpu_signature *cpu_sig;
70 int err;
71 };
72
73 /*
74 * Those patch levels cannot be updated to newer ones and thus should be final.
75 */
76 static u32 final_levels[] = {
77 0x01000098,
78 0x0100009f,
79 0x010000af,
80 0, /* T-101 terminator */
81 };
82
83 /*
84 * Check the current patch level on this CPU.
85 *
86 * Returns:
87 * - true: if update should stop
88 * - false: otherwise
89 */
amd_check_current_patch_level(void)90 static bool amd_check_current_patch_level(void)
91 {
92 u32 lvl, dummy, i;
93 u32 *levels;
94
95 native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
96
97 if (IS_ENABLED(CONFIG_X86_32))
98 levels = (u32 *)__pa_nodebug(&final_levels);
99 else
100 levels = final_levels;
101
102 for (i = 0; levels[i]; i++) {
103 if (lvl == levels[i])
104 return true;
105 }
106 return false;
107 }
108
check_loader_disabled_bsp(void)109 static bool __init check_loader_disabled_bsp(void)
110 {
111 static const char *__dis_opt_str = "dis_ucode_ldr";
112
113 #ifdef CONFIG_X86_32
114 const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
115 const char *option = (const char *)__pa_nodebug(__dis_opt_str);
116 bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
117
118 #else /* CONFIG_X86_64 */
119 const char *cmdline = boot_command_line;
120 const char *option = __dis_opt_str;
121 bool *res = &dis_ucode_ldr;
122 #endif
123
124 /*
125 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
126 * completely accurate as xen pv guests don't see that CPUID bit set but
127 * that's good enough as they don't land on the BSP path anyway.
128 */
129 if (native_cpuid_ecx(1) & BIT(31))
130 return *res;
131
132 if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
133 if (amd_check_current_patch_level())
134 return *res;
135 }
136
137 if (cmdline_find_option_bool(cmdline, option) <= 0)
138 *res = false;
139
140 return *res;
141 }
142
143 extern struct builtin_fw __start_builtin_fw[];
144 extern struct builtin_fw __end_builtin_fw[];
145
get_builtin_firmware(struct cpio_data * cd,const char * name)146 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
147 {
148 struct builtin_fw *b_fw;
149
150 for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
151 if (!strcmp(name, b_fw->name)) {
152 cd->size = b_fw->size;
153 cd->data = b_fw->data;
154 return true;
155 }
156 }
157 return false;
158 }
159
load_ucode_bsp(void)160 void __init load_ucode_bsp(void)
161 {
162 unsigned int cpuid_1_eax;
163 bool intel = true;
164
165 if (!have_cpuid_p())
166 return;
167
168 cpuid_1_eax = native_cpuid_eax(1);
169
170 switch (x86_cpuid_vendor()) {
171 case X86_VENDOR_INTEL:
172 if (x86_family(cpuid_1_eax) < 6)
173 return;
174 break;
175
176 case X86_VENDOR_AMD:
177 if (x86_family(cpuid_1_eax) < 0x10)
178 return;
179 intel = false;
180 break;
181
182 default:
183 return;
184 }
185
186 if (check_loader_disabled_bsp())
187 return;
188
189 if (intel)
190 load_ucode_intel_bsp();
191 else
192 load_ucode_amd_bsp(cpuid_1_eax);
193 }
194
check_loader_disabled_ap(void)195 static bool check_loader_disabled_ap(void)
196 {
197 #ifdef CONFIG_X86_32
198 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
199 #else
200 return dis_ucode_ldr;
201 #endif
202 }
203
load_ucode_ap(void)204 void load_ucode_ap(void)
205 {
206 unsigned int cpuid_1_eax;
207
208 if (check_loader_disabled_ap())
209 return;
210
211 cpuid_1_eax = native_cpuid_eax(1);
212
213 switch (x86_cpuid_vendor()) {
214 case X86_VENDOR_INTEL:
215 if (x86_family(cpuid_1_eax) >= 6)
216 load_ucode_intel_ap();
217 break;
218 case X86_VENDOR_AMD:
219 if (x86_family(cpuid_1_eax) >= 0x10)
220 load_ucode_amd_ap(cpuid_1_eax);
221 break;
222 default:
223 break;
224 }
225 }
226
save_microcode_in_initrd(void)227 static int __init save_microcode_in_initrd(void)
228 {
229 struct cpuinfo_x86 *c = &boot_cpu_data;
230 int ret = -EINVAL;
231
232 switch (c->x86_vendor) {
233 case X86_VENDOR_INTEL:
234 if (c->x86 >= 6)
235 ret = save_microcode_in_initrd_intel();
236 break;
237 case X86_VENDOR_AMD:
238 if (c->x86 >= 0x10)
239 ret = save_microcode_in_initrd_amd(cpuid_eax(1));
240 break;
241 default:
242 break;
243 }
244
245 initrd_gone = true;
246
247 return ret;
248 }
249
find_microcode_in_initrd(const char * path,bool use_pa)250 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
251 {
252 #ifdef CONFIG_BLK_DEV_INITRD
253 unsigned long start = 0;
254 size_t size;
255
256 #ifdef CONFIG_X86_32
257 struct boot_params *params;
258
259 if (use_pa)
260 params = (struct boot_params *)__pa_nodebug(&boot_params);
261 else
262 params = &boot_params;
263
264 size = params->hdr.ramdisk_size;
265
266 /*
267 * Set start only if we have an initrd image. We cannot use initrd_start
268 * because it is not set that early yet.
269 */
270 if (size)
271 start = params->hdr.ramdisk_image;
272
273 # else /* CONFIG_X86_64 */
274 size = (unsigned long)boot_params.ext_ramdisk_size << 32;
275 size |= boot_params.hdr.ramdisk_size;
276
277 if (size) {
278 start = (unsigned long)boot_params.ext_ramdisk_image << 32;
279 start |= boot_params.hdr.ramdisk_image;
280
281 start += PAGE_OFFSET;
282 }
283 # endif
284
285 /*
286 * Fixup the start address: after reserve_initrd() runs, initrd_start
287 * has the virtual address of the beginning of the initrd. It also
288 * possibly relocates the ramdisk. In either case, initrd_start contains
289 * the updated address so use that instead.
290 *
291 * initrd_gone is for the hotplug case where we've thrown out initrd
292 * already.
293 */
294 if (!use_pa) {
295 if (initrd_gone)
296 return (struct cpio_data){ NULL, 0, "" };
297 if (initrd_start)
298 start = initrd_start;
299 } else {
300 /*
301 * The picture with physical addresses is a bit different: we
302 * need to get the *physical* address to which the ramdisk was
303 * relocated, i.e., relocated_ramdisk (not initrd_start) and
304 * since we're running from physical addresses, we need to access
305 * relocated_ramdisk through its *physical* address too.
306 */
307 u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
308 if (*rr)
309 start = *rr;
310 }
311
312 return find_cpio_data(path, (void *)start, size, NULL);
313 #else /* !CONFIG_BLK_DEV_INITRD */
314 return (struct cpio_data){ NULL, 0, "" };
315 #endif
316 }
317
reload_early_microcode(unsigned int cpu)318 void reload_early_microcode(unsigned int cpu)
319 {
320 int vendor, family;
321
322 vendor = x86_cpuid_vendor();
323 family = x86_cpuid_family();
324
325 switch (vendor) {
326 case X86_VENDOR_INTEL:
327 if (family >= 6)
328 reload_ucode_intel();
329 break;
330 case X86_VENDOR_AMD:
331 if (family >= 0x10)
332 reload_ucode_amd(cpu);
333 break;
334 default:
335 break;
336 }
337 }
338
collect_cpu_info_local(void * arg)339 static void collect_cpu_info_local(void *arg)
340 {
341 struct cpu_info_ctx *ctx = arg;
342
343 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
344 ctx->cpu_sig);
345 }
346
collect_cpu_info_on_target(int cpu,struct cpu_signature * cpu_sig)347 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
348 {
349 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
350 int ret;
351
352 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
353 if (!ret)
354 ret = ctx.err;
355
356 return ret;
357 }
358
collect_cpu_info(int cpu)359 static int collect_cpu_info(int cpu)
360 {
361 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
362 int ret;
363
364 memset(uci, 0, sizeof(*uci));
365
366 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
367 if (!ret)
368 uci->valid = 1;
369
370 return ret;
371 }
372
apply_microcode_local(void * arg)373 static void apply_microcode_local(void *arg)
374 {
375 enum ucode_state *err = arg;
376
377 *err = microcode_ops->apply_microcode(smp_processor_id());
378 }
379
apply_microcode_on_target(int cpu)380 static int apply_microcode_on_target(int cpu)
381 {
382 enum ucode_state err;
383 int ret;
384
385 ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
386 if (!ret) {
387 if (err == UCODE_ERROR)
388 ret = 1;
389 }
390 return ret;
391 }
392
393 /* fake device for request_firmware */
394 static struct platform_device *microcode_pdev;
395
396 #ifdef CONFIG_MICROCODE_LATE_LOADING
397 /*
398 * Late loading dance. Why the heavy-handed stomp_machine effort?
399 *
400 * - HT siblings must be idle and not execute other code while the other sibling
401 * is loading microcode in order to avoid any negative interactions caused by
402 * the loading.
403 *
404 * - In addition, microcode update on the cores must be serialized until this
405 * requirement can be relaxed in the future. Right now, this is conservative
406 * and good.
407 */
408 #define SPINUNIT 100 /* 100 nsec */
409
check_online_cpus(void)410 static int check_online_cpus(void)
411 {
412 unsigned int cpu;
413
414 /*
415 * Make sure all CPUs are online. It's fine for SMT to be disabled if
416 * all the primary threads are still online.
417 */
418 for_each_present_cpu(cpu) {
419 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
420 pr_err("Not all CPUs online, aborting microcode update.\n");
421 return -EINVAL;
422 }
423 }
424
425 return 0;
426 }
427
428 static atomic_t late_cpus_in;
429 static atomic_t late_cpus_out;
430
__wait_for_cpus(atomic_t * t,long long timeout)431 static int __wait_for_cpus(atomic_t *t, long long timeout)
432 {
433 int all_cpus = num_online_cpus();
434
435 atomic_inc(t);
436
437 while (atomic_read(t) < all_cpus) {
438 if (timeout < SPINUNIT) {
439 pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
440 all_cpus - atomic_read(t));
441 return 1;
442 }
443
444 ndelay(SPINUNIT);
445 timeout -= SPINUNIT;
446
447 touch_nmi_watchdog();
448 }
449 return 0;
450 }
451
452 /*
453 * Returns:
454 * < 0 - on error
455 * 0 - success (no update done or microcode was updated)
456 */
__reload_late(void * info)457 static int __reload_late(void *info)
458 {
459 int cpu = smp_processor_id();
460 enum ucode_state err;
461 int ret = 0;
462
463 /*
464 * Wait for all CPUs to arrive. A load will not be attempted unless all
465 * CPUs show up.
466 * */
467 if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
468 return -1;
469
470 /*
471 * On an SMT system, it suffices to load the microcode on one sibling of
472 * the core because the microcode engine is shared between the threads.
473 * Synchronization still needs to take place so that no concurrent
474 * loading attempts happen on multiple threads of an SMT core. See
475 * below.
476 */
477 if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
478 apply_microcode_local(&err);
479 else
480 goto wait_for_siblings;
481
482 if (err >= UCODE_NFOUND) {
483 if (err == UCODE_ERROR)
484 pr_warn("Error reloading microcode on CPU %d\n", cpu);
485
486 ret = -1;
487 }
488
489 wait_for_siblings:
490 if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
491 panic("Timeout during microcode update!\n");
492
493 /*
494 * At least one thread has completed update on each core.
495 * For others, simply call the update to make sure the
496 * per-cpu cpuinfo can be updated with right microcode
497 * revision.
498 */
499 if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
500 apply_microcode_local(&err);
501
502 return ret;
503 }
504
505 /*
506 * Reload microcode late on all CPUs. Wait for a sec until they
507 * all gather together.
508 */
microcode_reload_late(void)509 static int microcode_reload_late(void)
510 {
511 int old = boot_cpu_data.microcode, ret;
512 struct cpuinfo_x86 prev_info;
513
514 atomic_set(&late_cpus_in, 0);
515 atomic_set(&late_cpus_out, 0);
516
517 /*
518 * Take a snapshot before the microcode update in order to compare and
519 * check whether any bits changed after an update.
520 */
521 store_cpu_caps(&prev_info);
522
523 ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
524 if (!ret) {
525 pr_info("Reload succeeded, microcode revision: 0x%x -> 0x%x\n",
526 old, boot_cpu_data.microcode);
527 microcode_check(&prev_info);
528 } else {
529 pr_info("Reload failed, current microcode revision: 0x%x\n",
530 boot_cpu_data.microcode);
531 }
532
533 return ret;
534 }
535
reload_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)536 static ssize_t reload_store(struct device *dev,
537 struct device_attribute *attr,
538 const char *buf, size_t size)
539 {
540 enum ucode_state tmp_ret = UCODE_OK;
541 int bsp = boot_cpu_data.cpu_index;
542 unsigned long val;
543 ssize_t ret = 0;
544
545 ret = kstrtoul(buf, 0, &val);
546 if (ret)
547 return ret;
548
549 if (val != 1)
550 return size;
551
552 cpus_read_lock();
553
554 ret = check_online_cpus();
555 if (ret)
556 goto put;
557
558 tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev, true);
559 if (tmp_ret != UCODE_NEW)
560 goto put;
561
562 mutex_lock(µcode_mutex);
563 ret = microcode_reload_late();
564 mutex_unlock(µcode_mutex);
565
566 put:
567 cpus_read_unlock();
568
569 if (ret == 0)
570 ret = size;
571
572 return ret;
573 }
574
575 static DEVICE_ATTR_WO(reload);
576 #endif
577
version_show(struct device * dev,struct device_attribute * attr,char * buf)578 static ssize_t version_show(struct device *dev,
579 struct device_attribute *attr, char *buf)
580 {
581 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
582
583 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
584 }
585
pf_show(struct device * dev,struct device_attribute * attr,char * buf)586 static ssize_t pf_show(struct device *dev,
587 struct device_attribute *attr, char *buf)
588 {
589 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
590
591 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
592 }
593
594 static DEVICE_ATTR(version, 0444, version_show, NULL);
595 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
596
597 static struct attribute *mc_default_attrs[] = {
598 &dev_attr_version.attr,
599 &dev_attr_processor_flags.attr,
600 NULL
601 };
602
603 static const struct attribute_group mc_attr_group = {
604 .attrs = mc_default_attrs,
605 .name = "microcode",
606 };
607
microcode_fini_cpu(int cpu)608 static void microcode_fini_cpu(int cpu)
609 {
610 if (microcode_ops->microcode_fini_cpu)
611 microcode_ops->microcode_fini_cpu(cpu);
612 }
613
microcode_resume_cpu(int cpu)614 static enum ucode_state microcode_resume_cpu(int cpu)
615 {
616 if (apply_microcode_on_target(cpu))
617 return UCODE_ERROR;
618
619 pr_debug("CPU%d updated upon resume\n", cpu);
620
621 return UCODE_OK;
622 }
623
microcode_init_cpu(int cpu,bool refresh_fw)624 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
625 {
626 enum ucode_state ustate;
627 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
628
629 if (uci->valid)
630 return UCODE_OK;
631
632 if (collect_cpu_info(cpu))
633 return UCODE_ERROR;
634
635 /* --dimm. Trigger a delayed update? */
636 if (system_state != SYSTEM_RUNNING)
637 return UCODE_NFOUND;
638
639 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, refresh_fw);
640 if (ustate == UCODE_NEW) {
641 pr_debug("CPU%d updated upon init\n", cpu);
642 apply_microcode_on_target(cpu);
643 }
644
645 return ustate;
646 }
647
microcode_update_cpu(int cpu)648 static enum ucode_state microcode_update_cpu(int cpu)
649 {
650 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
651
652 /* Refresh CPU microcode revision after resume. */
653 collect_cpu_info(cpu);
654
655 if (uci->valid)
656 return microcode_resume_cpu(cpu);
657
658 return microcode_init_cpu(cpu, false);
659 }
660
mc_device_add(struct device * dev,struct subsys_interface * sif)661 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
662 {
663 int err, cpu = dev->id;
664
665 if (!cpu_online(cpu))
666 return 0;
667
668 pr_debug("CPU%d added\n", cpu);
669
670 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
671 if (err)
672 return err;
673
674 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
675 return -EINVAL;
676
677 return err;
678 }
679
mc_device_remove(struct device * dev,struct subsys_interface * sif)680 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
681 {
682 int cpu = dev->id;
683
684 if (!cpu_online(cpu))
685 return;
686
687 pr_debug("CPU%d removed\n", cpu);
688 microcode_fini_cpu(cpu);
689 sysfs_remove_group(&dev->kobj, &mc_attr_group);
690 }
691
692 static struct subsys_interface mc_cpu_interface = {
693 .name = "microcode",
694 .subsys = &cpu_subsys,
695 .add_dev = mc_device_add,
696 .remove_dev = mc_device_remove,
697 };
698
699 /**
700 * microcode_bsp_resume - Update boot CPU microcode during resume.
701 */
microcode_bsp_resume(void)702 void microcode_bsp_resume(void)
703 {
704 int cpu = smp_processor_id();
705 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
706
707 if (uci->valid && uci->mc)
708 microcode_ops->apply_microcode(cpu);
709 else if (!uci->mc)
710 reload_early_microcode(cpu);
711 }
712
713 static struct syscore_ops mc_syscore_ops = {
714 .resume = microcode_bsp_resume,
715 };
716
mc_cpu_starting(unsigned int cpu)717 static int mc_cpu_starting(unsigned int cpu)
718 {
719 microcode_update_cpu(cpu);
720 pr_debug("CPU%d added\n", cpu);
721 return 0;
722 }
723
mc_cpu_online(unsigned int cpu)724 static int mc_cpu_online(unsigned int cpu)
725 {
726 struct device *dev = get_cpu_device(cpu);
727
728 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
729 pr_err("Failed to create group for CPU%d\n", cpu);
730 return 0;
731 }
732
mc_cpu_down_prep(unsigned int cpu)733 static int mc_cpu_down_prep(unsigned int cpu)
734 {
735 struct device *dev;
736
737 dev = get_cpu_device(cpu);
738 /* Suspend is in progress, only remove the interface */
739 sysfs_remove_group(&dev->kobj, &mc_attr_group);
740 pr_debug("CPU%d removed\n", cpu);
741
742 return 0;
743 }
744
745 static struct attribute *cpu_root_microcode_attrs[] = {
746 #ifdef CONFIG_MICROCODE_LATE_LOADING
747 &dev_attr_reload.attr,
748 #endif
749 NULL
750 };
751
752 static const struct attribute_group cpu_root_microcode_group = {
753 .name = "microcode",
754 .attrs = cpu_root_microcode_attrs,
755 };
756
microcode_init(void)757 int __init microcode_init(void)
758 {
759 struct cpuinfo_x86 *c = &boot_cpu_data;
760 int error;
761
762 if (dis_ucode_ldr)
763 return -EINVAL;
764
765 if (c->x86_vendor == X86_VENDOR_INTEL)
766 microcode_ops = init_intel_microcode();
767 else if (c->x86_vendor == X86_VENDOR_AMD)
768 microcode_ops = init_amd_microcode();
769 else
770 pr_err("no support for this CPU vendor\n");
771
772 if (!microcode_ops)
773 return -ENODEV;
774
775 microcode_pdev = platform_device_register_simple("microcode", -1,
776 NULL, 0);
777 if (IS_ERR(microcode_pdev))
778 return PTR_ERR(microcode_pdev);
779
780 cpus_read_lock();
781 mutex_lock(µcode_mutex);
782
783 error = subsys_interface_register(&mc_cpu_interface);
784 if (!error)
785 perf_check_microcode();
786 mutex_unlock(µcode_mutex);
787 cpus_read_unlock();
788
789 if (error)
790 goto out_pdev;
791
792 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
793 &cpu_root_microcode_group);
794
795 if (error) {
796 pr_err("Error creating microcode group!\n");
797 goto out_driver;
798 }
799
800 register_syscore_ops(&mc_syscore_ops);
801 cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
802 mc_cpu_starting, NULL);
803 cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
804 mc_cpu_online, mc_cpu_down_prep);
805
806 pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
807
808 return 0;
809
810 out_driver:
811 cpus_read_lock();
812 mutex_lock(µcode_mutex);
813
814 subsys_interface_unregister(&mc_cpu_interface);
815
816 mutex_unlock(µcode_mutex);
817 cpus_read_unlock();
818
819 out_pdev:
820 platform_device_unregister(microcode_pdev);
821 return error;
822
823 }
824 fs_initcall(save_microcode_in_initrd);
825 late_initcall(microcode_init);
826