xref: /openbmc/linux/arch/x86/kernel/cpu/microcode/core.c (revision 228662b0)
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  */
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 
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 void __init load_ucode_bsp(void)
144 {
145 	unsigned int cpuid_1_eax;
146 	bool intel = true;
147 
148 	if (!have_cpuid_p())
149 		return;
150 
151 	cpuid_1_eax = native_cpuid_eax(1);
152 
153 	switch (x86_cpuid_vendor()) {
154 	case X86_VENDOR_INTEL:
155 		if (x86_family(cpuid_1_eax) < 6)
156 			return;
157 		break;
158 
159 	case X86_VENDOR_AMD:
160 		if (x86_family(cpuid_1_eax) < 0x10)
161 			return;
162 		intel = false;
163 		break;
164 
165 	default:
166 		return;
167 	}
168 
169 	if (check_loader_disabled_bsp())
170 		return;
171 
172 	if (intel)
173 		load_ucode_intel_bsp();
174 	else
175 		load_ucode_amd_bsp(cpuid_1_eax);
176 }
177 
178 static bool check_loader_disabled_ap(void)
179 {
180 #ifdef CONFIG_X86_32
181 	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
182 #else
183 	return dis_ucode_ldr;
184 #endif
185 }
186 
187 void load_ucode_ap(void)
188 {
189 	unsigned int cpuid_1_eax;
190 
191 	if (check_loader_disabled_ap())
192 		return;
193 
194 	cpuid_1_eax = native_cpuid_eax(1);
195 
196 	switch (x86_cpuid_vendor()) {
197 	case X86_VENDOR_INTEL:
198 		if (x86_family(cpuid_1_eax) >= 6)
199 			load_ucode_intel_ap();
200 		break;
201 	case X86_VENDOR_AMD:
202 		if (x86_family(cpuid_1_eax) >= 0x10)
203 			load_ucode_amd_ap(cpuid_1_eax);
204 		break;
205 	default:
206 		break;
207 	}
208 }
209 
210 static int __init save_microcode_in_initrd(void)
211 {
212 	struct cpuinfo_x86 *c = &boot_cpu_data;
213 	int ret = -EINVAL;
214 
215 	switch (c->x86_vendor) {
216 	case X86_VENDOR_INTEL:
217 		if (c->x86 >= 6)
218 			ret = save_microcode_in_initrd_intel();
219 		break;
220 	case X86_VENDOR_AMD:
221 		if (c->x86 >= 0x10)
222 			ret = save_microcode_in_initrd_amd(cpuid_eax(1));
223 		break;
224 	default:
225 		break;
226 	}
227 
228 	initrd_gone = true;
229 
230 	return ret;
231 }
232 
233 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
234 {
235 #ifdef CONFIG_BLK_DEV_INITRD
236 	unsigned long start = 0;
237 	size_t size;
238 
239 #ifdef CONFIG_X86_32
240 	struct boot_params *params;
241 
242 	if (use_pa)
243 		params = (struct boot_params *)__pa_nodebug(&boot_params);
244 	else
245 		params = &boot_params;
246 
247 	size = params->hdr.ramdisk_size;
248 
249 	/*
250 	 * Set start only if we have an initrd image. We cannot use initrd_start
251 	 * because it is not set that early yet.
252 	 */
253 	if (size)
254 		start = params->hdr.ramdisk_image;
255 
256 # else /* CONFIG_X86_64 */
257 	size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
258 	size |= boot_params.hdr.ramdisk_size;
259 
260 	if (size) {
261 		start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
262 		start |= boot_params.hdr.ramdisk_image;
263 
264 		start += PAGE_OFFSET;
265 	}
266 # endif
267 
268 	/*
269 	 * Fixup the start address: after reserve_initrd() runs, initrd_start
270 	 * has the virtual address of the beginning of the initrd. It also
271 	 * possibly relocates the ramdisk. In either case, initrd_start contains
272 	 * the updated address so use that instead.
273 	 *
274 	 * initrd_gone is for the hotplug case where we've thrown out initrd
275 	 * already.
276 	 */
277 	if (!use_pa) {
278 		if (initrd_gone)
279 			return (struct cpio_data){ NULL, 0, "" };
280 		if (initrd_start)
281 			start = initrd_start;
282 	} else {
283 		/*
284 		 * The picture with physical addresses is a bit different: we
285 		 * need to get the *physical* address to which the ramdisk was
286 		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
287 		 * since we're running from physical addresses, we need to access
288 		 * relocated_ramdisk through its *physical* address too.
289 		 */
290 		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
291 		if (*rr)
292 			start = *rr;
293 	}
294 
295 	return find_cpio_data(path, (void *)start, size, NULL);
296 #else /* !CONFIG_BLK_DEV_INITRD */
297 	return (struct cpio_data){ NULL, 0, "" };
298 #endif
299 }
300 
301 void reload_early_microcode(void)
302 {
303 	int vendor, family;
304 
305 	vendor = x86_cpuid_vendor();
306 	family = x86_cpuid_family();
307 
308 	switch (vendor) {
309 	case X86_VENDOR_INTEL:
310 		if (family >= 6)
311 			reload_ucode_intel();
312 		break;
313 	case X86_VENDOR_AMD:
314 		if (family >= 0x10)
315 			reload_ucode_amd();
316 		break;
317 	default:
318 		break;
319 	}
320 }
321 
322 static void collect_cpu_info_local(void *arg)
323 {
324 	struct cpu_info_ctx *ctx = arg;
325 
326 	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
327 						   ctx->cpu_sig);
328 }
329 
330 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
331 {
332 	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
333 	int ret;
334 
335 	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
336 	if (!ret)
337 		ret = ctx.err;
338 
339 	return ret;
340 }
341 
342 static int collect_cpu_info(int cpu)
343 {
344 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
345 	int ret;
346 
347 	memset(uci, 0, sizeof(*uci));
348 
349 	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
350 	if (!ret)
351 		uci->valid = 1;
352 
353 	return ret;
354 }
355 
356 static void apply_microcode_local(void *arg)
357 {
358 	enum ucode_state *err = arg;
359 
360 	*err = microcode_ops->apply_microcode(smp_processor_id());
361 }
362 
363 static int apply_microcode_on_target(int cpu)
364 {
365 	enum ucode_state err;
366 	int ret;
367 
368 	ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
369 	if (!ret) {
370 		if (err == UCODE_ERROR)
371 			ret = 1;
372 	}
373 	return ret;
374 }
375 
376 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
377 static int do_microcode_update(const void __user *buf, size_t size)
378 {
379 	int error = 0;
380 	int cpu;
381 
382 	for_each_online_cpu(cpu) {
383 		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
384 		enum ucode_state ustate;
385 
386 		if (!uci->valid)
387 			continue;
388 
389 		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
390 		if (ustate == UCODE_ERROR) {
391 			error = -1;
392 			break;
393 		} else if (ustate == UCODE_NEW) {
394 			apply_microcode_on_target(cpu);
395 		}
396 	}
397 
398 	return error;
399 }
400 
401 static int microcode_open(struct inode *inode, struct file *file)
402 {
403 	return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
404 }
405 
406 static ssize_t microcode_write(struct file *file, const char __user *buf,
407 			       size_t len, loff_t *ppos)
408 {
409 	ssize_t ret = -EINVAL;
410 	unsigned long nr_pages = totalram_pages();
411 
412 	if ((len >> PAGE_SHIFT) > nr_pages) {
413 		pr_err("too much data (max %ld pages)\n", nr_pages);
414 		return ret;
415 	}
416 
417 	cpus_read_lock();
418 	mutex_lock(&microcode_mutex);
419 
420 	if (do_microcode_update(buf, len) == 0)
421 		ret = (ssize_t)len;
422 
423 	if (ret > 0)
424 		perf_check_microcode();
425 
426 	mutex_unlock(&microcode_mutex);
427 	cpus_read_unlock();
428 
429 	return ret;
430 }
431 
432 static const struct file_operations microcode_fops = {
433 	.owner			= THIS_MODULE,
434 	.write			= microcode_write,
435 	.open			= microcode_open,
436 	.llseek		= no_llseek,
437 };
438 
439 static struct miscdevice microcode_dev = {
440 	.minor			= MICROCODE_MINOR,
441 	.name			= "microcode",
442 	.nodename		= "cpu/microcode",
443 	.fops			= &microcode_fops,
444 };
445 
446 static int __init microcode_dev_init(void)
447 {
448 	int error;
449 
450 	error = misc_register(&microcode_dev);
451 	if (error) {
452 		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
453 		return error;
454 	}
455 
456 	return 0;
457 }
458 
459 static void __exit microcode_dev_exit(void)
460 {
461 	misc_deregister(&microcode_dev);
462 }
463 #else
464 #define microcode_dev_init()	0
465 #define microcode_dev_exit()	do { } while (0)
466 #endif
467 
468 /* fake device for request_firmware */
469 static struct platform_device	*microcode_pdev;
470 
471 /*
472  * Late loading dance. Why the heavy-handed stomp_machine effort?
473  *
474  * - HT siblings must be idle and not execute other code while the other sibling
475  *   is loading microcode in order to avoid any negative interactions caused by
476  *   the loading.
477  *
478  * - In addition, microcode update on the cores must be serialized until this
479  *   requirement can be relaxed in the future. Right now, this is conservative
480  *   and good.
481  */
482 #define SPINUNIT 100 /* 100 nsec */
483 
484 static int check_online_cpus(void)
485 {
486 	unsigned int cpu;
487 
488 	/*
489 	 * Make sure all CPUs are online.  It's fine for SMT to be disabled if
490 	 * all the primary threads are still online.
491 	 */
492 	for_each_present_cpu(cpu) {
493 		if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
494 			pr_err("Not all CPUs online, aborting microcode update.\n");
495 			return -EINVAL;
496 		}
497 	}
498 
499 	return 0;
500 }
501 
502 static atomic_t late_cpus_in;
503 static atomic_t late_cpus_out;
504 
505 static int __wait_for_cpus(atomic_t *t, long long timeout)
506 {
507 	int all_cpus = num_online_cpus();
508 
509 	atomic_inc(t);
510 
511 	while (atomic_read(t) < all_cpus) {
512 		if (timeout < SPINUNIT) {
513 			pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
514 				all_cpus - atomic_read(t));
515 			return 1;
516 		}
517 
518 		ndelay(SPINUNIT);
519 		timeout -= SPINUNIT;
520 
521 		touch_nmi_watchdog();
522 	}
523 	return 0;
524 }
525 
526 /*
527  * Returns:
528  * < 0 - on error
529  *   0 - success (no update done or microcode was updated)
530  */
531 static int __reload_late(void *info)
532 {
533 	int cpu = smp_processor_id();
534 	enum ucode_state err;
535 	int ret = 0;
536 
537 	/*
538 	 * Wait for all CPUs to arrive. A load will not be attempted unless all
539 	 * CPUs show up.
540 	 * */
541 	if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
542 		return -1;
543 
544 	/*
545 	 * On an SMT system, it suffices to load the microcode on one sibling of
546 	 * the core because the microcode engine is shared between the threads.
547 	 * Synchronization still needs to take place so that no concurrent
548 	 * loading attempts happen on multiple threads of an SMT core. See
549 	 * below.
550 	 */
551 	if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
552 		apply_microcode_local(&err);
553 	else
554 		goto wait_for_siblings;
555 
556 	if (err >= UCODE_NFOUND) {
557 		if (err == UCODE_ERROR)
558 			pr_warn("Error reloading microcode on CPU %d\n", cpu);
559 
560 		ret = -1;
561 	}
562 
563 wait_for_siblings:
564 	if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
565 		panic("Timeout during microcode update!\n");
566 
567 	/*
568 	 * At least one thread has completed update on each core.
569 	 * For others, simply call the update to make sure the
570 	 * per-cpu cpuinfo can be updated with right microcode
571 	 * revision.
572 	 */
573 	if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
574 		apply_microcode_local(&err);
575 
576 	return ret;
577 }
578 
579 /*
580  * Reload microcode late on all CPUs. Wait for a sec until they
581  * all gather together.
582  */
583 static int microcode_reload_late(void)
584 {
585 	int ret;
586 
587 	atomic_set(&late_cpus_in,  0);
588 	atomic_set(&late_cpus_out, 0);
589 
590 	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
591 	if (ret == 0)
592 		microcode_check();
593 
594 	pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
595 
596 	return ret;
597 }
598 
599 static ssize_t reload_store(struct device *dev,
600 			    struct device_attribute *attr,
601 			    const char *buf, size_t size)
602 {
603 	enum ucode_state tmp_ret = UCODE_OK;
604 	int bsp = boot_cpu_data.cpu_index;
605 	unsigned long val;
606 	ssize_t ret = 0;
607 
608 	ret = kstrtoul(buf, 0, &val);
609 	if (ret)
610 		return ret;
611 
612 	if (val != 1)
613 		return size;
614 
615 	cpus_read_lock();
616 
617 	ret = check_online_cpus();
618 	if (ret)
619 		goto put;
620 
621 	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
622 	if (tmp_ret != UCODE_NEW)
623 		goto put;
624 
625 	mutex_lock(&microcode_mutex);
626 	ret = microcode_reload_late();
627 	mutex_unlock(&microcode_mutex);
628 
629 put:
630 	cpus_read_unlock();
631 
632 	if (ret == 0)
633 		ret = size;
634 
635 	return ret;
636 }
637 
638 static ssize_t version_show(struct device *dev,
639 			struct device_attribute *attr, char *buf)
640 {
641 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
642 
643 	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
644 }
645 
646 static ssize_t pf_show(struct device *dev,
647 			struct device_attribute *attr, char *buf)
648 {
649 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
650 
651 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
652 }
653 
654 static DEVICE_ATTR_WO(reload);
655 static DEVICE_ATTR(version, 0444, version_show, NULL);
656 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
657 
658 static struct attribute *mc_default_attrs[] = {
659 	&dev_attr_version.attr,
660 	&dev_attr_processor_flags.attr,
661 	NULL
662 };
663 
664 static const struct attribute_group mc_attr_group = {
665 	.attrs			= mc_default_attrs,
666 	.name			= "microcode",
667 };
668 
669 static void microcode_fini_cpu(int cpu)
670 {
671 	if (microcode_ops->microcode_fini_cpu)
672 		microcode_ops->microcode_fini_cpu(cpu);
673 }
674 
675 static enum ucode_state microcode_resume_cpu(int cpu)
676 {
677 	if (apply_microcode_on_target(cpu))
678 		return UCODE_ERROR;
679 
680 	pr_debug("CPU%d updated upon resume\n", cpu);
681 
682 	return UCODE_OK;
683 }
684 
685 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
686 {
687 	enum ucode_state ustate;
688 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
689 
690 	if (uci->valid)
691 		return UCODE_OK;
692 
693 	if (collect_cpu_info(cpu))
694 		return UCODE_ERROR;
695 
696 	/* --dimm. Trigger a delayed update? */
697 	if (system_state != SYSTEM_RUNNING)
698 		return UCODE_NFOUND;
699 
700 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
701 	if (ustate == UCODE_NEW) {
702 		pr_debug("CPU%d updated upon init\n", cpu);
703 		apply_microcode_on_target(cpu);
704 	}
705 
706 	return ustate;
707 }
708 
709 static enum ucode_state microcode_update_cpu(int cpu)
710 {
711 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
712 
713 	/* Refresh CPU microcode revision after resume. */
714 	collect_cpu_info(cpu);
715 
716 	if (uci->valid)
717 		return microcode_resume_cpu(cpu);
718 
719 	return microcode_init_cpu(cpu, false);
720 }
721 
722 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
723 {
724 	int err, cpu = dev->id;
725 
726 	if (!cpu_online(cpu))
727 		return 0;
728 
729 	pr_debug("CPU%d added\n", cpu);
730 
731 	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
732 	if (err)
733 		return err;
734 
735 	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
736 		return -EINVAL;
737 
738 	return err;
739 }
740 
741 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
742 {
743 	int cpu = dev->id;
744 
745 	if (!cpu_online(cpu))
746 		return;
747 
748 	pr_debug("CPU%d removed\n", cpu);
749 	microcode_fini_cpu(cpu);
750 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
751 }
752 
753 static struct subsys_interface mc_cpu_interface = {
754 	.name			= "microcode",
755 	.subsys			= &cpu_subsys,
756 	.add_dev		= mc_device_add,
757 	.remove_dev		= mc_device_remove,
758 };
759 
760 /**
761  * microcode_bsp_resume - Update boot CPU microcode during resume.
762  */
763 void microcode_bsp_resume(void)
764 {
765 	int cpu = smp_processor_id();
766 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
767 
768 	if (uci->valid && uci->mc)
769 		microcode_ops->apply_microcode(cpu);
770 	else if (!uci->mc)
771 		reload_early_microcode();
772 }
773 
774 static struct syscore_ops mc_syscore_ops = {
775 	.resume			= microcode_bsp_resume,
776 };
777 
778 static int mc_cpu_starting(unsigned int cpu)
779 {
780 	microcode_update_cpu(cpu);
781 	pr_debug("CPU%d added\n", cpu);
782 	return 0;
783 }
784 
785 static int mc_cpu_online(unsigned int cpu)
786 {
787 	struct device *dev = get_cpu_device(cpu);
788 
789 	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
790 		pr_err("Failed to create group for CPU%d\n", cpu);
791 	return 0;
792 }
793 
794 static int mc_cpu_down_prep(unsigned int cpu)
795 {
796 	struct device *dev;
797 
798 	dev = get_cpu_device(cpu);
799 	/* Suspend is in progress, only remove the interface */
800 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
801 	pr_debug("CPU%d removed\n", cpu);
802 
803 	return 0;
804 }
805 
806 static struct attribute *cpu_root_microcode_attrs[] = {
807 	&dev_attr_reload.attr,
808 	NULL
809 };
810 
811 static const struct attribute_group cpu_root_microcode_group = {
812 	.name  = "microcode",
813 	.attrs = cpu_root_microcode_attrs,
814 };
815 
816 static int __init microcode_init(void)
817 {
818 	struct cpuinfo_x86 *c = &boot_cpu_data;
819 	int error;
820 
821 	if (dis_ucode_ldr)
822 		return -EINVAL;
823 
824 	if (c->x86_vendor == X86_VENDOR_INTEL)
825 		microcode_ops = init_intel_microcode();
826 	else if (c->x86_vendor == X86_VENDOR_AMD)
827 		microcode_ops = init_amd_microcode();
828 	else
829 		pr_err("no support for this CPU vendor\n");
830 
831 	if (!microcode_ops)
832 		return -ENODEV;
833 
834 	microcode_pdev = platform_device_register_simple("microcode", -1,
835 							 NULL, 0);
836 	if (IS_ERR(microcode_pdev))
837 		return PTR_ERR(microcode_pdev);
838 
839 	cpus_read_lock();
840 	mutex_lock(&microcode_mutex);
841 
842 	error = subsys_interface_register(&mc_cpu_interface);
843 	if (!error)
844 		perf_check_microcode();
845 	mutex_unlock(&microcode_mutex);
846 	cpus_read_unlock();
847 
848 	if (error)
849 		goto out_pdev;
850 
851 	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
852 				   &cpu_root_microcode_group);
853 
854 	if (error) {
855 		pr_err("Error creating microcode group!\n");
856 		goto out_driver;
857 	}
858 
859 	error = microcode_dev_init();
860 	if (error)
861 		goto out_ucode_group;
862 
863 	register_syscore_ops(&mc_syscore_ops);
864 	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
865 				  mc_cpu_starting, NULL);
866 	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
867 				  mc_cpu_online, mc_cpu_down_prep);
868 
869 	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
870 
871 	return 0;
872 
873  out_ucode_group:
874 	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
875 			   &cpu_root_microcode_group);
876 
877  out_driver:
878 	cpus_read_lock();
879 	mutex_lock(&microcode_mutex);
880 
881 	subsys_interface_unregister(&mc_cpu_interface);
882 
883 	mutex_unlock(&microcode_mutex);
884 	cpus_read_unlock();
885 
886  out_pdev:
887 	platform_device_unregister(microcode_pdev);
888 	return error;
889 
890 }
891 fs_initcall(save_microcode_in_initrd);
892 late_initcall(microcode_init);
893