xref: /openbmc/linux/arch/x86/kernel/cpu/microcode/core.c (revision 0edbfea5)
1 /*
2  * CPU Microcode Update Driver for Linux
3  *
4  * Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
5  *	      2006	Shaohua Li <shaohua.li@intel.com>
6  *	      2013-2015	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/syscore_ops.h>
26 #include <linux/miscdevice.h>
27 #include <linux/capability.h>
28 #include <linux/firmware.h>
29 #include <linux/kernel.h>
30 #include <linux/mutex.h>
31 #include <linux/cpu.h>
32 #include <linux/fs.h>
33 #include <linux/mm.h>
34 
35 #include <asm/microcode_intel.h>
36 #include <asm/cpu_device_id.h>
37 #include <asm/microcode_amd.h>
38 #include <asm/perf_event.h>
39 #include <asm/microcode.h>
40 #include <asm/processor.h>
41 #include <asm/cmdline.h>
42 
43 #define MICROCODE_VERSION	"2.01"
44 
45 static struct microcode_ops	*microcode_ops;
46 static bool dis_ucode_ldr;
47 
48 /*
49  * Synchronization.
50  *
51  * All non cpu-hotplug-callback call sites use:
52  *
53  * - microcode_mutex to synchronize with each other;
54  * - get/put_online_cpus() to synchronize with
55  *   the cpu-hotplug-callback call sites.
56  *
57  * We guarantee that only a single cpu is being
58  * updated at any particular moment of time.
59  */
60 static DEFINE_MUTEX(microcode_mutex);
61 
62 struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
63 EXPORT_SYMBOL_GPL(ucode_cpu_info);
64 
65 /*
66  * Operations that are run on a target cpu:
67  */
68 
69 struct cpu_info_ctx {
70 	struct cpu_signature	*cpu_sig;
71 	int			err;
72 };
73 
74 static bool __init check_loader_disabled_bsp(void)
75 {
76 	static const char *__dis_opt_str = "dis_ucode_ldr";
77 
78 #ifdef CONFIG_X86_32
79 	const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
80 	const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
81 	bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
82 
83 #else /* CONFIG_X86_64 */
84 	const char *cmdline = boot_command_line;
85 	const char *option  = __dis_opt_str;
86 	bool *res = &dis_ucode_ldr;
87 #endif
88 
89 	if (cmdline_find_option_bool(cmdline, option))
90 		*res = true;
91 
92 	return *res;
93 }
94 
95 extern struct builtin_fw __start_builtin_fw[];
96 extern struct builtin_fw __end_builtin_fw[];
97 
98 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
99 {
100 #ifdef CONFIG_FW_LOADER
101 	struct builtin_fw *b_fw;
102 
103 	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
104 		if (!strcmp(name, b_fw->name)) {
105 			cd->size = b_fw->size;
106 			cd->data = b_fw->data;
107 			return true;
108 		}
109 	}
110 #endif
111 	return false;
112 }
113 
114 void __init load_ucode_bsp(void)
115 {
116 	int vendor;
117 	unsigned int family;
118 
119 	if (check_loader_disabled_bsp())
120 		return;
121 
122 	if (!have_cpuid_p())
123 		return;
124 
125 	vendor = x86_cpuid_vendor();
126 	family = x86_cpuid_family();
127 
128 	switch (vendor) {
129 	case X86_VENDOR_INTEL:
130 		if (family >= 6)
131 			load_ucode_intel_bsp();
132 		break;
133 	case X86_VENDOR_AMD:
134 		if (family >= 0x10)
135 			load_ucode_amd_bsp(family);
136 		break;
137 	default:
138 		break;
139 	}
140 }
141 
142 static bool check_loader_disabled_ap(void)
143 {
144 #ifdef CONFIG_X86_32
145 	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
146 #else
147 	return dis_ucode_ldr;
148 #endif
149 }
150 
151 void load_ucode_ap(void)
152 {
153 	int vendor, family;
154 
155 	if (check_loader_disabled_ap())
156 		return;
157 
158 	if (!have_cpuid_p())
159 		return;
160 
161 	vendor = x86_cpuid_vendor();
162 	family = x86_cpuid_family();
163 
164 	switch (vendor) {
165 	case X86_VENDOR_INTEL:
166 		if (family >= 6)
167 			load_ucode_intel_ap();
168 		break;
169 	case X86_VENDOR_AMD:
170 		if (family >= 0x10)
171 			load_ucode_amd_ap();
172 		break;
173 	default:
174 		break;
175 	}
176 }
177 
178 int __init save_microcode_in_initrd(void)
179 {
180 	struct cpuinfo_x86 *c = &boot_cpu_data;
181 
182 	switch (c->x86_vendor) {
183 	case X86_VENDOR_INTEL:
184 		if (c->x86 >= 6)
185 			save_microcode_in_initrd_intel();
186 		break;
187 	case X86_VENDOR_AMD:
188 		if (c->x86 >= 0x10)
189 			save_microcode_in_initrd_amd();
190 		break;
191 	default:
192 		break;
193 	}
194 
195 	return 0;
196 }
197 
198 void reload_early_microcode(void)
199 {
200 	int vendor, family;
201 
202 	vendor = x86_cpuid_vendor();
203 	family = x86_cpuid_family();
204 
205 	switch (vendor) {
206 	case X86_VENDOR_INTEL:
207 		if (family >= 6)
208 			reload_ucode_intel();
209 		break;
210 	case X86_VENDOR_AMD:
211 		if (family >= 0x10)
212 			reload_ucode_amd();
213 		break;
214 	default:
215 		break;
216 	}
217 }
218 
219 static void collect_cpu_info_local(void *arg)
220 {
221 	struct cpu_info_ctx *ctx = arg;
222 
223 	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
224 						   ctx->cpu_sig);
225 }
226 
227 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
228 {
229 	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
230 	int ret;
231 
232 	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
233 	if (!ret)
234 		ret = ctx.err;
235 
236 	return ret;
237 }
238 
239 static int collect_cpu_info(int cpu)
240 {
241 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
242 	int ret;
243 
244 	memset(uci, 0, sizeof(*uci));
245 
246 	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
247 	if (!ret)
248 		uci->valid = 1;
249 
250 	return ret;
251 }
252 
253 struct apply_microcode_ctx {
254 	int err;
255 };
256 
257 static void apply_microcode_local(void *arg)
258 {
259 	struct apply_microcode_ctx *ctx = arg;
260 
261 	ctx->err = microcode_ops->apply_microcode(smp_processor_id());
262 }
263 
264 static int apply_microcode_on_target(int cpu)
265 {
266 	struct apply_microcode_ctx ctx = { .err = 0 };
267 	int ret;
268 
269 	ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
270 	if (!ret)
271 		ret = ctx.err;
272 
273 	return ret;
274 }
275 
276 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
277 static int do_microcode_update(const void __user *buf, size_t size)
278 {
279 	int error = 0;
280 	int cpu;
281 
282 	for_each_online_cpu(cpu) {
283 		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
284 		enum ucode_state ustate;
285 
286 		if (!uci->valid)
287 			continue;
288 
289 		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
290 		if (ustate == UCODE_ERROR) {
291 			error = -1;
292 			break;
293 		} else if (ustate == UCODE_OK)
294 			apply_microcode_on_target(cpu);
295 	}
296 
297 	return error;
298 }
299 
300 static int microcode_open(struct inode *inode, struct file *file)
301 {
302 	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
303 }
304 
305 static ssize_t microcode_write(struct file *file, const char __user *buf,
306 			       size_t len, loff_t *ppos)
307 {
308 	ssize_t ret = -EINVAL;
309 
310 	if ((len >> PAGE_SHIFT) > totalram_pages) {
311 		pr_err("too much data (max %ld pages)\n", totalram_pages);
312 		return ret;
313 	}
314 
315 	get_online_cpus();
316 	mutex_lock(&microcode_mutex);
317 
318 	if (do_microcode_update(buf, len) == 0)
319 		ret = (ssize_t)len;
320 
321 	if (ret > 0)
322 		perf_check_microcode();
323 
324 	mutex_unlock(&microcode_mutex);
325 	put_online_cpus();
326 
327 	return ret;
328 }
329 
330 static const struct file_operations microcode_fops = {
331 	.owner			= THIS_MODULE,
332 	.write			= microcode_write,
333 	.open			= microcode_open,
334 	.llseek		= no_llseek,
335 };
336 
337 static struct miscdevice microcode_dev = {
338 	.minor			= MICROCODE_MINOR,
339 	.name			= "microcode",
340 	.nodename		= "cpu/microcode",
341 	.fops			= &microcode_fops,
342 };
343 
344 static int __init microcode_dev_init(void)
345 {
346 	int error;
347 
348 	error = misc_register(&microcode_dev);
349 	if (error) {
350 		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
351 		return error;
352 	}
353 
354 	return 0;
355 }
356 
357 static void __exit microcode_dev_exit(void)
358 {
359 	misc_deregister(&microcode_dev);
360 }
361 #else
362 #define microcode_dev_init()	0
363 #define microcode_dev_exit()	do { } while (0)
364 #endif
365 
366 /* fake device for request_firmware */
367 static struct platform_device	*microcode_pdev;
368 
369 static int reload_for_cpu(int cpu)
370 {
371 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
372 	enum ucode_state ustate;
373 	int err = 0;
374 
375 	if (!uci->valid)
376 		return err;
377 
378 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
379 	if (ustate == UCODE_OK)
380 		apply_microcode_on_target(cpu);
381 	else
382 		if (ustate == UCODE_ERROR)
383 			err = -EINVAL;
384 	return err;
385 }
386 
387 static ssize_t reload_store(struct device *dev,
388 			    struct device_attribute *attr,
389 			    const char *buf, size_t size)
390 {
391 	unsigned long val;
392 	int cpu;
393 	ssize_t ret = 0, tmp_ret;
394 
395 	ret = kstrtoul(buf, 0, &val);
396 	if (ret)
397 		return ret;
398 
399 	if (val != 1)
400 		return size;
401 
402 	get_online_cpus();
403 	mutex_lock(&microcode_mutex);
404 	for_each_online_cpu(cpu) {
405 		tmp_ret = reload_for_cpu(cpu);
406 		if (tmp_ret != 0)
407 			pr_warn("Error reloading microcode on CPU %d\n", cpu);
408 
409 		/* save retval of the first encountered reload error */
410 		if (!ret)
411 			ret = tmp_ret;
412 	}
413 	if (!ret)
414 		perf_check_microcode();
415 	mutex_unlock(&microcode_mutex);
416 	put_online_cpus();
417 
418 	if (!ret)
419 		ret = size;
420 
421 	return ret;
422 }
423 
424 static ssize_t version_show(struct device *dev,
425 			struct device_attribute *attr, char *buf)
426 {
427 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
428 
429 	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
430 }
431 
432 static ssize_t pf_show(struct device *dev,
433 			struct device_attribute *attr, char *buf)
434 {
435 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
436 
437 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
438 }
439 
440 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
441 static DEVICE_ATTR(version, 0400, version_show, NULL);
442 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
443 
444 static struct attribute *mc_default_attrs[] = {
445 	&dev_attr_version.attr,
446 	&dev_attr_processor_flags.attr,
447 	NULL
448 };
449 
450 static struct attribute_group mc_attr_group = {
451 	.attrs			= mc_default_attrs,
452 	.name			= "microcode",
453 };
454 
455 static void microcode_fini_cpu(int cpu)
456 {
457 	microcode_ops->microcode_fini_cpu(cpu);
458 }
459 
460 static enum ucode_state microcode_resume_cpu(int cpu)
461 {
462 	pr_debug("CPU%d updated upon resume\n", cpu);
463 
464 	if (apply_microcode_on_target(cpu))
465 		return UCODE_ERROR;
466 
467 	return UCODE_OK;
468 }
469 
470 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
471 {
472 	enum ucode_state ustate;
473 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
474 
475 	if (uci->valid)
476 		return UCODE_OK;
477 
478 	if (collect_cpu_info(cpu))
479 		return UCODE_ERROR;
480 
481 	/* --dimm. Trigger a delayed update? */
482 	if (system_state != SYSTEM_RUNNING)
483 		return UCODE_NFOUND;
484 
485 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
486 						     refresh_fw);
487 
488 	if (ustate == UCODE_OK) {
489 		pr_debug("CPU%d updated upon init\n", cpu);
490 		apply_microcode_on_target(cpu);
491 	}
492 
493 	return ustate;
494 }
495 
496 static enum ucode_state microcode_update_cpu(int cpu)
497 {
498 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
499 
500 	if (uci->valid)
501 		return microcode_resume_cpu(cpu);
502 
503 	return microcode_init_cpu(cpu, false);
504 }
505 
506 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
507 {
508 	int err, cpu = dev->id;
509 
510 	if (!cpu_online(cpu))
511 		return 0;
512 
513 	pr_debug("CPU%d added\n", cpu);
514 
515 	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
516 	if (err)
517 		return err;
518 
519 	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
520 		return -EINVAL;
521 
522 	return err;
523 }
524 
525 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
526 {
527 	int cpu = dev->id;
528 
529 	if (!cpu_online(cpu))
530 		return;
531 
532 	pr_debug("CPU%d removed\n", cpu);
533 	microcode_fini_cpu(cpu);
534 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
535 }
536 
537 static struct subsys_interface mc_cpu_interface = {
538 	.name			= "microcode",
539 	.subsys			= &cpu_subsys,
540 	.add_dev		= mc_device_add,
541 	.remove_dev		= mc_device_remove,
542 };
543 
544 /**
545  * mc_bp_resume - Update boot CPU microcode during resume.
546  */
547 static void mc_bp_resume(void)
548 {
549 	int cpu = smp_processor_id();
550 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
551 
552 	if (uci->valid && uci->mc)
553 		microcode_ops->apply_microcode(cpu);
554 	else if (!uci->mc)
555 		reload_early_microcode();
556 }
557 
558 static struct syscore_ops mc_syscore_ops = {
559 	.resume			= mc_bp_resume,
560 };
561 
562 static int
563 mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
564 {
565 	unsigned int cpu = (unsigned long)hcpu;
566 	struct device *dev;
567 
568 	dev = get_cpu_device(cpu);
569 
570 	switch (action & ~CPU_TASKS_FROZEN) {
571 	case CPU_ONLINE:
572 		microcode_update_cpu(cpu);
573 		pr_debug("CPU%d added\n", cpu);
574 		/*
575 		 * "break" is missing on purpose here because we want to fall
576 		 * through in order to create the sysfs group.
577 		 */
578 
579 	case CPU_DOWN_FAILED:
580 		if (sysfs_create_group(&dev->kobj, &mc_attr_group))
581 			pr_err("Failed to create group for CPU%d\n", cpu);
582 		break;
583 
584 	case CPU_DOWN_PREPARE:
585 		/* Suspend is in progress, only remove the interface */
586 		sysfs_remove_group(&dev->kobj, &mc_attr_group);
587 		pr_debug("CPU%d removed\n", cpu);
588 		break;
589 
590 	/*
591 	 * case CPU_DEAD:
592 	 *
593 	 * When a CPU goes offline, don't free up or invalidate the copy of
594 	 * the microcode in kernel memory, so that we can reuse it when the
595 	 * CPU comes back online without unnecessarily requesting the userspace
596 	 * for it again.
597 	 */
598 	}
599 
600 	/* The CPU refused to come up during a system resume */
601 	if (action == CPU_UP_CANCELED_FROZEN)
602 		microcode_fini_cpu(cpu);
603 
604 	return NOTIFY_OK;
605 }
606 
607 static struct notifier_block mc_cpu_notifier = {
608 	.notifier_call	= mc_cpu_callback,
609 };
610 
611 static struct attribute *cpu_root_microcode_attrs[] = {
612 	&dev_attr_reload.attr,
613 	NULL
614 };
615 
616 static struct attribute_group cpu_root_microcode_group = {
617 	.name  = "microcode",
618 	.attrs = cpu_root_microcode_attrs,
619 };
620 
621 int __init microcode_init(void)
622 {
623 	struct cpuinfo_x86 *c = &boot_cpu_data;
624 	int error;
625 
626 	if (dis_ucode_ldr)
627 		return -EINVAL;
628 
629 	if (c->x86_vendor == X86_VENDOR_INTEL)
630 		microcode_ops = init_intel_microcode();
631 	else if (c->x86_vendor == X86_VENDOR_AMD)
632 		microcode_ops = init_amd_microcode();
633 	else
634 		pr_err("no support for this CPU vendor\n");
635 
636 	if (!microcode_ops)
637 		return -ENODEV;
638 
639 	microcode_pdev = platform_device_register_simple("microcode", -1,
640 							 NULL, 0);
641 	if (IS_ERR(microcode_pdev))
642 		return PTR_ERR(microcode_pdev);
643 
644 	get_online_cpus();
645 	mutex_lock(&microcode_mutex);
646 
647 	error = subsys_interface_register(&mc_cpu_interface);
648 	if (!error)
649 		perf_check_microcode();
650 	mutex_unlock(&microcode_mutex);
651 	put_online_cpus();
652 
653 	if (error)
654 		goto out_pdev;
655 
656 	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
657 				   &cpu_root_microcode_group);
658 
659 	if (error) {
660 		pr_err("Error creating microcode group!\n");
661 		goto out_driver;
662 	}
663 
664 	error = microcode_dev_init();
665 	if (error)
666 		goto out_ucode_group;
667 
668 	register_syscore_ops(&mc_syscore_ops);
669 	register_hotcpu_notifier(&mc_cpu_notifier);
670 
671 	pr_info("Microcode Update Driver: v" MICROCODE_VERSION
672 		" <tigran@aivazian.fsnet.co.uk>, Peter Oruba\n");
673 
674 	return 0;
675 
676  out_ucode_group:
677 	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
678 			   &cpu_root_microcode_group);
679 
680  out_driver:
681 	get_online_cpus();
682 	mutex_lock(&microcode_mutex);
683 
684 	subsys_interface_unregister(&mc_cpu_interface);
685 
686 	mutex_unlock(&microcode_mutex);
687 	put_online_cpus();
688 
689  out_pdev:
690 	platform_device_unregister(microcode_pdev);
691 	return error;
692 
693 }
694 late_initcall(microcode_init);
695