xref: /linux/arch/x86/kernel/cpu/microcode/core.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732) 
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  * This driver allows to upgrade microcode on x86 processors.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License
12  * as published by the Free Software Foundation; either version
13  * 2 of the License, or (at your option) any later version.
14  */
15 
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 
18 #include <linux/platform_device.h>
19 #include <linux/miscdevice.h>
20 #include <linux/capability.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/cpu.h>
25 #include <linux/fs.h>
26 #include <linux/mm.h>
27 #include <linux/syscore_ops.h>
28 
29 #include <asm/microcode.h>
30 #include <asm/processor.h>
31 #include <asm/cpu_device_id.h>
32 #include <asm/perf_event.h>
33 
34 MODULE_DESCRIPTION("Microcode Update Driver");
35 MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
36 MODULE_LICENSE("GPL");
37 
38 #define MICROCODE_VERSION	"2.00"
39 
40 static struct microcode_ops	*microcode_ops;
41 
42 bool dis_ucode_ldr;
43 module_param(dis_ucode_ldr, bool, 0);
44 
45 /*
46  * Synchronization.
47  *
48  * All non cpu-hotplug-callback call sites use:
49  *
50  * - microcode_mutex to synchronize with each other;
51  * - get/put_online_cpus() to synchronize with
52  *   the cpu-hotplug-callback call sites.
53  *
54  * We guarantee that only a single cpu is being
55  * updated at any particular moment of time.
56  */
57 static DEFINE_MUTEX(microcode_mutex);
58 
59 struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
60 EXPORT_SYMBOL_GPL(ucode_cpu_info);
61 
62 /*
63  * Operations that are run on a target cpu:
64  */
65 
66 struct cpu_info_ctx {
67 	struct cpu_signature	*cpu_sig;
68 	int			err;
69 };
70 
71 static void collect_cpu_info_local(void *arg)
72 {
73 	struct cpu_info_ctx *ctx = arg;
74 
75 	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
76 						   ctx->cpu_sig);
77 }
78 
79 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
80 {
81 	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
82 	int ret;
83 
84 	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
85 	if (!ret)
86 		ret = ctx.err;
87 
88 	return ret;
89 }
90 
91 static int collect_cpu_info(int cpu)
92 {
93 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
94 	int ret;
95 
96 	memset(uci, 0, sizeof(*uci));
97 
98 	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
99 	if (!ret)
100 		uci->valid = 1;
101 
102 	return ret;
103 }
104 
105 struct apply_microcode_ctx {
106 	int err;
107 };
108 
109 static void apply_microcode_local(void *arg)
110 {
111 	struct apply_microcode_ctx *ctx = arg;
112 
113 	ctx->err = microcode_ops->apply_microcode(smp_processor_id());
114 }
115 
116 static int apply_microcode_on_target(int cpu)
117 {
118 	struct apply_microcode_ctx ctx = { .err = 0 };
119 	int ret;
120 
121 	ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
122 	if (!ret)
123 		ret = ctx.err;
124 
125 	return ret;
126 }
127 
128 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
129 static int do_microcode_update(const void __user *buf, size_t size)
130 {
131 	int error = 0;
132 	int cpu;
133 
134 	for_each_online_cpu(cpu) {
135 		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
136 		enum ucode_state ustate;
137 
138 		if (!uci->valid)
139 			continue;
140 
141 		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
142 		if (ustate == UCODE_ERROR) {
143 			error = -1;
144 			break;
145 		} else if (ustate == UCODE_OK)
146 			apply_microcode_on_target(cpu);
147 	}
148 
149 	return error;
150 }
151 
152 static int microcode_open(struct inode *inode, struct file *file)
153 {
154 	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
155 }
156 
157 static ssize_t microcode_write(struct file *file, const char __user *buf,
158 			       size_t len, loff_t *ppos)
159 {
160 	ssize_t ret = -EINVAL;
161 
162 	if ((len >> PAGE_SHIFT) > totalram_pages) {
163 		pr_err("too much data (max %ld pages)\n", totalram_pages);
164 		return ret;
165 	}
166 
167 	get_online_cpus();
168 	mutex_lock(&microcode_mutex);
169 
170 	if (do_microcode_update(buf, len) == 0)
171 		ret = (ssize_t)len;
172 
173 	if (ret > 0)
174 		perf_check_microcode();
175 
176 	mutex_unlock(&microcode_mutex);
177 	put_online_cpus();
178 
179 	return ret;
180 }
181 
182 static const struct file_operations microcode_fops = {
183 	.owner			= THIS_MODULE,
184 	.write			= microcode_write,
185 	.open			= microcode_open,
186 	.llseek		= no_llseek,
187 };
188 
189 static struct miscdevice microcode_dev = {
190 	.minor			= MICROCODE_MINOR,
191 	.name			= "microcode",
192 	.nodename		= "cpu/microcode",
193 	.fops			= &microcode_fops,
194 };
195 
196 static int __init microcode_dev_init(void)
197 {
198 	int error;
199 
200 	error = misc_register(&microcode_dev);
201 	if (error) {
202 		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
203 		return error;
204 	}
205 
206 	return 0;
207 }
208 
209 static void __exit microcode_dev_exit(void)
210 {
211 	misc_deregister(&microcode_dev);
212 }
213 
214 MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
215 MODULE_ALIAS("devname:cpu/microcode");
216 #else
217 #define microcode_dev_init()	0
218 #define microcode_dev_exit()	do { } while (0)
219 #endif
220 
221 /* fake device for request_firmware */
222 static struct platform_device	*microcode_pdev;
223 
224 static int reload_for_cpu(int cpu)
225 {
226 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
227 	enum ucode_state ustate;
228 	int err = 0;
229 
230 	if (!uci->valid)
231 		return err;
232 
233 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
234 	if (ustate == UCODE_OK)
235 		apply_microcode_on_target(cpu);
236 	else
237 		if (ustate == UCODE_ERROR)
238 			err = -EINVAL;
239 	return err;
240 }
241 
242 static ssize_t reload_store(struct device *dev,
243 			    struct device_attribute *attr,
244 			    const char *buf, size_t size)
245 {
246 	unsigned long val;
247 	int cpu;
248 	ssize_t ret = 0, tmp_ret;
249 
250 	ret = kstrtoul(buf, 0, &val);
251 	if (ret)
252 		return ret;
253 
254 	if (val != 1)
255 		return size;
256 
257 	get_online_cpus();
258 	mutex_lock(&microcode_mutex);
259 	for_each_online_cpu(cpu) {
260 		tmp_ret = reload_for_cpu(cpu);
261 		if (tmp_ret != 0)
262 			pr_warn("Error reloading microcode on CPU %d\n", cpu);
263 
264 		/* save retval of the first encountered reload error */
265 		if (!ret)
266 			ret = tmp_ret;
267 	}
268 	if (!ret)
269 		perf_check_microcode();
270 	mutex_unlock(&microcode_mutex);
271 	put_online_cpus();
272 
273 	if (!ret)
274 		ret = size;
275 
276 	return ret;
277 }
278 
279 static ssize_t version_show(struct device *dev,
280 			struct device_attribute *attr, char *buf)
281 {
282 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
283 
284 	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
285 }
286 
287 static ssize_t pf_show(struct device *dev,
288 			struct device_attribute *attr, char *buf)
289 {
290 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
291 
292 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
293 }
294 
295 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
296 static DEVICE_ATTR(version, 0400, version_show, NULL);
297 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
298 
299 static struct attribute *mc_default_attrs[] = {
300 	&dev_attr_version.attr,
301 	&dev_attr_processor_flags.attr,
302 	NULL
303 };
304 
305 static struct attribute_group mc_attr_group = {
306 	.attrs			= mc_default_attrs,
307 	.name			= "microcode",
308 };
309 
310 static void microcode_fini_cpu(int cpu)
311 {
312 	microcode_ops->microcode_fini_cpu(cpu);
313 }
314 
315 static enum ucode_state microcode_resume_cpu(int cpu)
316 {
317 	pr_debug("CPU%d updated upon resume\n", cpu);
318 
319 	if (apply_microcode_on_target(cpu))
320 		return UCODE_ERROR;
321 
322 	return UCODE_OK;
323 }
324 
325 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
326 {
327 	enum ucode_state ustate;
328 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
329 
330 	if (uci && uci->valid)
331 		return UCODE_OK;
332 
333 	if (collect_cpu_info(cpu))
334 		return UCODE_ERROR;
335 
336 	/* --dimm. Trigger a delayed update? */
337 	if (system_state != SYSTEM_RUNNING)
338 		return UCODE_NFOUND;
339 
340 	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
341 						     refresh_fw);
342 
343 	if (ustate == UCODE_OK) {
344 		pr_debug("CPU%d updated upon init\n", cpu);
345 		apply_microcode_on_target(cpu);
346 	}
347 
348 	return ustate;
349 }
350 
351 static enum ucode_state microcode_update_cpu(int cpu)
352 {
353 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
354 
355 	if (uci->valid)
356 		return microcode_resume_cpu(cpu);
357 
358 	return microcode_init_cpu(cpu, false);
359 }
360 
361 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
362 {
363 	int err, cpu = dev->id;
364 
365 	if (!cpu_online(cpu))
366 		return 0;
367 
368 	pr_debug("CPU%d added\n", cpu);
369 
370 	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
371 	if (err)
372 		return err;
373 
374 	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
375 		return -EINVAL;
376 
377 	return err;
378 }
379 
380 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
381 {
382 	int cpu = dev->id;
383 
384 	if (!cpu_online(cpu))
385 		return;
386 
387 	pr_debug("CPU%d removed\n", cpu);
388 	microcode_fini_cpu(cpu);
389 	sysfs_remove_group(&dev->kobj, &mc_attr_group);
390 }
391 
392 static struct subsys_interface mc_cpu_interface = {
393 	.name			= "microcode",
394 	.subsys			= &cpu_subsys,
395 	.add_dev		= mc_device_add,
396 	.remove_dev		= mc_device_remove,
397 };
398 
399 /**
400  * mc_bp_resume - Update boot CPU microcode during resume.
401  */
402 static void mc_bp_resume(void)
403 {
404 	int cpu = smp_processor_id();
405 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
406 
407 	if (uci->valid && uci->mc)
408 		microcode_ops->apply_microcode(cpu);
409 	else if (!uci->mc)
410 		reload_early_microcode();
411 }
412 
413 static struct syscore_ops mc_syscore_ops = {
414 	.resume			= mc_bp_resume,
415 };
416 
417 static int
418 mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
419 {
420 	unsigned int cpu = (unsigned long)hcpu;
421 	struct device *dev;
422 
423 	dev = get_cpu_device(cpu);
424 
425 	switch (action & ~CPU_TASKS_FROZEN) {
426 	case CPU_ONLINE:
427 		microcode_update_cpu(cpu);
428 		pr_debug("CPU%d added\n", cpu);
429 		/*
430 		 * "break" is missing on purpose here because we want to fall
431 		 * through in order to create the sysfs group.
432 		 */
433 
434 	case CPU_DOWN_FAILED:
435 		if (sysfs_create_group(&dev->kobj, &mc_attr_group))
436 			pr_err("Failed to create group for CPU%d\n", cpu);
437 		break;
438 
439 	case CPU_DOWN_PREPARE:
440 		/* Suspend is in progress, only remove the interface */
441 		sysfs_remove_group(&dev->kobj, &mc_attr_group);
442 		pr_debug("CPU%d removed\n", cpu);
443 		break;
444 
445 	/*
446 	 * case CPU_DEAD:
447 	 *
448 	 * When a CPU goes offline, don't free up or invalidate the copy of
449 	 * the microcode in kernel memory, so that we can reuse it when the
450 	 * CPU comes back online without unnecessarily requesting the userspace
451 	 * for it again.
452 	 */
453 	}
454 
455 	/* The CPU refused to come up during a system resume */
456 	if (action == CPU_UP_CANCELED_FROZEN)
457 		microcode_fini_cpu(cpu);
458 
459 	return NOTIFY_OK;
460 }
461 
462 static struct notifier_block mc_cpu_notifier = {
463 	.notifier_call	= mc_cpu_callback,
464 };
465 
466 #ifdef MODULE
467 /* Autoload on Intel and AMD systems */
468 static const struct x86_cpu_id __initconst microcode_id[] = {
469 #ifdef CONFIG_MICROCODE_INTEL
470 	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, },
471 #endif
472 #ifdef CONFIG_MICROCODE_AMD
473 	{ X86_VENDOR_AMD, X86_FAMILY_ANY, X86_MODEL_ANY, },
474 #endif
475 	{}
476 };
477 MODULE_DEVICE_TABLE(x86cpu, microcode_id);
478 #endif
479 
480 static struct attribute *cpu_root_microcode_attrs[] = {
481 	&dev_attr_reload.attr,
482 	NULL
483 };
484 
485 static struct attribute_group cpu_root_microcode_group = {
486 	.name  = "microcode",
487 	.attrs = cpu_root_microcode_attrs,
488 };
489 
490 static int __init microcode_init(void)
491 {
492 	struct cpuinfo_x86 *c = &cpu_data(0);
493 	int error;
494 
495 	if (paravirt_enabled() || dis_ucode_ldr)
496 		return -EINVAL;
497 
498 	if (c->x86_vendor == X86_VENDOR_INTEL)
499 		microcode_ops = init_intel_microcode();
500 	else if (c->x86_vendor == X86_VENDOR_AMD)
501 		microcode_ops = init_amd_microcode();
502 	else
503 		pr_err("no support for this CPU vendor\n");
504 
505 	if (!microcode_ops)
506 		return -ENODEV;
507 
508 	microcode_pdev = platform_device_register_simple("microcode", -1,
509 							 NULL, 0);
510 	if (IS_ERR(microcode_pdev))
511 		return PTR_ERR(microcode_pdev);
512 
513 	get_online_cpus();
514 	mutex_lock(&microcode_mutex);
515 
516 	error = subsys_interface_register(&mc_cpu_interface);
517 	if (!error)
518 		perf_check_microcode();
519 	mutex_unlock(&microcode_mutex);
520 	put_online_cpus();
521 
522 	if (error)
523 		goto out_pdev;
524 
525 	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
526 				   &cpu_root_microcode_group);
527 
528 	if (error) {
529 		pr_err("Error creating microcode group!\n");
530 		goto out_driver;
531 	}
532 
533 	error = microcode_dev_init();
534 	if (error)
535 		goto out_ucode_group;
536 
537 	register_syscore_ops(&mc_syscore_ops);
538 	register_hotcpu_notifier(&mc_cpu_notifier);
539 
540 	pr_info("Microcode Update Driver: v" MICROCODE_VERSION
541 		" <tigran@aivazian.fsnet.co.uk>, Peter Oruba\n");
542 
543 	return 0;
544 
545  out_ucode_group:
546 	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
547 			   &cpu_root_microcode_group);
548 
549  out_driver:
550 	get_online_cpus();
551 	mutex_lock(&microcode_mutex);
552 
553 	subsys_interface_unregister(&mc_cpu_interface);
554 
555 	mutex_unlock(&microcode_mutex);
556 	put_online_cpus();
557 
558  out_pdev:
559 	platform_device_unregister(microcode_pdev);
560 	return error;
561 
562 }
563 module_init(microcode_init);
564 
565 static void __exit microcode_exit(void)
566 {
567 	struct cpuinfo_x86 *c = &cpu_data(0);
568 
569 	microcode_dev_exit();
570 
571 	unregister_hotcpu_notifier(&mc_cpu_notifier);
572 	unregister_syscore_ops(&mc_syscore_ops);
573 
574 	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
575 			   &cpu_root_microcode_group);
576 
577 	get_online_cpus();
578 	mutex_lock(&microcode_mutex);
579 
580 	subsys_interface_unregister(&mc_cpu_interface);
581 
582 	mutex_unlock(&microcode_mutex);
583 	put_online_cpus();
584 
585 	platform_device_unregister(microcode_pdev);
586 
587 	microcode_ops = NULL;
588 
589 	if (c->x86_vendor == X86_VENDOR_AMD)
590 		exit_amd_microcode();
591 
592 	pr_info("Microcode Update Driver: v" MICROCODE_VERSION " removed.\n");
593 }
594 module_exit(microcode_exit);
595