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
 45static struct microcode_ops	*microcode_ops;
 46static 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 */
 60static DEFINE_MUTEX(microcode_mutex);
 61
 62struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
 63EXPORT_SYMBOL_GPL(ucode_cpu_info);
 64
 65/*
 66 * Operations that are run on a target cpu:
 67 */
 68
 69struct cpu_info_ctx {
 70	struct cpu_signature	*cpu_sig;
 71	int			err;
 72};
 73
 74static 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
 95extern struct builtin_fw __start_builtin_fw[];
 96extern struct builtin_fw __end_builtin_fw[];
 97
 98bool 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
114void __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
142static 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
151void 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
178int __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
198void 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
219static 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
227static 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
239static 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
253struct apply_microcode_ctx {
254	int err;
255};
256
257static 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
264static 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
277static 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
300static int microcode_open(struct inode *inode, struct file *file)
301{
302	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
303}
304
305static 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
330static const struct file_operations microcode_fops = {
331	.owner			= THIS_MODULE,
332	.write			= microcode_write,
333	.open			= microcode_open,
334	.llseek		= no_llseek,
335};
336
337static struct miscdevice microcode_dev = {
338	.minor			= MICROCODE_MINOR,
339	.name			= "microcode",
340	.nodename		= "cpu/microcode",
341	.fops			= &microcode_fops,
342};
343
344static 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
357static 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 */
367static struct platform_device	*microcode_pdev;
368
369static 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
387static 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
424static 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
432static 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
440static DEVICE_ATTR(reload, 0200, NULL, reload_store);
441static DEVICE_ATTR(version, 0400, version_show, NULL);
442static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
443
444static struct attribute *mc_default_attrs[] = {
445	&dev_attr_version.attr,
446	&dev_attr_processor_flags.attr,
447	NULL
448};
449
450static struct attribute_group mc_attr_group = {
451	.attrs			= mc_default_attrs,
452	.name			= "microcode",
453};
454
455static void microcode_fini_cpu(int cpu)
456{
457	microcode_ops->microcode_fini_cpu(cpu);
458}
459
460static 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
470static 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
496static 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
506static 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
525static 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
537static 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 */
547static 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
558static struct syscore_ops mc_syscore_ops = {
559	.resume			= mc_bp_resume,
560};
561
562static int
563mc_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
607static struct notifier_block mc_cpu_notifier = {
608	.notifier_call	= mc_cpu_callback,
609};
610
611static struct attribute *cpu_root_microcode_attrs[] = {
612	&dev_attr_reload.attr,
613	NULL
614};
615
616static struct attribute_group cpu_root_microcode_group = {
617	.name  = "microcode",
618	.attrs = cpu_root_microcode_attrs,
619};
620
621int __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}
694late_initcall(microcode_init);