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 *	      2013-2016	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#include <asm/setup.h>
 43
 44#define DRIVER_VERSION	"2.2"
 45
 46static struct microcode_ops	*microcode_ops;
 47static bool dis_ucode_ldr = true;
 48
 49bool initrd_gone;
 50
 51LIST_HEAD(microcode_cache);
 52
 53/*
 54 * Synchronization.
 55 *
 56 * All non cpu-hotplug-callback call sites use:
 57 *
 58 * - microcode_mutex to synchronize with each other;
 59 * - get/put_online_cpus() to synchronize with
 60 *   the cpu-hotplug-callback call sites.
 61 *
 62 * We guarantee that only a single cpu is being
 63 * updated at any particular moment of time.
 64 */
 65static DEFINE_MUTEX(microcode_mutex);
 66
 67struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
 68
 69/*
 70 * Operations that are run on a target cpu:
 71 */
 72
 73struct cpu_info_ctx {
 74	struct cpu_signature	*cpu_sig;
 75	int			err;
 76};
 77
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 78static bool __init check_loader_disabled_bsp(void)
 79{
 80	static const char *__dis_opt_str = "dis_ucode_ldr";
 81	u32 a, b, c, d;
 82
 83#ifdef CONFIG_X86_32
 84	const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
 85	const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
 86	bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
 87
 88#else /* CONFIG_X86_64 */
 89	const char *cmdline = boot_command_line;
 90	const char *option  = __dis_opt_str;
 91	bool *res = &dis_ucode_ldr;
 92#endif
 93
 94	if (!have_cpuid_p())
 95		return *res;
 96
 97	a = 1;
 98	c = 0;
 99	native_cpuid(&a, &b, &c, &d);
100
101	/*
102	 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
103	 * completely accurate as xen pv guests don't see that CPUID bit set but
104	 * that's good enough as they don't land on the BSP path anyway.
105	 */
106	if (c & BIT(31))
107		return *res;
108
 
 
 
 
 
109	if (cmdline_find_option_bool(cmdline, option) <= 0)
110		*res = false;
111
112	return *res;
113}
114
115extern struct builtin_fw __start_builtin_fw[];
116extern struct builtin_fw __end_builtin_fw[];
117
118bool get_builtin_firmware(struct cpio_data *cd, const char *name)
119{
120#ifdef CONFIG_FW_LOADER
121	struct builtin_fw *b_fw;
122
123	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
124		if (!strcmp(name, b_fw->name)) {
125			cd->size = b_fw->size;
126			cd->data = b_fw->data;
127			return true;
128		}
129	}
130#endif
131	return false;
132}
133
134void __init load_ucode_bsp(void)
135{
136	int vendor;
137	unsigned int family;
138
139	if (check_loader_disabled_bsp())
140		return;
141
142	vendor = x86_cpuid_vendor();
143	family = x86_cpuid_family();
144
145	switch (vendor) {
146	case X86_VENDOR_INTEL:
147		if (family >= 6)
148			load_ucode_intel_bsp();
149		break;
 
150	case X86_VENDOR_AMD:
151		if (family >= 0x10)
152			load_ucode_amd_bsp(family);
 
153		break;
 
154	default:
155		break;
156	}
 
 
 
 
 
 
 
 
157}
158
159static bool check_loader_disabled_ap(void)
160{
161#ifdef CONFIG_X86_32
162	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
163#else
164	return dis_ucode_ldr;
165#endif
166}
167
168void load_ucode_ap(void)
169{
170	int vendor, family;
171
172	if (check_loader_disabled_ap())
173		return;
174
175	vendor = x86_cpuid_vendor();
176	family = x86_cpuid_family();
177
178	switch (vendor) {
179	case X86_VENDOR_INTEL:
180		if (family >= 6)
181			load_ucode_intel_ap();
182		break;
183	case X86_VENDOR_AMD:
184		if (family >= 0x10)
185			load_ucode_amd_ap(family);
186		break;
187	default:
188		break;
189	}
190}
191
192static int __init save_microcode_in_initrd(void)
193{
194	struct cpuinfo_x86 *c = &boot_cpu_data;
195	int ret = -EINVAL;
196
197	switch (c->x86_vendor) {
198	case X86_VENDOR_INTEL:
199		if (c->x86 >= 6)
200			ret = save_microcode_in_initrd_intel();
201		break;
202	case X86_VENDOR_AMD:
203		if (c->x86 >= 0x10)
204			ret = save_microcode_in_initrd_amd(c->x86);
205		break;
206	default:
207		break;
208	}
209
210	initrd_gone = true;
211
212	return ret;
213}
214
215struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
216{
217#ifdef CONFIG_BLK_DEV_INITRD
218	unsigned long start = 0;
219	size_t size;
220
221#ifdef CONFIG_X86_32
222	struct boot_params *params;
223
224	if (use_pa)
225		params = (struct boot_params *)__pa_nodebug(&boot_params);
226	else
227		params = &boot_params;
228
229	size = params->hdr.ramdisk_size;
230
231	/*
232	 * Set start only if we have an initrd image. We cannot use initrd_start
233	 * because it is not set that early yet.
234	 */
235	if (size)
236		start = params->hdr.ramdisk_image;
237
238# else /* CONFIG_X86_64 */
239	size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
240	size |= boot_params.hdr.ramdisk_size;
241
242	if (size) {
243		start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
244		start |= boot_params.hdr.ramdisk_image;
245
246		start += PAGE_OFFSET;
247	}
248# endif
249
250	/*
251	 * Fixup the start address: after reserve_initrd() runs, initrd_start
252	 * has the virtual address of the beginning of the initrd. It also
253	 * possibly relocates the ramdisk. In either case, initrd_start contains
254	 * the updated address so use that instead.
255	 *
256	 * initrd_gone is for the hotplug case where we've thrown out initrd
257	 * already.
258	 */
259	if (!use_pa) {
260		if (initrd_gone)
261			return (struct cpio_data){ NULL, 0, "" };
262		if (initrd_start)
263			start = initrd_start;
 
 
 
 
 
 
 
 
 
 
 
264	}
265
266	return find_cpio_data(path, (void *)start, size, NULL);
267#else /* !CONFIG_BLK_DEV_INITRD */
268	return (struct cpio_data){ NULL, 0, "" };
269#endif
270}
271
272void reload_early_microcode(void)
273{
274	int vendor, family;
275
276	vendor = x86_cpuid_vendor();
277	family = x86_cpuid_family();
278
279	switch (vendor) {
280	case X86_VENDOR_INTEL:
281		if (family >= 6)
282			reload_ucode_intel();
283		break;
284	case X86_VENDOR_AMD:
285		if (family >= 0x10)
286			reload_ucode_amd();
287		break;
288	default:
289		break;
290	}
291}
292
293static void collect_cpu_info_local(void *arg)
294{
295	struct cpu_info_ctx *ctx = arg;
296
297	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
298						   ctx->cpu_sig);
299}
300
301static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
302{
303	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
304	int ret;
305
306	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
307	if (!ret)
308		ret = ctx.err;
309
310	return ret;
311}
 
 
 
 
 
 
 
 
 
 
 
312
313static int collect_cpu_info(int cpu)
314{
315	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
316	int ret;
317
318	memset(uci, 0, sizeof(*uci));
319
320	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
321	if (!ret)
322		uci->valid = 1;
 
 
 
 
 
 
 
323
324	return ret;
325}
326
327struct apply_microcode_ctx {
328	int err;
329};
330
331static void apply_microcode_local(void *arg)
332{
333	struct apply_microcode_ctx *ctx = arg;
334
335	ctx->err = microcode_ops->apply_microcode(smp_processor_id());
336}
337
338static int apply_microcode_on_target(int cpu)
339{
340	struct apply_microcode_ctx ctx = { .err = 0 };
341	int ret;
342
343	ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
344	if (!ret)
345		ret = ctx.err;
346
347	return ret;
348}
349
350#ifdef CONFIG_MICROCODE_OLD_INTERFACE
351static int do_microcode_update(const void __user *buf, size_t size)
352{
353	int error = 0;
354	int cpu;
355
356	for_each_online_cpu(cpu) {
357		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
358		enum ucode_state ustate;
359
360		if (!uci->valid)
361			continue;
362
363		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
364		if (ustate == UCODE_ERROR) {
365			error = -1;
366			break;
367		} else if (ustate == UCODE_OK)
368			apply_microcode_on_target(cpu);
369	}
370
371	return error;
372}
373
374static int microcode_open(struct inode *inode, struct file *file)
 
 
 
 
 
375{
376	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
377}
 
378
379static ssize_t microcode_write(struct file *file, const char __user *buf,
380			       size_t len, loff_t *ppos)
381{
382	ssize_t ret = -EINVAL;
 
 
383
384	if ((len >> PAGE_SHIFT) > totalram_pages) {
385		pr_err("too much data (max %ld pages)\n", totalram_pages);
386		return ret;
387	}
 
 
 
 
 
 
 
388
389	get_online_cpus();
390	mutex_lock(&microcode_mutex);
 
391
392	if (do_microcode_update(buf, len) == 0)
393		ret = (ssize_t)len;
394
395	if (ret > 0)
396		perf_check_microcode();
 
397
398	mutex_unlock(&microcode_mutex);
399	put_online_cpus();
 
 
 
 
 
 
400
401	return ret;
402}
403
404static const struct file_operations microcode_fops = {
405	.owner			= THIS_MODULE,
406	.write			= microcode_write,
407	.open			= microcode_open,
408	.llseek		= no_llseek,
409};
410
411static struct miscdevice microcode_dev = {
412	.minor			= MICROCODE_MINOR,
413	.name			= "microcode",
414	.nodename		= "cpu/microcode",
415	.fops			= &microcode_fops,
416};
417
418static int __init microcode_dev_init(void)
419{
420	int error;
421
422	error = misc_register(&microcode_dev);
423	if (error) {
424		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
425		return error;
426	}
427
428	return 0;
429}
430
431static void __exit microcode_dev_exit(void)
432{
433	misc_deregister(&microcode_dev);
434}
435#else
436#define microcode_dev_init()	0
437#define microcode_dev_exit()	do { } while (0)
438#endif
439
440/* fake device for request_firmware */
441static struct platform_device	*microcode_pdev;
442
443static int reload_for_cpu(int cpu)
444{
445	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
446	enum ucode_state ustate;
447	int err = 0;
448
449	if (!uci->valid)
450		return err;
451
452	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
453	if (ustate == UCODE_OK)
454		apply_microcode_on_target(cpu);
455	else
456		if (ustate == UCODE_ERROR)
457			err = -EINVAL;
458	return err;
459}
460
461static ssize_t reload_store(struct device *dev,
462			    struct device_attribute *attr,
463			    const char *buf, size_t size)
464{
 
 
465	unsigned long val;
466	int cpu;
467	ssize_t ret = 0, tmp_ret;
468
469	ret = kstrtoul(buf, 0, &val);
470	if (ret)
471		return ret;
472
473	if (val != 1)
474		return size;
475
476	get_online_cpus();
477	mutex_lock(&microcode_mutex);
478	for_each_online_cpu(cpu) {
479		tmp_ret = reload_for_cpu(cpu);
480		if (tmp_ret != 0)
481			pr_warn("Error reloading microcode on CPU %d\n", cpu);
482
483		/* save retval of the first encountered reload error */
484		if (!ret)
485			ret = tmp_ret;
486	}
487	if (!ret)
488		perf_check_microcode();
 
 
 
 
489	mutex_unlock(&microcode_mutex);
490	put_online_cpus();
491
492	if (!ret)
 
 
 
493		ret = size;
494
 
 
495	return ret;
496}
497
 
 
 
498static ssize_t version_show(struct device *dev,
499			struct device_attribute *attr, char *buf)
500{
501	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
502
503	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
504}
505
506static ssize_t pf_show(struct device *dev,
507			struct device_attribute *attr, char *buf)
508{
509	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
510
511	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
512}
513
514static DEVICE_ATTR(reload, 0200, NULL, reload_store);
515static DEVICE_ATTR(version, 0400, version_show, NULL);
516static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
517
518static struct attribute *mc_default_attrs[] = {
519	&dev_attr_version.attr,
520	&dev_attr_processor_flags.attr,
521	NULL
522};
523
524static struct attribute_group mc_attr_group = {
525	.attrs			= mc_default_attrs,
526	.name			= "microcode",
527};
528
529static void microcode_fini_cpu(int cpu)
530{
531	if (microcode_ops->microcode_fini_cpu)
532		microcode_ops->microcode_fini_cpu(cpu);
533}
534
535static enum ucode_state microcode_resume_cpu(int cpu)
536{
537	if (apply_microcode_on_target(cpu))
538		return UCODE_ERROR;
539
540	pr_debug("CPU%d updated upon resume\n", cpu);
541
542	return UCODE_OK;
543}
544
545static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
546{
547	enum ucode_state ustate;
548	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
549
550	if (uci->valid)
551		return UCODE_OK;
552
553	if (collect_cpu_info(cpu))
554		return UCODE_ERROR;
555
556	/* --dimm. Trigger a delayed update? */
557	if (system_state != SYSTEM_RUNNING)
558		return UCODE_NFOUND;
559
560	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
561						     refresh_fw);
562
563	if (ustate == UCODE_OK) {
564		pr_debug("CPU%d updated upon init\n", cpu);
565		apply_microcode_on_target(cpu);
566	}
567
568	return ustate;
569}
570
571static enum ucode_state microcode_update_cpu(int cpu)
572{
573	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
574
575	/* Refresh CPU microcode revision after resume. */
576	collect_cpu_info(cpu);
577
578	if (uci->valid)
579		return microcode_resume_cpu(cpu);
580
581	return microcode_init_cpu(cpu, false);
582}
583
584static int mc_device_add(struct device *dev, struct subsys_interface *sif)
585{
586	int err, cpu = dev->id;
587
588	if (!cpu_online(cpu))
589		return 0;
590
591	pr_debug("CPU%d added\n", cpu);
592
593	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
594	if (err)
595		return err;
596
597	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
598		return -EINVAL;
599
600	return err;
601}
602
603static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
604{
605	int cpu = dev->id;
606
607	if (!cpu_online(cpu))
608		return;
609
610	pr_debug("CPU%d removed\n", cpu);
611	microcode_fini_cpu(cpu);
612	sysfs_remove_group(&dev->kobj, &mc_attr_group);
613}
614
615static struct subsys_interface mc_cpu_interface = {
616	.name			= "microcode",
617	.subsys			= &cpu_subsys,
618	.add_dev		= mc_device_add,
619	.remove_dev		= mc_device_remove,
620};
621
622/**
623 * mc_bp_resume - Update boot CPU microcode during resume.
624 */
625static void mc_bp_resume(void)
626{
627	int cpu = smp_processor_id();
628	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
629
630	if (uci->valid && uci->mc)
631		microcode_ops->apply_microcode(cpu);
632	else if (!uci->mc)
633		reload_early_microcode();
634}
635
636static struct syscore_ops mc_syscore_ops = {
637	.resume			= mc_bp_resume,
638};
639
640static int mc_cpu_online(unsigned int cpu)
641{
642	struct device *dev;
643
644	dev = get_cpu_device(cpu);
645	microcode_update_cpu(cpu);
646	pr_debug("CPU%d added\n", cpu);
 
 
 
 
 
647
648	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
649		pr_err("Failed to create group for CPU%d\n", cpu);
650	return 0;
651}
652
653static int mc_cpu_down_prep(unsigned int cpu)
654{
655	struct device *dev;
656
657	dev = get_cpu_device(cpu);
 
 
 
658	/* Suspend is in progress, only remove the interface */
659	sysfs_remove_group(&dev->kobj, &mc_attr_group);
660	pr_debug("CPU%d removed\n", cpu);
661
662	return 0;
663}
664
 
 
 
 
 
 
 
 
 
 
 
 
 
 
665static struct attribute *cpu_root_microcode_attrs[] = {
 
666	&dev_attr_reload.attr,
 
667	NULL
668};
669
670static struct attribute_group cpu_root_microcode_group = {
671	.name  = "microcode",
672	.attrs = cpu_root_microcode_attrs,
673};
674
675int __init microcode_init(void)
676{
677	struct cpuinfo_x86 *c = &boot_cpu_data;
678	int error;
679
680	if (dis_ucode_ldr)
681		return -EINVAL;
682
683	if (c->x86_vendor == X86_VENDOR_INTEL)
684		microcode_ops = init_intel_microcode();
685	else if (c->x86_vendor == X86_VENDOR_AMD)
686		microcode_ops = init_amd_microcode();
687	else
688		pr_err("no support for this CPU vendor\n");
689
690	if (!microcode_ops)
691		return -ENODEV;
692
693	microcode_pdev = platform_device_register_simple("microcode", -1,
694							 NULL, 0);
695	if (IS_ERR(microcode_pdev))
696		return PTR_ERR(microcode_pdev);
697
698	get_online_cpus();
699	mutex_lock(&microcode_mutex);
700
701	error = subsys_interface_register(&mc_cpu_interface);
702	if (!error)
703		perf_check_microcode();
704	mutex_unlock(&microcode_mutex);
705	put_online_cpus();
706
707	if (error)
708		goto out_pdev;
709
710	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
711				   &cpu_root_microcode_group);
712
713	if (error) {
714		pr_err("Error creating microcode group!\n");
715		goto out_driver;
716	}
717
718	error = microcode_dev_init();
719	if (error)
720		goto out_ucode_group;
721
722	register_syscore_ops(&mc_syscore_ops);
 
 
723	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
724				  mc_cpu_online, mc_cpu_down_prep);
725
726	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
727
728	return 0;
729
730 out_ucode_group:
731	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
732			   &cpu_root_microcode_group);
733
734 out_driver:
735	get_online_cpus();
736	mutex_lock(&microcode_mutex);
737
738	subsys_interface_unregister(&mc_cpu_interface);
739
740	mutex_unlock(&microcode_mutex);
741	put_online_cpus();
742
743 out_pdev:
744	platform_device_unregister(microcode_pdev);
745	return error;
746
747}
748fs_initcall(save_microcode_in_initrd);
749late_initcall(microcode_init);

  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
 45static struct microcode_ops	*microcode_ops;
 46static bool dis_ucode_ldr = true;
 47
 48bool initrd_gone;
 49
 50LIST_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 */
 64static DEFINE_MUTEX(microcode_mutex);
 65
 66struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
 67
 
 
 
 
 68struct 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 */
 76static 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 */
 90static 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
109static 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
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
143void __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
178static 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
187void 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
210static 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
233struct 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
301void 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/* fake device for request_firmware */
323static struct platform_device	*microcode_pdev;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
324
325#ifdef CONFIG_MICROCODE_LATE_LOADING
326/*
327 * Late loading dance. Why the heavy-handed stomp_machine effort?
328 *
329 * - HT siblings must be idle and not execute other code while the other sibling
330 *   is loading microcode in order to avoid any negative interactions caused by
331 *   the loading.
332 *
333 * - In addition, microcode update on the cores must be serialized until this
334 *   requirement can be relaxed in the future. Right now, this is conservative
335 *   and good.
336 */
337#define SPINUNIT 100 /* 100 nsec */
338
339static int check_online_cpus(void)
340{
341	unsigned int cpu;
 
 
 
342
343	/*
344	 * Make sure all CPUs are online.  It's fine for SMT to be disabled if
345	 * all the primary threads are still online.
346	 */
347	for_each_present_cpu(cpu) {
348		if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
349			pr_err("Not all CPUs online, aborting microcode update.\n");
350			return -EINVAL;
351		}
352	}
353
354	return 0;
355}
356
357static atomic_t late_cpus_in;
358static atomic_t late_cpus_out;
 
359
360static int __wait_for_cpus(atomic_t *t, long long timeout)
361{
362	int all_cpus = num_online_cpus();
363
364	atomic_inc(t);
 
 
 
 
 
 
 
 
 
 
 
 
 
365
366	while (atomic_read(t) < all_cpus) {
367		if (timeout < SPINUNIT) {
368			pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
369				all_cpus - atomic_read(t));
370			return 1;
371		}
 
 
 
372
373		ndelay(SPINUNIT);
374		timeout -= SPINUNIT;
375
376		touch_nmi_watchdog();
 
 
 
 
 
377	}
378	return 0;
 
379}
380
381/*
382 * Returns:
383 * < 0 - on error
384 *   0 - success (no update done or microcode was updated)
385 */
386static int __reload_late(void *info)
387{
388	int cpu = smp_processor_id();
389	enum ucode_state err;
390	int ret = 0;
391
392	/*
393	 * Wait for all CPUs to arrive. A load will not be attempted unless all
394	 * CPUs show up.
395	 * */
396	if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
397		return -1;
398
399	/*
400	 * On an SMT system, it suffices to load the microcode on one sibling of
401	 * the core because the microcode engine is shared between the threads.
402	 * Synchronization still needs to take place so that no concurrent
403	 * loading attempts happen on multiple threads of an SMT core. See
404	 * below.
405	 */
406	if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
407		err = microcode_ops->apply_microcode(cpu);
408	else
409		goto wait_for_siblings;
410
411	if (err >= UCODE_NFOUND) {
412		if (err == UCODE_ERROR)
413			pr_warn("Error reloading microcode on CPU %d\n", cpu);
414
415		ret = -1;
416	}
417
418wait_for_siblings:
419	if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
420		panic("Timeout during microcode update!\n");
421
422	/*
423	 * At least one thread has completed update on each core.
424	 * For others, simply call the update to make sure the
425	 * per-cpu cpuinfo can be updated with right microcode
426	 * revision.
427	 */
428	if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
429		err = microcode_ops->apply_microcode(cpu);
430
431	return ret;
432}
433
434/*
435 * Reload microcode late on all CPUs. Wait for a sec until they
436 * all gather together.
437 */
438static int microcode_reload_late(void)
 
 
 
 
 
 
 
 
 
 
439{
440	int old = boot_cpu_data.microcode, ret;
 
 
 
 
 
 
 
 
 
441
442	pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n");
443	pr_err("You should switch to early loading, if possible.\n");
 
 
 
 
 
 
444
445	atomic_set(&late_cpus_in,  0);
446	atomic_set(&late_cpus_out, 0);
447
448	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
449	if (ret == 0)
450		microcode_check();
 
 
451
452	pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n",
453		old, boot_cpu_data.microcode);
454
455	return ret;
 
 
 
 
 
 
456}
457
458static ssize_t reload_store(struct device *dev,
459			    struct device_attribute *attr,
460			    const char *buf, size_t size)
461{
462	enum ucode_state tmp_ret = UCODE_OK;
463	int bsp = boot_cpu_data.cpu_index;
464	unsigned long val;
465	ssize_t ret = 0;
 
466
467	ret = kstrtoul(buf, 0, &val);
468	if (ret)
469		return ret;
470
471	if (val != 1)
472		return size;
473
474	cpus_read_lock();
 
 
 
 
 
475
476	ret = check_online_cpus();
477	if (ret)
478		goto put;
479
480	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev);
481	if (tmp_ret != UCODE_NEW)
482		goto put;
483
484	mutex_lock(&microcode_mutex);
485	ret = microcode_reload_late();
486	mutex_unlock(&microcode_mutex);
 
487
488put:
489	cpus_read_unlock();
490
491	if (ret == 0)
492		ret = size;
493
494	add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
495
496	return ret;
497}
498
499static DEVICE_ATTR_WO(reload);
500#endif
501
502static ssize_t version_show(struct device *dev,
503			struct device_attribute *attr, char *buf)
504{
505	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
506
507	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
508}
509
510static ssize_t pf_show(struct device *dev,
511			struct device_attribute *attr, char *buf)
512{
513	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
514
515	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
516}
517
518static DEVICE_ATTR(version, 0444, version_show, NULL);
519static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
 
520
521static struct attribute *mc_default_attrs[] = {
522	&dev_attr_version.attr,
523	&dev_attr_processor_flags.attr,
524	NULL
525};
526
527static const struct attribute_group mc_attr_group = {
528	.attrs			= mc_default_attrs,
529	.name			= "microcode",
530};
531
532static void microcode_fini_cpu(int cpu)
533{
534	if (microcode_ops->microcode_fini_cpu)
535		microcode_ops->microcode_fini_cpu(cpu);
536}
537
538static enum ucode_state microcode_init_cpu(int cpu)
 
 
 
 
 
 
 
 
 
 
539{
 
540	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
541
542	memset(uci, 0, sizeof(*uci));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
543
544	microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
 
545
546	return microcode_ops->apply_microcode(cpu);
547}
548
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
549/**
550 * microcode_bsp_resume - Update boot CPU microcode during resume.
551 */
552void microcode_bsp_resume(void)
553{
554	int cpu = smp_processor_id();
555	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
556
557	if (uci->mc)
558		microcode_ops->apply_microcode(cpu);
559	else
560		reload_early_microcode();
561}
562
563static struct syscore_ops mc_syscore_ops = {
564	.resume	= microcode_bsp_resume,
565};
566
567static int mc_cpu_starting(unsigned int cpu)
568{
569	enum ucode_state err = microcode_ops->apply_microcode(cpu);
570
571	pr_debug("%s: CPU%d, err: %d\n", __func__, cpu, err);
572
573	return err == UCODE_ERROR;
574}
575
576static int mc_cpu_online(unsigned int cpu)
577{
578	struct device *dev = get_cpu_device(cpu);
579
580	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
581		pr_err("Failed to create group for CPU%d\n", cpu);
582	return 0;
583}
584
585static int mc_cpu_down_prep(unsigned int cpu)
586{
587	struct device *dev;
588
589	dev = get_cpu_device(cpu);
590
591	microcode_fini_cpu(cpu);
592
593	/* Suspend is in progress, only remove the interface */
594	sysfs_remove_group(&dev->kobj, &mc_attr_group);
595	pr_debug("%s: CPU%d\n", __func__, cpu);
596
597	return 0;
598}
599
600static void setup_online_cpu(struct work_struct *work)
601{
602	int cpu = smp_processor_id();
603	enum ucode_state err;
604
605	err = microcode_init_cpu(cpu);
606	if (err == UCODE_ERROR) {
607		pr_err("Error applying microcode on CPU%d\n", cpu);
608		return;
609	}
610
611	mc_cpu_online(cpu);
612}
613
614static struct attribute *cpu_root_microcode_attrs[] = {
615#ifdef CONFIG_MICROCODE_LATE_LOADING
616	&dev_attr_reload.attr,
617#endif
618	NULL
619};
620
621static const struct attribute_group cpu_root_microcode_group = {
622	.name  = "microcode",
623	.attrs = cpu_root_microcode_attrs,
624};
625
626static int __init microcode_init(void)
627{
628	struct cpuinfo_x86 *c = &boot_cpu_data;
629	int error;
630
631	if (dis_ucode_ldr)
632		return -EINVAL;
633
634	if (c->x86_vendor == X86_VENDOR_INTEL)
635		microcode_ops = init_intel_microcode();
636	else if (c->x86_vendor == X86_VENDOR_AMD)
637		microcode_ops = init_amd_microcode();
638	else
639		pr_err("no support for this CPU vendor\n");
640
641	if (!microcode_ops)
642		return -ENODEV;
643
644	microcode_pdev = platform_device_register_simple("microcode", -1, NULL, 0);
 
645	if (IS_ERR(microcode_pdev))
646		return PTR_ERR(microcode_pdev);
647
648	error = sysfs_create_group(&cpu_subsys.dev_root->kobj, &cpu_root_microcode_group);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
649	if (error) {
650		pr_err("Error creating microcode group!\n");
651		goto out_pdev;
652	}
653
654	/* Do per-CPU setup */
655	schedule_on_each_cpu(setup_online_cpu);
 
656
657	register_syscore_ops(&mc_syscore_ops);
658	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
659				  mc_cpu_starting, NULL);
660	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
661				  mc_cpu_online, mc_cpu_down_prep);
662
663	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
664
665	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
666
667 out_pdev:
668	platform_device_unregister(microcode_pdev);
669	return error;
670
671}
672fs_initcall(save_microcode_in_initrd);
673late_initcall(microcode_init);