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  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);