2 * CPU Microcode Update Driver for Linux
4 * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
5 * 2006 Shaohua Li <shaohua.li@intel.com>
6 * 2013-2016 Borislav Petkov <bp@alien8.de>
8 * X86 CPU microcode early update for Linux:
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>
14 * This driver allows to upgrade microcode on x86 processors.
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.
22 #define pr_fmt(fmt) "microcode: " fmt
24 #include <linux/platform_device.h>
25 #include <linux/stop_machine.h>
26 #include <linux/syscore_ops.h>
27 #include <linux/miscdevice.h>
28 #include <linux/capability.h>
29 #include <linux/firmware.h>
30 #include <linux/kernel.h>
31 #include <linux/delay.h>
32 #include <linux/mutex.h>
33 #include <linux/cpu.h>
34 #include <linux/nmi.h>
38 #include <asm/microcode_intel.h>
39 #include <asm/cpu_device_id.h>
40 #include <asm/microcode_amd.h>
41 #include <asm/perf_event.h>
42 #include <asm/microcode.h>
43 #include <asm/processor.h>
44 #include <asm/cmdline.h>
45 #include <asm/setup.h>
47 #define DRIVER_VERSION "2.2"
49 static struct microcode_ops *microcode_ops;
50 static bool dis_ucode_ldr = true;
54 LIST_HEAD(microcode_cache);
59 * All non cpu-hotplug-callback call sites use:
61 * - microcode_mutex to synchronize with each other;
62 * - get/put_online_cpus() to synchronize with
63 * the cpu-hotplug-callback call sites.
65 * We guarantee that only a single cpu is being
66 * updated at any particular moment of time.
68 static DEFINE_MUTEX(microcode_mutex);
71 * Serialize late loading so that CPUs get updated one-by-one.
73 static DEFINE_RAW_SPINLOCK(update_lock);
75 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
78 struct cpu_signature *cpu_sig;
83 * Those patch levels cannot be updated to newer ones and thus should be final.
85 static u32 final_levels[] = {
89 0, /* T-101 terminator */
93 * Check the current patch level on this CPU.
96 * - true: if update should stop
99 static bool amd_check_current_patch_level(void)
104 native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
106 if (IS_ENABLED(CONFIG_X86_32))
107 levels = (u32 *)__pa_nodebug(&final_levels);
109 levels = final_levels;
111 for (i = 0; levels[i]; i++) {
112 if (lvl == levels[i])
118 static bool __init check_loader_disabled_bsp(void)
120 static const char *__dis_opt_str = "dis_ucode_ldr";
123 const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
124 const char *option = (const char *)__pa_nodebug(__dis_opt_str);
125 bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
127 #else /* CONFIG_X86_64 */
128 const char *cmdline = boot_command_line;
129 const char *option = __dis_opt_str;
130 bool *res = &dis_ucode_ldr;
134 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
135 * completely accurate as xen pv guests don't see that CPUID bit set but
136 * that's good enough as they don't land on the BSP path anyway.
138 if (native_cpuid_ecx(1) & BIT(31))
141 if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
142 if (amd_check_current_patch_level())
146 if (cmdline_find_option_bool(cmdline, option) <= 0)
152 extern struct builtin_fw __start_builtin_fw[];
153 extern struct builtin_fw __end_builtin_fw[];
155 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
157 #ifdef CONFIG_FW_LOADER
158 struct builtin_fw *b_fw;
160 for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
161 if (!strcmp(name, b_fw->name)) {
162 cd->size = b_fw->size;
163 cd->data = b_fw->data;
171 void __init load_ucode_bsp(void)
173 unsigned int cpuid_1_eax;
179 cpuid_1_eax = native_cpuid_eax(1);
181 switch (x86_cpuid_vendor()) {
182 case X86_VENDOR_INTEL:
183 if (x86_family(cpuid_1_eax) < 6)
188 if (x86_family(cpuid_1_eax) < 0x10)
197 if (check_loader_disabled_bsp())
201 load_ucode_intel_bsp();
203 load_ucode_amd_bsp(cpuid_1_eax);
206 static bool check_loader_disabled_ap(void)
209 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
211 return dis_ucode_ldr;
215 void load_ucode_ap(void)
217 unsigned int cpuid_1_eax;
219 if (check_loader_disabled_ap())
222 cpuid_1_eax = native_cpuid_eax(1);
224 switch (x86_cpuid_vendor()) {
225 case X86_VENDOR_INTEL:
226 if (x86_family(cpuid_1_eax) >= 6)
227 load_ucode_intel_ap();
230 if (x86_family(cpuid_1_eax) >= 0x10)
231 load_ucode_amd_ap(cpuid_1_eax);
238 static int __init save_microcode_in_initrd(void)
240 struct cpuinfo_x86 *c = &boot_cpu_data;
243 switch (c->x86_vendor) {
244 case X86_VENDOR_INTEL:
246 ret = save_microcode_in_initrd_intel();
250 ret = save_microcode_in_initrd_amd(cpuid_eax(1));
261 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
263 #ifdef CONFIG_BLK_DEV_INITRD
264 unsigned long start = 0;
268 struct boot_params *params;
271 params = (struct boot_params *)__pa_nodebug(&boot_params);
273 params = &boot_params;
275 size = params->hdr.ramdisk_size;
278 * Set start only if we have an initrd image. We cannot use initrd_start
279 * because it is not set that early yet.
282 start = params->hdr.ramdisk_image;
284 # else /* CONFIG_X86_64 */
285 size = (unsigned long)boot_params.ext_ramdisk_size << 32;
286 size |= boot_params.hdr.ramdisk_size;
289 start = (unsigned long)boot_params.ext_ramdisk_image << 32;
290 start |= boot_params.hdr.ramdisk_image;
292 start += PAGE_OFFSET;
297 * Fixup the start address: after reserve_initrd() runs, initrd_start
298 * has the virtual address of the beginning of the initrd. It also
299 * possibly relocates the ramdisk. In either case, initrd_start contains
300 * the updated address so use that instead.
302 * initrd_gone is for the hotplug case where we've thrown out initrd
307 return (struct cpio_data){ NULL, 0, "" };
309 start = initrd_start;
312 * The picture with physical addresses is a bit different: we
313 * need to get the *physical* address to which the ramdisk was
314 * relocated, i.e., relocated_ramdisk (not initrd_start) and
315 * since we're running from physical addresses, we need to access
316 * relocated_ramdisk through its *physical* address too.
318 u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
323 return find_cpio_data(path, (void *)start, size, NULL);
324 #else /* !CONFIG_BLK_DEV_INITRD */
325 return (struct cpio_data){ NULL, 0, "" };
329 void reload_early_microcode(void)
333 vendor = x86_cpuid_vendor();
334 family = x86_cpuid_family();
337 case X86_VENDOR_INTEL:
339 reload_ucode_intel();
350 static void collect_cpu_info_local(void *arg)
352 struct cpu_info_ctx *ctx = arg;
354 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
358 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
360 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
363 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
370 static int collect_cpu_info(int cpu)
372 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
375 memset(uci, 0, sizeof(*uci));
377 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
384 static void apply_microcode_local(void *arg)
386 enum ucode_state *err = arg;
388 *err = microcode_ops->apply_microcode(smp_processor_id());
391 static int apply_microcode_on_target(int cpu)
393 enum ucode_state err;
396 ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
398 if (err == UCODE_ERROR)
404 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
405 static int do_microcode_update(const void __user *buf, size_t size)
410 for_each_online_cpu(cpu) {
411 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
412 enum ucode_state ustate;
417 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
418 if (ustate == UCODE_ERROR) {
421 } else if (ustate == UCODE_NEW) {
422 apply_microcode_on_target(cpu);
429 static int microcode_open(struct inode *inode, struct file *file)
431 return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
434 static ssize_t microcode_write(struct file *file, const char __user *buf,
435 size_t len, loff_t *ppos)
437 ssize_t ret = -EINVAL;
439 if ((len >> PAGE_SHIFT) > totalram_pages) {
440 pr_err("too much data (max %ld pages)\n", totalram_pages);
445 mutex_lock(µcode_mutex);
447 if (do_microcode_update(buf, len) == 0)
451 perf_check_microcode();
453 mutex_unlock(µcode_mutex);
459 static const struct file_operations microcode_fops = {
460 .owner = THIS_MODULE,
461 .write = microcode_write,
462 .open = microcode_open,
466 static struct miscdevice microcode_dev = {
467 .minor = MICROCODE_MINOR,
469 .nodename = "cpu/microcode",
470 .fops = µcode_fops,
473 static int __init microcode_dev_init(void)
477 error = misc_register(µcode_dev);
479 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
486 static void __exit microcode_dev_exit(void)
488 misc_deregister(µcode_dev);
491 #define microcode_dev_init() 0
492 #define microcode_dev_exit() do { } while (0)
495 /* fake device for request_firmware */
496 static struct platform_device *microcode_pdev;
499 * Late loading dance. Why the heavy-handed stomp_machine effort?
501 * - HT siblings must be idle and not execute other code while the other sibling
502 * is loading microcode in order to avoid any negative interactions caused by
505 * - In addition, microcode update on the cores must be serialized until this
506 * requirement can be relaxed in the future. Right now, this is conservative
509 #define SPINUNIT 100 /* 100 nsec */
511 static int check_online_cpus(void)
516 * Make sure all CPUs are online. It's fine for SMT to be disabled if
517 * all the primary threads are still online.
519 for_each_present_cpu(cpu) {
520 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
521 pr_err("Not all CPUs online, aborting microcode update.\n");
529 static atomic_t late_cpus_in;
530 static atomic_t late_cpus_out;
532 static int __wait_for_cpus(atomic_t *t, long long timeout)
534 int all_cpus = num_online_cpus();
538 while (atomic_read(t) < all_cpus) {
539 if (timeout < SPINUNIT) {
540 pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
541 all_cpus - atomic_read(t));
548 touch_nmi_watchdog();
557 * 1 - microcode was updated
559 static int __reload_late(void *info)
561 int cpu = smp_processor_id();
562 enum ucode_state err;
566 * Wait for all CPUs to arrive. A load will not be attempted unless all
569 if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
572 raw_spin_lock(&update_lock);
573 apply_microcode_local(&err);
574 raw_spin_unlock(&update_lock);
576 /* siblings return UCODE_OK because their engine got updated already */
577 if (err > UCODE_NFOUND) {
578 pr_warn("Error reloading microcode on CPU %d\n", cpu);
580 } else if (err == UCODE_UPDATED || err == UCODE_OK) {
585 * Increase the wait timeout to a safe value here since we're
586 * serializing the microcode update and that could take a while on a
587 * large number of CPUs. And that is fine as the *actual* timeout will
588 * be determined by the last CPU finished updating and thus cut short.
590 if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC * num_online_cpus()))
591 panic("Timeout during microcode update!\n");
597 * Reload microcode late on all CPUs. Wait for a sec until they
598 * all gather together.
600 static int microcode_reload_late(void)
604 atomic_set(&late_cpus_in, 0);
605 atomic_set(&late_cpus_out, 0);
607 ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
614 static ssize_t reload_store(struct device *dev,
615 struct device_attribute *attr,
616 const char *buf, size_t size)
618 enum ucode_state tmp_ret = UCODE_OK;
619 int bsp = boot_cpu_data.cpu_index;
623 ret = kstrtoul(buf, 0, &val);
632 ret = check_online_cpus();
636 tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev, true);
637 if (tmp_ret != UCODE_NEW)
640 mutex_lock(µcode_mutex);
641 ret = microcode_reload_late();
642 mutex_unlock(µcode_mutex);
653 static ssize_t version_show(struct device *dev,
654 struct device_attribute *attr, char *buf)
656 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
658 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
661 static ssize_t pf_show(struct device *dev,
662 struct device_attribute *attr, char *buf)
664 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
666 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
669 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
670 static DEVICE_ATTR(version, 0400, version_show, NULL);
671 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
673 static struct attribute *mc_default_attrs[] = {
674 &dev_attr_version.attr,
675 &dev_attr_processor_flags.attr,
679 static const struct attribute_group mc_attr_group = {
680 .attrs = mc_default_attrs,
684 static void microcode_fini_cpu(int cpu)
686 if (microcode_ops->microcode_fini_cpu)
687 microcode_ops->microcode_fini_cpu(cpu);
690 static enum ucode_state microcode_resume_cpu(int cpu)
692 if (apply_microcode_on_target(cpu))
695 pr_debug("CPU%d updated upon resume\n", cpu);
700 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
702 enum ucode_state ustate;
703 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
708 if (collect_cpu_info(cpu))
711 /* --dimm. Trigger a delayed update? */
712 if (system_state != SYSTEM_RUNNING)
715 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, refresh_fw);
716 if (ustate == UCODE_NEW) {
717 pr_debug("CPU%d updated upon init\n", cpu);
718 apply_microcode_on_target(cpu);
724 static enum ucode_state microcode_update_cpu(int cpu)
726 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
728 /* Refresh CPU microcode revision after resume. */
729 collect_cpu_info(cpu);
732 return microcode_resume_cpu(cpu);
734 return microcode_init_cpu(cpu, false);
737 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
739 int err, cpu = dev->id;
741 if (!cpu_online(cpu))
744 pr_debug("CPU%d added\n", cpu);
746 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
750 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
756 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
760 if (!cpu_online(cpu))
763 pr_debug("CPU%d removed\n", cpu);
764 microcode_fini_cpu(cpu);
765 sysfs_remove_group(&dev->kobj, &mc_attr_group);
768 static struct subsys_interface mc_cpu_interface = {
770 .subsys = &cpu_subsys,
771 .add_dev = mc_device_add,
772 .remove_dev = mc_device_remove,
776 * microcode_bsp_resume - Update boot CPU microcode during resume.
778 void microcode_bsp_resume(void)
780 int cpu = smp_processor_id();
781 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
783 if (uci->valid && uci->mc)
784 microcode_ops->apply_microcode(cpu);
786 reload_early_microcode();
789 static struct syscore_ops mc_syscore_ops = {
790 .resume = microcode_bsp_resume,
793 static int mc_cpu_starting(unsigned int cpu)
795 microcode_update_cpu(cpu);
796 pr_debug("CPU%d added\n", cpu);
800 static int mc_cpu_online(unsigned int cpu)
802 struct device *dev = get_cpu_device(cpu);
804 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
805 pr_err("Failed to create group for CPU%d\n", cpu);
809 static int mc_cpu_down_prep(unsigned int cpu)
813 dev = get_cpu_device(cpu);
814 /* Suspend is in progress, only remove the interface */
815 sysfs_remove_group(&dev->kobj, &mc_attr_group);
816 pr_debug("CPU%d removed\n", cpu);
821 static struct attribute *cpu_root_microcode_attrs[] = {
822 &dev_attr_reload.attr,
826 static const struct attribute_group cpu_root_microcode_group = {
828 .attrs = cpu_root_microcode_attrs,
831 int __init microcode_init(void)
833 struct cpuinfo_x86 *c = &boot_cpu_data;
839 if (c->x86_vendor == X86_VENDOR_INTEL)
840 microcode_ops = init_intel_microcode();
841 else if (c->x86_vendor == X86_VENDOR_AMD)
842 microcode_ops = init_amd_microcode();
844 pr_err("no support for this CPU vendor\n");
849 microcode_pdev = platform_device_register_simple("microcode", -1,
851 if (IS_ERR(microcode_pdev))
852 return PTR_ERR(microcode_pdev);
855 mutex_lock(µcode_mutex);
857 error = subsys_interface_register(&mc_cpu_interface);
859 perf_check_microcode();
860 mutex_unlock(µcode_mutex);
866 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
867 &cpu_root_microcode_group);
870 pr_err("Error creating microcode group!\n");
874 error = microcode_dev_init();
876 goto out_ucode_group;
878 register_syscore_ops(&mc_syscore_ops);
879 cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
880 mc_cpu_starting, NULL);
881 cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
882 mc_cpu_online, mc_cpu_down_prep);
884 pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
889 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
890 &cpu_root_microcode_group);
894 mutex_lock(µcode_mutex);
896 subsys_interface_unregister(&mc_cpu_interface);
898 mutex_unlock(µcode_mutex);
902 platform_device_unregister(microcode_pdev);
906 fs_initcall(save_microcode_in_initrd);
907 late_initcall(microcode_init);