1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * CPU Microcode Update Driver for Linux
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>
9 * X86 CPU microcode early update for Linux:
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>
15 * This driver allows to upgrade microcode on x86 processors.
18 #define pr_fmt(fmt) "microcode: " fmt
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>
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>
43 #define DRIVER_VERSION "2.2"
45 static struct microcode_ops *microcode_ops;
46 static bool dis_ucode_ldr = true;
50 LIST_HEAD(microcode_cache);
55 * All non cpu-hotplug-callback call sites use:
57 * - microcode_mutex to synchronize with each other;
58 * - get/put_online_cpus() to synchronize with
59 * the cpu-hotplug-callback call sites.
61 * We guarantee that only a single cpu is being
62 * updated at any particular moment of time.
64 static DEFINE_MUTEX(microcode_mutex);
66 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
69 struct cpu_signature *cpu_sig;
74 * Those patch levels cannot be updated to newer ones and thus should be final.
76 static u32 final_levels[] = {
80 0, /* T-101 terminator */
84 * Check the current patch level on this CPU.
87 * - true: if update should stop
90 static bool amd_check_current_patch_level(void)
95 native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
97 if (IS_ENABLED(CONFIG_X86_32))
98 levels = (u32 *)__pa_nodebug(&final_levels);
100 levels = final_levels;
102 for (i = 0; levels[i]; i++) {
103 if (lvl == levels[i])
109 static bool __init check_loader_disabled_bsp(void)
111 static const char *__dis_opt_str = "dis_ucode_ldr";
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);
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;
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.
129 if (native_cpuid_ecx(1) & BIT(31))
132 if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
133 if (amd_check_current_patch_level())
137 if (cmdline_find_option_bool(cmdline, option) <= 0)
143 extern struct builtin_fw __start_builtin_fw[];
144 extern struct builtin_fw __end_builtin_fw[];
146 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
148 #ifdef CONFIG_FW_LOADER
149 struct builtin_fw *b_fw;
151 for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
152 if (!strcmp(name, b_fw->name)) {
153 cd->size = b_fw->size;
154 cd->data = b_fw->data;
162 void __init load_ucode_bsp(void)
164 unsigned int cpuid_1_eax;
170 cpuid_1_eax = native_cpuid_eax(1);
172 switch (x86_cpuid_vendor()) {
173 case X86_VENDOR_INTEL:
174 if (x86_family(cpuid_1_eax) < 6)
179 if (x86_family(cpuid_1_eax) < 0x10)
188 if (check_loader_disabled_bsp())
192 load_ucode_intel_bsp();
194 load_ucode_amd_bsp(cpuid_1_eax);
197 static bool check_loader_disabled_ap(void)
200 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
202 return dis_ucode_ldr;
206 void load_ucode_ap(void)
208 unsigned int cpuid_1_eax;
210 if (check_loader_disabled_ap())
213 cpuid_1_eax = native_cpuid_eax(1);
215 switch (x86_cpuid_vendor()) {
216 case X86_VENDOR_INTEL:
217 if (x86_family(cpuid_1_eax) >= 6)
218 load_ucode_intel_ap();
221 if (x86_family(cpuid_1_eax) >= 0x10)
222 load_ucode_amd_ap(cpuid_1_eax);
229 static int __init save_microcode_in_initrd(void)
231 struct cpuinfo_x86 *c = &boot_cpu_data;
234 switch (c->x86_vendor) {
235 case X86_VENDOR_INTEL:
237 ret = save_microcode_in_initrd_intel();
241 ret = save_microcode_in_initrd_amd(cpuid_eax(1));
252 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
254 #ifdef CONFIG_BLK_DEV_INITRD
255 unsigned long start = 0;
259 struct boot_params *params;
262 params = (struct boot_params *)__pa_nodebug(&boot_params);
264 params = &boot_params;
266 size = params->hdr.ramdisk_size;
269 * Set start only if we have an initrd image. We cannot use initrd_start
270 * because it is not set that early yet.
273 start = params->hdr.ramdisk_image;
275 # else /* CONFIG_X86_64 */
276 size = (unsigned long)boot_params.ext_ramdisk_size << 32;
277 size |= boot_params.hdr.ramdisk_size;
280 start = (unsigned long)boot_params.ext_ramdisk_image << 32;
281 start |= boot_params.hdr.ramdisk_image;
283 start += PAGE_OFFSET;
288 * Fixup the start address: after reserve_initrd() runs, initrd_start
289 * has the virtual address of the beginning of the initrd. It also
290 * possibly relocates the ramdisk. In either case, initrd_start contains
291 * the updated address so use that instead.
293 * initrd_gone is for the hotplug case where we've thrown out initrd
298 return (struct cpio_data){ NULL, 0, "" };
300 start = initrd_start;
303 * The picture with physical addresses is a bit different: we
304 * need to get the *physical* address to which the ramdisk was
305 * relocated, i.e., relocated_ramdisk (not initrd_start) and
306 * since we're running from physical addresses, we need to access
307 * relocated_ramdisk through its *physical* address too.
309 u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
314 return find_cpio_data(path, (void *)start, size, NULL);
315 #else /* !CONFIG_BLK_DEV_INITRD */
316 return (struct cpio_data){ NULL, 0, "" };
320 void reload_early_microcode(void)
324 vendor = x86_cpuid_vendor();
325 family = x86_cpuid_family();
328 case X86_VENDOR_INTEL:
330 reload_ucode_intel();
341 static void collect_cpu_info_local(void *arg)
343 struct cpu_info_ctx *ctx = arg;
345 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
349 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
351 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
354 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
361 static int collect_cpu_info(int cpu)
363 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
366 memset(uci, 0, sizeof(*uci));
368 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
375 static void apply_microcode_local(void *arg)
377 enum ucode_state *err = arg;
379 *err = microcode_ops->apply_microcode(smp_processor_id());
382 static int apply_microcode_on_target(int cpu)
384 enum ucode_state err;
387 ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
389 if (err == UCODE_ERROR)
395 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
396 static int do_microcode_update(const void __user *buf, size_t size)
401 for_each_online_cpu(cpu) {
402 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
403 enum ucode_state ustate;
408 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
409 if (ustate == UCODE_ERROR) {
412 } else if (ustate == UCODE_NEW) {
413 apply_microcode_on_target(cpu);
420 static int microcode_open(struct inode *inode, struct file *file)
422 return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
425 static ssize_t microcode_write(struct file *file, const char __user *buf,
426 size_t len, loff_t *ppos)
428 ssize_t ret = -EINVAL;
429 unsigned long nr_pages = totalram_pages();
431 if ((len >> PAGE_SHIFT) > nr_pages) {
432 pr_err("too much data (max %ld pages)\n", nr_pages);
437 mutex_lock(µcode_mutex);
439 if (do_microcode_update(buf, len) == 0)
443 perf_check_microcode();
445 mutex_unlock(µcode_mutex);
451 static const struct file_operations microcode_fops = {
452 .owner = THIS_MODULE,
453 .write = microcode_write,
454 .open = microcode_open,
458 static struct miscdevice microcode_dev = {
459 .minor = MICROCODE_MINOR,
461 .nodename = "cpu/microcode",
462 .fops = µcode_fops,
465 static int __init microcode_dev_init(void)
469 error = misc_register(µcode_dev);
471 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
478 static void __exit microcode_dev_exit(void)
480 misc_deregister(µcode_dev);
483 #define microcode_dev_init() 0
484 #define microcode_dev_exit() do { } while (0)
487 /* fake device for request_firmware */
488 static struct platform_device *microcode_pdev;
491 * Late loading dance. Why the heavy-handed stomp_machine effort?
493 * - HT siblings must be idle and not execute other code while the other sibling
494 * is loading microcode in order to avoid any negative interactions caused by
497 * - In addition, microcode update on the cores must be serialized until this
498 * requirement can be relaxed in the future. Right now, this is conservative
501 #define SPINUNIT 100 /* 100 nsec */
503 static int check_online_cpus(void)
508 * Make sure all CPUs are online. It's fine for SMT to be disabled if
509 * all the primary threads are still online.
511 for_each_present_cpu(cpu) {
512 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
513 pr_err("Not all CPUs online, aborting microcode update.\n");
521 static atomic_t late_cpus_in;
522 static atomic_t late_cpus_out;
524 static int __wait_for_cpus(atomic_t *t, long long timeout)
526 int all_cpus = num_online_cpus();
530 while (atomic_read(t) < all_cpus) {
531 if (timeout < SPINUNIT) {
532 pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
533 all_cpus - atomic_read(t));
540 touch_nmi_watchdog();
549 * 1 - microcode was updated
551 static int __reload_late(void *info)
553 int cpu = smp_processor_id();
554 enum ucode_state err;
558 * Wait for all CPUs to arrive. A load will not be attempted unless all
561 if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
565 * On an SMT system, it suffices to load the microcode on one sibling of
566 * the core because the microcode engine is shared between the threads.
567 * Synchronization still needs to take place so that no concurrent
568 * loading attempts happen on multiple threads of an SMT core. See
571 if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
572 apply_microcode_local(&err);
574 goto wait_for_siblings;
576 if (err > UCODE_NFOUND) {
577 pr_warn("Error reloading microcode on CPU %d\n", cpu);
579 } else if (err == UCODE_UPDATED || err == UCODE_OK) {
584 if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
585 panic("Timeout during microcode update!\n");
588 * At least one thread has completed update on each core.
589 * For others, simply call the update to make sure the
590 * per-cpu cpuinfo can be updated with right microcode
593 if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
594 apply_microcode_local(&err);
600 * Reload microcode late on all CPUs. Wait for a sec until they
601 * all gather together.
603 static int microcode_reload_late(void)
607 atomic_set(&late_cpus_in, 0);
608 atomic_set(&late_cpus_out, 0);
610 ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
614 pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
619 static ssize_t reload_store(struct device *dev,
620 struct device_attribute *attr,
621 const char *buf, size_t size)
623 enum ucode_state tmp_ret = UCODE_OK;
624 int bsp = boot_cpu_data.cpu_index;
628 ret = kstrtoul(buf, 0, &val);
635 tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev, true);
636 if (tmp_ret != UCODE_NEW)
641 ret = check_online_cpus();
645 mutex_lock(µcode_mutex);
646 ret = microcode_reload_late();
647 mutex_unlock(µcode_mutex);
658 static ssize_t version_show(struct device *dev,
659 struct device_attribute *attr, char *buf)
661 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
663 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
666 static ssize_t pf_show(struct device *dev,
667 struct device_attribute *attr, char *buf)
669 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
671 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
674 static DEVICE_ATTR_WO(reload);
675 static DEVICE_ATTR(version, 0444, version_show, NULL);
676 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
678 static struct attribute *mc_default_attrs[] = {
679 &dev_attr_version.attr,
680 &dev_attr_processor_flags.attr,
684 static const struct attribute_group mc_attr_group = {
685 .attrs = mc_default_attrs,
689 static void microcode_fini_cpu(int cpu)
691 if (microcode_ops->microcode_fini_cpu)
692 microcode_ops->microcode_fini_cpu(cpu);
695 static enum ucode_state microcode_resume_cpu(int cpu)
697 if (apply_microcode_on_target(cpu))
700 pr_debug("CPU%d updated upon resume\n", cpu);
705 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
707 enum ucode_state ustate;
708 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
713 if (collect_cpu_info(cpu))
716 /* --dimm. Trigger a delayed update? */
717 if (system_state != SYSTEM_RUNNING)
720 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, refresh_fw);
721 if (ustate == UCODE_NEW) {
722 pr_debug("CPU%d updated upon init\n", cpu);
723 apply_microcode_on_target(cpu);
729 static enum ucode_state microcode_update_cpu(int cpu)
731 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
733 /* Refresh CPU microcode revision after resume. */
734 collect_cpu_info(cpu);
737 return microcode_resume_cpu(cpu);
739 return microcode_init_cpu(cpu, false);
742 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
744 int err, cpu = dev->id;
746 if (!cpu_online(cpu))
749 pr_debug("CPU%d added\n", cpu);
751 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
755 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
761 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
765 if (!cpu_online(cpu))
768 pr_debug("CPU%d removed\n", cpu);
769 microcode_fini_cpu(cpu);
770 sysfs_remove_group(&dev->kobj, &mc_attr_group);
773 static struct subsys_interface mc_cpu_interface = {
775 .subsys = &cpu_subsys,
776 .add_dev = mc_device_add,
777 .remove_dev = mc_device_remove,
781 * mc_bp_resume - Update boot CPU microcode during resume.
783 static void mc_bp_resume(void)
785 int cpu = smp_processor_id();
786 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
788 if (uci->valid && uci->mc)
789 microcode_ops->apply_microcode(cpu);
791 reload_early_microcode();
794 static struct syscore_ops mc_syscore_ops = {
795 .resume = mc_bp_resume,
798 static int mc_cpu_starting(unsigned int cpu)
800 microcode_update_cpu(cpu);
801 pr_debug("CPU%d added\n", cpu);
805 static int mc_cpu_online(unsigned int cpu)
807 struct device *dev = get_cpu_device(cpu);
809 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
810 pr_err("Failed to create group for CPU%d\n", cpu);
814 static int mc_cpu_down_prep(unsigned int cpu)
818 dev = get_cpu_device(cpu);
819 /* Suspend is in progress, only remove the interface */
820 sysfs_remove_group(&dev->kobj, &mc_attr_group);
821 pr_debug("CPU%d removed\n", cpu);
826 static struct attribute *cpu_root_microcode_attrs[] = {
827 &dev_attr_reload.attr,
831 static const struct attribute_group cpu_root_microcode_group = {
833 .attrs = cpu_root_microcode_attrs,
836 int __init microcode_init(void)
838 struct cpuinfo_x86 *c = &boot_cpu_data;
844 if (c->x86_vendor == X86_VENDOR_INTEL)
845 microcode_ops = init_intel_microcode();
846 else if (c->x86_vendor == X86_VENDOR_AMD)
847 microcode_ops = init_amd_microcode();
849 pr_err("no support for this CPU vendor\n");
854 microcode_pdev = platform_device_register_simple("microcode", -1,
856 if (IS_ERR(microcode_pdev))
857 return PTR_ERR(microcode_pdev);
860 mutex_lock(µcode_mutex);
862 error = subsys_interface_register(&mc_cpu_interface);
864 perf_check_microcode();
865 mutex_unlock(µcode_mutex);
871 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
872 &cpu_root_microcode_group);
875 pr_err("Error creating microcode group!\n");
879 error = microcode_dev_init();
881 goto out_ucode_group;
883 register_syscore_ops(&mc_syscore_ops);
884 cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
885 mc_cpu_starting, NULL);
886 cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
887 mc_cpu_online, mc_cpu_down_prep);
889 pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
894 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
895 &cpu_root_microcode_group);
899 mutex_lock(µcode_mutex);
901 subsys_interface_unregister(&mc_cpu_interface);
903 mutex_unlock(µcode_mutex);
907 platform_device_unregister(microcode_pdev);
911 fs_initcall(save_microcode_in_initrd);
912 late_initcall(microcode_init);