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 * - cpus_read_lock/unlock() 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 void __init load_ucode_bsp(void)
145 unsigned int cpuid_1_eax;
151 cpuid_1_eax = native_cpuid_eax(1);
153 switch (x86_cpuid_vendor()) {
154 case X86_VENDOR_INTEL:
155 if (x86_family(cpuid_1_eax) < 6)
160 if (x86_family(cpuid_1_eax) < 0x10)
169 if (check_loader_disabled_bsp())
173 load_ucode_intel_bsp();
175 load_ucode_amd_bsp(cpuid_1_eax);
178 static bool check_loader_disabled_ap(void)
181 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
183 return dis_ucode_ldr;
187 void load_ucode_ap(void)
189 unsigned int cpuid_1_eax;
191 if (check_loader_disabled_ap())
194 cpuid_1_eax = native_cpuid_eax(1);
196 switch (x86_cpuid_vendor()) {
197 case X86_VENDOR_INTEL:
198 if (x86_family(cpuid_1_eax) >= 6)
199 load_ucode_intel_ap();
202 if (x86_family(cpuid_1_eax) >= 0x10)
203 load_ucode_amd_ap(cpuid_1_eax);
210 static int __init save_microcode_in_initrd(void)
212 struct cpuinfo_x86 *c = &boot_cpu_data;
215 switch (c->x86_vendor) {
216 case X86_VENDOR_INTEL:
218 ret = save_microcode_in_initrd_intel();
222 ret = save_microcode_in_initrd_amd(cpuid_eax(1));
233 struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
235 #ifdef CONFIG_BLK_DEV_INITRD
236 unsigned long start = 0;
240 struct boot_params *params;
243 params = (struct boot_params *)__pa_nodebug(&boot_params);
245 params = &boot_params;
247 size = params->hdr.ramdisk_size;
250 * Set start only if we have an initrd image. We cannot use initrd_start
251 * because it is not set that early yet.
254 start = params->hdr.ramdisk_image;
256 # else /* CONFIG_X86_64 */
257 size = (unsigned long)boot_params.ext_ramdisk_size << 32;
258 size |= boot_params.hdr.ramdisk_size;
261 start = (unsigned long)boot_params.ext_ramdisk_image << 32;
262 start |= boot_params.hdr.ramdisk_image;
264 start += PAGE_OFFSET;
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.
274 * initrd_gone is for the hotplug case where we've thrown out initrd
279 return (struct cpio_data){ NULL, 0, "" };
281 start = initrd_start;
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.
290 u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
295 return find_cpio_data(path, (void *)start, size, NULL);
296 #else /* !CONFIG_BLK_DEV_INITRD */
297 return (struct cpio_data){ NULL, 0, "" };
301 void reload_early_microcode(void)
305 vendor = x86_cpuid_vendor();
306 family = x86_cpuid_family();
309 case X86_VENDOR_INTEL:
311 reload_ucode_intel();
322 static void collect_cpu_info_local(void *arg)
324 struct cpu_info_ctx *ctx = arg;
326 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
330 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
332 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
335 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
342 static int collect_cpu_info(int cpu)
344 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
347 memset(uci, 0, sizeof(*uci));
349 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
356 static void apply_microcode_local(void *arg)
358 enum ucode_state *err = arg;
360 *err = microcode_ops->apply_microcode(smp_processor_id());
363 static int apply_microcode_on_target(int cpu)
365 enum ucode_state err;
368 ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
370 if (err == UCODE_ERROR)
376 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
377 static int do_microcode_update(const void __user *buf, size_t size)
382 for_each_online_cpu(cpu) {
383 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
384 enum ucode_state ustate;
389 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
390 if (ustate == UCODE_ERROR) {
393 } else if (ustate == UCODE_NEW) {
394 apply_microcode_on_target(cpu);
401 static int microcode_open(struct inode *inode, struct file *file)
403 return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
406 static ssize_t microcode_write(struct file *file, const char __user *buf,
407 size_t len, loff_t *ppos)
409 ssize_t ret = -EINVAL;
410 unsigned long nr_pages = totalram_pages();
412 if ((len >> PAGE_SHIFT) > nr_pages) {
413 pr_err("too much data (max %ld pages)\n", nr_pages);
418 mutex_lock(µcode_mutex);
420 if (do_microcode_update(buf, len) == 0)
424 perf_check_microcode();
426 mutex_unlock(µcode_mutex);
432 static const struct file_operations microcode_fops = {
433 .owner = THIS_MODULE,
434 .write = microcode_write,
435 .open = microcode_open,
439 static struct miscdevice microcode_dev = {
440 .minor = MICROCODE_MINOR,
442 .nodename = "cpu/microcode",
443 .fops = µcode_fops,
446 static int __init microcode_dev_init(void)
450 error = misc_register(µcode_dev);
452 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
459 static void __exit microcode_dev_exit(void)
461 misc_deregister(µcode_dev);
464 #define microcode_dev_init() 0
465 #define microcode_dev_exit() do { } while (0)
468 /* fake device for request_firmware */
469 static struct platform_device *microcode_pdev;
472 * Late loading dance. Why the heavy-handed stomp_machine effort?
474 * - HT siblings must be idle and not execute other code while the other sibling
475 * is loading microcode in order to avoid any negative interactions caused by
478 * - In addition, microcode update on the cores must be serialized until this
479 * requirement can be relaxed in the future. Right now, this is conservative
482 #define SPINUNIT 100 /* 100 nsec */
484 static int check_online_cpus(void)
489 * Make sure all CPUs are online. It's fine for SMT to be disabled if
490 * all the primary threads are still online.
492 for_each_present_cpu(cpu) {
493 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
494 pr_err("Not all CPUs online, aborting microcode update.\n");
502 static atomic_t late_cpus_in;
503 static atomic_t late_cpus_out;
505 static int __wait_for_cpus(atomic_t *t, long long timeout)
507 int all_cpus = num_online_cpus();
511 while (atomic_read(t) < all_cpus) {
512 if (timeout < SPINUNIT) {
513 pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
514 all_cpus - atomic_read(t));
521 touch_nmi_watchdog();
529 * 0 - success (no update done or microcode was updated)
531 static int __reload_late(void *info)
533 int cpu = smp_processor_id();
534 enum ucode_state err;
538 * Wait for all CPUs to arrive. A load will not be attempted unless all
541 if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
545 * On an SMT system, it suffices to load the microcode on one sibling of
546 * the core because the microcode engine is shared between the threads.
547 * Synchronization still needs to take place so that no concurrent
548 * loading attempts happen on multiple threads of an SMT core. See
551 if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
552 apply_microcode_local(&err);
554 goto wait_for_siblings;
556 if (err >= UCODE_NFOUND) {
557 if (err == UCODE_ERROR)
558 pr_warn("Error reloading microcode on CPU %d\n", cpu);
564 if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC))
565 panic("Timeout during microcode update!\n");
568 * At least one thread has completed update on each core.
569 * For others, simply call the update to make sure the
570 * per-cpu cpuinfo can be updated with right microcode
573 if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
574 apply_microcode_local(&err);
580 * Reload microcode late on all CPUs. Wait for a sec until they
581 * all gather together.
583 static int microcode_reload_late(void)
587 atomic_set(&late_cpus_in, 0);
588 atomic_set(&late_cpus_out, 0);
590 ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
594 pr_info("Reload completed, microcode revision: 0x%x\n", boot_cpu_data.microcode);
599 static ssize_t reload_store(struct device *dev,
600 struct device_attribute *attr,
601 const char *buf, size_t size)
603 enum ucode_state tmp_ret = UCODE_OK;
604 int bsp = boot_cpu_data.cpu_index;
608 ret = kstrtoul(buf, 0, &val);
617 ret = check_online_cpus();
621 tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev, true);
622 if (tmp_ret != UCODE_NEW)
625 mutex_lock(µcode_mutex);
626 ret = microcode_reload_late();
627 mutex_unlock(µcode_mutex);
638 static ssize_t version_show(struct device *dev,
639 struct device_attribute *attr, char *buf)
641 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
643 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
646 static ssize_t pf_show(struct device *dev,
647 struct device_attribute *attr, char *buf)
649 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
651 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
654 static DEVICE_ATTR_WO(reload);
655 static DEVICE_ATTR(version, 0444, version_show, NULL);
656 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
658 static struct attribute *mc_default_attrs[] = {
659 &dev_attr_version.attr,
660 &dev_attr_processor_flags.attr,
664 static const struct attribute_group mc_attr_group = {
665 .attrs = mc_default_attrs,
669 static void microcode_fini_cpu(int cpu)
671 if (microcode_ops->microcode_fini_cpu)
672 microcode_ops->microcode_fini_cpu(cpu);
675 static enum ucode_state microcode_resume_cpu(int cpu)
677 if (apply_microcode_on_target(cpu))
680 pr_debug("CPU%d updated upon resume\n", cpu);
685 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
687 enum ucode_state ustate;
688 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
693 if (collect_cpu_info(cpu))
696 /* --dimm. Trigger a delayed update? */
697 if (system_state != SYSTEM_RUNNING)
700 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, refresh_fw);
701 if (ustate == UCODE_NEW) {
702 pr_debug("CPU%d updated upon init\n", cpu);
703 apply_microcode_on_target(cpu);
709 static enum ucode_state microcode_update_cpu(int cpu)
711 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
713 /* Refresh CPU microcode revision after resume. */
714 collect_cpu_info(cpu);
717 return microcode_resume_cpu(cpu);
719 return microcode_init_cpu(cpu, false);
722 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
724 int err, cpu = dev->id;
726 if (!cpu_online(cpu))
729 pr_debug("CPU%d added\n", cpu);
731 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
735 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
741 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
745 if (!cpu_online(cpu))
748 pr_debug("CPU%d removed\n", cpu);
749 microcode_fini_cpu(cpu);
750 sysfs_remove_group(&dev->kobj, &mc_attr_group);
753 static struct subsys_interface mc_cpu_interface = {
755 .subsys = &cpu_subsys,
756 .add_dev = mc_device_add,
757 .remove_dev = mc_device_remove,
761 * mc_bp_resume - Update boot CPU microcode during resume.
763 static void mc_bp_resume(void)
765 int cpu = smp_processor_id();
766 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
768 if (uci->valid && uci->mc)
769 microcode_ops->apply_microcode(cpu);
771 reload_early_microcode();
774 static struct syscore_ops mc_syscore_ops = {
775 .resume = mc_bp_resume,
778 static int mc_cpu_starting(unsigned int cpu)
780 microcode_update_cpu(cpu);
781 pr_debug("CPU%d added\n", cpu);
785 static int mc_cpu_online(unsigned int cpu)
787 struct device *dev = get_cpu_device(cpu);
789 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
790 pr_err("Failed to create group for CPU%d\n", cpu);
794 static int mc_cpu_down_prep(unsigned int cpu)
798 dev = get_cpu_device(cpu);
799 /* Suspend is in progress, only remove the interface */
800 sysfs_remove_group(&dev->kobj, &mc_attr_group);
801 pr_debug("CPU%d removed\n", cpu);
806 static struct attribute *cpu_root_microcode_attrs[] = {
807 &dev_attr_reload.attr,
811 static const struct attribute_group cpu_root_microcode_group = {
813 .attrs = cpu_root_microcode_attrs,
816 static int __init microcode_init(void)
818 struct cpuinfo_x86 *c = &boot_cpu_data;
824 if (c->x86_vendor == X86_VENDOR_INTEL)
825 microcode_ops = init_intel_microcode();
826 else if (c->x86_vendor == X86_VENDOR_AMD)
827 microcode_ops = init_amd_microcode();
829 pr_err("no support for this CPU vendor\n");
834 microcode_pdev = platform_device_register_simple("microcode", -1,
836 if (IS_ERR(microcode_pdev))
837 return PTR_ERR(microcode_pdev);
840 mutex_lock(µcode_mutex);
842 error = subsys_interface_register(&mc_cpu_interface);
844 perf_check_microcode();
845 mutex_unlock(µcode_mutex);
851 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
852 &cpu_root_microcode_group);
855 pr_err("Error creating microcode group!\n");
859 error = microcode_dev_init();
861 goto out_ucode_group;
863 register_syscore_ops(&mc_syscore_ops);
864 cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
865 mc_cpu_starting, NULL);
866 cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
867 mc_cpu_online, mc_cpu_down_prep);
869 pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
874 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
875 &cpu_root_microcode_group);
879 mutex_lock(µcode_mutex);
881 subsys_interface_unregister(&mc_cpu_interface);
883 mutex_unlock(µcode_mutex);
887 platform_device_unregister(microcode_pdev);
891 fs_initcall(save_microcode_in_initrd);
892 late_initcall(microcode_init);