2 * CPU Microcode Update Driver for Linux
4 * Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
5 * 2006 Shaohua Li <shaohua.li@intel.com>
6 * 2013-2015 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/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>
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>
43 #define MICROCODE_VERSION "2.01"
45 static struct microcode_ops *microcode_ops;
47 static bool dis_ucode_ldr = true;
49 static int __init disable_loader(char *str)
54 __setup("dis_ucode_ldr", disable_loader);
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);
70 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
71 EXPORT_SYMBOL_GPL(ucode_cpu_info);
74 * Operations that are run on a target cpu:
78 struct cpu_signature *cpu_sig;
82 static bool __init check_loader_disabled_bsp(void)
86 const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
87 const char *opt = "dis_ucode_ldr";
88 const char *option = (const char *)__pa_nodebug(opt);
89 bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
91 #else /* CONFIG_X86_64 */
92 const char *cmdline = boot_command_line;
93 const char *option = "dis_ucode_ldr";
94 bool *res = &dis_ucode_ldr;
99 native_cpuid(&a, &b, &c, &d);
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.
109 if (cmdline_find_option_bool(cmdline, option) <= 0)
115 extern struct builtin_fw __start_builtin_fw[];
116 extern struct builtin_fw __end_builtin_fw[];
118 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
120 #ifdef CONFIG_FW_LOADER
121 struct builtin_fw *b_fw;
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;
134 void __init load_ucode_bsp(void)
143 vendor = x86_vendor();
144 family = x86_family();
147 case X86_VENDOR_INTEL:
162 if (check_loader_disabled_bsp())
166 load_ucode_intel_bsp();
168 load_ucode_amd_bsp(family);
171 static bool check_loader_disabled_ap(void)
174 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
176 return dis_ucode_ldr;
180 void load_ucode_ap(void)
184 if (check_loader_disabled_ap())
187 vendor = x86_vendor();
188 family = x86_family();
191 case X86_VENDOR_INTEL:
193 load_ucode_intel_ap();
204 int __init save_microcode_in_initrd(void)
206 struct cpuinfo_x86 *c = &boot_cpu_data;
208 switch (c->x86_vendor) {
209 case X86_VENDOR_INTEL:
211 save_microcode_in_initrd_intel();
215 save_microcode_in_initrd_amd();
224 void reload_early_microcode(void)
228 vendor = x86_vendor();
229 family = x86_family();
232 case X86_VENDOR_INTEL:
234 reload_ucode_intel();
245 static void collect_cpu_info_local(void *arg)
247 struct cpu_info_ctx *ctx = arg;
249 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
253 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
255 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
258 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
265 static int collect_cpu_info(int cpu)
267 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
270 memset(uci, 0, sizeof(*uci));
272 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
279 struct apply_microcode_ctx {
283 static void apply_microcode_local(void *arg)
285 struct apply_microcode_ctx *ctx = arg;
287 ctx->err = microcode_ops->apply_microcode(smp_processor_id());
290 static int apply_microcode_on_target(int cpu)
292 struct apply_microcode_ctx ctx = { .err = 0 };
295 ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
302 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
303 static int do_microcode_update(const void __user *buf, size_t size)
308 for_each_online_cpu(cpu) {
309 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
310 enum ucode_state ustate;
315 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
316 if (ustate == UCODE_ERROR) {
319 } else if (ustate == UCODE_OK)
320 apply_microcode_on_target(cpu);
326 static int microcode_open(struct inode *inode, struct file *file)
328 return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
331 static ssize_t microcode_write(struct file *file, const char __user *buf,
332 size_t len, loff_t *ppos)
334 ssize_t ret = -EINVAL;
336 if ((len >> PAGE_SHIFT) > totalram_pages) {
337 pr_err("too much data (max %ld pages)\n", totalram_pages);
342 mutex_lock(µcode_mutex);
344 if (do_microcode_update(buf, len) == 0)
348 perf_check_microcode();
350 mutex_unlock(µcode_mutex);
356 static const struct file_operations microcode_fops = {
357 .owner = THIS_MODULE,
358 .write = microcode_write,
359 .open = microcode_open,
363 static struct miscdevice microcode_dev = {
364 .minor = MICROCODE_MINOR,
366 .nodename = "cpu/microcode",
367 .fops = µcode_fops,
370 static int __init microcode_dev_init(void)
374 error = misc_register(µcode_dev);
376 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
383 static void __exit microcode_dev_exit(void)
385 misc_deregister(µcode_dev);
388 #define microcode_dev_init() 0
389 #define microcode_dev_exit() do { } while (0)
392 /* fake device for request_firmware */
393 static struct platform_device *microcode_pdev;
395 static int reload_for_cpu(int cpu)
397 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
398 enum ucode_state ustate;
404 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, true);
405 if (ustate == UCODE_OK)
406 apply_microcode_on_target(cpu);
408 if (ustate == UCODE_ERROR)
413 static ssize_t reload_store(struct device *dev,
414 struct device_attribute *attr,
415 const char *buf, size_t size)
419 ssize_t ret = 0, tmp_ret;
421 ret = kstrtoul(buf, 0, &val);
429 mutex_lock(µcode_mutex);
430 for_each_online_cpu(cpu) {
431 tmp_ret = reload_for_cpu(cpu);
433 pr_warn("Error reloading microcode on CPU %d\n", cpu);
435 /* save retval of the first encountered reload error */
440 perf_check_microcode();
441 mutex_unlock(µcode_mutex);
450 static ssize_t version_show(struct device *dev,
451 struct device_attribute *attr, char *buf)
453 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
455 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
458 static ssize_t pf_show(struct device *dev,
459 struct device_attribute *attr, char *buf)
461 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
463 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
466 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
467 static DEVICE_ATTR(version, 0400, version_show, NULL);
468 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
470 static struct attribute *mc_default_attrs[] = {
471 &dev_attr_version.attr,
472 &dev_attr_processor_flags.attr,
476 static struct attribute_group mc_attr_group = {
477 .attrs = mc_default_attrs,
481 static void microcode_fini_cpu(int cpu)
483 microcode_ops->microcode_fini_cpu(cpu);
486 static enum ucode_state microcode_resume_cpu(int cpu)
488 pr_debug("CPU%d updated upon resume\n", cpu);
490 if (apply_microcode_on_target(cpu))
496 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
498 enum ucode_state ustate;
499 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
501 if (uci && uci->valid)
504 if (collect_cpu_info(cpu))
507 /* --dimm. Trigger a delayed update? */
508 if (system_state != SYSTEM_RUNNING)
511 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev,
514 if (ustate == UCODE_OK) {
515 pr_debug("CPU%d updated upon init\n", cpu);
516 apply_microcode_on_target(cpu);
522 static enum ucode_state microcode_update_cpu(int cpu)
524 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
527 return microcode_resume_cpu(cpu);
529 return microcode_init_cpu(cpu, false);
532 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
534 int err, cpu = dev->id;
536 if (!cpu_online(cpu))
539 pr_debug("CPU%d added\n", cpu);
541 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
545 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
551 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
555 if (!cpu_online(cpu))
558 pr_debug("CPU%d removed\n", cpu);
559 microcode_fini_cpu(cpu);
560 sysfs_remove_group(&dev->kobj, &mc_attr_group);
563 static struct subsys_interface mc_cpu_interface = {
565 .subsys = &cpu_subsys,
566 .add_dev = mc_device_add,
567 .remove_dev = mc_device_remove,
571 * mc_bp_resume - Update boot CPU microcode during resume.
573 static void mc_bp_resume(void)
575 int cpu = smp_processor_id();
576 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
578 if (uci->valid && uci->mc)
579 microcode_ops->apply_microcode(cpu);
581 reload_early_microcode();
584 static struct syscore_ops mc_syscore_ops = {
585 .resume = mc_bp_resume,
589 mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
591 unsigned int cpu = (unsigned long)hcpu;
594 dev = get_cpu_device(cpu);
596 switch (action & ~CPU_TASKS_FROZEN) {
598 microcode_update_cpu(cpu);
599 pr_debug("CPU%d added\n", cpu);
601 * "break" is missing on purpose here because we want to fall
602 * through in order to create the sysfs group.
605 case CPU_DOWN_FAILED:
606 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
607 pr_err("Failed to create group for CPU%d\n", cpu);
610 case CPU_DOWN_PREPARE:
611 /* Suspend is in progress, only remove the interface */
612 sysfs_remove_group(&dev->kobj, &mc_attr_group);
613 pr_debug("CPU%d removed\n", cpu);
619 * When a CPU goes offline, don't free up or invalidate the copy of
620 * the microcode in kernel memory, so that we can reuse it when the
621 * CPU comes back online without unnecessarily requesting the userspace
626 /* The CPU refused to come up during a system resume */
627 if (action == CPU_UP_CANCELED_FROZEN)
628 microcode_fini_cpu(cpu);
633 static struct notifier_block mc_cpu_notifier = {
634 .notifier_call = mc_cpu_callback,
637 static struct attribute *cpu_root_microcode_attrs[] = {
638 &dev_attr_reload.attr,
642 static struct attribute_group cpu_root_microcode_group = {
644 .attrs = cpu_root_microcode_attrs,
647 int __init microcode_init(void)
649 struct cpuinfo_x86 *c = &boot_cpu_data;
652 if (paravirt_enabled() || dis_ucode_ldr)
655 if (c->x86_vendor == X86_VENDOR_INTEL)
656 microcode_ops = init_intel_microcode();
657 else if (c->x86_vendor == X86_VENDOR_AMD)
658 microcode_ops = init_amd_microcode();
660 pr_err("no support for this CPU vendor\n");
665 microcode_pdev = platform_device_register_simple("microcode", -1,
667 if (IS_ERR(microcode_pdev))
668 return PTR_ERR(microcode_pdev);
671 mutex_lock(µcode_mutex);
673 error = subsys_interface_register(&mc_cpu_interface);
675 perf_check_microcode();
676 mutex_unlock(µcode_mutex);
682 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
683 &cpu_root_microcode_group);
686 pr_err("Error creating microcode group!\n");
690 error = microcode_dev_init();
692 goto out_ucode_group;
694 register_syscore_ops(&mc_syscore_ops);
695 register_hotcpu_notifier(&mc_cpu_notifier);
697 pr_info("Microcode Update Driver: v" MICROCODE_VERSION
698 " <tigran@aivazian.fsnet.co.uk>, Peter Oruba\n");
703 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
704 &cpu_root_microcode_group);
708 mutex_lock(µcode_mutex);
710 subsys_interface_unregister(&mc_cpu_interface);
712 mutex_unlock(µcode_mutex);
716 platform_device_unregister(microcode_pdev);
720 late_initcall(microcode_init);