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 * This driver allows to upgrade microcode on x86 processors.
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/platform_device.h>
19 #include <linux/miscdevice.h>
20 #include <linux/capability.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/cpu.h>
27 #include <linux/syscore_ops.h>
29 #include <asm/microcode.h>
30 #include <asm/processor.h>
31 #include <asm/cpu_device_id.h>
32 #include <asm/perf_event.h>
34 MODULE_DESCRIPTION("Microcode Update Driver");
35 MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
36 MODULE_LICENSE("GPL");
38 #define MICROCODE_VERSION "2.00"
40 static struct microcode_ops *microcode_ops;
43 module_param(dis_ucode_ldr, bool, 0);
48 * All non cpu-hotplug-callback call sites use:
50 * - microcode_mutex to synchronize with each other;
51 * - get/put_online_cpus() to synchronize with
52 * the cpu-hotplug-callback call sites.
54 * We guarantee that only a single cpu is being
55 * updated at any particular moment of time.
57 static DEFINE_MUTEX(microcode_mutex);
59 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
60 EXPORT_SYMBOL_GPL(ucode_cpu_info);
63 * Operations that are run on a target cpu:
67 struct cpu_signature *cpu_sig;
71 static void collect_cpu_info_local(void *arg)
73 struct cpu_info_ctx *ctx = arg;
75 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
79 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
81 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
84 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
91 static int collect_cpu_info(int cpu)
93 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
96 memset(uci, 0, sizeof(*uci));
98 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
105 struct apply_microcode_ctx {
109 static void apply_microcode_local(void *arg)
111 struct apply_microcode_ctx *ctx = arg;
113 ctx->err = microcode_ops->apply_microcode(smp_processor_id());
116 static int apply_microcode_on_target(int cpu)
118 struct apply_microcode_ctx ctx = { .err = 0 };
121 ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
128 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
129 static int do_microcode_update(const void __user *buf, size_t size)
134 for_each_online_cpu(cpu) {
135 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
136 enum ucode_state ustate;
141 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
142 if (ustate == UCODE_ERROR) {
145 } else if (ustate == UCODE_OK)
146 apply_microcode_on_target(cpu);
152 static int microcode_open(struct inode *inode, struct file *file)
154 return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
157 static ssize_t microcode_write(struct file *file, const char __user *buf,
158 size_t len, loff_t *ppos)
160 ssize_t ret = -EINVAL;
162 if ((len >> PAGE_SHIFT) > totalram_pages) {
163 pr_err("too much data (max %ld pages)\n", totalram_pages);
168 mutex_lock(µcode_mutex);
170 if (do_microcode_update(buf, len) == 0)
174 perf_check_microcode();
176 mutex_unlock(µcode_mutex);
182 static const struct file_operations microcode_fops = {
183 .owner = THIS_MODULE,
184 .write = microcode_write,
185 .open = microcode_open,
189 static struct miscdevice microcode_dev = {
190 .minor = MICROCODE_MINOR,
192 .nodename = "cpu/microcode",
193 .fops = µcode_fops,
196 static int __init microcode_dev_init(void)
200 error = misc_register(µcode_dev);
202 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
209 static void __exit microcode_dev_exit(void)
211 misc_deregister(µcode_dev);
214 MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
215 MODULE_ALIAS("devname:cpu/microcode");
217 #define microcode_dev_init() 0
218 #define microcode_dev_exit() do { } while (0)
221 /* fake device for request_firmware */
222 static struct platform_device *microcode_pdev;
224 static int reload_for_cpu(int cpu)
226 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
227 enum ucode_state ustate;
233 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, true);
234 if (ustate == UCODE_OK)
235 apply_microcode_on_target(cpu);
237 if (ustate == UCODE_ERROR)
242 static ssize_t reload_store(struct device *dev,
243 struct device_attribute *attr,
244 const char *buf, size_t size)
248 ssize_t ret = 0, tmp_ret;
250 ret = kstrtoul(buf, 0, &val);
258 mutex_lock(µcode_mutex);
259 for_each_online_cpu(cpu) {
260 tmp_ret = reload_for_cpu(cpu);
262 pr_warn("Error reloading microcode on CPU %d\n", cpu);
264 /* save retval of the first encountered reload error */
269 perf_check_microcode();
270 mutex_unlock(µcode_mutex);
279 static ssize_t version_show(struct device *dev,
280 struct device_attribute *attr, char *buf)
282 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
284 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
287 static ssize_t pf_show(struct device *dev,
288 struct device_attribute *attr, char *buf)
290 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
292 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
295 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
296 static DEVICE_ATTR(version, 0400, version_show, NULL);
297 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
299 static struct attribute *mc_default_attrs[] = {
300 &dev_attr_version.attr,
301 &dev_attr_processor_flags.attr,
305 static struct attribute_group mc_attr_group = {
306 .attrs = mc_default_attrs,
310 static void microcode_fini_cpu(int cpu)
312 microcode_ops->microcode_fini_cpu(cpu);
315 static enum ucode_state microcode_resume_cpu(int cpu)
317 pr_debug("CPU%d updated upon resume\n", cpu);
319 if (apply_microcode_on_target(cpu))
325 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
327 enum ucode_state ustate;
328 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
330 if (uci && uci->valid)
333 if (collect_cpu_info(cpu))
336 /* --dimm. Trigger a delayed update? */
337 if (system_state != SYSTEM_RUNNING)
340 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev,
343 if (ustate == UCODE_OK) {
344 pr_debug("CPU%d updated upon init\n", cpu);
345 apply_microcode_on_target(cpu);
351 static enum ucode_state microcode_update_cpu(int cpu)
353 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
356 return microcode_resume_cpu(cpu);
358 return microcode_init_cpu(cpu, false);
361 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
363 int err, cpu = dev->id;
365 if (!cpu_online(cpu))
368 pr_debug("CPU%d added\n", cpu);
370 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
374 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
380 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
384 if (!cpu_online(cpu))
387 pr_debug("CPU%d removed\n", cpu);
388 microcode_fini_cpu(cpu);
389 sysfs_remove_group(&dev->kobj, &mc_attr_group);
392 static struct subsys_interface mc_cpu_interface = {
394 .subsys = &cpu_subsys,
395 .add_dev = mc_device_add,
396 .remove_dev = mc_device_remove,
400 * mc_bp_resume - Update boot CPU microcode during resume.
402 static void mc_bp_resume(void)
404 int cpu = smp_processor_id();
405 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
407 if (uci->valid && uci->mc)
408 microcode_ops->apply_microcode(cpu);
410 reload_early_microcode();
413 static struct syscore_ops mc_syscore_ops = {
414 .resume = mc_bp_resume,
418 mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
420 unsigned int cpu = (unsigned long)hcpu;
423 dev = get_cpu_device(cpu);
425 switch (action & ~CPU_TASKS_FROZEN) {
427 microcode_update_cpu(cpu);
428 pr_debug("CPU%d added\n", cpu);
430 * "break" is missing on purpose here because we want to fall
431 * through in order to create the sysfs group.
434 case CPU_DOWN_FAILED:
435 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
436 pr_err("Failed to create group for CPU%d\n", cpu);
439 case CPU_DOWN_PREPARE:
440 /* Suspend is in progress, only remove the interface */
441 sysfs_remove_group(&dev->kobj, &mc_attr_group);
442 pr_debug("CPU%d removed\n", cpu);
448 * When a CPU goes offline, don't free up or invalidate the copy of
449 * the microcode in kernel memory, so that we can reuse it when the
450 * CPU comes back online without unnecessarily requesting the userspace
455 /* The CPU refused to come up during a system resume */
456 if (action == CPU_UP_CANCELED_FROZEN)
457 microcode_fini_cpu(cpu);
462 static struct notifier_block mc_cpu_notifier = {
463 .notifier_call = mc_cpu_callback,
467 /* Autoload on Intel and AMD systems */
468 static const struct x86_cpu_id __initconst microcode_id[] = {
469 #ifdef CONFIG_MICROCODE_INTEL
470 { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, },
472 #ifdef CONFIG_MICROCODE_AMD
473 { X86_VENDOR_AMD, X86_FAMILY_ANY, X86_MODEL_ANY, },
477 MODULE_DEVICE_TABLE(x86cpu, microcode_id);
480 static struct attribute *cpu_root_microcode_attrs[] = {
481 &dev_attr_reload.attr,
485 static struct attribute_group cpu_root_microcode_group = {
487 .attrs = cpu_root_microcode_attrs,
490 static int __init microcode_init(void)
492 struct cpuinfo_x86 *c = &cpu_data(0);
495 if (paravirt_enabled() || dis_ucode_ldr)
498 if (c->x86_vendor == X86_VENDOR_INTEL)
499 microcode_ops = init_intel_microcode();
500 else if (c->x86_vendor == X86_VENDOR_AMD)
501 microcode_ops = init_amd_microcode();
503 pr_err("no support for this CPU vendor\n");
508 microcode_pdev = platform_device_register_simple("microcode", -1,
510 if (IS_ERR(microcode_pdev))
511 return PTR_ERR(microcode_pdev);
514 mutex_lock(µcode_mutex);
516 error = subsys_interface_register(&mc_cpu_interface);
518 perf_check_microcode();
519 mutex_unlock(µcode_mutex);
525 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
526 &cpu_root_microcode_group);
529 pr_err("Error creating microcode group!\n");
533 error = microcode_dev_init();
535 goto out_ucode_group;
537 register_syscore_ops(&mc_syscore_ops);
538 register_hotcpu_notifier(&mc_cpu_notifier);
540 pr_info("Microcode Update Driver: v" MICROCODE_VERSION
541 " <tigran@aivazian.fsnet.co.uk>, Peter Oruba\n");
546 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
547 &cpu_root_microcode_group);
551 mutex_lock(µcode_mutex);
553 subsys_interface_unregister(&mc_cpu_interface);
555 mutex_unlock(µcode_mutex);
559 platform_device_unregister(microcode_pdev);
563 module_init(microcode_init);
565 static void __exit microcode_exit(void)
567 struct cpuinfo_x86 *c = &cpu_data(0);
569 microcode_dev_exit();
571 unregister_hotcpu_notifier(&mc_cpu_notifier);
572 unregister_syscore_ops(&mc_syscore_ops);
574 sysfs_remove_group(&cpu_subsys.dev_root->kobj,
575 &cpu_root_microcode_group);
578 mutex_lock(µcode_mutex);
580 subsys_interface_unregister(&mc_cpu_interface);
582 mutex_unlock(µcode_mutex);
585 platform_device_unregister(microcode_pdev);
587 microcode_ops = NULL;
589 if (c->x86_vendor == X86_VENDOR_AMD)
590 exit_amd_microcode();
592 pr_info("Microcode Update Driver: v" MICROCODE_VERSION " removed.\n");
594 module_exit(microcode_exit);