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;
46 static bool dis_ucode_ldr = true;
51 * All non cpu-hotplug-callback call sites use:
53 * - microcode_mutex to synchronize with each other;
54 * - get/put_online_cpus() to synchronize with
55 * the cpu-hotplug-callback call sites.
57 * We guarantee that only a single cpu is being
58 * updated at any particular moment of time.
60 static DEFINE_MUTEX(microcode_mutex);
62 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
65 * Operations that are run on a target cpu:
69 struct cpu_signature *cpu_sig;
73 static bool __init check_loader_disabled_bsp(void)
75 static const char *__dis_opt_str = "dis_ucode_ldr";
79 const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
80 const char *option = (const char *)__pa_nodebug(__dis_opt_str);
81 bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
83 #else /* CONFIG_X86_64 */
84 const char *cmdline = boot_command_line;
85 const char *option = __dis_opt_str;
86 bool *res = &dis_ucode_ldr;
91 native_cpuid(&a, &b, &c, &d);
94 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
95 * completely accurate as xen pv guests don't see that CPUID bit set but
96 * that's good enough as they don't land on the BSP path anyway.
101 if (cmdline_find_option_bool(cmdline, option) <= 0)
107 extern struct builtin_fw __start_builtin_fw[];
108 extern struct builtin_fw __end_builtin_fw[];
110 bool get_builtin_firmware(struct cpio_data *cd, const char *name)
112 #ifdef CONFIG_FW_LOADER
113 struct builtin_fw *b_fw;
115 for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
116 if (!strcmp(name, b_fw->name)) {
117 cd->size = b_fw->size;
118 cd->data = b_fw->data;
126 void __init load_ucode_bsp(void)
135 vendor = x86_cpuid_vendor();
136 family = x86_cpuid_family();
139 case X86_VENDOR_INTEL:
154 if (check_loader_disabled_bsp())
158 load_ucode_intel_bsp();
160 load_ucode_amd_bsp(family);
163 static bool check_loader_disabled_ap(void)
166 return *((bool *)__pa_nodebug(&dis_ucode_ldr));
168 return dis_ucode_ldr;
172 void load_ucode_ap(void)
176 if (check_loader_disabled_ap())
179 vendor = x86_cpuid_vendor();
180 family = x86_cpuid_family();
183 case X86_VENDOR_INTEL:
185 load_ucode_intel_ap();
196 static int __init save_microcode_in_initrd(void)
198 struct cpuinfo_x86 *c = &boot_cpu_data;
200 switch (c->x86_vendor) {
201 case X86_VENDOR_INTEL:
203 return save_microcode_in_initrd_intel();
207 return save_microcode_in_initrd_amd();
216 void reload_early_microcode(void)
220 vendor = x86_cpuid_vendor();
221 family = x86_cpuid_family();
224 case X86_VENDOR_INTEL:
226 reload_ucode_intel();
237 static void collect_cpu_info_local(void *arg)
239 struct cpu_info_ctx *ctx = arg;
241 ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
245 static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
247 struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
250 ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
257 static int collect_cpu_info(int cpu)
259 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
262 memset(uci, 0, sizeof(*uci));
264 ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
271 struct apply_microcode_ctx {
275 static void apply_microcode_local(void *arg)
277 struct apply_microcode_ctx *ctx = arg;
279 ctx->err = microcode_ops->apply_microcode(smp_processor_id());
282 static int apply_microcode_on_target(int cpu)
284 struct apply_microcode_ctx ctx = { .err = 0 };
287 ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
294 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
295 static int do_microcode_update(const void __user *buf, size_t size)
300 for_each_online_cpu(cpu) {
301 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
302 enum ucode_state ustate;
307 ustate = microcode_ops->request_microcode_user(cpu, buf, size);
308 if (ustate == UCODE_ERROR) {
311 } else if (ustate == UCODE_OK)
312 apply_microcode_on_target(cpu);
318 static int microcode_open(struct inode *inode, struct file *file)
320 return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
323 static ssize_t microcode_write(struct file *file, const char __user *buf,
324 size_t len, loff_t *ppos)
326 ssize_t ret = -EINVAL;
328 if ((len >> PAGE_SHIFT) > totalram_pages) {
329 pr_err("too much data (max %ld pages)\n", totalram_pages);
334 mutex_lock(µcode_mutex);
336 if (do_microcode_update(buf, len) == 0)
340 perf_check_microcode();
342 mutex_unlock(µcode_mutex);
348 static const struct file_operations microcode_fops = {
349 .owner = THIS_MODULE,
350 .write = microcode_write,
351 .open = microcode_open,
355 static struct miscdevice microcode_dev = {
356 .minor = MICROCODE_MINOR,
358 .nodename = "cpu/microcode",
359 .fops = µcode_fops,
362 static int __init microcode_dev_init(void)
366 error = misc_register(µcode_dev);
368 pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
375 static void __exit microcode_dev_exit(void)
377 misc_deregister(µcode_dev);
380 #define microcode_dev_init() 0
381 #define microcode_dev_exit() do { } while (0)
384 /* fake device for request_firmware */
385 static struct platform_device *microcode_pdev;
387 static int check_online_cpus(void)
392 * Make sure all CPUs are online. It's fine for SMT to be disabled if
393 * all the primary threads are still online.
395 for_each_present_cpu(cpu) {
396 if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
397 pr_err("Not all CPUs online, aborting microcode update.\n");
405 static int reload_for_cpu(int cpu)
407 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
408 enum ucode_state ustate;
414 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev, true);
415 if (ustate == UCODE_OK)
416 apply_microcode_on_target(cpu);
418 if (ustate == UCODE_ERROR)
423 static ssize_t reload_store(struct device *dev,
424 struct device_attribute *attr,
425 const char *buf, size_t size)
429 ssize_t ret = 0, tmp_ret;
431 ret = kstrtoul(buf, 0, &val);
440 ret = check_online_cpus();
444 mutex_lock(µcode_mutex);
446 for_each_online_cpu(cpu) {
447 tmp_ret = reload_for_cpu(cpu);
449 pr_warn("Error reloading microcode on CPU %d\n", cpu);
451 /* save retval of the first encountered reload error */
456 perf_check_microcode();
457 mutex_unlock(µcode_mutex);
468 static ssize_t version_show(struct device *dev,
469 struct device_attribute *attr, char *buf)
471 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
473 return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
476 static ssize_t pf_show(struct device *dev,
477 struct device_attribute *attr, char *buf)
479 struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
481 return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
484 static DEVICE_ATTR(reload, 0200, NULL, reload_store);
485 static DEVICE_ATTR(version, 0400, version_show, NULL);
486 static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
488 static struct attribute *mc_default_attrs[] = {
489 &dev_attr_version.attr,
490 &dev_attr_processor_flags.attr,
494 static struct attribute_group mc_attr_group = {
495 .attrs = mc_default_attrs,
499 static void microcode_fini_cpu(int cpu)
501 microcode_ops->microcode_fini_cpu(cpu);
504 static enum ucode_state microcode_resume_cpu(int cpu)
506 pr_debug("CPU%d updated upon resume\n", cpu);
508 if (apply_microcode_on_target(cpu))
514 static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
516 enum ucode_state ustate;
517 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
522 if (collect_cpu_info(cpu))
525 /* --dimm. Trigger a delayed update? */
526 if (system_state != SYSTEM_RUNNING)
529 ustate = microcode_ops->request_microcode_fw(cpu, µcode_pdev->dev,
532 if (ustate == UCODE_OK) {
533 pr_debug("CPU%d updated upon init\n", cpu);
534 apply_microcode_on_target(cpu);
540 static enum ucode_state microcode_update_cpu(int cpu)
542 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
545 return microcode_resume_cpu(cpu);
547 return microcode_init_cpu(cpu, false);
550 static int mc_device_add(struct device *dev, struct subsys_interface *sif)
552 int err, cpu = dev->id;
554 if (!cpu_online(cpu))
557 pr_debug("CPU%d added\n", cpu);
559 err = sysfs_create_group(&dev->kobj, &mc_attr_group);
563 if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
569 static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
573 if (!cpu_online(cpu))
576 pr_debug("CPU%d removed\n", cpu);
577 microcode_fini_cpu(cpu);
578 sysfs_remove_group(&dev->kobj, &mc_attr_group);
581 static struct subsys_interface mc_cpu_interface = {
583 .subsys = &cpu_subsys,
584 .add_dev = mc_device_add,
585 .remove_dev = mc_device_remove,
589 * microcode_bsp_resume - Update boot CPU microcode during resume.
591 void microcode_bsp_resume(void)
593 int cpu = smp_processor_id();
594 struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
596 if (uci->valid && uci->mc)
597 microcode_ops->apply_microcode(cpu);
599 reload_early_microcode();
602 static struct syscore_ops mc_syscore_ops = {
603 .resume = microcode_bsp_resume,
606 static int mc_cpu_online(unsigned int cpu)
610 dev = get_cpu_device(cpu);
611 microcode_update_cpu(cpu);
612 pr_debug("CPU%d added\n", cpu);
614 if (sysfs_create_group(&dev->kobj, &mc_attr_group))
615 pr_err("Failed to create group for CPU%d\n", cpu);
619 static int mc_cpu_down_prep(unsigned int cpu)
623 dev = get_cpu_device(cpu);
624 /* Suspend is in progress, only remove the interface */
625 sysfs_remove_group(&dev->kobj, &mc_attr_group);
626 pr_debug("CPU%d removed\n", cpu);
628 * When a CPU goes offline, don't free up or invalidate the copy of
629 * the microcode in kernel memory, so that we can reuse it when the
630 * CPU comes back online without unnecessarily requesting the userspace
636 static struct attribute *cpu_root_microcode_attrs[] = {
637 &dev_attr_reload.attr,
641 static struct attribute_group cpu_root_microcode_group = {
643 .attrs = cpu_root_microcode_attrs,
646 int __init microcode_init(void)
648 struct cpuinfo_x86 *c = &boot_cpu_data;
654 if (c->x86_vendor == X86_VENDOR_INTEL)
655 microcode_ops = init_intel_microcode();
656 else if (c->x86_vendor == X86_VENDOR_AMD)
657 microcode_ops = init_amd_microcode();
659 pr_err("no support for this CPU vendor\n");
664 microcode_pdev = platform_device_register_simple("microcode", -1,
666 if (IS_ERR(microcode_pdev))
667 return PTR_ERR(microcode_pdev);
670 mutex_lock(µcode_mutex);
672 error = subsys_interface_register(&mc_cpu_interface);
674 perf_check_microcode();
675 mutex_unlock(µcode_mutex);
681 error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
682 &cpu_root_microcode_group);
685 pr_err("Error creating microcode group!\n");
689 error = microcode_dev_init();
691 goto out_ucode_group;
693 register_syscore_ops(&mc_syscore_ops);
694 cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
695 mc_cpu_online, mc_cpu_down_prep);
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 fs_initcall(save_microcode_in_initrd);
721 late_initcall(microcode_init);