arch/x86/kernel/microcode_core.c - arm/linux-arm64-legacy - Git at Google

 /*
  *	Intel CPU Microcode Update Driver for Linux
  *
  *	Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
  *		      2006	Shaohua Li <shaohua.li@intel.com>
  *
  *	This driver allows to upgrade microcode on Intel processors
  *	belonging to IA-32 family - PentiumPro, Pentium II,
  *	Pentium III, Xeon, Pentium 4, etc.
  *
  *	Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
  *	Software Developer's Manual
  *	Order Number 253668 or free download from:
  *
  *	http://developer.intel.com/design/pentium4/manuals/253668.htm
  *
  *	For more information, go to http://www.urbanmyth.org/microcode
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
  *	as published by the Free Software Foundation; either version
  *	2 of the License, or (at your option) any later version.
  *
  *	1.0	16 Feb 2000, Tigran Aivazian <tigran@sco.com>
  *		Initial release.
  *	1.01	18 Feb 2000, Tigran Aivazian <tigran@sco.com>
  *		Added read() support + cleanups.
  *	1.02	21 Feb 2000, Tigran Aivazian <tigran@sco.com>
  *		Added 'device trimming' support. open(O_WRONLY) zeroes
  *		and frees the saved copy of applied microcode.
  *	1.03	29 Feb 2000, Tigran Aivazian <tigran@sco.com>
  *		Made to use devfs (/dev/cpu/microcode) + cleanups.
  *	1.04	06 Jun 2000, Simon Trimmer <simon@veritas.com>
  *		Added misc device support (now uses both devfs and misc).
  *		Added MICROCODE_IOCFREE ioctl to clear memory.
  *	1.05	09 Jun 2000, Simon Trimmer <simon@veritas.com>
  *		Messages for error cases (non Intel & no suitable microcode).
  *	1.06	03 Aug 2000, Tigran Aivazian <tigran@veritas.com>
  *		Removed ->release(). Removed exclusive open and status bitmap.
  *		Added microcode_rwsem to serialize read()/write()/ioctl().
  *		Removed global kernel lock usage.
  *	1.07	07 Sep 2000, Tigran Aivazian <tigran@veritas.com>
  *		Write 0 to 0x8B msr and then cpuid before reading revision,
  *		so that it works even if there were no update done by the
  *		BIOS. Otherwise, reading from 0x8B gives junk (which happened
  *		to be 0 on my machine which is why it worked even when I
  *		disabled update by the BIOS)
  *		Thanks to Eric W. Biederman <ebiederman@lnxi.com> for the fix.
  *	1.08	11 Dec 2000, Richard Schaal <richard.schaal@intel.com> and
  *			     Tigran Aivazian <tigran@veritas.com>
  *		Intel Pentium 4 processor support and bugfixes.
  *	1.09	30 Oct 2001, Tigran Aivazian <tigran@veritas.com>
  *		Bugfix for HT (Hyper-Threading) enabled processors
  *		whereby processor resources are shared by all logical processors
  *		in a single CPU package.
  *	1.10	28 Feb 2002 Asit K Mallick <asit.k.mallick@intel.com> and
  *		Tigran Aivazian <tigran@veritas.com>,
  *		Serialize updates as required on HT processors due to
  *		speculative nature of implementation.
  *	1.11	22 Mar 2002 Tigran Aivazian <tigran@veritas.com>
  *		Fix the panic when writing zero-length microcode chunk.
  *	1.12	29 Sep 2003 Nitin Kamble <nitin.a.kamble@intel.com>,
  *		Jun Nakajima <jun.nakajima@intel.com>
  *		Support for the microcode updates in the new format.
  *	1.13	10 Oct 2003 Tigran Aivazian <tigran@veritas.com>
  *		Removed ->read() method and obsoleted MICROCODE_IOCFREE ioctl
  *		because we no longer hold a copy of applied microcode
  *		in kernel memory.
  *	1.14	25 Jun 2004 Tigran Aivazian <tigran@veritas.com>
  *		Fix sigmatch() macro to handle old CPUs with pf == 0.
  *		Thanks to Stuart Swales for pointing out this bug.
  */
 #include <linux/capability.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/smp_lock.h>
 #include <linux/cpumask.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/miscdevice.h>
 #include <linux/spinlock.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/mutex.h>
 #include <linux/cpu.h>
 #include <linux/firmware.h>
 #include <linux/platform_device.h>

 #include <asm/msr.h>
 #include <asm/uaccess.h>
 #include <asm/processor.h>
 #include <asm/microcode.h>

 MODULE_DESCRIPTION("Microcode Update Driver");
 MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
 MODULE_LICENSE("GPL");

 #define MICROCODE_VERSION 	"2.00"

 struct microcode_ops *microcode_ops;

 /* no concurrent ->write()s are allowed on /dev/cpu/microcode */
 static DEFINE_MUTEX(microcode_mutex);

 struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
 EXPORT_SYMBOL_GPL(ucode_cpu_info);

 #ifdef CONFIG_MICROCODE_OLD_INTERFACE
 static int do_microcode_update(const void __user *buf, size_t size)
 {
 	cpumask_t old;
 	int error = 0;
 	int cpu;

 	old = current->cpus_allowed;

 	for_each_online_cpu(cpu) {
 		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

 		if (!uci->valid)
 			continue;

 		set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
 		error = microcode_ops->request_microcode_user(cpu, buf, size);
 		if (error < 0)
 			goto out;
 		if (!error)
 			microcode_ops->apply_microcode(cpu);
 	}
 out:
 	set_cpus_allowed_ptr(current, &old);
 	return error;
 }

 static int microcode_open(struct inode *unused1, struct file *unused2)
 {
 	cycle_kernel_lock();
 	return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
 }

 static ssize_t microcode_write(struct file *file, const char __user *buf,
 			       size_t len, loff_t *ppos)
 {
 	ssize_t ret;

 	if ((len >> PAGE_SHIFT) > num_physpages) {
 		printk(KERN_ERR "microcode: too much data (max %ld pages)\n",
 		       num_physpages);
 		return -EINVAL;
 	}

 	get_online_cpus();
 	mutex_lock(&microcode_mutex);

 	ret = do_microcode_update(buf, len);
 	if (!ret)
 		ret = (ssize_t)len;

 	mutex_unlock(&microcode_mutex);
 	put_online_cpus();

 	return ret;
 }

 static const struct file_operations microcode_fops = {
 	.owner		= THIS_MODULE,
 	.write		= microcode_write,
 	.open		= microcode_open,
 };

 static struct miscdevice microcode_dev = {
 	.minor		= MICROCODE_MINOR,
 	.name		= "microcode",
 	.fops		= &microcode_fops,
 };

 static int __init microcode_dev_init(void)
 {
 	int error;

 	error = misc_register(&microcode_dev);
 	if (error) {
 		printk(KERN_ERR
 			"microcode: can't misc_register on minor=%d\n",
 			MICROCODE_MINOR);
 		return error;
 	}

 	return 0;
 }

 static void microcode_dev_exit(void)
 {
 	misc_deregister(&microcode_dev);
 }

 MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
 #else
 #define microcode_dev_init() 0
 #define microcode_dev_exit() do { } while (0)
 #endif

 /* fake device for request_firmware */
 struct platform_device *microcode_pdev;

 static ssize_t reload_store(struct sys_device *dev,
 			    struct sysdev_attribute *attr,
 			    const char *buf, size_t sz)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
 	char *end;
 	unsigned long val = simple_strtoul(buf, &end, 0);
 	int err = 0;
 	int cpu = dev->id;

 	if (end == buf)
 		return -EINVAL;
 	if (val == 1) {
 		cpumask_t old = current->cpus_allowed;

 		get_online_cpus();
 		if (cpu_online(cpu)) {
 			set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
 			mutex_lock(&microcode_mutex);
 			if (uci->valid) {
 				err = microcode_ops->request_microcode_fw(cpu,
 						&microcode_pdev->dev);
 				if (!err)
 					microcode_ops->apply_microcode(cpu);
 			}
 			mutex_unlock(&microcode_mutex);
 			set_cpus_allowed_ptr(current, &old);
 		}
 		put_online_cpus();
 	}
 	if (err)
 		return err;
 	return sz;
 }

 static ssize_t version_show(struct sys_device *dev,
 			struct sysdev_attribute *attr, char *buf)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

 	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
 }

 static ssize_t pf_show(struct sys_device *dev,
 			struct sysdev_attribute *attr, char *buf)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 }

 static SYSDEV_ATTR(reload, 0200, NULL, reload_store);
 static SYSDEV_ATTR(version, 0400, version_show, NULL);
 static SYSDEV_ATTR(processor_flags, 0400, pf_show, NULL);

 static struct attribute *mc_default_attrs[] = {
 	&attr_reload.attr,
 	&attr_version.attr,
 	&attr_processor_flags.attr,
 	NULL
 };

 static struct attribute_group mc_attr_group = {
 	.attrs = mc_default_attrs,
 	.name = "microcode",
 };

 static void microcode_fini_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

 	mutex_lock(&microcode_mutex);
 	microcode_ops->microcode_fini_cpu(cpu);
 	uci->valid = 0;
 	mutex_unlock(&microcode_mutex);
 }

 static void collect_cpu_info(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

 	memset(uci, 0, sizeof(*uci));
 	if (!microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig))
 		uci->valid = 1;
 }

 static int microcode_resume_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 	struct cpu_signature nsig;

 	pr_debug("microcode: CPU%d resumed\n", cpu);

 	if (!uci->mc)
 		return 1;

 	/*
 	 * Let's verify that the 'cached' ucode does belong
 	 * to this cpu (a bit of paranoia):
 	 */
 	if (microcode_ops->collect_cpu_info(cpu, &nsig)) {
 		microcode_fini_cpu(cpu);
 		return -1;
 	}

 	if (memcmp(&nsig, &uci->cpu_sig, sizeof(nsig))) {
 		microcode_fini_cpu(cpu);
 		/* Should we look for a new ucode here? */
 		return 1;
 	}

 	return 0;
 }

 void microcode_update_cpu(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 	int err = 0;

 	/*
 	 * Check if the system resume is in progress (uci->valid != NULL),
 	 * otherwise just request a firmware:
 	 */
 	if (uci->valid) {
 		err = microcode_resume_cpu(cpu);
 	} else {
 		collect_cpu_info(cpu);
 		if (uci->valid && system_state == SYSTEM_RUNNING)
 			err = microcode_ops->request_microcode_fw(cpu,
 					&microcode_pdev->dev);
 	}
 	if (!err)
 		microcode_ops->apply_microcode(cpu);
 }

 static void microcode_init_cpu(int cpu)
 {
 	cpumask_t old = current->cpus_allowed;

 	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
 	/* We should bind the task to the CPU */
 	BUG_ON(raw_smp_processor_id() != cpu);

 	mutex_lock(&microcode_mutex);
 	microcode_update_cpu(cpu);
 	mutex_unlock(&microcode_mutex);

 	set_cpus_allowed_ptr(current, &old);
 }

 static int mc_sysdev_add(struct sys_device *sys_dev)
 {
 	int err, cpu = sys_dev->id;
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

 	if (!cpu_online(cpu))
 		return 0;

 	pr_debug("microcode: CPU%d added\n", cpu);
 	memset(uci, 0, sizeof(*uci));

 	err = sysfs_create_group(&sys_dev->kobj, &mc_attr_group);
 	if (err)
 		return err;

 	microcode_init_cpu(cpu);
 	return 0;
 }

 static int mc_sysdev_remove(struct sys_device *sys_dev)
 {
 	int cpu = sys_dev->id;

 	if (!cpu_online(cpu))
 		return 0;

 	pr_debug("microcode: CPU%d removed\n", cpu);
 	microcode_fini_cpu(cpu);
 	sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
 	return 0;
 }

 static int mc_sysdev_resume(struct sys_device *dev)
 {
 	int cpu = dev->id;

 	if (!cpu_online(cpu))
 		return 0;

 	/* only CPU 0 will apply ucode here */
 	microcode_update_cpu(0);
 	return 0;
 }

 static struct sysdev_driver mc_sysdev_driver = {
 	.add = mc_sysdev_add,
 	.remove = mc_sysdev_remove,
 	.resume = mc_sysdev_resume,
 };

 static __cpuinit int
 mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
 {
 	unsigned int cpu = (unsigned long)hcpu;
 	struct sys_device *sys_dev;

 	sys_dev = get_cpu_sysdev(cpu);
 	switch (action) {
 	case CPU_ONLINE:
 	case CPU_ONLINE_FROZEN:
 		microcode_init_cpu(cpu);
 	case CPU_DOWN_FAILED:
 	case CPU_DOWN_FAILED_FROZEN:
 		pr_debug("microcode: CPU%d added\n", cpu);
 		if (sysfs_create_group(&sys_dev->kobj, &mc_attr_group))
 			printk(KERN_ERR "microcode: Failed to create the sysfs "
 				"group for CPU%d\n", cpu);
 		break;
 	case CPU_DOWN_PREPARE:
 	case CPU_DOWN_PREPARE_FROZEN:
 		/* Suspend is in progress, only remove the interface */
 		sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
 		pr_debug("microcode: CPU%d removed\n", cpu);
 		break;
 	case CPU_DEAD:
 	case CPU_UP_CANCELED_FROZEN:
 		/* The CPU refused to come up during a system resume */
 		microcode_fini_cpu(cpu);
 		break;
 	}
 	return NOTIFY_OK;
 }

 static struct notifier_block __refdata mc_cpu_notifier = {
 	.notifier_call = mc_cpu_callback,
 };

 static int __init microcode_init(void)
 {
 	struct cpuinfo_x86 *c = &cpu_data(0);
 	int error;

 	if (c->x86_vendor == X86_VENDOR_INTEL)
 		microcode_ops = init_intel_microcode();
 	else if (c->x86_vendor == X86_VENDOR_AMD)
 		microcode_ops = init_amd_microcode();

 	if (!microcode_ops) {
 		printk(KERN_ERR "microcode: no support for this CPU vendor\n");
 		return -ENODEV;
 	}

 	error = microcode_dev_init();
 	if (error)
 		return error;
 	microcode_pdev = platform_device_register_simple("microcode", -1,
 							 NULL, 0);
 	if (IS_ERR(microcode_pdev)) {
 		microcode_dev_exit();
 		return PTR_ERR(microcode_pdev);
 	}

 	get_online_cpus();
 	error = sysdev_driver_register(&cpu_sysdev_class, &mc_sysdev_driver);
 	put_online_cpus();
 	if (error) {
 		microcode_dev_exit();
 		platform_device_unregister(microcode_pdev);
 		return error;
 	}

 	register_hotcpu_notifier(&mc_cpu_notifier);

 	printk(KERN_INFO
 	       "Microcode Update Driver: v" MICROCODE_VERSION
 	       " <tigran@aivazian.fsnet.co.uk>"
 	       " <peter.oruba@amd.com>\n");

 	return 0;
 }

 static void __exit microcode_exit(void)
 {
 	microcode_dev_exit();

 	unregister_hotcpu_notifier(&mc_cpu_notifier);

 	get_online_cpus();
 	sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
 	put_online_cpus();

 	platform_device_unregister(microcode_pdev);

 	microcode_ops = NULL;

 	printk(KERN_INFO
 	       "Microcode Update Driver: v" MICROCODE_VERSION " removed.\n");
 }

 module_init(microcode_init);
 module_exit(microcode_exit);
	/*
	* Intel CPU Microcode Update Driver for Linux
	*
	* Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
	* 2006 Shaohua Li <shaohua.li@intel.com>
	*
	* This driver allows to upgrade microcode on Intel processors
	* belonging to IA-32 family - PentiumPro, Pentium II,
	* Pentium III, Xeon, Pentium 4, etc.
	*
	* Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
	* Software Developer's Manual
	* Order Number 253668 or free download from:
	*
	* http://developer.intel.com/design/pentium4/manuals/253668.htm
	*
	* For more information, go to http://www.urbanmyth.org/microcode
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*
	* 1.0 16 Feb 2000, Tigran Aivazian <tigran@sco.com>
	* Initial release.
	* 1.01 18 Feb 2000, Tigran Aivazian <tigran@sco.com>
	* Added read() support + cleanups.
	* 1.02 21 Feb 2000, Tigran Aivazian <tigran@sco.com>
	* Added 'device trimming' support. open(O_WRONLY) zeroes
	* and frees the saved copy of applied microcode.
	* 1.03 29 Feb 2000, Tigran Aivazian <tigran@sco.com>
	* Made to use devfs (/dev/cpu/microcode) + cleanups.
	* 1.04 06 Jun 2000, Simon Trimmer <simon@veritas.com>
	* Added misc device support (now uses both devfs and misc).
	* Added MICROCODE_IOCFREE ioctl to clear memory.
	* 1.05 09 Jun 2000, Simon Trimmer <simon@veritas.com>
	* Messages for error cases (non Intel & no suitable microcode).
	* 1.06 03 Aug 2000, Tigran Aivazian <tigran@veritas.com>
	* Removed ->release(). Removed exclusive open and status bitmap.
	* Added microcode_rwsem to serialize read()/write()/ioctl().
	* Removed global kernel lock usage.
	* 1.07 07 Sep 2000, Tigran Aivazian <tigran@veritas.com>
	* Write 0 to 0x8B msr and then cpuid before reading revision,
	* so that it works even if there were no update done by the
	* BIOS. Otherwise, reading from 0x8B gives junk (which happened
	* to be 0 on my machine which is why it worked even when I
	* disabled update by the BIOS)
	* Thanks to Eric W. Biederman <ebiederman@lnxi.com> for the fix.
	* 1.08 11 Dec 2000, Richard Schaal <richard.schaal@intel.com> and
	* Tigran Aivazian <tigran@veritas.com>
	* Intel Pentium 4 processor support and bugfixes.
	* 1.09 30 Oct 2001, Tigran Aivazian <tigran@veritas.com>
	* Bugfix for HT (Hyper-Threading) enabled processors
	* whereby processor resources are shared by all logical processors
	* in a single CPU package.
	* 1.10 28 Feb 2002 Asit K Mallick <asit.k.mallick@intel.com> and
	* Tigran Aivazian <tigran@veritas.com>,
	* Serialize updates as required on HT processors due to
	* speculative nature of implementation.
	* 1.11 22 Mar 2002 Tigran Aivazian <tigran@veritas.com>
	* Fix the panic when writing zero-length microcode chunk.
	* 1.12 29 Sep 2003 Nitin Kamble <nitin.a.kamble@intel.com>,
	* Jun Nakajima <jun.nakajima@intel.com>
	* Support for the microcode updates in the new format.
	* 1.13 10 Oct 2003 Tigran Aivazian <tigran@veritas.com>
	* Removed ->read() method and obsoleted MICROCODE_IOCFREE ioctl
	* because we no longer hold a copy of applied microcode
	* in kernel memory.
	* 1.14 25 Jun 2004 Tigran Aivazian <tigran@veritas.com>
	* Fix sigmatch() macro to handle old CPUs with pf == 0.
	* Thanks to Stuart Swales for pointing out this bug.
	*/
	#include <linux/capability.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/sched.h>
	#include <linux/smp_lock.h>
	#include <linux/cpumask.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/vmalloc.h>
	#include <linux/miscdevice.h>
	#include <linux/spinlock.h>
	#include <linux/mm.h>
	#include <linux/fs.h>
	#include <linux/mutex.h>
	#include <linux/cpu.h>
	#include <linux/firmware.h>
	#include <linux/platform_device.h>

	#include <asm/msr.h>
	#include <asm/uaccess.h>
	#include <asm/processor.h>
	#include <asm/microcode.h>

	MODULE_DESCRIPTION("Microcode Update Driver");
	MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
	MODULE_LICENSE("GPL");

	#define MICROCODE_VERSION "2.00"

	struct microcode_ops *microcode_ops;

	/* no concurrent ->write()s are allowed on /dev/cpu/microcode */
	static DEFINE_MUTEX(microcode_mutex);

	struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
	EXPORT_SYMBOL_GPL(ucode_cpu_info);

	#ifdef CONFIG_MICROCODE_OLD_INTERFACE
	static int do_microcode_update(const void __user *buf, size_t size)
	{
	cpumask_t old;
	int error = 0;
	int cpu;

	old = current->cpus_allowed;

	for_each_online_cpu(cpu) {
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	if (!uci->valid)
	continue;

	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
	error = microcode_ops->request_microcode_user(cpu, buf, size);
	if (error < 0)
	goto out;
	if (!error)
	microcode_ops->apply_microcode(cpu);
	}
	out:
	set_cpus_allowed_ptr(current, &old);
	return error;
	}

	static int microcode_open(struct inode unused1, struct file unused2)
	{
	cycle_kernel_lock();
	return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
	}

	static ssize_t microcode_write(struct file file, const char __user buf,
	size_t len, loff_t *ppos)
	{
	ssize_t ret;

	if ((len >> PAGE_SHIFT) > num_physpages) {
	printk(KERN_ERR "microcode: too much data (max %ld pages)\n",
	num_physpages);
	return -EINVAL;
	}

	get_online_cpus();
	mutex_lock(&microcode_mutex);

	ret = do_microcode_update(buf, len);
	if (!ret)
	ret = (ssize_t)len;

	mutex_unlock(&microcode_mutex);
	put_online_cpus();

	return ret;
	}

	static const struct file_operations microcode_fops = {
	.owner = THIS_MODULE,
	.write = microcode_write,
	.open = microcode_open,
	};

	static struct miscdevice microcode_dev = {
	.minor = MICROCODE_MINOR,
	.name = "microcode",
	.fops = &microcode_fops,
	};

	static int __init microcode_dev_init(void)
	{
	int error;

	error = misc_register(&microcode_dev);
	if (error) {
	printk(KERN_ERR
	"microcode: can't misc_register on minor=%d\n",
	MICROCODE_MINOR);
	return error;
	}

	return 0;
	}

	static void microcode_dev_exit(void)
	{
	misc_deregister(&microcode_dev);
	}

	MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
	#else
	#define microcode_dev_init() 0
	#define microcode_dev_exit() do { } while (0)
	#endif

	/* fake device for request_firmware */
	struct platform_device *microcode_pdev;

	static ssize_t reload_store(struct sys_device *dev,
	struct sysdev_attribute *attr,
	const char *buf, size_t sz)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
	char *end;
	unsigned long val = simple_strtoul(buf, &end, 0);
	int err = 0;
	int cpu = dev->id;

	if (end == buf)
	return -EINVAL;
	if (val == 1) {
	cpumask_t old = current->cpus_allowed;

	get_online_cpus();
	if (cpu_online(cpu)) {
	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
	mutex_lock(&microcode_mutex);
	if (uci->valid) {
	err = microcode_ops->request_microcode_fw(cpu,
	&microcode_pdev->dev);
	if (!err)
	microcode_ops->apply_microcode(cpu);
	}
	mutex_unlock(&microcode_mutex);
	set_cpus_allowed_ptr(current, &old);
	}
	put_online_cpus();
	}
	if (err)
	return err;
	return sz;
	}

	static ssize_t version_show(struct sys_device *dev,
	struct sysdev_attribute attr, char buf)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
	}

	static ssize_t pf_show(struct sys_device *dev,
	struct sysdev_attribute attr, char buf)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;

	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
	}

	static SYSDEV_ATTR(reload, 0200, NULL, reload_store);
	static SYSDEV_ATTR(version, 0400, version_show, NULL);
	static SYSDEV_ATTR(processor_flags, 0400, pf_show, NULL);

	static struct attribute *mc_default_attrs[] = {
	&attr_reload.attr,
	&attr_version.attr,
	&attr_processor_flags.attr,
	NULL
	};

	static struct attribute_group mc_attr_group = {
	.attrs = mc_default_attrs,
	.name = "microcode",
	};

	static void microcode_fini_cpu(int cpu)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	mutex_lock(&microcode_mutex);
	microcode_ops->microcode_fini_cpu(cpu);
	uci->valid = 0;
	mutex_unlock(&microcode_mutex);
	}

	static void collect_cpu_info(int cpu)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	memset(uci, 0, sizeof(*uci));
	if (!microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig))
	uci->valid = 1;
	}

	static int microcode_resume_cpu(int cpu)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	struct cpu_signature nsig;

	pr_debug("microcode: CPU%d resumed\n", cpu);

	if (!uci->mc)
	return 1;

	/*
	* Let's verify that the 'cached' ucode does belong
	* to this cpu (a bit of paranoia):
	*/
	if (microcode_ops->collect_cpu_info(cpu, &nsig)) {
	microcode_fini_cpu(cpu);
	return -1;
	}

	if (memcmp(&nsig, &uci->cpu_sig, sizeof(nsig))) {
	microcode_fini_cpu(cpu);
	/* Should we look for a new ucode here? */
	return 1;
	}

	return 0;
	}

	void microcode_update_cpu(int cpu)
	{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	int err = 0;

	/*
	* Check if the system resume is in progress (uci->valid != NULL),
	* otherwise just request a firmware:
	*/
	if (uci->valid) {
	err = microcode_resume_cpu(cpu);
	} else {
	collect_cpu_info(cpu);
	if (uci->valid && system_state == SYSTEM_RUNNING)
	err = microcode_ops->request_microcode_fw(cpu,
	&microcode_pdev->dev);
	}
	if (!err)
	microcode_ops->apply_microcode(cpu);
	}

	static void microcode_init_cpu(int cpu)
	{
	cpumask_t old = current->cpus_allowed;

	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
	/* We should bind the task to the CPU */
	BUG_ON(raw_smp_processor_id() != cpu);

	mutex_lock(&microcode_mutex);
	microcode_update_cpu(cpu);
	mutex_unlock(&microcode_mutex);

	set_cpus_allowed_ptr(current, &old);
	}

	static int mc_sysdev_add(struct sys_device *sys_dev)
	{
	int err, cpu = sys_dev->id;
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	if (!cpu_online(cpu))
	return 0;

	pr_debug("microcode: CPU%d added\n", cpu);
	memset(uci, 0, sizeof(*uci));

	err = sysfs_create_group(&sys_dev->kobj, &mc_attr_group);
	if (err)
	return err;

	microcode_init_cpu(cpu);
	return 0;
	}

	static int mc_sysdev_remove(struct sys_device *sys_dev)
	{
	int cpu = sys_dev->id;

	if (!cpu_online(cpu))
	return 0;

	pr_debug("microcode: CPU%d removed\n", cpu);
	microcode_fini_cpu(cpu);
	sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
	return 0;
	}

	static int mc_sysdev_resume(struct sys_device *dev)
	{
	int cpu = dev->id;

	if (!cpu_online(cpu))
	return 0;

	/* only CPU 0 will apply ucode here */
	microcode_update_cpu(0);
	return 0;
	}

	static struct sysdev_driver mc_sysdev_driver = {
	.add = mc_sysdev_add,
	.remove = mc_sysdev_remove,
	.resume = mc_sysdev_resume,
	};

	static __cpuinit int
	mc_cpu_callback(struct notifier_block nb, unsigned long action, void hcpu)
	{
	unsigned int cpu = (unsigned long)hcpu;
	struct sys_device *sys_dev;

	sys_dev = get_cpu_sysdev(cpu);
	switch (action) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
	microcode_init_cpu(cpu);
	case CPU_DOWN_FAILED:
	case CPU_DOWN_FAILED_FROZEN:
	pr_debug("microcode: CPU%d added\n", cpu);
	if (sysfs_create_group(&sys_dev->kobj, &mc_attr_group))
	printk(KERN_ERR "microcode: Failed to create the sysfs "
	"group for CPU%d\n", cpu);
	break;
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
	/* Suspend is in progress, only remove the interface */
	sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
	pr_debug("microcode: CPU%d removed\n", cpu);
	break;
	case CPU_DEAD:
	case CPU_UP_CANCELED_FROZEN:
	/* The CPU refused to come up during a system resume */
	microcode_fini_cpu(cpu);
	break;
	}
	return NOTIFY_OK;
	}

	static struct notifier_block __refdata mc_cpu_notifier = {
	.notifier_call = mc_cpu_callback,
	};

	static int __init microcode_init(void)
	{
	struct cpuinfo_x86 *c = &cpu_data(0);
	int error;

	if (c->x86_vendor == X86_VENDOR_INTEL)
	microcode_ops = init_intel_microcode();
	else if (c->x86_vendor == X86_VENDOR_AMD)
	microcode_ops = init_amd_microcode();

	if (!microcode_ops) {
	printk(KERN_ERR "microcode: no support for this CPU vendor\n");
	return -ENODEV;
	}

	error = microcode_dev_init();
	if (error)
	return error;
	microcode_pdev = platform_device_register_simple("microcode", -1,
	NULL, 0);
	if (IS_ERR(microcode_pdev)) {
	microcode_dev_exit();
	return PTR_ERR(microcode_pdev);
	}

	get_online_cpus();
	error = sysdev_driver_register(&cpu_sysdev_class, &mc_sysdev_driver);
	put_online_cpus();
	if (error) {
	microcode_dev_exit();
	platform_device_unregister(microcode_pdev);
	return error;
	}

	register_hotcpu_notifier(&mc_cpu_notifier);

	printk(KERN_INFO
	"Microcode Update Driver: v" MICROCODE_VERSION
	" <tigran@aivazian.fsnet.co.uk>"
	" <peter.oruba@amd.com>\n");

	return 0;
	}

	static void __exit microcode_exit(void)
	{
	microcode_dev_exit();

	unregister_hotcpu_notifier(&mc_cpu_notifier);

	get_online_cpus();
	sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
	put_online_cpus();

	platform_device_unregister(microcode_pdev);

	microcode_ops = NULL;

	printk(KERN_INFO
	"Microcode Update Driver: v" MICROCODE_VERSION " removed.\n");
	}

	module_init(microcode_init);
	module_exit(microcode_exit);