microcode.c

linux 内核源代码

	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;
	}

	lock_cpu_hotplug();
	mutex_lock(&microcode_mutex);

	user_buffer = (void __user *) buf;
	user_buffer_size = (int) len;

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

	mutex_unlock(&microcode_mutex);
	unlock_cpu_hotplug();

	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

static long get_next_ucode_from_buffer(void **mc, void *buf,
	unsigned long size, long offset)
{
	microcode_header_t *mc_header;
	unsigned long total_size;

	/* No more data */
	if (offset >= size)
		return 0;
	mc_header = (microcode_header_t *)(buf + offset);
	total_size = get_totalsize(mc_header);

	if (offset + total_size > size) {
		printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
		return -EINVAL;
	}

	*mc = vmalloc(total_size);
	if (!*mc) {
		printk(KERN_ERR "microcode: error! Can not allocate memory\n");
		return -ENOMEM;
	}
	memcpy(*mc, buf + offset, total_size);
	return offset + total_size;
}

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

static int cpu_request_microcode(int cpu)
{
	char name[30];
	struct cpuinfo_x86 *c = &cpu_data(cpu);
	const struct firmware *firmware;
	void *buf;
	unsigned long size;
	long offset = 0;
	int error;
	void *mc;

	/* We should bind the task to the CPU */
	BUG_ON(cpu != raw_smp_processor_id());
	sprintf(name,"intel-ucode/%02x-%02x-%02x",
		c->x86, c->x86_model, c->x86_mask);
	error = request_firmware(&firmware, name, &microcode_pdev->dev);
	if (error) {
		pr_debug("ucode data file %s load failed\n", name);
		return error;
	}
	buf = (void *)firmware->data;
	size = firmware->size;
	while ((offset = get_next_ucode_from_buffer(&mc, buf, size, offset))
			> 0) {
		error = microcode_sanity_check(mc);
		if (error)
			break;
		error = get_maching_microcode(mc, cpu);
		if (error < 0)
			break;
		/*
		 * It's possible the data file has multiple matching ucode,
		 * lets keep searching till the latest version
		 */
		if (error == 1) {
			apply_microcode(cpu);
			error = 0;
		}
		vfree(mc);
	}
	if (offset > 0)
		vfree(mc);
	if (offset < 0)
		error = offset;
	release_firmware(firmware);

	return error;
}

static int apply_microcode_check_cpu(int cpu)
{
	struct cpuinfo_x86 *c = &cpu_data(cpu);
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	cpumask_t old;
	unsigned int val[2];
	int err = 0;

	/* Check if the microcode is available */
	if (!uci->mc)
		return 0;

	old = current->cpus_allowed;
	set_cpus_allowed(current, cpumask_of_cpu(cpu));

	/* Check if the microcode we have in memory matches the CPU */
	if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
	    cpu_has(c, X86_FEATURE_IA64) || uci->sig != cpuid_eax(0x00000001))
		err = -EINVAL;

	if (!err && ((c->x86_model >= 5) || (c->x86 > 6))) {
		/* get processor flags from MSR 0x17 */
		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
		if (uci->pf != (1 << ((val[1] >> 18) & 7)))
			err = -EINVAL;
	}

	if (!err) {
		wrmsr(MSR_IA32_UCODE_REV, 0, 0);
		/* see notes above for revision 1.07.  Apparent chip bug */
		sync_core();
		/* get the current revision from MSR 0x8B */
		rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
		if (uci->rev != val[1])
			err = -EINVAL;
	}

	if (!err)
		apply_microcode(cpu);
	else
		printk(KERN_ERR "microcode: Could not apply microcode to CPU%d:"
			" sig=0x%x, pf=0x%x, rev=0x%x\n",
			cpu, uci->sig, uci->pf, uci->rev);

	set_cpus_allowed(current, old);
	return err;
}

static void microcode_init_cpu(int cpu, int resume)
{
	cpumask_t old;
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	old = current->cpus_allowed;

	set_cpus_allowed(current, cpumask_of_cpu(cpu));
	mutex_lock(&microcode_mutex);
	collect_cpu_info(cpu);
	if (uci->valid && system_state == SYSTEM_RUNNING && !resume)
		cpu_request_microcode(cpu);
	mutex_unlock(&microcode_mutex);
	set_cpus_allowed(current, old);
}

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

	mutex_lock(&microcode_mutex);
	uci->valid = 0;
	vfree(uci->mc);
	uci->mc = NULL;
	mutex_unlock(&microcode_mutex);
}

static ssize_t reload_store(struct sys_device *dev, 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;

		old = current->cpus_allowed;

		lock_cpu_hotplug();
		set_cpus_allowed(current, cpumask_of_cpu(cpu));

		mutex_lock(&microcode_mutex);
		if (uci->valid)
			err = cpu_request_microcode(cpu);
		mutex_unlock(&microcode_mutex);
		unlock_cpu_hotplug();
		set_cpus_allowed(current, old);
	}
	if (err)
		return err;
	return sz;
}

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

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

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

	return sprintf(buf, "0x%x\n", uci->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 int __mc_sysdev_add(struct sys_device *sys_dev, int resume)
{
	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, resume);

	return 0;
}

static int mc_sysdev_add(struct sys_device *sys_dev)
{
	return __mc_sysdev_add(sys_dev, 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;
	pr_debug("Microcode:CPU %d resumed\n", cpu);
	/* only CPU 0 will apply ucode here */
	apply_microcode(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_UP_CANCELED_FROZEN:
		/* The CPU refused to come up during a system resume */
		microcode_fini_cpu(cpu);
		break;
	case CPU_ONLINE:
	case CPU_DOWN_FAILED:
		mc_sysdev_add(sys_dev);
		break;
	case CPU_ONLINE_FROZEN:
		/* System-wide resume is in progress, try to apply microcode */
		if (apply_microcode_check_cpu(cpu)) {
			/* The application of microcode failed */
			microcode_fini_cpu(cpu);
			__mc_sysdev_add(sys_dev, 1);
			break;
		}
	case CPU_DOWN_FAILED_FROZEN:
		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:
		mc_sysdev_remove(sys_dev);
		break;
	case CPU_DOWN_PREPARE_FROZEN:
		/* Suspend is in progress, only remove the interface */
		sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);
		break;
	}
	return NOTIFY_OK;
}

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

static int __init microcode_init (void)
{
	int error;

	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);
	}

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

	register_hotcpu_notifier(&mc_cpu_notifier);

	printk(KERN_INFO 
		"IA-32 Microcode Update Driver: v" MICROCODE_VERSION " <[e-mail]>\n");
	return 0;
}

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

	unregister_hotcpu_notifier(&mc_cpu_notifier);

	lock_cpu_hotplug();
	sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
	unlock_cpu_hotplug();

	platform_device_unregister(microcode_pdev);
}

module_init(microcode_init)
module_exit(microcode_exit)