/*
 *      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;

        microcode_ops->microcode_fini_cpu(cpu);
        uci->valid = 0;
}

static void microcode_fini_cpu(int cpu)
{
        mutex_lock(&microcode_mutex);
        __microcode_fini_cpu(cpu);
        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);
                printk(KERN_ERR "failed to collect_cpu_info for resuming cpu #%d\n",
                                cpu);
                return -1;
        }

        if ((nsig.sig != uci->cpu_sig.sig) || (nsig.pf != uci->cpu_sig.pf)) {
                __microcode_fini_cpu(cpu);
                printk(KERN_ERR "cached ucode doesn't match the resuming cpu #%d\n",
                                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\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);