microcode_core.c

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/*
 *  Intel CPU Microcode Update Driver for Linux
 *
 *  Copyright (C) 2000-2006 Tigran Aivazian <[email protected]>
 *            2006  Shaohua Li <[email protected]>
 *
 *  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/Assets/PDF/manual/253668.pdf 
 *
 *  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 <[email protected]>
 *      Initial release.
 *  1.01    18 Feb 2000, Tigran Aivazian <[email protected]>
 *      Added read() support + cleanups.
 *  1.02    21 Feb 2000, Tigran Aivazian <[email protected]>
 *      Added 'device trimming' support. open(O_WRONLY) zeroes
 *      and frees the saved copy of applied microcode.
 *  1.03    29 Feb 2000, Tigran Aivazian <[email protected]>
 *      Made to use devfs (/dev/cpu/microcode) + cleanups.
 *  1.04    06 Jun 2000, Simon Trimmer <[email protected]>
 *      Added misc device support (now uses both devfs and misc).
 *      Added MICROCODE_IOCFREE ioctl to clear memory.
 *  1.05    09 Jun 2000, Simon Trimmer <[email protected]>
 *      Messages for error cases (non Intel & no suitable microcode).
 *  1.06    03 Aug 2000, Tigran Aivazian <[email protected]>
 *      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 <[email protected]>
 *      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 <[email protected]> for the fix.
 *  1.08    11 Dec 2000, Richard Schaal <[email protected]> and
 *               Tigran Aivazian <[email protected]>
 *      Intel Pentium 4 processor support and bugfixes.
 *  1.09    30 Oct 2001, Tigran Aivazian <[email protected]>
 *      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 <[email protected]> and
 *      Tigran Aivazian <[email protected]>,
 *      Serialize updates as required on HT processors due to
 *      speculative nature of implementation.
 *  1.11    22 Mar 2002 Tigran Aivazian <[email protected]>
 *      Fix the panic when writing zero-length microcode chunk.
 *  1.12    29 Sep 2003 Nitin Kamble <[email protected]>,
 *      Jun Nakajima <[email protected]>
 *      Support for the microcode updates in the new format.
 *  1.13    10 Oct 2003 Tigran Aivazian <[email protected]>
 *      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 <[email protected]>
 *      Fix sigmatch() macro to handle old CPUs with pf == 0.
 *      Thanks to Stuart Swales for pointing out this bug.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/syscore_ops.h>

#include <asm/microcode.h>
#include <asm/processor.h>
#include <asm/cpu_device_id.h>
#include <asm/perf_event.h>

MODULE_DESCRIPTION("Microcode Update Driver");
MODULE_AUTHOR("Tigran Aivazian <[email protected]>");
MODULE_LICENSE("GPL");

#define MICROCODE_VERSION   "2.00"

static struct microcode_ops *microcode_ops;

/*
 * Synchronization.
 *
 * All non cpu-hotplug-callback call sites use:
 *
 * - microcode_mutex to synchronize with each other;
 * - get/put_online_cpus() to synchronize with
 *   the cpu-hotplug-callback call sites.
 *
 * We guarantee that only a single cpu is being
 * updated at any particular moment of time.
 */
static DEFINE_MUTEX(microcode_mutex);

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

/*
 * Operations that are run on a target cpu:
 */

struct cpu_info_ctx {
    struct cpu_signature    *cpu_sig;
    int         err;
};

static void collect_cpu_info_local(void *arg)
{
    struct cpu_info_ctx *ctx = arg;

    ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
                           ctx->cpu_sig);
}

static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
{
    struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
    int ret;

    ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
    if (!ret)
        ret = ctx.err;

    return ret;
}

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

    memset(uci, 0, sizeof(*uci));

    ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
    if (!ret)
        uci->valid = 1;

    return ret;
}

struct apply_microcode_ctx {
    int err;
};

static void apply_microcode_local(void *arg)
{
    struct apply_microcode_ctx *ctx = arg;

    ctx->err = microcode_ops->apply_microcode(smp_processor_id());
}

static int apply_microcode_on_target(int cpu)
{
    struct apply_microcode_ctx ctx = { .err = 0 };
    int ret;

    ret = smp_call_function_single(cpu, apply_microcode_local, &ctx, 1);
    if (!ret)
        ret = ctx.err;

    return ret;
}

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

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

        if (!uci->valid)
            continue;

        ustate = microcode_ops->request_microcode_user(cpu, buf, size);
        if (ustate == UCODE_ERROR) {
            error = -1;
            break;
        } else if (ustate == UCODE_OK)
            apply_microcode_on_target(cpu);
    }

    return error;
}

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

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

    if ((len >> PAGE_SHIFT) > totalram_pages) {
        pr_err("too much data (max %ld pages)\n", totalram_pages);
        return ret;
    }

    get_online_cpus();
    mutex_lock(&microcode_mutex);

    if (do_microcode_update(buf, len) == 0)
        ret = (ssize_t)len;

    if (ret > 0)
        perf_check_microcode();

    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,
    .llseek     = no_llseek,
};

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

static int __init microcode_dev_init(void)
{
    int error;

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

    return 0;
}

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

MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
MODULE_ALIAS("devname:cpu/microcode");
#else
#define microcode_dev_init()    0
#define microcode_dev_exit()    do { } while (0)
#endif

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

static int reload_for_cpu(int cpu)
{
    struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
    enum ucode_state ustate;
    int err = 0;

    if (!uci->valid)
        return err;

    ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, true);
    if (ustate == UCODE_OK)
        apply_microcode_on_target(cpu);
    else
        if (ustate == UCODE_ERROR)
            err = -EINVAL;
    return err;
}

static ssize_t reload_store(struct device *dev,
                struct device_attribute *attr,
                const char *buf, size_t size)
{
    unsigned long val;
    int cpu;
    ssize_t ret = 0, tmp_ret;

    ret = kstrtoul(buf, 0, &val);
    if (ret)
        return ret;

    if (val != 1)
        return size;

    get_online_cpus();
    mutex_lock(&microcode_mutex);
    for_each_online_cpu(cpu) {
        tmp_ret = reload_for_cpu(cpu);
        if (tmp_ret != 0)
            pr_warn("Error reloading microcode on CPU %d\n", cpu);

        /* save retval of the first encountered reload error */
        if (!ret)
            ret = tmp_ret;
    }
    if (!ret)
        perf_check_microcode();
    mutex_unlock(&microcode_mutex);
    put_online_cpus();

    if (!ret)
        ret = size;

    return ret;
}

static ssize_t version_show(struct device *dev,
            struct device_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 device *dev,
            struct device_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 DEVICE_ATTR(reload, 0200, NULL, reload_store);
static DEVICE_ATTR(version, 0400, version_show, NULL);
static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);

static struct attribute *mc_default_attrs[] = {
    &dev_attr_version.attr,
    &dev_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 enum ucode_state microcode_resume_cpu(int cpu)
{
    pr_debug("CPU%d updated upon resume\n", cpu);

    if (apply_microcode_on_target(cpu))
        return UCODE_ERROR;

    return UCODE_OK;
}

static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
{
    enum ucode_state ustate;

    if (collect_cpu_info(cpu))
        return UCODE_ERROR;

    /* --dimm. Trigger a delayed update? */
    if (system_state != SYSTEM_RUNNING)
        return UCODE_NFOUND;

    ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev,
                             refresh_fw);

    if (ustate == UCODE_OK) {
        pr_debug("CPU%d updated upon init\n", cpu);
        apply_microcode_on_target(cpu);
    }

    return ustate;
}

static enum ucode_state microcode_update_cpu(int cpu)
{
    struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

    if (uci->valid)
        return microcode_resume_cpu(cpu);

    return microcode_init_cpu(cpu, false);
}

static int mc_device_add(struct device *dev, struct subsys_interface *sif)
{
    int err, cpu = dev->id;

    if (!cpu_online(cpu))
        return 0;

    pr_debug("CPU%d added\n", cpu);

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

    if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
        return -EINVAL;

    return err;
}

static int mc_device_remove(struct device *dev, struct subsys_interface *sif)
{
    int cpu = dev->id;

    if (!cpu_online(cpu))
        return 0;

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

static struct subsys_interface mc_cpu_interface = {
    .name           = "microcode",
    .subsys         = &cpu_subsys,
    .add_dev        = mc_device_add,
    .remove_dev     = mc_device_remove,
};

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

    if (uci->valid && uci->mc)
        microcode_ops->apply_microcode(cpu);
}

static struct syscore_ops mc_syscore_ops = {
    .resume         = mc_bp_resume,
};

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

    dev = get_cpu_device(cpu);

    switch (action & ~CPU_TASKS_FROZEN) {
    case CPU_ONLINE:
        microcode_update_cpu(cpu);
        pr_debug("CPU%d added\n", cpu);
        /*
         * "break" is missing on purpose here because we want to fall
         * through in order to create the sysfs group.
         */

    case CPU_DOWN_FAILED:
        if (sysfs_create_group(&dev->kobj, &mc_attr_group))
            pr_err("Failed to create group for CPU%d\n", cpu);
        break;

    case CPU_DOWN_PREPARE:
        /* Suspend is in progress, only remove the interface */
        sysfs_remove_group(&dev->kobj, &mc_attr_group);
        pr_debug("CPU%d removed\n", cpu);
        break;

    /*
     * case CPU_DEAD:
     *
     * When a CPU goes offline, don't free up or invalidate the copy of
     * the microcode in kernel memory, so that we can reuse it when the
     * CPU comes back online without unnecessarily requesting the userspace
     * for it again.
     */
    }

    /* The CPU refused to come up during a system resume */
    if (action == CPU_UP_CANCELED_FROZEN)
        microcode_fini_cpu(cpu);

    return NOTIFY_OK;
}

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

#ifdef MODULE
/* Autoload on Intel and AMD systems */
static const struct x86_cpu_id __initconst microcode_id[] = {
#ifdef CONFIG_MICROCODE_INTEL
    { X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, },
#endif
#ifdef CONFIG_MICROCODE_AMD
    { X86_VENDOR_AMD, X86_FAMILY_ANY, X86_MODEL_ANY, },
#endif
    {}
};
MODULE_DEVICE_TABLE(x86cpu, microcode_id);
#endif

static struct attribute *cpu_root_microcode_attrs[] = {
    &dev_attr_reload.attr,
    NULL
};

static struct attribute_group cpu_root_microcode_group = {
    .name  = "microcode",
    .attrs = cpu_root_microcode_attrs,
};

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();
    else
        pr_err("no support for this CPU vendor\n");

    if (!microcode_ops)
        return -ENODEV;

    microcode_pdev = platform_device_register_simple("microcode", -1,
                             NULL, 0);
    if (IS_ERR(microcode_pdev))
        return PTR_ERR(microcode_pdev);

    get_online_cpus();
    mutex_lock(&microcode_mutex);

    error = subsys_interface_register(&mc_cpu_interface);
    if (!error)
        perf_check_microcode();
    mutex_unlock(&microcode_mutex);
    put_online_cpus();

    if (error)
        goto out_pdev;

    error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
                   &cpu_root_microcode_group);

    if (error) {
        pr_err("Error creating microcode group!\n");
        goto out_driver;
    }

    error = microcode_dev_init();
    if (error)
        goto out_ucode_group;

    register_syscore_ops(&mc_syscore_ops);
    register_hotcpu_notifier(&mc_cpu_notifier);

    pr_info("Microcode Update Driver: v" MICROCODE_VERSION
        " <[email protected]>, Peter Oruba\n");

    return 0;

 out_ucode_group:
    sysfs_remove_group(&cpu_subsys.dev_root->kobj,
               &cpu_root_microcode_group);

 out_driver:
    get_online_cpus();
    mutex_lock(&microcode_mutex);

    subsys_interface_unregister(&mc_cpu_interface);

    mutex_unlock(&microcode_mutex);
    put_online_cpus();

 out_pdev:
    platform_device_unregister(microcode_pdev);
    return error;

}
module_init(microcode_init);

static void __exit microcode_exit(void)
{
    struct cpuinfo_x86 *c = &cpu_data(0);

    microcode_dev_exit();

    unregister_hotcpu_notifier(&mc_cpu_notifier);
    unregister_syscore_ops(&mc_syscore_ops);

    sysfs_remove_group(&cpu_subsys.dev_root->kobj,
               &cpu_root_microcode_group);

    get_online_cpus();
    mutex_lock(&microcode_mutex);

    subsys_interface_unregister(&mc_cpu_interface);

    mutex_unlock(&microcode_mutex);
    put_online_cpus();

    platform_device_unregister(microcode_pdev);

    microcode_ops = NULL;

    if (c->x86_vendor == X86_VENDOR_AMD)
        exit_amd_microcode();

    pr_info("Microcode Update Driver: v" MICROCODE_VERSION " removed.\n");
}
module_exit(microcode_exit);