1 files changed, 850 insertions, 0 deletions

diff --git a/arch/x86/kernel/microcode.c b/arch/x86/kernel/microcode.c
new file mode 100644
index 000000000000..09cf78110358
--- /dev/null
+++ b/arch/x86/kernel/microcode.c
@@ -0,0 +1,850 @@
+/*
+ *      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 8.10 of Volume III, Intel Pentium 4 Manual, 
+ *      Order Number 245472 or free download from:
+ *              
+ *      http://developer.intel.com/design/pentium4/manuals/245472.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.
+ */
+
+//#define DEBUG /* pr_debug */
+#include <linux/capability.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.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>
+
+MODULE_DESCRIPTION("Intel CPU (IA-32) Microcode Update Driver");
+MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
+MODULE_LICENSE("GPL");
+
+#define MICROCODE_VERSION       "1.14a"
+
+#define DEFAULT_UCODE_DATASIZE  (2000)    /* 2000 bytes */
+#define MC_HEADER_SIZE          (sizeof (microcode_header_t))     /* 48 bytes */
+#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE) /* 2048 bytes */
+#define EXT_HEADER_SIZE         (sizeof (struct extended_sigtable)) /* 20 bytes */
+#define EXT_SIGNATURE_SIZE      (sizeof (struct extended_signature)) /* 12 bytes */
+#define DWSIZE                  (sizeof (u32))
+#define get_totalsize(mc) \
+        (((microcode_t *)mc)->hdr.totalsize ? \
+         ((microcode_t *)mc)->hdr.totalsize : DEFAULT_UCODE_TOTALSIZE)
+#define get_datasize(mc) \
+        (((microcode_t *)mc)->hdr.datasize ? \
+         ((microcode_t *)mc)->hdr.datasize : DEFAULT_UCODE_DATASIZE)
+
+#define sigmatch(s1, s2, p1, p2) \
+        (((s1) == (s2)) && (((p1) & (p2)) || (((p1) == 0) && ((p2) == 0))))
+
+#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)
+
+/* serialize access to the physical write to MSR 0x79 */
+static DEFINE_SPINLOCK(microcode_update_lock);
+
+/* no concurrent ->write()s are allowed on /dev/cpu/microcode */
+static DEFINE_MUTEX(microcode_mutex);
+
+static struct ucode_cpu_info {
+        int valid;
+        unsigned int sig;
+        unsigned int pf;
+        unsigned int rev;
+        microcode_t *mc;
+} ucode_cpu_info[NR_CPUS];
+
+static void collect_cpu_info(int cpu_num)
+{
+        struct cpuinfo_x86 *c = cpu_data + cpu_num;
+        struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;
+        unsigned int val[2];
+
+        /* We should bind the task to the CPU */
+        BUG_ON(raw_smp_processor_id() != cpu_num);
+        uci->pf = uci->rev = 0;
+        uci->mc = NULL;
+        uci->valid = 1;
+
+        if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
+                cpu_has(c, X86_FEATURE_IA64)) {
+                printk(KERN_ERR "microcode: CPU%d not a capable Intel "
+                        "processor\n", cpu_num);
+                uci->valid = 0;
+                return;
+        }
+
+        uci->sig = cpuid_eax(0x00000001);
+
+        if ((c->x86_model >= 5) || (c->x86 > 6)) {
+                /* get processor flags from MSR 0x17 */
+                rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
+                uci->pf = 1 << ((val[1] >> 18) & 7);
+        }
+
+        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], uci->rev);
+        pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
+                        uci->sig, uci->pf, uci->rev);
+}
+
+static inline int microcode_update_match(int cpu_num,
+        microcode_header_t *mc_header, int sig, int pf)
+{
+        struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;
+
+        if (!sigmatch(sig, uci->sig, pf, uci->pf)
+                || mc_header->rev <= uci->rev)
+                return 0;
+        return 1;
+}
+
+static int microcode_sanity_check(void *mc)
+{
+        microcode_header_t *mc_header = mc;
+        struct extended_sigtable *ext_header = NULL;
+        struct extended_signature *ext_sig;
+        unsigned long total_size, data_size, ext_table_size;
+        int sum, orig_sum, ext_sigcount = 0, i;
+
+        total_size = get_totalsize(mc_header);
+        data_size = get_datasize(mc_header);
+        if (data_size + MC_HEADER_SIZE > total_size) {
+                printk(KERN_ERR "microcode: error! "
+                        "Bad data size in microcode data file\n");
+                return -EINVAL;
+        }
+
+        if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
+                printk(KERN_ERR "microcode: error! "
+                        "Unknown microcode update format\n");
+                return -EINVAL;
+        }
+        ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
+        if (ext_table_size) {
+                if ((ext_table_size < EXT_HEADER_SIZE)
+                 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
+                        printk(KERN_ERR "microcode: error! "
+                                "Small exttable size in microcode data file\n");
+                        return -EINVAL;
+                }
+                ext_header = mc + MC_HEADER_SIZE + data_size;
+                if (ext_table_size != exttable_size(ext_header)) {
+                        printk(KERN_ERR "microcode: error! "
+                                "Bad exttable size in microcode data file\n");
+                        return -EFAULT;
+                }
+                ext_sigcount = ext_header->count;
+        }
+
+        /* check extended table checksum */
+        if (ext_table_size) {
+                int ext_table_sum = 0;
+                int *ext_tablep = (int *)ext_header;
+
+                i = ext_table_size / DWSIZE;
+                while (i--)
+                        ext_table_sum += ext_tablep[i];
+                if (ext_table_sum) {
+                        printk(KERN_WARNING "microcode: aborting, "
+                                "bad extended signature table checksum\n");
+                        return -EINVAL;
+                }
+        }
+
+        /* calculate the checksum */
+        orig_sum = 0;
+        i = (MC_HEADER_SIZE + data_size) / DWSIZE;
+        while (i--)
+                orig_sum += ((int *)mc)[i];
+        if (orig_sum) {
+                printk(KERN_ERR "microcode: aborting, bad checksum\n");
+                return -EINVAL;
+        }
+        if (!ext_table_size)
+                return 0;
+        /* check extended signature checksum */
+        for (i = 0; i < ext_sigcount; i++) {
+                ext_sig = (struct extended_signature *)((void *)ext_header
+                        + EXT_HEADER_SIZE + EXT_SIGNATURE_SIZE * i);
+                sum = orig_sum
+                        - (mc_header->sig + mc_header->pf + mc_header->cksum)
+                        + (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
+                if (sum) {
+                        printk(KERN_ERR "microcode: aborting, bad checksum\n");
+                        return -EINVAL;
+                }
+        }
+        return 0;
+}
+
+/*
+ * return 0 - no update found
+ * return 1 - found update
+ * return < 0 - error
+ */
+static int get_maching_microcode(void *mc, int cpu)
+{
+        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+        microcode_header_t *mc_header = mc;
+        struct extended_sigtable *ext_header;
+        unsigned long total_size = get_totalsize(mc_header);
+        int ext_sigcount, i;
+        struct extended_signature *ext_sig;
+        void *new_mc;
+
+        if (microcode_update_match(cpu, mc_header,
+                        mc_header->sig, mc_header->pf))
+                goto find;
+
+        if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
+                return 0;
+
+        ext_header = (struct extended_sigtable *)(mc +
+                        get_datasize(mc_header) + MC_HEADER_SIZE);
+        ext_sigcount = ext_header->count;
+        ext_sig = (struct extended_signature *)((void *)ext_header
+                        + EXT_HEADER_SIZE);
+        for (i = 0; i < ext_sigcount; i++) {
+                if (microcode_update_match(cpu, mc_header,
+                                ext_sig->sig, ext_sig->pf))
+                        goto find;
+                ext_sig++;
+        }
+        return 0;
+find:
+        pr_debug("microcode: CPU %d found a matching microcode update with"
+                " version 0x%x (current=0x%x)\n", cpu, mc_header->rev,uci->rev);
+        new_mc = vmalloc(total_size);
+        if (!new_mc) {
+                printk(KERN_ERR "microcode: error! Can not allocate memory\n");
+                return -ENOMEM;
+        }
+
+        /* free previous update file */
+        vfree(uci->mc);
+
+        memcpy(new_mc, mc, total_size);
+        uci->mc = new_mc;
+        return 1;
+}
+
+static void apply_microcode(int cpu)
+{
+        unsigned long flags;
+        unsigned int val[2];
+        int cpu_num = raw_smp_processor_id();
+        struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;
+
+        /* We should bind the task to the CPU */
+        BUG_ON(cpu_num != cpu);
+
+        if (uci->mc == NULL)
+                return;
+
+        /* serialize access to the physical write to MSR 0x79 */
+        spin_lock_irqsave(&microcode_update_lock, flags);          
+
+        /* write microcode via MSR 0x79 */
+        wrmsr(MSR_IA32_UCODE_WRITE,
+                (unsigned long) uci->mc->bits, 
+                (unsigned long) uci->mc->bits >> 16 >> 16);
+        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]);
+
+        spin_unlock_irqrestore(&microcode_update_lock, flags);
+        if (val[1] != uci->mc->hdr.rev) {
+                printk(KERN_ERR "microcode: CPU%d updated from revision "
+                        "0x%x to 0x%x failed\n", cpu_num, uci->rev, val[1]);
+                return;
+        }
+        pr_debug("microcode: CPU%d updated from revision "
+               "0x%x to 0x%x, date = %08x \n", 
+               cpu_num, uci->rev, val[1], uci->mc->hdr.date);
+        uci->rev = val[1];
+}
+
+#ifdef CONFIG_MICROCODE_OLD_INTERFACE
+static void __user *user_buffer;        /* user area microcode data buffer */
+static unsigned int user_buffer_size;   /* it's size */
+
+static long get_next_ucode(void **mc, long offset)
+{
+        microcode_header_t mc_header;
+        unsigned long total_size;
+
+        /* No more data */
+        if (offset >= user_buffer_size)
+                return 0;
+        if (copy_from_user(&mc_header, user_buffer + offset, MC_HEADER_SIZE)) {
+                printk(KERN_ERR "microcode: error! Can not read user data\n");
+                return -EFAULT;
+        }
+        total_size = get_totalsize(&mc_header);
+        if (offset + total_size > user_buffer_size) {
+                printk(KERN_ERR "microcode: error! Bad total size in microcode "
+                                "data file\n");
+                return -EINVAL;
+        }
+        *mc = vmalloc(total_size);
+        if (!*mc)
+                return -ENOMEM;
+        if (copy_from_user(*mc, user_buffer + offset, total_size)) {
+                printk(KERN_ERR "microcode: error! Can not read user data\n");
+                vfree(*mc);
+                return -EFAULT;
+        }
+        return offset + total_size;
+}
+
+static int do_microcode_update (void)
+{
+        long cursor = 0;
+        int error = 0;
+        void *new_mc = NULL;
+        int cpu;
+        cpumask_t old;
+
+        old = current->cpus_allowed;
+
+        while ((cursor = get_next_ucode(&new_mc, cursor)) > 0) {
+                error = microcode_sanity_check(new_mc);
+                if (error)
+                        goto out;
+                /*
+                 * It's possible the data file has multiple matching ucode,
+                 * lets keep searching till the latest version
+                 */
+                for_each_online_cpu(cpu) {
+                        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+                        if (!uci->valid)
+                                continue;
+                        set_cpus_allowed(current, cpumask_of_cpu(cpu));
+                        error = get_maching_microcode(new_mc, cpu);
+                        if (error < 0)
+                                goto out;
+                        if (error == 1)
+                                apply_microcode(cpu);
+                }
+                vfree(new_mc);
+        }
+out:
+        if (cursor > 0)
+                vfree(new_mc);
+        if (cursor < 0)
+                error = cursor;
+        set_cpus_allowed(current, old);
+        return error;
+}
+
+static int microcode_open (struct inode *unused1, struct file *unused2)
+{
+        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 " <tigran@aivazian.fsnet.co.uk>\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)