/*
 *      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");

struct microcode_header_intel {
        unsigned int            hdrver;
        unsigned int            rev;
        unsigned int            date;
        unsigned int            sig;
        unsigned int            cksum;
        unsigned int            ldrver;
        unsigned int            pf;
        unsigned int            datasize;
        unsigned int            totalsize;
        unsigned int            reserved[3];
};

struct microcode_intel {
        struct microcode_header_intel hdr;
        unsigned int            bits[0];
};

/* microcode format is extended from prescott processors */
struct extended_signature {
        unsigned int            sig;
        unsigned int            pf;
        unsigned int            cksum;
};

struct extended_sigtable {
        unsigned int            count;
        unsigned int            cksum;
        unsigned int            reserved[3];
        struct extended_signature sigs[0];
};

#define DEFAULT_UCODE_DATASIZE  (2000)
#define MC_HEADER_SIZE          (sizeof(struct microcode_header_intel))
#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
#define EXT_HEADER_SIZE         (sizeof(struct extended_sigtable))
#define EXT_SIGNATURE_SIZE      (sizeof(struct extended_signature))
#define DWSIZE                  (sizeof(u32))
#define get_totalsize(mc) \
        (((struct microcode_intel *)mc)->hdr.totalsize ? \
         ((struct microcode_intel *)mc)->hdr.totalsize : \
         DEFAULT_UCODE_TOTALSIZE)

#define get_datasize(mc) \
        (((struct microcode_intel *)mc)->hdr.datasize ? \
         ((struct microcode_intel *)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);

static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
{
        struct cpuinfo_x86 *c = &cpu_data(cpu_num);
        unsigned long flags;
        unsigned int val[2];

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

        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);
                return -1;
        }

        csig->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]);
                csig->pf = 1 << ((val[1] >> 18) & 7);
        }

        /* serialize access to the physical write to MSR 0x79 */
        spin_lock_irqsave(&microcode_update_lock, flags);

        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], csig->rev);
        spin_unlock_irqrestore(&microcode_update_lock, flags);

        pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
                        csig->sig, csig->pf, csig->rev);

        return 0;
}

static inline int update_match_cpu(struct cpu_signature *csig, int sig, int pf)
{
        return (!sigmatch(sig, csig->sig, pf, csig->pf)) ? 0 : 1;
}

static inline int 
update_match_revision(struct microcode_header_intel *mc_header, int rev)
{
        return (mc_header->rev <= rev) ? 0 : 1;
}

static int microcode_sanity_check(void *mc)
{
        struct microcode_header_intel *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 = (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
 */
static int
get_matching_microcode(struct cpu_signature *cpu_sig, void *mc, int rev)
{
        struct microcode_header_intel *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;

        if (!update_match_revision(mc_header, rev))
                return 0;

        if (update_match_cpu(cpu_sig, mc_header->sig, mc_header->pf))
                return 1;

        /* Look for ext. headers: */
        if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
                return 0;

        ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
        ext_sigcount = ext_header->count;
        ext_sig = (void *)ext_header + EXT_HEADER_SIZE;

        for (i = 0; i < ext_sigcount; i++) {
                if (update_match_cpu(cpu_sig, ext_sig->sig, ext_sig->pf))
                        return 1;
                ext_sig++;
        }
        return 0;
}

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;
        struct microcode_intel *mc_intel = uci->mc;

        /* We should bind the task to the CPU */
        BUG_ON(cpu_num != cpu);

        if (mc_intel == 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) mc_intel->bits,
              (unsigned long) mc_intel->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] != mc_intel->hdr.rev) {
                printk(KERN_ERR "microcode: CPU%d update from revision "
                        "0x%x to 0x%x failed\n", cpu_num, uci->cpu_sig.rev, val[1]);
                return;
        }
        printk(KERN_INFO "microcode: CPU%d updated from revision "
               "0x%x to 0x%x, date = %04x-%02x-%02x \n",
                cpu_num, uci->cpu_sig.rev, val[1],
                mc_intel->hdr.date & 0xffff,
                mc_intel->hdr.date >> 24,
                (mc_intel->hdr.date >> 16) & 0xff);
        uci->cpu_sig.rev = val[1];
}

static int generic_load_microcode(int cpu, void *data, size_t size,
                int (*get_ucode_data)(void *, const void *, size_t))
{
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        u8 *ucode_ptr = data, *new_mc = NULL, *mc;
        int new_rev = uci->cpu_sig.rev;
        unsigned int leftover = size;

        while (leftover) {
                struct microcode_header_intel mc_header;
                unsigned int mc_size;

                if (get_ucode_data(&mc_header, ucode_ptr, sizeof(mc_header)))
                        break;

                mc_size = get_totalsize(&mc_header);
                if (!mc_size || mc_size > leftover) {
                        printk(KERN_ERR "microcode: error!"
                                        "Bad data in microcode data file\n");
                        break;
                }

                mc = vmalloc(mc_size);
                if (!mc)
                        break;

                if (get_ucode_data(mc, ucode_ptr, mc_size) ||
                    microcode_sanity_check(mc) < 0) {
                        vfree(mc);
                        break;
                }

                if (get_matching_microcode(&uci->cpu_sig, mc, new_rev)) {
                        if (new_mc)
                                vfree(new_mc);
                        new_rev = mc_header.rev;
                        new_mc  = mc;
                } else
                        vfree(mc);

                ucode_ptr += mc_size;
                leftover  -= mc_size;
        }

        if (new_mc) {
                if (!leftover) {
                        if (uci->mc)
                                vfree(uci->mc);
                        uci->mc = (struct microcode_intel *)new_mc;
                        pr_debug("microcode: CPU%d found a matching microcode update with"
                                 " version 0x%x (current=0x%x)\n",
                                cpu, new_rev, uci->cpu_sig.rev);
                } else
                        vfree(new_mc);
        }

        return (int)leftover;
}

static int get_ucode_fw(void *to, const void *from, size_t n)
{
        memcpy(to, from, n);
        return 0;
}

static int request_microcode_fw(int cpu, struct device *device)
{
        char name[30];
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        const struct firmware *firmware;
        int ret;

        /* 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);
        ret = request_firmware(&firmware, name, device);
        if (ret) {
                pr_debug("microcode: data file %s load failed\n", name);
                return ret;
        }

        ret = generic_load_microcode(cpu, (void*)firmware->data, firmware->size,
                        &get_ucode_fw);

        release_firmware(firmware);

        return ret;
}

static int get_ucode_user(void *to, const void *from, size_t n)
{
        return copy_from_user(to, from, n);
}

static int request_microcode_user(int cpu, const void __user *buf, size_t size)
{
        /* We should bind the task to the CPU */
        BUG_ON(cpu != raw_smp_processor_id());

        return generic_load_microcode(cpu, (void*)buf, size, &get_ucode_user);
}

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

        vfree(uci->mc);
        uci->mc = NULL;
}

struct microcode_ops microcode_intel_ops = {
        .request_microcode_user           = request_microcode_user,
        .request_microcode_fw             = request_microcode_fw,
        .collect_cpu_info                 = collect_cpu_info,
        .apply_microcode                  = apply_microcode,
        .microcode_fini_cpu               = microcode_fini_cpu,
};

struct microcode_ops * __init init_intel_microcode(void)
{
        return &microcode_intel_ops;
}