/*
 * 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.
 */

#include <xen/config.h>
#include <xen/cpu.h>
#include <xen/lib.h>
#include <xen/kernel.h>
#include <xen/init.h>
#include <xen/notifier.h>
#include <xen/sched.h>
#include <xen/smp.h>
#include <xen/softirq.h>
#include <xen/spinlock.h>
#include <xen/tasklet.h>
#include <xen/guest_access.h>
#include <xen/earlycpio.h>

#include <asm/msr.h>
#include <asm/processor.h>
#include <asm/setup.h>
#include <asm/microcode.h>

static module_t __initdata ucode_mod;
static void *(*__initdata ucode_mod_map)(const module_t *);
static signed int __initdata ucode_mod_idx;
static bool_t __initdata ucode_mod_forced;
static cpumask_t __initdata init_mask;

/*
 * If we scan the initramfs.cpio for the early microcode code
 * and find it, then 'ucode_blob' will contain the pointer
 * and the size of said blob. It is allocated from Xen's heap
 * memory.
 */
struct ucode_mod_blob {
    void *data;
    size_t size;
};

static struct ucode_mod_blob __initdata ucode_blob;
/*
 * By default we will NOT parse the multiboot modules to see if there is
 * cpio image with the microcode images.
 */
static bool_t __initdata ucode_scan;

void __init microcode_set_module(unsigned int idx)
{
    ucode_mod_idx = idx;
    ucode_mod_forced = 1;
}

/*
 * The format is '[<integer>|scan]'. Both options are optional.
 * If the EFI has forced which of the multiboot payloads is to be used,
 * no parsing will be attempted.
 */
static void __init parse_ucode(char *s)
{
    if ( ucode_mod_forced ) /* Forced by EFI */
       return;

    if ( !strncmp(s, "scan", 4) )
        ucode_scan = 1;
    else
        ucode_mod_idx = simple_strtol(s, NULL, 0);
}
custom_param("ucode", parse_ucode);

/*
 * 8MB ought to be enough.
 */
#define MAX_EARLY_CPIO_MICROCODE (8 << 20)

void __init microcode_scan_module(
    unsigned long *module_map,
    const multiboot_info_t *mbi,
    void *(*bootmap)(const module_t *))
{
    module_t *mod = (module_t *)__va(mbi->mods_addr);
    uint64_t *_blob_start;
    unsigned long _blob_size;
    struct cpio_data cd;
    long offset;
    const char *p = NULL;
    int i;

    ucode_blob.size = 0;
    if ( !ucode_scan )
        return;

    if ( boot_cpu_data.x86_vendor == X86_VENDOR_AMD )
        p = "kernel/x86/microcode/AuthenticAMD.bin";
    else if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
        p = "kernel/x86/microcode/GenuineIntel.bin";
    else
        return;

    /*
     * Try all modules and see whichever could be the microcode blob.
     */
    for ( i = 1 /* Ignore dom0 kernel */; i < mbi->mods_count; i++ )
    {
        if ( !test_bit(i, module_map) )
            continue;

        _blob_start = bootmap(&mod[i]);
        _blob_size = mod[i].mod_end;
        if ( !_blob_start )
        {
            printk("Could not map multiboot module #%d (size: %ld)\n",
                   i, _blob_size);
            continue;
        }
        cd.data = NULL;
        cd.size = 0;
        cd = find_cpio_data(p, _blob_start, _blob_size, &offset /* ignore */);
        if ( cd.data )
        {
                /*
                 * This is an arbitrary check - it would be sad if the blob
                 * consumed most of the memory and did not allow guests
                 * to launch.
                 */
                if ( cd.size > MAX_EARLY_CPIO_MICROCODE )
                {
                    printk("Multiboot %d microcode payload too big! (%ld, we can do %d)\n",
                           i, cd.size, MAX_EARLY_CPIO_MICROCODE);
                    goto err;
                }
                ucode_blob.size = cd.size;
                ucode_blob.data = xmalloc_bytes(cd.size);
                if ( !ucode_blob.data )
                    cd.data = NULL;
                else
                    memcpy(ucode_blob.data, cd.data, cd.size);
        }
        bootmap(NULL);
        if ( cd.data )
            break;
    }
    return;
err:
    bootmap(NULL);
}
void __init microcode_grab_module(
    unsigned long *module_map,
    const multiboot_info_t *mbi,
    void *(*map)(const module_t *))
{
    module_t *mod = (module_t *)__va(mbi->mods_addr);

    if ( ucode_mod_idx < 0 )
        ucode_mod_idx += mbi->mods_count;
    if ( ucode_mod_idx <= 0 || ucode_mod_idx >= mbi->mods_count ||
         !__test_and_clear_bit(ucode_mod_idx, module_map) )
        goto scan;
    ucode_mod = mod[ucode_mod_idx];
    ucode_mod_map = map;
scan:
    if ( ucode_scan )
        microcode_scan_module(module_map, mbi, map);
}

const struct microcode_ops *microcode_ops;

static DEFINE_SPINLOCK(microcode_mutex);

DEFINE_PER_CPU(struct ucode_cpu_info, ucode_cpu_info);

struct microcode_info {
    unsigned int cpu;
    uint32_t buffer_size;
    int error;
    char buffer[1];
};

static void __microcode_fini_cpu(int cpu)
{
    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);

    xfree(uci->mc.mc_valid);
    memset(uci, 0, sizeof(*uci));
}

static void microcode_fini_cpu(int cpu)
{
    spin_lock(&microcode_mutex);
    __microcode_fini_cpu(cpu);
    spin_unlock(&microcode_mutex);
}

int microcode_resume_cpu(int cpu)
{
    int err;
    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
    struct cpu_signature nsig;
    unsigned int cpu2;

    if ( !microcode_ops )
        return 0;

    spin_lock(&microcode_mutex);

    err = microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
    if ( err )
    {
        __microcode_fini_cpu(cpu);
        spin_unlock(&microcode_mutex);
        return err;
    }

    if ( uci->mc.mc_valid )
    {
        err = microcode_ops->microcode_resume_match(cpu, uci->mc.mc_valid);
        if ( err >= 0 )
        {
            if ( err )
                err = microcode_ops->apply_microcode(cpu);
            spin_unlock(&microcode_mutex);
            return err;
        }
    }

    nsig = uci->cpu_sig;
    __microcode_fini_cpu(cpu);
    uci->cpu_sig = nsig;

    err = -EIO;
    for_each_online_cpu ( cpu2 )
    {
        uci = &per_cpu(ucode_cpu_info, cpu2);
        if ( uci->mc.mc_valid &&
             microcode_ops->microcode_resume_match(cpu, uci->mc.mc_valid) > 0 )
        {
            err = microcode_ops->apply_microcode(cpu);
            break;
        }
    }

    __microcode_fini_cpu(cpu);
    spin_unlock(&microcode_mutex);

    return err;
}

static int microcode_update_cpu(const void *buf, size_t size)
{
    int err;
    unsigned int cpu = smp_processor_id();
    struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);

    spin_lock(&microcode_mutex);

    err = microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig);
    if ( likely(!err) )
        err = microcode_ops->cpu_request_microcode(cpu, buf, size);
    else
        __microcode_fini_cpu(cpu);

    spin_unlock(&microcode_mutex);

    return err;
}

static long do_microcode_update(void *_info)
{
    struct microcode_info *info = _info;
    int error;

    BUG_ON(info->cpu != smp_processor_id());

    error = microcode_update_cpu(info->buffer, info->buffer_size);
    if ( error )
        info->error = error;

    info->cpu = cpumask_next(info->cpu, &cpu_online_map);
    if ( info->cpu < nr_cpu_ids )
        return continue_hypercall_on_cpu(info->cpu, do_microcode_update, info);

    error = info->error;
    xfree(info);
    return error;
}

int microcode_update(XEN_GUEST_HANDLE_PARAM(const_void) buf, unsigned long len)
{
    int ret;
    struct microcode_info *info;

    if ( len != (uint32_t)len )
        return -E2BIG;

    if ( microcode_ops == NULL )
        return -EINVAL;

    info = xmalloc_bytes(sizeof(*info) + len);
    if ( info == NULL )
        return -ENOMEM;

    ret = copy_from_guest(info->buffer, buf, len);
    if ( ret != 0 )
    {
        xfree(info);
        return ret;
    }

    info->buffer_size = len;
    info->error = 0;
    info->cpu = cpumask_first(&cpu_online_map);

    if ( microcode_ops->start_update )
    {
        ret = microcode_ops->start_update();
        if ( ret != 0 )
        {
            xfree(info);
            return ret;
        }
    }

    return continue_hypercall_on_cpu(info->cpu, do_microcode_update, info);
}

static void __init _do_microcode_update(unsigned long data)
{
    void *_data = (void *)data;
    size_t len = ucode_blob.size ? ucode_blob.size : ucode_mod.mod_end;

    microcode_update_cpu(_data, len);
    cpumask_set_cpu(smp_processor_id(), &init_mask);
}

static int __init microcode_init(void)
{
    void *data;
    static struct tasklet __initdata tasklet;
    unsigned int cpu;

    if ( !microcode_ops )
        return 0;

    if ( !ucode_mod.mod_end && !ucode_blob.size )
        return 0;

    data = ucode_blob.size ? ucode_blob.data : ucode_mod_map(&ucode_mod);

    if ( !data )
        return -ENOMEM;

    if ( microcode_ops->start_update && microcode_ops->start_update() != 0 )
        goto out;

    softirq_tasklet_init(&tasklet, _do_microcode_update, (unsigned long)data);

    for_each_online_cpu ( cpu )
    {
        tasklet_schedule_on_cpu(&tasklet, cpu);
        do {
            process_pending_softirqs();
        } while ( !cpumask_test_cpu(cpu, &init_mask) );
    }

out:
    if ( ucode_blob.size )
        xfree(data);
    else
        ucode_mod_map(NULL);

    return 0;
}
__initcall(microcode_init);

static int microcode_percpu_callback(
    struct notifier_block *nfb, unsigned long action, void *hcpu)
{
    unsigned int cpu = (unsigned long)hcpu;

    switch ( action )
    {
    case CPU_DEAD:
        microcode_fini_cpu(cpu);
        break;
    }

    return NOTIFY_DONE;
}

static struct notifier_block microcode_percpu_nfb = {
    .notifier_call = microcode_percpu_callback,
};

static int __init microcode_presmp_init(void)
{
    if ( microcode_ops )
    {
        if ( ucode_mod.mod_end || ucode_blob.size )
        {
            void *data;
            size_t len;
            int rc = 0;

            if ( ucode_blob.size )
            {
                len = ucode_blob.size;
                data = ucode_blob.data;
            }
            else
            {
                len = ucode_mod.mod_end;
                data = ucode_mod_map(&ucode_mod);
            }
            if ( data )
                rc = microcode_update_cpu(data, len);
            else
                rc = -ENOMEM;

            if ( !ucode_blob.size )
                ucode_mod_map(NULL);

            if ( rc )
            {
                if ( ucode_blob.size )
                {
                    xfree(ucode_blob.data);
                    ucode_blob.size = 0;
                    ucode_blob.data = NULL;
                }
                else
                    ucode_mod.mod_end = 0;
            }
        }

        register_cpu_notifier(&microcode_percpu_nfb);
    }

    return 0;
}
presmp_initcall(microcode_presmp_init);