/*
 *      Intel CPU microcode early update for Linux
 *
 *      Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
 *                         H Peter Anvin" <hpa@zytor.com>
 *
 *      This allows to early upgrade microcode on Intel processors
 *      belonging to IA-32 family - PentiumPro, Pentium II,
 *      Pentium III, Xeon, Pentium 4, etc.
 *
 *      Reference: Section 9.11 of Volume 3, IA-32 Intel Architecture
 *      Software Developer's Manual.
 *
 *      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.
 */

/*
 * This needs to be before all headers so that pr_debug in printk.h doesn't turn
 * printk calls into no_printk().
 *
 *#define DEBUG
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/earlycpio.h>
#include <linux/initrd.h>
#include <linux/cpu.h>
#include <asm/msr.h>
#include <asm/microcode_intel.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/setup.h>

#undef pr_fmt
#define pr_fmt(fmt)     "microcode: " fmt

static unsigned long mc_saved_in_initrd[MAX_UCODE_COUNT];
static struct mc_saved_data {
        unsigned int mc_saved_count;
        struct microcode_intel **mc_saved;
} mc_saved_data;

static enum ucode_state
load_microcode_early(struct microcode_intel **saved,
                     unsigned int num_saved, struct ucode_cpu_info *uci)
{
        struct microcode_intel *ucode_ptr, *new_mc = NULL;
        struct microcode_header_intel *mc_hdr;
        int new_rev, ret, i;

        new_rev = uci->cpu_sig.rev;

        for (i = 0; i < num_saved; i++) {
                ucode_ptr = saved[i];
                mc_hdr    = (struct microcode_header_intel *)ucode_ptr;

                ret = get_matching_microcode(uci->cpu_sig.sig,
                                             uci->cpu_sig.pf,
                                             new_rev,
                                             ucode_ptr);
                if (!ret)
                        continue;

                new_rev = mc_hdr->rev;
                new_mc  = ucode_ptr;
        }

        if (!new_mc)
                return UCODE_NFOUND;

        uci->mc = (struct microcode_intel *)new_mc;
        return UCODE_OK;
}

static inline void
copy_initrd_ptrs(struct microcode_intel **mc_saved, unsigned long *initrd,
                  unsigned long off, int num_saved)
{
        int i;

        for (i = 0; i < num_saved; i++)
                mc_saved[i] = (struct microcode_intel *)(initrd[i] + off);
}

#ifdef CONFIG_X86_32
static void
microcode_phys(struct microcode_intel **mc_saved_tmp,
               struct mc_saved_data *mc_saved_data)
{
        int i;
        struct microcode_intel ***mc_saved;

        mc_saved = (struct microcode_intel ***)
                   __pa_nodebug(&mc_saved_data->mc_saved);
        for (i = 0; i < mc_saved_data->mc_saved_count; i++) {
                struct microcode_intel *p;

                p = *(struct microcode_intel **)
                        __pa_nodebug(mc_saved_data->mc_saved + i);
                mc_saved_tmp[i] = (struct microcode_intel *)__pa_nodebug(p);
        }
}
#endif

static enum ucode_state
load_microcode(struct mc_saved_data *mc_saved_data, unsigned long *initrd,
               unsigned long initrd_start, struct ucode_cpu_info *uci)
{
        struct microcode_intel *mc_saved_tmp[MAX_UCODE_COUNT];
        unsigned int count = mc_saved_data->mc_saved_count;

        if (!mc_saved_data->mc_saved) {
                copy_initrd_ptrs(mc_saved_tmp, initrd, initrd_start, count);

                return load_microcode_early(mc_saved_tmp, count, uci);
        } else {
#ifdef CONFIG_X86_32
                microcode_phys(mc_saved_tmp, mc_saved_data);
                return load_microcode_early(mc_saved_tmp, count, uci);
#else
                return load_microcode_early(mc_saved_data->mc_saved,
                                                    count, uci);
#endif
        }
}

/*
 * Given CPU signature and a microcode patch, this function finds if the
 * microcode patch has matching family and model with the CPU.
 */
static enum ucode_state
matching_model_microcode(struct microcode_header_intel *mc_header,
                        unsigned long sig)
{
        unsigned int fam, model;
        unsigned int fam_ucode, model_ucode;
        struct extended_sigtable *ext_header;
        unsigned long total_size = get_totalsize(mc_header);
        unsigned long data_size = get_datasize(mc_header);
        int ext_sigcount, i;
        struct extended_signature *ext_sig;

        fam   = __x86_family(sig);
        model = x86_model(sig);

        fam_ucode   = __x86_family(mc_header->sig);
        model_ucode = x86_model(mc_header->sig);

        if (fam == fam_ucode && model == model_ucode)
                return UCODE_OK;

        /* Look for ext. headers: */
        if (total_size <= data_size + MC_HEADER_SIZE)
                return UCODE_NFOUND;

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

        for (i = 0; i < ext_sigcount; i++) {
                fam_ucode   = __x86_family(ext_sig->sig);
                model_ucode = x86_model(ext_sig->sig);

                if (fam == fam_ucode && model == model_ucode)
                        return UCODE_OK;

                ext_sig++;
        }
        return UCODE_NFOUND;
}

static int
save_microcode(struct mc_saved_data *mc_saved_data,
               struct microcode_intel **mc_saved_src,
               unsigned int mc_saved_count)
{
        int i, j;
        struct microcode_intel **saved_ptr;
        int ret;

        if (!mc_saved_count)
                return -EINVAL;

        /*
         * Copy new microcode data.
         */
        saved_ptr = kcalloc(mc_saved_count, sizeof(struct microcode_intel *), GFP_KERNEL);
        if (!saved_ptr)
                return -ENOMEM;

        for (i = 0; i < mc_saved_count; i++) {
                struct microcode_header_intel *mc_hdr;
                struct microcode_intel *mc;
                unsigned long size;

                if (!mc_saved_src[i]) {
                        ret = -EINVAL;
                        goto err;
                }

                mc     = mc_saved_src[i];
                mc_hdr = &mc->hdr;
                size   = get_totalsize(mc_hdr);

                saved_ptr[i] = kmalloc(size, GFP_KERNEL);
                if (!saved_ptr[i]) {
                        ret = -ENOMEM;
                        goto err;
                }

                memcpy(saved_ptr[i], mc, size);
        }

        /*
         * Point to newly saved microcode.
         */
        mc_saved_data->mc_saved = saved_ptr;
        mc_saved_data->mc_saved_count = mc_saved_count;

        return 0;

err:
        for (j = 0; j <= i; j++)
                kfree(saved_ptr[j]);
        kfree(saved_ptr);

        return ret;
}

/*
 * A microcode patch in ucode_ptr is saved into mc_saved
 * - if it has matching signature and newer revision compared to an existing
 *   patch mc_saved.
 * - or if it is a newly discovered microcode patch.
 *
 * The microcode patch should have matching model with CPU.
 *
 * Returns: The updated number @num_saved of saved microcode patches.
 */
static unsigned int _save_mc(struct microcode_intel **mc_saved,
                             u8 *ucode_ptr, unsigned int num_saved)
{
        struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
        unsigned int sig, pf, new_rev;
        int found = 0, i;

        mc_hdr = (struct microcode_header_intel *)ucode_ptr;

        for (i = 0; i < num_saved; i++) {
                mc_saved_hdr = (struct microcode_header_intel *)mc_saved[i];
                sig          = mc_saved_hdr->sig;
                pf           = mc_saved_hdr->pf;
                new_rev      = mc_hdr->rev;

                if (!get_matching_sig(sig, pf, new_rev, ucode_ptr))
                        continue;

                found = 1;

                if (!revision_is_newer(mc_hdr, new_rev))
                        continue;

                /*
                 * Found an older ucode saved earlier. Replace it with
                 * this newer one.
                 */
                mc_saved[i] = (struct microcode_intel *)ucode_ptr;
                break;
        }

        /* Newly detected microcode, save it to memory. */
        if (i >= num_saved && !found)
                mc_saved[num_saved++] = (struct microcode_intel *)ucode_ptr;

        return num_saved;
}

/*
 * Get microcode matching with BSP's model. Only CPUs with the same model as
 * BSP can stay in the platform.
 */
static enum ucode_state __init
get_matching_model_microcode(int cpu, unsigned long start,
                             void *data, size_t size,
                             struct mc_saved_data *mc_saved_data,
                             unsigned long *mc_saved_in_initrd,
                             struct ucode_cpu_info *uci)
{
        u8 *ucode_ptr = data;
        unsigned int leftover = size;
        enum ucode_state state = UCODE_OK;
        unsigned int mc_size;
        struct microcode_header_intel *mc_header;
        struct microcode_intel *mc_saved_tmp[MAX_UCODE_COUNT];
        unsigned int mc_saved_count = mc_saved_data->mc_saved_count;
        int i;

        while (leftover && mc_saved_count < ARRAY_SIZE(mc_saved_tmp)) {

                if (leftover < sizeof(mc_header))
                        break;

                mc_header = (struct microcode_header_intel *)ucode_ptr;

                mc_size = get_totalsize(mc_header);
                if (!mc_size || mc_size > leftover ||
                        microcode_sanity_check(ucode_ptr, 0) < 0)
                        break;

                leftover -= mc_size;

                /*
                 * Since APs with same family and model as the BSP may boot in
                 * the platform, we need to find and save microcode patches
                 * with the same family and model as the BSP.
                 */
                if (matching_model_microcode(mc_header, uci->cpu_sig.sig) !=
                         UCODE_OK) {
                        ucode_ptr += mc_size;
                        continue;
                }

                mc_saved_count = _save_mc(mc_saved_tmp, ucode_ptr, mc_saved_count);

                ucode_ptr += mc_size;
        }

        if (leftover) {
                state = UCODE_ERROR;
                goto out;
        }

        if (mc_saved_count == 0) {
                state = UCODE_NFOUND;
                goto out;
        }

        for (i = 0; i < mc_saved_count; i++)
                mc_saved_in_initrd[i] = (unsigned long)mc_saved_tmp[i] - start;

        mc_saved_data->mc_saved_count = mc_saved_count;
out:
        return state;
}

static int collect_cpu_info_early(struct ucode_cpu_info *uci)
{
        unsigned int val[2];
        unsigned int family, model;
        struct cpu_signature csig;
        unsigned int eax, ebx, ecx, edx;

        csig.sig = 0;
        csig.pf = 0;
        csig.rev = 0;

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

        eax = 0x00000001;
        ecx = 0;
        native_cpuid(&eax, &ebx, &ecx, &edx);
        csig.sig = eax;

        family = __x86_family(csig.sig);
        model  = x86_model(csig.sig);

        if ((model >= 5) || (family > 6)) {
                /* get processor flags from MSR 0x17 */
                native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
                csig.pf = 1 << ((val[1] >> 18) & 7);
        }
        native_wrmsr(MSR_IA32_UCODE_REV, 0, 0);

        /* As documented in the SDM: Do a CPUID 1 here */
        sync_core();

        /* get the current revision from MSR 0x8B */
        native_rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);

        csig.rev = val[1];

        uci->cpu_sig = csig;
        uci->valid = 1;

        return 0;
}

#ifdef DEBUG
static void __ref show_saved_mc(void)
{
        int i, j;
        unsigned int sig, pf, rev, total_size, data_size, date;
        struct ucode_cpu_info uci;

        if (mc_saved_data.mc_saved_count == 0) {
                pr_debug("no microcode data saved.\n");
                return;
        }
        pr_debug("Total microcode saved: %d\n", mc_saved_data.mc_saved_count);

        collect_cpu_info_early(&uci);

        sig = uci.cpu_sig.sig;
        pf = uci.cpu_sig.pf;
        rev = uci.cpu_sig.rev;
        pr_debug("CPU: sig=0x%x, pf=0x%x, rev=0x%x\n", sig, pf, rev);

        for (i = 0; i < mc_saved_data.mc_saved_count; i++) {
                struct microcode_header_intel *mc_saved_header;
                struct extended_sigtable *ext_header;
                int ext_sigcount;
                struct extended_signature *ext_sig;

                mc_saved_header = (struct microcode_header_intel *)
                                  mc_saved_data.mc_saved[i];
                sig = mc_saved_header->sig;
                pf = mc_saved_header->pf;
                rev = mc_saved_header->rev;
                total_size = get_totalsize(mc_saved_header);
                data_size = get_datasize(mc_saved_header);
                date = mc_saved_header->date;

                pr_debug("mc_saved[%d]: sig=0x%x, pf=0x%x, rev=0x%x, toal size=0x%x, date = %04x-%02x-%02x\n",
                         i, sig, pf, rev, total_size,
                         date & 0xffff,
                         date >> 24,
                         (date >> 16) & 0xff);

                /* Look for ext. headers: */
                if (total_size <= data_size + MC_HEADER_SIZE)
                        continue;

                ext_header = (void *) mc_saved_header + data_size + MC_HEADER_SIZE;
                ext_sigcount = ext_header->count;
                ext_sig = (void *)ext_header + EXT_HEADER_SIZE;

                for (j = 0; j < ext_sigcount; j++) {
                        sig = ext_sig->sig;
                        pf = ext_sig->pf;

                        pr_debug("\tExtended[%d]: sig=0x%x, pf=0x%x\n",
                                 j, sig, pf);

                        ext_sig++;
                }

        }
}
#else
static inline void show_saved_mc(void)
{
}
#endif

#if defined(CONFIG_MICROCODE_INTEL_EARLY) && defined(CONFIG_HOTPLUG_CPU)
static DEFINE_MUTEX(x86_cpu_microcode_mutex);
/*
 * Save this mc into mc_saved_data. So it will be loaded early when a CPU is
 * hot added or resumes.
 *
 * Please make sure this mc should be a valid microcode patch before calling
 * this function.
 */
int save_mc_for_early(u8 *mc)
{
        struct microcode_intel *mc_saved_tmp[MAX_UCODE_COUNT];
        unsigned int mc_saved_count_init;
        unsigned int mc_saved_count;
        struct microcode_intel **mc_saved;
        int ret = 0;
        int i;

        /*
         * Hold hotplug lock so mc_saved_data is not accessed by a CPU in
         * hotplug.
         */
        mutex_lock(&x86_cpu_microcode_mutex);

        mc_saved_count_init = mc_saved_data.mc_saved_count;
        mc_saved_count = mc_saved_data.mc_saved_count;
        mc_saved = mc_saved_data.mc_saved;

        if (mc_saved && mc_saved_count)
                memcpy(mc_saved_tmp, mc_saved,
                       mc_saved_count * sizeof(struct microcode_intel *));
        /*
         * Save the microcode patch mc in mc_save_tmp structure if it's a newer
         * version.
         */
        mc_saved_count = _save_mc(mc_saved_tmp, mc, mc_saved_count);

        /*
         * Save the mc_save_tmp in global mc_saved_data.
         */
        ret = save_microcode(&mc_saved_data, mc_saved_tmp, mc_saved_count);
        if (ret) {
                pr_err("Cannot save microcode patch.\n");
                goto out;
        }

        show_saved_mc();

        /*
         * Free old saved microcode data.
         */
        if (mc_saved) {
                for (i = 0; i < mc_saved_count_init; i++)
                        kfree(mc_saved[i]);
                kfree(mc_saved);
        }

out:
        mutex_unlock(&x86_cpu_microcode_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(save_mc_for_early);
#endif

static __initdata char ucode_name[] = "kernel/x86/microcode/GenuineIntel.bin";
static __init enum ucode_state
scan_microcode(struct mc_saved_data *mc_saved_data, unsigned long *initrd,
               unsigned long start, unsigned long size,
               struct ucode_cpu_info *uci)
{
        struct cpio_data cd;
        long offset = 0;
#ifdef CONFIG_X86_32
        char *p = (char *)__pa_nodebug(ucode_name);
#else
        char *p = ucode_name;
#endif

        cd.data = NULL;
        cd.size = 0;

        cd = find_cpio_data(p, (void *)start, size, &offset);
        if (!cd.data)
                return UCODE_ERROR;

        return get_matching_model_microcode(0, start, cd.data, cd.size,
                                            mc_saved_data, initrd, uci);
}

/*
 * Print ucode update info.
 */
static void
print_ucode_info(struct ucode_cpu_info *uci, unsigned int date)
{
        int cpu = smp_processor_id();

        pr_info("CPU%d microcode updated early to revision 0x%x, date = %04x-%02x-%02x\n",
                cpu,
                uci->cpu_sig.rev,
                date & 0xffff,
                date >> 24,
                (date >> 16) & 0xff);
}

#ifdef CONFIG_X86_32

static int delay_ucode_info;
static int current_mc_date;

/*
 * Print early updated ucode info after printk works. This is delayed info dump.
 */
void show_ucode_info_early(void)
{
        struct ucode_cpu_info uci;

        if (delay_ucode_info) {
                collect_cpu_info_early(&uci);
                print_ucode_info(&uci, current_mc_date);
                delay_ucode_info = 0;
        }
}

/*
 * At this point, we can not call printk() yet. Keep microcode patch number in
 * mc_saved_data.mc_saved and delay printing microcode info in
 * show_ucode_info_early() until printk() works.
 */
static void print_ucode(struct ucode_cpu_info *uci)
{
        struct microcode_intel *mc_intel;
        int *delay_ucode_info_p;
        int *current_mc_date_p;

        mc_intel = uci->mc;
        if (mc_intel == NULL)
                return;

        delay_ucode_info_p = (int *)__pa_nodebug(&delay_ucode_info);
        current_mc_date_p = (int *)__pa_nodebug(&current_mc_date);

        *delay_ucode_info_p = 1;
        *current_mc_date_p = mc_intel->hdr.date;
}
#else

/*
 * Flush global tlb. We only do this in x86_64 where paging has been enabled
 * already and PGE should be enabled as well.
 */
static inline void flush_tlb_early(void)
{
        __native_flush_tlb_global_irq_disabled();
}

static inline void print_ucode(struct ucode_cpu_info *uci)
{
        struct microcode_intel *mc_intel;

        mc_intel = uci->mc;
        if (mc_intel == NULL)
                return;

        print_ucode_info(uci, mc_intel->hdr.date);
}
#endif

static int apply_microcode_early(struct ucode_cpu_info *uci, bool early)
{
        struct microcode_intel *mc_intel;
        unsigned int val[2];

        mc_intel = uci->mc;
        if (mc_intel == NULL)
                return 0;

        /* write microcode via MSR 0x79 */
        native_wrmsr(MSR_IA32_UCODE_WRITE,
              (unsigned long) mc_intel->bits,
              (unsigned long) mc_intel->bits >> 16 >> 16);
        native_wrmsr(MSR_IA32_UCODE_REV, 0, 0);

        /* As documented in the SDM: Do a CPUID 1 here */
        sync_core();

        /* get the current revision from MSR 0x8B */
        native_rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
        if (val[1] != mc_intel->hdr.rev)
                return -1;

#ifdef CONFIG_X86_64
        /* Flush global tlb. This is precaution. */
        flush_tlb_early();
#endif
        uci->cpu_sig.rev = val[1];

        if (early)
                print_ucode(uci);
        else
                print_ucode_info(uci, mc_intel->hdr.date);

        return 0;
}

/*
 * This function converts microcode patch offsets previously stored in
 * mc_saved_in_initrd to pointers and stores the pointers in mc_saved_data.
 */
int __init save_microcode_in_initrd_intel(void)
{
        unsigned int count = mc_saved_data.mc_saved_count;
        struct microcode_intel *mc_saved[MAX_UCODE_COUNT];
        int ret = 0;

        if (count == 0)
                return ret;

        copy_initrd_ptrs(mc_saved, mc_saved_in_initrd, initrd_start, count);
        ret = save_microcode(&mc_saved_data, mc_saved, count);
        if (ret)
                pr_err("Cannot save microcode patches from initrd.\n");

        show_saved_mc();

        return ret;
}

static void __init
_load_ucode_intel_bsp(struct mc_saved_data *mc_saved_data,
                      unsigned long *initrd,
                      unsigned long start, unsigned long size)
{
        struct ucode_cpu_info uci;
        enum ucode_state ret;

        collect_cpu_info_early(&uci);

        ret = scan_microcode(mc_saved_data, initrd, start, size, &uci);
        if (ret != UCODE_OK)
                return;

        ret = load_microcode(mc_saved_data, initrd, start, &uci);
        if (ret != UCODE_OK)
                return;

        apply_microcode_early(&uci, true);
}

void __init load_ucode_intel_bsp(void)
{
        u64 start, size;
#ifdef CONFIG_X86_32
        struct boot_params *p;

        p       = (struct boot_params *)__pa_nodebug(&boot_params);
        start   = p->hdr.ramdisk_image;
        size    = p->hdr.ramdisk_size;

        _load_ucode_intel_bsp(
                        (struct mc_saved_data *)__pa_nodebug(&mc_saved_data),
                        (unsigned long *)__pa_nodebug(&mc_saved_in_initrd),
                        start, size);
#else
        start   = boot_params.hdr.ramdisk_image + PAGE_OFFSET;
        size    = boot_params.hdr.ramdisk_size;

        _load_ucode_intel_bsp(&mc_saved_data, mc_saved_in_initrd, start, size);
#endif
}

void load_ucode_intel_ap(void)
{
        struct mc_saved_data *mc_saved_data_p;
        struct ucode_cpu_info uci;
        unsigned long *mc_saved_in_initrd_p;
        unsigned long initrd_start_addr;
        enum ucode_state ret;
#ifdef CONFIG_X86_32
        unsigned long *initrd_start_p;

        mc_saved_in_initrd_p =
                (unsigned long *)__pa_nodebug(mc_saved_in_initrd);
        mc_saved_data_p = (struct mc_saved_data *)__pa_nodebug(&mc_saved_data);
        initrd_start_p = (unsigned long *)__pa_nodebug(&initrd_start);
        initrd_start_addr = (unsigned long)__pa_nodebug(*initrd_start_p);
#else
        mc_saved_data_p = &mc_saved_data;
        mc_saved_in_initrd_p = mc_saved_in_initrd;
        initrd_start_addr = initrd_start;
#endif

        /*
         * If there is no valid ucode previously saved in memory, no need to
         * update ucode on this AP.
         */
        if (mc_saved_data_p->mc_saved_count == 0)
                return;

        collect_cpu_info_early(&uci);
        ret = load_microcode(mc_saved_data_p, mc_saved_in_initrd_p,
                             initrd_start_addr, &uci);

        if (ret != UCODE_OK)
                return;

        apply_microcode_early(&uci, true);
}

void reload_ucode_intel(void)
{
        struct ucode_cpu_info uci;
        enum ucode_state ret;

        if (!mc_saved_data.mc_saved_count)
                return;

        collect_cpu_info_early(&uci);

        ret = load_microcode_early(mc_saved_data.mc_saved,
                                   mc_saved_data.mc_saved_count, &uci);
        if (ret != UCODE_OK)
                return;

        apply_microcode_early(&uci, false);
}