// SPDX-License-Identifier: GPL-2.0-only
/*
 *  AMD CPU Microcode Update Driver for Linux
 *
 *  This driver allows to upgrade microcode on F10h AMD
 *  CPUs and later.
 *
 *  Copyright (C) 2008-2011 Advanced Micro Devices Inc.
 *                2013-2018 Borislav Petkov <bp@alien8.de>
 *
 *  Author: Peter Oruba <peter.oruba@amd.com>
 *
 *  Based on work by:
 *  Tigran Aivazian <aivazian.tigran@gmail.com>
 *
 *  early loader:
 *  Copyright (C) 2013 Advanced Micro Devices, Inc.
 *
 *  Author: Jacob Shin <jacob.shin@amd.com>
 *  Fixes: Borislav Petkov <bp@suse.de>
 */
#define pr_fmt(fmt) "microcode: " fmt

#include <linux/earlycpio.h>
#include <linux/firmware.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/initrd.h>
#include <linux/kernel.h>
#include <linux/pci.h>

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

static struct equiv_cpu_table {
        unsigned int num_entries;
        struct equiv_cpu_entry *entry;
} equiv_table;

/*
 * This points to the current valid container of microcode patches which we will
 * save from the initrd/builtin before jettisoning its contents. @mc is the
 * microcode patch we found to match.
 */
struct cont_desc {
        struct microcode_amd *mc;
        u32                  cpuid_1_eax;
        u32                  psize;
        u8                   *data;
        size_t               size;
};

static u32 ucode_new_rev;
static u8 amd_ucode_patch[PATCH_MAX_SIZE];

/*
 * Microcode patch container file is prepended to the initrd in cpio
 * format. See Documentation/x86/microcode.rst
 */
static const char
ucode_path[] __maybe_unused = "kernel/x86/microcode/AuthenticAMD.bin";

static u16 find_equiv_id(struct equiv_cpu_table *et, u32 sig)
{
        unsigned int i;

        if (!et || !et->num_entries)
                return 0;

        for (i = 0; i < et->num_entries; i++) {
                struct equiv_cpu_entry *e = &et->entry[i];

                if (sig == e->installed_cpu)
                        return e->equiv_cpu;

                e++;
        }
        return 0;
}

/*
 * Check whether there is a valid microcode container file at the beginning
 * of @buf of size @buf_size. Set @early to use this function in the early path.
 */
static bool verify_container(const u8 *buf, size_t buf_size, bool early)
{
        u32 cont_magic;

        if (buf_size <= CONTAINER_HDR_SZ) {
                if (!early)
                        pr_debug("Truncated microcode container header.\n");

                return false;
        }

        cont_magic = *(const u32 *)buf;
        if (cont_magic != UCODE_MAGIC) {
                if (!early)
                        pr_debug("Invalid magic value (0x%08x).\n", cont_magic);

                return false;
        }

        return true;
}

/*
 * Check whether there is a valid, non-truncated CPU equivalence table at the
 * beginning of @buf of size @buf_size. Set @early to use this function in the
 * early path.
 */
static bool verify_equivalence_table(const u8 *buf, size_t buf_size, bool early)
{
        const u32 *hdr = (const u32 *)buf;
        u32 cont_type, equiv_tbl_len;

        if (!verify_container(buf, buf_size, early))
                return false;

        cont_type = hdr[1];
        if (cont_type != UCODE_EQUIV_CPU_TABLE_TYPE) {
                if (!early)
                        pr_debug("Wrong microcode container equivalence table type: %u.\n",
                               cont_type);

                return false;
        }

        buf_size -= CONTAINER_HDR_SZ;

        equiv_tbl_len = hdr[2];
        if (equiv_tbl_len < sizeof(struct equiv_cpu_entry) ||
            buf_size < equiv_tbl_len) {
                if (!early)
                        pr_debug("Truncated equivalence table.\n");

                return false;
        }

        return true;
}

/*
 * Check whether there is a valid, non-truncated microcode patch section at the
 * beginning of @buf of size @buf_size. Set @early to use this function in the
 * early path.
 *
 * On success, @sh_psize returns the patch size according to the section header,
 * to the caller.
 */
static bool
__verify_patch_section(const u8 *buf, size_t buf_size, u32 *sh_psize, bool early)
{
        u32 p_type, p_size;
        const u32 *hdr;

        if (buf_size < SECTION_HDR_SIZE) {
                if (!early)
                        pr_debug("Truncated patch section.\n");

                return false;
        }

        hdr = (const u32 *)buf;
        p_type = hdr[0];
        p_size = hdr[1];

        if (p_type != UCODE_UCODE_TYPE) {
                if (!early)
                        pr_debug("Invalid type field (0x%x) in container file section header.\n",
                                p_type);

                return false;
        }

        if (p_size < sizeof(struct microcode_header_amd)) {
                if (!early)
                        pr_debug("Patch of size %u too short.\n", p_size);

                return false;
        }

        *sh_psize = p_size;

        return true;
}

/*
 * Check whether the passed remaining file @buf_size is large enough to contain
 * a patch of the indicated @sh_psize (and also whether this size does not
 * exceed the per-family maximum). @sh_psize is the size read from the section
 * header.
 */
static unsigned int __verify_patch_size(u8 family, u32 sh_psize, size_t buf_size)
{
        u32 max_size;

        if (family >= 0x15)
                return min_t(u32, sh_psize, buf_size);

#define F1XH_MPB_MAX_SIZE 2048
#define F14H_MPB_MAX_SIZE 1824

        switch (family) {
        case 0x10 ... 0x12:
                max_size = F1XH_MPB_MAX_SIZE;
                break;
        case 0x14:
                max_size = F14H_MPB_MAX_SIZE;
                break;
        default:
                WARN(1, "%s: WTF family: 0x%x\n", __func__, family);
                return 0;
                break;
        }

        if (sh_psize > min_t(u32, buf_size, max_size))
                return 0;

        return sh_psize;
}

/*
 * Verify the patch in @buf.
 *
 * Returns:
 * negative: on error
 * positive: patch is not for this family, skip it
 * 0: success
 */
static int
verify_patch(u8 family, const u8 *buf, size_t buf_size, u32 *patch_size, bool early)
{
        struct microcode_header_amd *mc_hdr;
        unsigned int ret;
        u32 sh_psize;
        u16 proc_id;
        u8 patch_fam;

        if (!__verify_patch_section(buf, buf_size, &sh_psize, early))
                return -1;

        /*
         * The section header length is not included in this indicated size
         * but is present in the leftover file length so we need to subtract
         * it before passing this value to the function below.
         */
        buf_size -= SECTION_HDR_SIZE;

        /*
         * Check if the remaining buffer is big enough to contain a patch of
         * size sh_psize, as the section claims.
         */
        if (buf_size < sh_psize) {
                if (!early)
                        pr_debug("Patch of size %u truncated.\n", sh_psize);

                return -1;
        }

        ret = __verify_patch_size(family, sh_psize, buf_size);
        if (!ret) {
                if (!early)
                        pr_debug("Per-family patch size mismatch.\n");
                return -1;
        }

        *patch_size = sh_psize;

        mc_hdr  = (struct microcode_header_amd *)(buf + SECTION_HDR_SIZE);
        if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
                if (!early)
                        pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n", mc_hdr->patch_id);
                return -1;
        }

        proc_id = mc_hdr->processor_rev_id;
        patch_fam = 0xf + (proc_id >> 12);
        if (patch_fam != family)
                return 1;

        return 0;
}

/*
 * This scans the ucode blob for the proper container as we can have multiple
 * containers glued together. Returns the equivalence ID from the equivalence
 * table or 0 if none found.
 * Returns the amount of bytes consumed while scanning. @desc contains all the
 * data we're going to use in later stages of the application.
 */
static size_t parse_container(u8 *ucode, size_t size, struct cont_desc *desc)
{
        struct equiv_cpu_table table;
        size_t orig_size = size;
        u32 *hdr = (u32 *)ucode;
        u16 eq_id;
        u8 *buf;

        if (!verify_equivalence_table(ucode, size, true))
                return 0;

        buf = ucode;

        table.entry = (struct equiv_cpu_entry *)(buf + CONTAINER_HDR_SZ);
        table.num_entries = hdr[2] / sizeof(struct equiv_cpu_entry);

        /*
         * Find the equivalence ID of our CPU in this table. Even if this table
         * doesn't contain a patch for the CPU, scan through the whole container
         * so that it can be skipped in case there are other containers appended.
         */
        eq_id = find_equiv_id(&table, desc->cpuid_1_eax);

        buf  += hdr[2] + CONTAINER_HDR_SZ;
        size -= hdr[2] + CONTAINER_HDR_SZ;

        /*
         * Scan through the rest of the container to find where it ends. We do
         * some basic sanity-checking too.
         */
        while (size > 0) {
                struct microcode_amd *mc;
                u32 patch_size;
                int ret;

                ret = verify_patch(x86_family(desc->cpuid_1_eax), buf, size, &patch_size, true);
                if (ret < 0) {
                        /*
                         * Patch verification failed, skip to the next
                         * container, if there's one:
                         */
                        goto out;
                } else if (ret > 0) {
                        goto skip;
                }

                mc = (struct microcode_amd *)(buf + SECTION_HDR_SIZE);
                if (eq_id == mc->hdr.processor_rev_id) {
                        desc->psize = patch_size;
                        desc->mc = mc;
                }

skip:
                /* Skip patch section header too: */
                buf  += patch_size + SECTION_HDR_SIZE;
                size -= patch_size + SECTION_HDR_SIZE;
        }

        /*
         * If we have found a patch (desc->mc), it means we're looking at the
         * container which has a patch for this CPU so return 0 to mean, @ucode
         * already points to the proper container. Otherwise, we return the size
         * we scanned so that we can advance to the next container in the
         * buffer.
         */
        if (desc->mc) {
                desc->data = ucode;
                desc->size = orig_size - size;

                return 0;
        }

out:
        return orig_size - size;
}

/*
 * Scan the ucode blob for the proper container as we can have multiple
 * containers glued together.
 */
static void scan_containers(u8 *ucode, size_t size, struct cont_desc *desc)
{
        while (size) {
                size_t s = parse_container(ucode, size, desc);
                if (!s)
                        return;

                /* catch wraparound */
                if (size >= s) {
                        ucode += s;
                        size  -= s;
                } else {
                        return;
                }
        }
}

static int __apply_microcode_amd(struct microcode_amd *mc)
{
        u32 rev, dummy;

        native_wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc->hdr.data_code);

        /* verify patch application was successful */
        native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
        if (rev != mc->hdr.patch_id)
                return -1;

        return 0;
}

/*
 * Early load occurs before we can vmalloc(). So we look for the microcode
 * patch container file in initrd, traverse equivalent cpu table, look for a
 * matching microcode patch, and update, all in initrd memory in place.
 * When vmalloc() is available for use later -- on 64-bit during first AP load,
 * and on 32-bit during save_microcode_in_initrd_amd() -- we can call
 * load_microcode_amd() to save equivalent cpu table and microcode patches in
 * kernel heap memory.
 *
 * Returns true if container found (sets @desc), false otherwise.
 */
static bool
apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size, bool save_patch)
{
        struct cont_desc desc = { 0 };
        u8 (*patch)[PATCH_MAX_SIZE];
        struct microcode_amd *mc;
        u32 rev, dummy, *new_rev;
        bool ret = false;

#ifdef CONFIG_X86_32
        new_rev = (u32 *)__pa_nodebug(&ucode_new_rev);
        patch   = (u8 (*)[PATCH_MAX_SIZE])__pa_nodebug(&amd_ucode_patch);
#else
        new_rev = &ucode_new_rev;
        patch   = &amd_ucode_patch;
#endif

        desc.cpuid_1_eax = cpuid_1_eax;

        scan_containers(ucode, size, &desc);

        mc = desc.mc;
        if (!mc)
                return ret;

        native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
        if (rev >= mc->hdr.patch_id)
                return ret;

        if (!__apply_microcode_amd(mc)) {
                *new_rev = mc->hdr.patch_id;
                ret      = true;

                if (save_patch)
                        memcpy(patch, mc, min_t(u32, desc.psize, PATCH_MAX_SIZE));
        }

        return ret;
}

static bool get_builtin_microcode(struct cpio_data *cp, unsigned int family)
{
#ifdef CONFIG_X86_64
        char fw_name[36] = "amd-ucode/microcode_amd.bin";

        if (family >= 0x15)
                snprintf(fw_name, sizeof(fw_name),
                         "amd-ucode/microcode_amd_fam%.2xh.bin", family);

        return get_builtin_firmware(cp, fw_name);
#else
        return false;
#endif
}

static void __load_ucode_amd(unsigned int cpuid_1_eax, struct cpio_data *ret)
{
        struct ucode_cpu_info *uci;
        struct cpio_data cp;
        const char *path;
        bool use_pa;

        if (IS_ENABLED(CONFIG_X86_32)) {
                uci     = (struct ucode_cpu_info *)__pa_nodebug(ucode_cpu_info);
                path    = (const char *)__pa_nodebug(ucode_path);
                use_pa  = true;
        } else {
                uci     = ucode_cpu_info;
                path    = ucode_path;
                use_pa  = false;
        }

        if (!get_builtin_microcode(&cp, x86_family(cpuid_1_eax)))
                cp = find_microcode_in_initrd(path, use_pa);

        /* Needed in load_microcode_amd() */
        uci->cpu_sig.sig = cpuid_1_eax;

        *ret = cp;
}

void __init load_ucode_amd_bsp(unsigned int cpuid_1_eax)
{
        struct cpio_data cp = { };

        __load_ucode_amd(cpuid_1_eax, &cp);
        if (!(cp.data && cp.size))
                return;

        apply_microcode_early_amd(cpuid_1_eax, cp.data, cp.size, true);
}

void load_ucode_amd_ap(unsigned int cpuid_1_eax)
{
        struct microcode_amd *mc;
        struct cpio_data cp;
        u32 *new_rev, rev, dummy;

        if (IS_ENABLED(CONFIG_X86_32)) {
                mc      = (struct microcode_amd *)__pa_nodebug(amd_ucode_patch);
                new_rev = (u32 *)__pa_nodebug(&ucode_new_rev);
        } else {
                mc      = (struct microcode_amd *)amd_ucode_patch;
                new_rev = &ucode_new_rev;
        }

        native_rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

        /* Check whether we have saved a new patch already: */
        if (*new_rev && rev < mc->hdr.patch_id) {
                if (!__apply_microcode_amd(mc)) {
                        *new_rev = mc->hdr.patch_id;
                        return;
                }
        }

        __load_ucode_amd(cpuid_1_eax, &cp);
        if (!(cp.data && cp.size))
                return;

        apply_microcode_early_amd(cpuid_1_eax, cp.data, cp.size, false);
}

static enum ucode_state
load_microcode_amd(bool save, u8 family, const u8 *data, size_t size);

int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
{
        struct cont_desc desc = { 0 };
        enum ucode_state ret;
        struct cpio_data cp;

        cp = find_microcode_in_initrd(ucode_path, false);
        if (!(cp.data && cp.size))
                return -EINVAL;

        desc.cpuid_1_eax = cpuid_1_eax;

        scan_containers(cp.data, cp.size, &desc);
        if (!desc.mc)
                return -EINVAL;

        ret = load_microcode_amd(true, x86_family(cpuid_1_eax), desc.data, desc.size);
        if (ret > UCODE_UPDATED)
                return -EINVAL;

        return 0;
}

void reload_ucode_amd(void)
{
        struct microcode_amd *mc;
        u32 rev, dummy;

        mc = (struct microcode_amd *)amd_ucode_patch;

        rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

        if (rev < mc->hdr.patch_id) {
                if (!__apply_microcode_amd(mc)) {
                        ucode_new_rev = mc->hdr.patch_id;
                        pr_info("reload patch_level=0x%08x\n", ucode_new_rev);
                }
        }
}
static u16 __find_equiv_id(unsigned int cpu)
{
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        return find_equiv_id(&equiv_table, uci->cpu_sig.sig);
}

/*
 * a small, trivial cache of per-family ucode patches
 */
static struct ucode_patch *cache_find_patch(u16 equiv_cpu)
{
        struct ucode_patch *p;

        list_for_each_entry(p, &microcode_cache, plist)
                if (p->equiv_cpu == equiv_cpu)
                        return p;
        return NULL;
}

static void update_cache(struct ucode_patch *new_patch)
{
        struct ucode_patch *p;

        list_for_each_entry(p, &microcode_cache, plist) {
                if (p->equiv_cpu == new_patch->equiv_cpu) {
                        if (p->patch_id >= new_patch->patch_id) {
                                /* we already have the latest patch */
                                kfree(new_patch->data);
                                kfree(new_patch);
                                return;
                        }

                        list_replace(&p->plist, &new_patch->plist);
                        kfree(p->data);
                        kfree(p);
                        return;
                }
        }
        /* no patch found, add it */
        list_add_tail(&new_patch->plist, &microcode_cache);
}

static void free_cache(void)
{
        struct ucode_patch *p, *tmp;

        list_for_each_entry_safe(p, tmp, &microcode_cache, plist) {
                __list_del(p->plist.prev, p->plist.next);
                kfree(p->data);
                kfree(p);
        }
}

static struct ucode_patch *find_patch(unsigned int cpu)
{
        u16 equiv_id;

        equiv_id = __find_equiv_id(cpu);
        if (!equiv_id)
                return NULL;

        return cache_find_patch(equiv_id);
}

static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
{
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
        struct ucode_patch *p;

        csig->sig = cpuid_eax(0x00000001);
        csig->rev = c->microcode;

        /*
         * a patch could have been loaded early, set uci->mc so that
         * mc_bp_resume() can call apply_microcode()
         */
        p = find_patch(cpu);
        if (p && (p->patch_id == csig->rev))
                uci->mc = p->data;

        pr_info("CPU%d: patch_level=0x%08x\n", cpu, csig->rev);

        return 0;
}

static enum ucode_state apply_microcode_amd(int cpu)
{
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        struct microcode_amd *mc_amd;
        struct ucode_cpu_info *uci;
        struct ucode_patch *p;
        enum ucode_state ret;
        u32 rev, dummy;

        BUG_ON(raw_smp_processor_id() != cpu);

        uci = ucode_cpu_info + cpu;

        p = find_patch(cpu);
        if (!p)
                return UCODE_NFOUND;

        mc_amd  = p->data;
        uci->mc = p->data;

        rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);

        /* need to apply patch? */
        if (rev >= mc_amd->hdr.patch_id) {
                ret = UCODE_OK;
                goto out;
        }

        if (__apply_microcode_amd(mc_amd)) {
                pr_err("CPU%d: update failed for patch_level=0x%08x\n",
                        cpu, mc_amd->hdr.patch_id);
                return UCODE_ERROR;
        }

        rev = mc_amd->hdr.patch_id;
        ret = UCODE_UPDATED;

        pr_info("CPU%d: new patch_level=0x%08x\n", cpu, rev);

out:
        uci->cpu_sig.rev = rev;
        c->microcode     = rev;

        /* Update boot_cpu_data's revision too, if we're on the BSP: */
        if (c->cpu_index == boot_cpu_data.cpu_index)
                boot_cpu_data.microcode = rev;

        return ret;
}

static size_t install_equiv_cpu_table(const u8 *buf, size_t buf_size)
{
        u32 equiv_tbl_len;
        const u32 *hdr;

        if (!verify_equivalence_table(buf, buf_size, false))
                return 0;

        hdr = (const u32 *)buf;
        equiv_tbl_len = hdr[2];

        equiv_table.entry = vmalloc(equiv_tbl_len);
        if (!equiv_table.entry) {
                pr_err("failed to allocate equivalent CPU table\n");
                return 0;
        }

        memcpy(equiv_table.entry, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
        equiv_table.num_entries = equiv_tbl_len / sizeof(struct equiv_cpu_entry);

        /* add header length */
        return equiv_tbl_len + CONTAINER_HDR_SZ;
}

static void free_equiv_cpu_table(void)
{
        vfree(equiv_table.entry);
        memset(&equiv_table, 0, sizeof(equiv_table));
}

static void cleanup(void)
{
        free_equiv_cpu_table();
        free_cache();
}

/*
 * Return a non-negative value even if some of the checks failed so that
 * we can skip over the next patch. If we return a negative value, we
 * signal a grave error like a memory allocation has failed and the
 * driver cannot continue functioning normally. In such cases, we tear
 * down everything we've used up so far and exit.
 */
static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover,
                                unsigned int *patch_size)
{
        struct microcode_header_amd *mc_hdr;
        struct ucode_patch *patch;
        u16 proc_id;
        int ret;

        ret = verify_patch(family, fw, leftover, patch_size, false);
        if (ret)
                return ret;

        patch = kzalloc(sizeof(*patch), GFP_KERNEL);
        if (!patch) {
                pr_err("Patch allocation failure.\n");
                return -EINVAL;
        }

        patch->data = kmemdup(fw + SECTION_HDR_SIZE, *patch_size, GFP_KERNEL);
        if (!patch->data) {
                pr_err("Patch data allocation failure.\n");
                kfree(patch);
                return -EINVAL;
        }

        mc_hdr      = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
        proc_id     = mc_hdr->processor_rev_id;

        INIT_LIST_HEAD(&patch->plist);
        patch->patch_id  = mc_hdr->patch_id;
        patch->equiv_cpu = proc_id;

        pr_debug("%s: Added patch_id: 0x%08x, proc_id: 0x%04x\n",
                 __func__, patch->patch_id, proc_id);

        /* ... and add to cache. */
        update_cache(patch);

        return 0;
}

static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
                                             size_t size)
{
        u8 *fw = (u8 *)data;
        size_t offset;

        offset = install_equiv_cpu_table(data, size);
        if (!offset)
                return UCODE_ERROR;

        fw   += offset;
        size -= offset;

        if (*(u32 *)fw != UCODE_UCODE_TYPE) {
                pr_err("invalid type field in container file section header\n");
                free_equiv_cpu_table();
                return UCODE_ERROR;
        }

        while (size > 0) {
                unsigned int crnt_size = 0;
                int ret;

                ret = verify_and_add_patch(family, fw, size, &crnt_size);
                if (ret < 0)
                        return UCODE_ERROR;

                fw   +=  crnt_size + SECTION_HDR_SIZE;
                size -= (crnt_size + SECTION_HDR_SIZE);
        }

        return UCODE_OK;
}

static enum ucode_state
load_microcode_amd(bool save, u8 family, const u8 *data, size_t size)
{
        struct ucode_patch *p;
        enum ucode_state ret;

        /* free old equiv table */
        free_equiv_cpu_table();

        ret = __load_microcode_amd(family, data, size);
        if (ret != UCODE_OK) {
                cleanup();
                return ret;
        }

        p = find_patch(0);
        if (!p) {
                return ret;
        } else {
                if (boot_cpu_data.microcode >= p->patch_id)
                        return ret;

                ret = UCODE_NEW;
        }

        /* save BSP's matching patch for early load */
        if (!save)
                return ret;

        memset(amd_ucode_patch, 0, PATCH_MAX_SIZE);
        memcpy(amd_ucode_patch, p->data, min_t(u32, ksize(p->data), PATCH_MAX_SIZE));

        return ret;
}

/*
 * AMD microcode firmware naming convention, up to family 15h they are in
 * the legacy file:
 *
 *    amd-ucode/microcode_amd.bin
 *
 * This legacy file is always smaller than 2K in size.
 *
 * Beginning with family 15h, they are in family-specific firmware files:
 *
 *    amd-ucode/microcode_amd_fam15h.bin
 *    amd-ucode/microcode_amd_fam16h.bin
 *    ...
 *
 * These might be larger than 2K.
 */
static enum ucode_state request_microcode_amd(int cpu, struct device *device,
                                              bool refresh_fw)
{
        char fw_name[36] = "amd-ucode/microcode_amd.bin";
        struct cpuinfo_x86 *c = &cpu_data(cpu);
        bool bsp = c->cpu_index == boot_cpu_data.cpu_index;
        enum ucode_state ret = UCODE_NFOUND;
        const struct firmware *fw;

        /* reload ucode container only on the boot cpu */
        if (!refresh_fw || !bsp)
                return UCODE_OK;

        if (c->x86 >= 0x15)
                snprintf(fw_name, sizeof(fw_name), "amd-ucode/microcode_amd_fam%.2xh.bin", c->x86);

        if (request_firmware_direct(&fw, (const char *)fw_name, device)) {
                pr_debug("failed to load file %s\n", fw_name);
                goto out;
        }

        ret = UCODE_ERROR;
        if (!verify_container(fw->data, fw->size, false))
                goto fw_release;

        ret = load_microcode_amd(bsp, c->x86, fw->data, fw->size);

 fw_release:
        release_firmware(fw);

 out:
        return ret;
}

static enum ucode_state
request_microcode_user(int cpu, const void __user *buf, size_t size)
{
        return UCODE_ERROR;
}

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

        uci->mc = NULL;
}

static struct microcode_ops microcode_amd_ops = {
        .request_microcode_user           = request_microcode_user,
        .request_microcode_fw             = request_microcode_amd,
        .collect_cpu_info                 = collect_cpu_info_amd,
        .apply_microcode                  = apply_microcode_amd,
        .microcode_fini_cpu               = microcode_fini_cpu_amd,
};

struct microcode_ops * __init init_amd_microcode(void)
{
        struct cpuinfo_x86 *c = &boot_cpu_data;

        if (c->x86_vendor != X86_VENDOR_AMD || c->x86 < 0x10) {
                pr_warn("AMD CPU family 0x%x not supported\n", c->x86);
                return NULL;
        }

        if (ucode_new_rev)
                pr_info_once("microcode updated early to new patch_level=0x%08x\n",
                             ucode_new_rev);

        return &microcode_amd_ops;
}

void __exit exit_amd_microcode(void)
{
        cleanup();
}