Initial commit: Linux kernel 4.19 for Unplugged OS

arch/x86/kernel/cpu/microcode/Makefile

@@ -0,0 +1,4 @@
+microcode-y				:= core.o
+obj-$(CONFIG_MICROCODE)			+= microcode.o
+microcode-$(CONFIG_MICROCODE_INTEL)	+= intel.o
+microcode-$(CONFIG_MICROCODE_AMD)	+= amd.o

arch/x86/kernel/cpu/microcode/amd.c

@@ -0,0 +1,818 @@
+/*
+ *  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.
+ *	          2013-2016 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>
+ *
+ *  Licensed under the terms of the GNU General Public
+ *  License version 2. See file COPYING for details.
+ */
+#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_entry *equiv_cpu_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.txt
+ */
+static const char
+ucode_path[] __maybe_unused = "kernel/x86/microcode/AuthenticAMD.bin";
+
+static u16 find_equiv_id(struct equiv_cpu_entry *equiv_table, u32 sig)
+{
+	for (; equiv_table && equiv_table->installed_cpu; equiv_table++) {
+		if (sig == equiv_table->installed_cpu)
+			return equiv_table->equiv_cpu;
+	}
+
+	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 ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
+{
+	struct equiv_cpu_entry *eq;
+	ssize_t orig_size = size;
+	u32 *hdr = (u32 *)ucode;
+	u16 eq_id;
+	u8 *buf;
+
+	/* Am I looking at an equivalence table header? */
+	if (hdr[0] != UCODE_MAGIC ||
+	    hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||
+	    hdr[2] == 0)
+		return CONTAINER_HDR_SZ;
+
+	buf = ucode;
+
+	eq = (struct equiv_cpu_entry *)(buf + CONTAINER_HDR_SZ);
+
+	/* Find the equivalence ID of our CPU in this table: */
+	eq_id = find_equiv_id(eq, 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;
+
+		hdr = (u32 *)buf;
+
+		if (hdr[0] != UCODE_UCODE_TYPE)
+			break;
+
+		/* Sanity-check patch size. */
+		patch_size = hdr[1];
+		if (patch_size > PATCH_MAX_SIZE)
+			break;
+
+		/* Skip patch section header: */
+		buf  += SECTION_HDR_SIZE;
+		size -= SECTION_HDR_SIZE;
+
+		mc = (struct microcode_amd *)buf;
+		if (eq_id == mc->hdr.processor_rev_id) {
+			desc->psize = patch_size;
+			desc->mc = mc;
+		}
+
+		buf  += patch_size;
+		size -= patch_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;
+	}
+
+	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)
+{
+	ssize_t rem = size;
+
+	while (rem >= 0) {
+		ssize_t s = parse_container(ucode, rem, desc);
+		if (!s)
+			return;
+
+		ucode += s;
+		rem   -= s;
+	}
+}
+
+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_cpu_table, uci->cpu_sig.sig);
+}
+
+static u32 find_cpu_family_by_equiv_cpu(u16 equiv_cpu)
+{
+	int i = 0;
+
+	BUG_ON(!equiv_cpu_table);
+
+	while (equiv_cpu_table[i].equiv_cpu != 0) {
+		if (equiv_cpu == equiv_cpu_table[i].equiv_cpu)
+			return equiv_cpu_table[i].installed_cpu;
+		i++;
+	}
+	return 0;
+}
+
+/*
+ * 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 unsigned int verify_patch_size(u8 family, u32 patch_size,
+				      unsigned int size)
+{
+	u32 max_size;
+
+#define F1XH_MPB_MAX_SIZE 2048
+#define F14H_MPB_MAX_SIZE 1824
+#define F15H_MPB_MAX_SIZE 4096
+#define F16H_MPB_MAX_SIZE 3458
+#define F17H_MPB_MAX_SIZE 3200
+
+	switch (family) {
+	case 0x14:
+		max_size = F14H_MPB_MAX_SIZE;
+		break;
+	case 0x15:
+		max_size = F15H_MPB_MAX_SIZE;
+		break;
+	case 0x16:
+		max_size = F16H_MPB_MAX_SIZE;
+		break;
+	case 0x17:
+		max_size = F17H_MPB_MAX_SIZE;
+		break;
+	default:
+		max_size = F1XH_MPB_MAX_SIZE;
+		break;
+	}
+
+	if (patch_size > min_t(u32, size, max_size)) {
+		pr_err("patch size mismatch\n");
+		return 0;
+	}
+
+	return patch_size;
+}
+
+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 int install_equiv_cpu_table(const u8 *buf)
+{
+	unsigned int *ibuf = (unsigned int *)buf;
+	unsigned int type = ibuf[1];
+	unsigned int size = ibuf[2];
+
+	if (type != UCODE_EQUIV_CPU_TABLE_TYPE || !size) {
+		pr_err("empty section/"
+		       "invalid type field in container file section header\n");
+		return -EINVAL;
+	}
+
+	equiv_cpu_table = vmalloc(size);
+	if (!equiv_cpu_table) {
+		pr_err("failed to allocate equivalent CPU table\n");
+		return -ENOMEM;
+	}
+
+	memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, size);
+
+	/* add header length */
+	return size + CONTAINER_HDR_SZ;
+}
+
+static void free_equiv_cpu_table(void)
+{
+	vfree(equiv_cpu_table);
+	equiv_cpu_table = NULL;
+}
+
+static void cleanup(void)
+{
+	free_equiv_cpu_table();
+	free_cache();
+}
+
+/*
+ * We return the current size 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)
+{
+	struct microcode_header_amd *mc_hdr;
+	struct ucode_patch *patch;
+	unsigned int patch_size, crnt_size, ret;
+	u32 proc_fam;
+	u16 proc_id;
+
+	patch_size  = *(u32 *)(fw + 4);
+	crnt_size   = patch_size + SECTION_HDR_SIZE;
+	mc_hdr	    = (struct microcode_header_amd *)(fw + SECTION_HDR_SIZE);
+	proc_id	    = mc_hdr->processor_rev_id;
+
+	proc_fam = find_cpu_family_by_equiv_cpu(proc_id);
+	if (!proc_fam) {
+		pr_err("No patch family for equiv ID: 0x%04x\n", proc_id);
+		return crnt_size;
+	}
+
+	/* check if patch is for the current family */
+	proc_fam = ((proc_fam >> 8) & 0xf) + ((proc_fam >> 20) & 0xff);
+	if (proc_fam != family)
+		return crnt_size;
+
+	if (mc_hdr->nb_dev_id || mc_hdr->sb_dev_id) {
+		pr_err("Patch-ID 0x%08x: chipset-specific code unsupported.\n",
+			mc_hdr->patch_id);
+		return crnt_size;
+	}
+
+	ret = verify_patch_size(family, patch_size, leftover);
+	if (!ret) {
+		pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id);
+		return crnt_size;
+	}
+
+	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;
+	}
+
+	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 crnt_size;
+}
+
+static enum ucode_state __load_microcode_amd(u8 family, const u8 *data,
+					     size_t size)
+{
+	enum ucode_state ret = UCODE_ERROR;
+	unsigned int leftover;
+	u8 *fw = (u8 *)data;
+	int crnt_size = 0;
+	int offset;
+
+	offset = install_equiv_cpu_table(data);
+	if (offset < 0) {
+		pr_err("failed to create equivalent cpu table\n");
+		return ret;
+	}
+	fw += offset;
+	leftover = size - offset;
+
+	if (*(u32 *)fw != UCODE_UCODE_TYPE) {
+		pr_err("invalid type field in container file section header\n");
+		free_equiv_cpu_table();
+		return ret;
+	}
+
+	while (leftover) {
+		crnt_size = verify_and_add_patch(family, fw, leftover);
+		if (crnt_size < 0)
+			return ret;
+
+		fw	 += crnt_size;
+		leftover -= crnt_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 (*(u32 *)fw->data != UCODE_MAGIC) {
+		pr_err("invalid magic value (0x%08x)\n", *(u32 *)fw->data);
+		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();
+}

arch/x86/kernel/cpu/microcode/core.c

@@ -0,0 +1,907 @@
+/*
+ * CPU Microcode Update Driver for Linux
+ *
+ * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
+ *	      2006	Shaohua Li <shaohua.li@intel.com>
+ *	      2013-2016	Borislav Petkov <bp@alien8.de>
+ *
+ * X86 CPU microcode early update for Linux:
+ *
+ *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
+ *			   H Peter Anvin" <hpa@zytor.com>
+ *		  (C) 2015 Borislav Petkov <bp@alien8.de>
+ *
+ * This driver allows to upgrade microcode on x86 processors.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "microcode: " fmt
+
+#include <linux/platform_device.h>
+#include <linux/stop_machine.h>
+#include <linux/syscore_ops.h>
+#include <linux/miscdevice.h>
+#include <linux/capability.h>
+#include <linux/firmware.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/cpu.h>
+#include <linux/nmi.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+#include <asm/microcode_intel.h>
+#include <asm/cpu_device_id.h>
+#include <asm/microcode_amd.h>
+#include <asm/perf_event.h>
+#include <asm/microcode.h>
+#include <asm/processor.h>
+#include <asm/cmdline.h>
+#include <asm/setup.h>
+
+#define DRIVER_VERSION	"2.2"
+
+static struct microcode_ops	*microcode_ops;
+static bool dis_ucode_ldr = true;
+
+bool initrd_gone;
+
+LIST_HEAD(microcode_cache);
+
+/*
+ * Synchronization.
+ *
+ * All non cpu-hotplug-callback call sites use:
+ *
+ * - microcode_mutex to synchronize with each other;
+ * - get/put_online_cpus() to synchronize with
+ *   the cpu-hotplug-callback call sites.
+ *
+ * We guarantee that only a single cpu is being
+ * updated at any particular moment of time.
+ */
+static DEFINE_MUTEX(microcode_mutex);
+
+/*
+ * Serialize late loading so that CPUs get updated one-by-one.
+ */
+static DEFINE_RAW_SPINLOCK(update_lock);
+
+struct ucode_cpu_info		ucode_cpu_info[NR_CPUS];
+
+struct cpu_info_ctx {
+	struct cpu_signature	*cpu_sig;
+	int			err;
+};
+
+/*
+ * Those patch levels cannot be updated to newer ones and thus should be final.
+ */
+static u32 final_levels[] = {
+	0x01000098,
+	0x0100009f,
+	0x010000af,
+	0, /* T-101 terminator */
+};
+
+/*
+ * Check the current patch level on this CPU.
+ *
+ * Returns:
+ *  - true: if update should stop
+ *  - false: otherwise
+ */
+static bool amd_check_current_patch_level(void)
+{
+	u32 lvl, dummy, i;
+	u32 *levels;
+
+	native_rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy);
+
+	if (IS_ENABLED(CONFIG_X86_32))
+		levels = (u32 *)__pa_nodebug(&final_levels);
+	else
+		levels = final_levels;
+
+	for (i = 0; levels[i]; i++) {
+		if (lvl == levels[i])
+			return true;
+	}
+	return false;
+}
+
+static bool __init check_loader_disabled_bsp(void)
+{
+	static const char *__dis_opt_str = "dis_ucode_ldr";
+
+#ifdef CONFIG_X86_32
+	const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
+	const char *option  = (const char *)__pa_nodebug(__dis_opt_str);
+	bool *res = (bool *)__pa_nodebug(&dis_ucode_ldr);
+
+#else /* CONFIG_X86_64 */
+	const char *cmdline = boot_command_line;
+	const char *option  = __dis_opt_str;
+	bool *res = &dis_ucode_ldr;
+#endif
+
+	/*
+	 * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
+	 * completely accurate as xen pv guests don't see that CPUID bit set but
+	 * that's good enough as they don't land on the BSP path anyway.
+	 */
+	if (native_cpuid_ecx(1) & BIT(31))
+		return *res;
+
+	if (x86_cpuid_vendor() == X86_VENDOR_AMD) {
+		if (amd_check_current_patch_level())
+			return *res;
+	}
+
+	if (cmdline_find_option_bool(cmdline, option) <= 0)
+		*res = false;
+
+	return *res;
+}
+
+extern struct builtin_fw __start_builtin_fw[];
+extern struct builtin_fw __end_builtin_fw[];
+
+bool get_builtin_firmware(struct cpio_data *cd, const char *name)
+{
+#ifdef CONFIG_FW_LOADER
+	struct builtin_fw *b_fw;
+
+	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
+		if (!strcmp(name, b_fw->name)) {
+			cd->size = b_fw->size;
+			cd->data = b_fw->data;
+			return true;
+		}
+	}
+#endif
+	return false;
+}
+
+void __init load_ucode_bsp(void)
+{
+	unsigned int cpuid_1_eax;
+	bool intel = true;
+
+	if (!have_cpuid_p())
+		return;
+
+	cpuid_1_eax = native_cpuid_eax(1);
+
+	switch (x86_cpuid_vendor()) {
+	case X86_VENDOR_INTEL:
+		if (x86_family(cpuid_1_eax) < 6)
+			return;
+		break;
+
+	case X86_VENDOR_AMD:
+		if (x86_family(cpuid_1_eax) < 0x10)
+			return;
+		intel = false;
+		break;
+
+	default:
+		return;
+	}
+
+	if (check_loader_disabled_bsp())
+		return;
+
+	if (intel)
+		load_ucode_intel_bsp();
+	else
+		load_ucode_amd_bsp(cpuid_1_eax);
+}
+
+static bool check_loader_disabled_ap(void)
+{
+#ifdef CONFIG_X86_32
+	return *((bool *)__pa_nodebug(&dis_ucode_ldr));
+#else
+	return dis_ucode_ldr;
+#endif
+}
+
+void load_ucode_ap(void)
+{
+	unsigned int cpuid_1_eax;
+
+	if (check_loader_disabled_ap())
+		return;
+
+	cpuid_1_eax = native_cpuid_eax(1);
+
+	switch (x86_cpuid_vendor()) {
+	case X86_VENDOR_INTEL:
+		if (x86_family(cpuid_1_eax) >= 6)
+			load_ucode_intel_ap();
+		break;
+	case X86_VENDOR_AMD:
+		if (x86_family(cpuid_1_eax) >= 0x10)
+			load_ucode_amd_ap(cpuid_1_eax);
+		break;
+	default:
+		break;
+	}
+}
+
+static int __init save_microcode_in_initrd(void)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	int ret = -EINVAL;
+
+	switch (c->x86_vendor) {
+	case X86_VENDOR_INTEL:
+		if (c->x86 >= 6)
+			ret = save_microcode_in_initrd_intel();
+		break;
+	case X86_VENDOR_AMD:
+		if (c->x86 >= 0x10)
+			ret = save_microcode_in_initrd_amd(cpuid_eax(1));
+		break;
+	default:
+		break;
+	}
+
+	initrd_gone = true;
+
+	return ret;
+}
+
+struct cpio_data find_microcode_in_initrd(const char *path, bool use_pa)
+{
+#ifdef CONFIG_BLK_DEV_INITRD
+	unsigned long start = 0;
+	size_t size;
+
+#ifdef CONFIG_X86_32
+	struct boot_params *params;
+
+	if (use_pa)
+		params = (struct boot_params *)__pa_nodebug(&boot_params);
+	else
+		params = &boot_params;
+
+	size = params->hdr.ramdisk_size;
+
+	/*
+	 * Set start only if we have an initrd image. We cannot use initrd_start
+	 * because it is not set that early yet.
+	 */
+	if (size)
+		start = params->hdr.ramdisk_image;
+
+# else /* CONFIG_X86_64 */
+	size  = (unsigned long)boot_params.ext_ramdisk_size << 32;
+	size |= boot_params.hdr.ramdisk_size;
+
+	if (size) {
+		start  = (unsigned long)boot_params.ext_ramdisk_image << 32;
+		start |= boot_params.hdr.ramdisk_image;
+
+		start += PAGE_OFFSET;
+	}
+# endif
+
+	/*
+	 * Fixup the start address: after reserve_initrd() runs, initrd_start
+	 * has the virtual address of the beginning of the initrd. It also
+	 * possibly relocates the ramdisk. In either case, initrd_start contains
+	 * the updated address so use that instead.
+	 *
+	 * initrd_gone is for the hotplug case where we've thrown out initrd
+	 * already.
+	 */
+	if (!use_pa) {
+		if (initrd_gone)
+			return (struct cpio_data){ NULL, 0, "" };
+		if (initrd_start)
+			start = initrd_start;
+	} else {
+		/*
+		 * The picture with physical addresses is a bit different: we
+		 * need to get the *physical* address to which the ramdisk was
+		 * relocated, i.e., relocated_ramdisk (not initrd_start) and
+		 * since we're running from physical addresses, we need to access
+		 * relocated_ramdisk through its *physical* address too.
+		 */
+		u64 *rr = (u64 *)__pa_nodebug(&relocated_ramdisk);
+		if (*rr)
+			start = *rr;
+	}
+
+	return find_cpio_data(path, (void *)start, size, NULL);
+#else /* !CONFIG_BLK_DEV_INITRD */
+	return (struct cpio_data){ NULL, 0, "" };
+#endif
+}
+
+void reload_early_microcode(void)
+{
+	int vendor, family;
+
+	vendor = x86_cpuid_vendor();
+	family = x86_cpuid_family();
+
+	switch (vendor) {
+	case X86_VENDOR_INTEL:
+		if (family >= 6)
+			reload_ucode_intel();
+		break;
+	case X86_VENDOR_AMD:
+		if (family >= 0x10)
+			reload_ucode_amd();
+		break;
+	default:
+		break;
+	}
+}
+
+static void collect_cpu_info_local(void *arg)
+{
+	struct cpu_info_ctx *ctx = arg;
+
+	ctx->err = microcode_ops->collect_cpu_info(smp_processor_id(),
+						   ctx->cpu_sig);
+}
+
+static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
+{
+	struct cpu_info_ctx ctx = { .cpu_sig = cpu_sig, .err = 0 };
+	int ret;
+
+	ret = smp_call_function_single(cpu, collect_cpu_info_local, &ctx, 1);
+	if (!ret)
+		ret = ctx.err;
+
+	return ret;
+}
+
+static int collect_cpu_info(int cpu)
+{
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+	int ret;
+
+	memset(uci, 0, sizeof(*uci));
+
+	ret = collect_cpu_info_on_target(cpu, &uci->cpu_sig);
+	if (!ret)
+		uci->valid = 1;
+
+	return ret;
+}
+
+static void apply_microcode_local(void *arg)
+{
+	enum ucode_state *err = arg;
+
+	*err = microcode_ops->apply_microcode(smp_processor_id());
+}
+
+static int apply_microcode_on_target(int cpu)
+{
+	enum ucode_state err;
+	int ret;
+
+	ret = smp_call_function_single(cpu, apply_microcode_local, &err, 1);
+	if (!ret) {
+		if (err == UCODE_ERROR)
+			ret = 1;
+	}
+	return ret;
+}
+
+#ifdef CONFIG_MICROCODE_OLD_INTERFACE
+static int do_microcode_update(const void __user *buf, size_t size)
+{
+	int error = 0;
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+		enum ucode_state ustate;
+
+		if (!uci->valid)
+			continue;
+
+		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
+		if (ustate == UCODE_ERROR) {
+			error = -1;
+			break;
+		} else if (ustate == UCODE_NEW) {
+			apply_microcode_on_target(cpu);
+		}
+	}
+
+	return error;
+}
+
+static int microcode_open(struct inode *inode, struct file *file)
+{
+	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
+}
+
+static ssize_t microcode_write(struct file *file, const char __user *buf,
+			       size_t len, loff_t *ppos)
+{
+	ssize_t ret = -EINVAL;
+
+	if ((len >> PAGE_SHIFT) > totalram_pages) {
+		pr_err("too much data (max %ld pages)\n", totalram_pages);
+		return ret;
+	}
+
+	get_online_cpus();
+	mutex_lock(&microcode_mutex);
+
+	if (do_microcode_update(buf, len) == 0)
+		ret = (ssize_t)len;
+
+	if (ret > 0)
+		perf_check_microcode();
+
+	mutex_unlock(&microcode_mutex);
+	put_online_cpus();
+
+	return ret;
+}
+
+static const struct file_operations microcode_fops = {
+	.owner			= THIS_MODULE,
+	.write			= microcode_write,
+	.open			= microcode_open,
+	.llseek		= no_llseek,
+};
+
+static struct miscdevice microcode_dev = {
+	.minor			= MICROCODE_MINOR,
+	.name			= "microcode",
+	.nodename		= "cpu/microcode",
+	.fops			= &microcode_fops,
+};
+
+static int __init microcode_dev_init(void)
+{
+	int error;
+
+	error = misc_register(&microcode_dev);
+	if (error) {
+		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
+		return error;
+	}
+
+	return 0;
+}
+
+static void __exit microcode_dev_exit(void)
+{
+	misc_deregister(&microcode_dev);
+}
+#else
+#define microcode_dev_init()	0
+#define microcode_dev_exit()	do { } while (0)
+#endif
+
+/* fake device for request_firmware */
+static struct platform_device	*microcode_pdev;
+
+/*
+ * Late loading dance. Why the heavy-handed stomp_machine effort?
+ *
+ * - HT siblings must be idle and not execute other code while the other sibling
+ *   is loading microcode in order to avoid any negative interactions caused by
+ *   the loading.
+ *
+ * - In addition, microcode update on the cores must be serialized until this
+ *   requirement can be relaxed in the future. Right now, this is conservative
+ *   and good.
+ */
+#define SPINUNIT 100 /* 100 nsec */
+
+static int check_online_cpus(void)
+{
+	unsigned int cpu;
+
+	/*
+	 * Make sure all CPUs are online.  It's fine for SMT to be disabled if
+	 * all the primary threads are still online.
+	 */
+	for_each_present_cpu(cpu) {
+		if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
+			pr_err("Not all CPUs online, aborting microcode update.\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static atomic_t late_cpus_in;
+static atomic_t late_cpus_out;
+
+static int __wait_for_cpus(atomic_t *t, long long timeout)
+{
+	int all_cpus = num_online_cpus();
+
+	atomic_inc(t);
+
+	while (atomic_read(t) < all_cpus) {
+		if (timeout < SPINUNIT) {
+			pr_err("Timeout while waiting for CPUs rendezvous, remaining: %d\n",
+				all_cpus - atomic_read(t));
+			return 1;
+		}
+
+		ndelay(SPINUNIT);
+		timeout -= SPINUNIT;
+
+		touch_nmi_watchdog();
+	}
+	return 0;
+}
+
+/*
+ * Returns:
+ * < 0 - on error
+ *   0 - no update done
+ *   1 - microcode was updated
+ */
+static int __reload_late(void *info)
+{
+	int cpu = smp_processor_id();
+	enum ucode_state err;
+	int ret = 0;
+
+	/*
+	 * Wait for all CPUs to arrive. A load will not be attempted unless all
+	 * CPUs show up.
+	 * */
+	if (__wait_for_cpus(&late_cpus_in, NSEC_PER_SEC))
+		return -1;
+
+	raw_spin_lock(&update_lock);
+	apply_microcode_local(&err);
+	raw_spin_unlock(&update_lock);
+
+	/* siblings return UCODE_OK because their engine got updated already */
+	if (err > UCODE_NFOUND) {
+		pr_warn("Error reloading microcode on CPU %d\n", cpu);
+		ret = -1;
+	} else if (err == UCODE_UPDATED || err == UCODE_OK) {
+		ret = 1;
+	}
+
+	/*
+	 * Increase the wait timeout to a safe value here since we're
+	 * serializing the microcode update and that could take a while on a
+	 * large number of CPUs. And that is fine as the *actual* timeout will
+	 * be determined by the last CPU finished updating and thus cut short.
+	 */
+	if (__wait_for_cpus(&late_cpus_out, NSEC_PER_SEC * num_online_cpus()))
+		panic("Timeout during microcode update!\n");
+
+	return ret;
+}
+
+/*
+ * Reload microcode late on all CPUs. Wait for a sec until they
+ * all gather together.
+ */
+static int microcode_reload_late(void)
+{
+	int ret;
+
+	atomic_set(&late_cpus_in,  0);
+	atomic_set(&late_cpus_out, 0);
+
+	ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
+	if (ret > 0)
+		microcode_check();
+
+	return ret;
+}
+
+static ssize_t reload_store(struct device *dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t size)
+{
+	enum ucode_state tmp_ret = UCODE_OK;
+	int bsp = boot_cpu_data.cpu_index;
+	unsigned long val;
+	ssize_t ret = 0;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val != 1)
+		return size;
+
+	get_online_cpus();
+
+	ret = check_online_cpus();
+	if (ret)
+		goto put;
+
+	tmp_ret = microcode_ops->request_microcode_fw(bsp, &microcode_pdev->dev, true);
+	if (tmp_ret != UCODE_NEW)
+		goto put;
+
+	mutex_lock(&microcode_mutex);
+	ret = microcode_reload_late();
+	mutex_unlock(&microcode_mutex);
+
+put:
+	put_online_cpus();
+
+	if (ret >= 0)
+		ret = size;
+
+	return ret;
+}
+
+static ssize_t version_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
+
+	return sprintf(buf, "0x%x\n", uci->cpu_sig.rev);
+}
+
+static ssize_t pf_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct ucode_cpu_info *uci = ucode_cpu_info + dev->id;
+
+	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
+}
+
+static DEVICE_ATTR_WO(reload);
+static DEVICE_ATTR(version, 0400, version_show, NULL);
+static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);
+
+static struct attribute *mc_default_attrs[] = {
+	&dev_attr_version.attr,
+	&dev_attr_processor_flags.attr,
+	NULL
+};
+
+static const struct attribute_group mc_attr_group = {
+	.attrs			= mc_default_attrs,
+	.name			= "microcode",
+};
+
+static void microcode_fini_cpu(int cpu)
+{
+	if (microcode_ops->microcode_fini_cpu)
+		microcode_ops->microcode_fini_cpu(cpu);
+}
+
+static enum ucode_state microcode_resume_cpu(int cpu)
+{
+	if (apply_microcode_on_target(cpu))
+		return UCODE_ERROR;
+
+	pr_debug("CPU%d updated upon resume\n", cpu);
+
+	return UCODE_OK;
+}
+
+static enum ucode_state microcode_init_cpu(int cpu, bool refresh_fw)
+{
+	enum ucode_state ustate;
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	if (uci->valid)
+		return UCODE_OK;
+
+	if (collect_cpu_info(cpu))
+		return UCODE_ERROR;
+
+	/* --dimm. Trigger a delayed update? */
+	if (system_state != SYSTEM_RUNNING)
+		return UCODE_NFOUND;
+
+	ustate = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev, refresh_fw);
+	if (ustate == UCODE_NEW) {
+		pr_debug("CPU%d updated upon init\n", cpu);
+		apply_microcode_on_target(cpu);
+	}
+
+	return ustate;
+}
+
+static enum ucode_state microcode_update_cpu(int cpu)
+{
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	/* Refresh CPU microcode revision after resume. */
+	collect_cpu_info(cpu);
+
+	if (uci->valid)
+		return microcode_resume_cpu(cpu);
+
+	return microcode_init_cpu(cpu, false);
+}
+
+static int mc_device_add(struct device *dev, struct subsys_interface *sif)
+{
+	int err, cpu = dev->id;
+
+	if (!cpu_online(cpu))
+		return 0;
+
+	pr_debug("CPU%d added\n", cpu);
+
+	err = sysfs_create_group(&dev->kobj, &mc_attr_group);
+	if (err)
+		return err;
+
+	if (microcode_init_cpu(cpu, true) == UCODE_ERROR)
+		return -EINVAL;
+
+	return err;
+}
+
+static void mc_device_remove(struct device *dev, struct subsys_interface *sif)
+{
+	int cpu = dev->id;
+
+	if (!cpu_online(cpu))
+		return;
+
+	pr_debug("CPU%d removed\n", cpu);
+	microcode_fini_cpu(cpu);
+	sysfs_remove_group(&dev->kobj, &mc_attr_group);
+}
+
+static struct subsys_interface mc_cpu_interface = {
+	.name			= "microcode",
+	.subsys			= &cpu_subsys,
+	.add_dev		= mc_device_add,
+	.remove_dev		= mc_device_remove,
+};
+
+/**
+ * mc_bp_resume - Update boot CPU microcode during resume.
+ */
+static void mc_bp_resume(void)
+{
+	int cpu = smp_processor_id();
+	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+	if (uci->valid && uci->mc)
+		microcode_ops->apply_microcode(cpu);
+	else if (!uci->mc)
+		reload_early_microcode();
+}
+
+static struct syscore_ops mc_syscore_ops = {
+	.resume			= mc_bp_resume,
+};
+
+static int mc_cpu_starting(unsigned int cpu)
+{
+	microcode_update_cpu(cpu);
+	pr_debug("CPU%d added\n", cpu);
+	return 0;
+}
+
+static int mc_cpu_online(unsigned int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
+
+	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
+		pr_err("Failed to create group for CPU%d\n", cpu);
+	return 0;
+}
+
+static int mc_cpu_down_prep(unsigned int cpu)
+{
+	struct device *dev;
+
+	dev = get_cpu_device(cpu);
+	/* Suspend is in progress, only remove the interface */
+	sysfs_remove_group(&dev->kobj, &mc_attr_group);
+	pr_debug("CPU%d removed\n", cpu);
+
+	return 0;
+}
+
+static struct attribute *cpu_root_microcode_attrs[] = {
+	&dev_attr_reload.attr,
+	NULL
+};
+
+static const struct attribute_group cpu_root_microcode_group = {
+	.name  = "microcode",
+	.attrs = cpu_root_microcode_attrs,
+};
+
+int __init microcode_init(void)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	int error;
+
+	if (dis_ucode_ldr)
+		return -EINVAL;
+
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		microcode_ops = init_intel_microcode();
+	else if (c->x86_vendor == X86_VENDOR_AMD)
+		microcode_ops = init_amd_microcode();
+	else
+		pr_err("no support for this CPU vendor\n");
+
+	if (!microcode_ops)
+		return -ENODEV;
+
+	microcode_pdev = platform_device_register_simple("microcode", -1,
+							 NULL, 0);
+	if (IS_ERR(microcode_pdev))
+		return PTR_ERR(microcode_pdev);
+
+	get_online_cpus();
+	mutex_lock(&microcode_mutex);
+
+	error = subsys_interface_register(&mc_cpu_interface);
+	if (!error)
+		perf_check_microcode();
+	mutex_unlock(&microcode_mutex);
+	put_online_cpus();
+
+	if (error)
+		goto out_pdev;
+
+	error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
+				   &cpu_root_microcode_group);
+
+	if (error) {
+		pr_err("Error creating microcode group!\n");
+		goto out_driver;
+	}
+
+	error = microcode_dev_init();
+	if (error)
+		goto out_ucode_group;
+
+	register_syscore_ops(&mc_syscore_ops);
+	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
+				  mc_cpu_starting, NULL);
+	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
+				  mc_cpu_online, mc_cpu_down_prep);
+
+	pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);
+
+	return 0;
+
+ out_ucode_group:
+	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
+			   &cpu_root_microcode_group);
+
+ out_driver:
+	get_online_cpus();
+	mutex_lock(&microcode_mutex);
+
+	subsys_interface_unregister(&mc_cpu_interface);
+
+	mutex_unlock(&microcode_mutex);
+	put_online_cpus();
+
+ out_pdev:
+	platform_device_unregister(microcode_pdev);
+	return error;
+
+}
+fs_initcall(save_microcode_in_initrd);
+late_initcall(microcode_init);