path: root/arch/x86/kernel/cpu/microcode/intel.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Intel CPU Microcode Update Driver for Linux
 *
 * Copyright (C) 2000-2006 Tigran Aivazian <aivazian.tigran@gmail.com>
 *		 2006 Shaohua Li <shaohua.li@intel.com>
 *
 * Intel CPU microcode early update for Linux
 *
 * Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
 *		      H Peter Anvin" <hpa@zytor.com>
 */

/*
 * This needs to be before all headers so that pr_debug in printk.h doesn't turn
 * printk calls into no_printk().
 *
 *#define DEBUG
 */
#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/slab.h>
#include <linux/cpu.h>
#include <linux/uio.h>
#include <linux/mm.h>

#include <asm/microcode_intel.h>
#include <asm/intel-family.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/setup.h>
#include <asm/msr.h>

static const char ucode_path[] = "kernel/x86/microcode/GenuineIntel.bin";

/* Current microcode patch used in early patching on the APs. */
static struct microcode_intel *intel_ucode_patch;

/* last level cache size per core */
static int llc_size_per_core;

static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
					unsigned int s2, unsigned int p2)
{
	if (s1 != s2)
		return false;

	/* Processor flags are either both 0 ... */
	if (!p1 && !p2)
		return true;

	/* ... or they intersect. */
	return p1 & p2;
}

/*
 * Returns 1 if update has been found, 0 otherwise.
 */
static int find_matching_signature(void *mc, unsigned int csig, int cpf)
{
	struct microcode_header_intel *mc_hdr = mc;
	struct extended_sigtable *ext_hdr;
	struct extended_signature *ext_sig;
	int i;

	if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
		return 1;

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

	ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
	ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;

	for (i = 0; i < ext_hdr->count; i++) {
		if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
			return 1;
		ext_sig++;
	}
	return 0;
}

/*
 * Returns 1 if update has been found, 0 otherwise.
 */
static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
{
	struct microcode_header_intel *mc_hdr = mc;

	if (mc_hdr->rev <= new_rev)
		return 0;

	return find_matching_signature(mc, csig, cpf);
}

static struct ucode_patch *memdup_patch(void *data, unsigned int size)
{
	struct ucode_patch *p;

	p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
	if (!p)
		return NULL;

	p->data = kmemdup(data, size, GFP_KERNEL);
	if (!p->data) {
		kfree(p);
		return NULL;
	}

	return p;
}

static void save_microcode_patch(struct ucode_cpu_info *uci, void *data, unsigned int size)
{
	struct microcode_header_intel *mc_hdr, *mc_saved_hdr;
	struct ucode_patch *iter, *tmp, *p = NULL;
	bool prev_found = false;
	unsigned int sig, pf;

	mc_hdr = (struct microcode_header_intel *)data;

	list_for_each_entry_safe(iter, tmp, &microcode_cache, plist) {
		mc_saved_hdr = (struct microcode_header_intel *)iter->data;
		sig	     = mc_saved_hdr->sig;
		pf	     = mc_saved_hdr->pf;

		if (find_matching_signature(data, sig, pf)) {
			prev_found = true;

			if (mc_hdr->rev <= mc_saved_hdr->rev)
				continue;

			p = memdup_patch(data, size);
			if (!p)
				pr_err("Error allocating buffer %p\n", data);