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>
 */
#define pr_fmt(fmt) "microcode: " fmt
#include <linux/earlycpio.h>
#include <linux/firmware.h>
#include <linux/uaccess.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/intel-family.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/setup.h>
#include <asm/msr.h>

#include "internal.h"

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

#define UCODE_BSP_LOADED	((struct microcode_intel *)0x1UL)

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

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

/* microcode format is extended from prescott processors */
struct extended_signature {
	unsigned int	sig;
	unsigned int	pf;
	unsigned int	cksum;
};

struct extended_sigtable {
	unsigned int			count;
	unsigned int			cksum;
	unsigned int			reserved[3];
	struct extended_signature	sigs[];
};

#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
#define EXT_HEADER_SIZE		(sizeof(struct extended_sigtable))
#define EXT_SIGNATURE_SIZE	(sizeof(struct extended_signature))

static inline unsigned int get_totalsize(struct microcode_header_intel *hdr)
{
	return hdr->datasize ? hdr->totalsize : DEFAULT_UCODE_TOTALSIZE;
}

static inline unsigned int exttable_size(struct extended_sigtable *et)
{
	return et->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE;
}

void intel_collect_cpu_info(struct cpu_signature *sig)
{
	sig->sig = cpuid_eax(1);
	sig->pf = 0;
	sig->rev = intel_get_microcode_revision();

	if (x86_model(sig->sig) >= 5 || x86_family(sig->sig) > 6) {
		unsigned int val[2];

		/* get processor flags from MSR 0x17 */
		native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
		sig->pf = 1 << ((val[1] >> 18) & 7);
	}
}
EXPORT_SYMBOL_GPL(intel_collect_cpu_info);

static inline bool cpu_signatures_match(struct cpu_signature *s1, unsigned int sig2,
					unsigned int pf2)
{
	if (s1->sig != sig2)
		return false;

	/* Processor flags are either both 0 or they intersect. */
	return ((!s1->pf && !pf2) || (s1->pf & pf2));
}

bool intel_find_matching_signature(void *mc, struct cpu_signature *sig)
{
	struct microcode_header_intel *mc_hdr = mc;
	struct extended_signature *ext_sig;
	struct extended_sigtable *ext_hdr;
	int i;

	if (cpu_signatures_match(sig, mc_hdr->sig, mc_hdr->pf))
		return true;

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

	ext_hdr = mc + intel_microcode_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(sig, ext_sig->sig, ext_sig->pf))
			return true;
		ext_sig++;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(intel_find_matching_signature);

/**
 * intel_microcode_sanity_check() - Sanity check microcode file.
 * @mc: Pointer to the microcode file contents.
 * @print_err: Display failure reason if true, silent if false.
 * @hdr_type: Type of file, i.e. normal microcode file or In Field Scan file.
 *            Validate if the microcode header type matches with the type
 *            specified here.
 *
 * Validate certain header fields and verify if computed checksum matches
 * with the one specified in the header.
 *
 * Return: 0 if the file passes all the checks, -EINVAL if any of the checks
 * fail.
 */
int intel_microcode_sanity_check(void *mc, bool print_err, int hdr_type)
{
	unsigned long total_size, data_size, ext_table_size;
	struct microcode_header_intel *mc_header = mc;
	struct extended_sigtable *ext_header = NULL;
	u32 sum, orig_sum, ext_sigcount = 0, i;
	struct extended_signature *ext_sig;

	total_size = get_totalsize(mc_header);
	data_size = intel_microcode_get_datasize(mc_header);

	if (data_size + MC_HEADER_SIZE > total_size) {
		if (print_err)
			pr_err("Error: bad microcode data file size.\n");
		return -EINVAL;
	}

	if (mc_header->ldrver != 1 || mc_header->hdrver != hdr_type) {
		if (print_err)
			pr_err("Error: invalid/unknown microcode update format. Header type %d\n",
			       mc_header->hdrver);
		return -EINVAL;
	}

	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
	if (ext_table_size) {
		u32 ext_table_sum = 0;
		u32 *ext_tablep;

		if (ext_table_size < EXT_HEADER_SIZE ||
		    ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
			if (print_err)
				pr_err("Error: truncated extended signature table.\n");
			return -EINVAL;
		}

		ext_header = mc + MC_HEADER_SIZE + data_size;
		if (ext_table_size != exttable_size(ext_header)) {
			if (print_err)
				pr_err("Error: extended signature table size mismatch.\n");
			return -EFAULT;
		}

		ext_sigcount = ext_header->count;

		/*
		 * Check extended table checksum: the sum of all dwords that
		 * comprise a valid table must be 0.
		 */
		ext_tablep = (u32 *)ext_header;

		i = ext_table_size / sizeof(u32);
		while (i--)
			ext_table_sum += ext_tablep[i];

		if (ext_table_sum) {
			if (print_err)
				pr_warn("Bad extended signature table checksum, aborting.\n");
			return -EINVAL;
		}
	}

	/*
	 * Calculate the checksum of update data and header. The checksum of
	 * valid update data and header including the extended signature table
	 * must be 0.
	 */
	orig_sum = 0;
	i = (MC_HEADER_SIZE + data_size) / sizeof(u32);
	while (i--)
		orig_sum += ((u32 *)mc)[i];

	if (orig_sum) {
		if (print_err)
			pr_err("Bad microcode data checksum, aborting.\n");
		return -EINVAL;
	}

	if (!ext_table_size)
		return 0;

	/*
	 * Check extended signature checksum: 0 => valid.
	 */
	for (i = 0; i < ext_sigcount; i++) {
		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
			  EXT_SIGNATURE_SIZE * i;

		sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -
		      (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
		if (sum) {
			if (print_err)
				pr_err("Bad extended signature checksum, aborting.\n");
			return -EINVAL;
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(intel_microcode_sanity_check);

static void update_ucode_pointer(struct microcode_intel *mc)
{
	kvfree(ucode_patch_va);

	/*
	 * Save the virtual address for early loading and for eventual free
	 * on late loading.
	 */
	ucode_patch_va = mc;
}

static void save_microcode_patch(struct microcode_intel *patch)
{
	unsigned int size = get_totalsize(&patch->hdr);
	struct microcode_intel *mc;

	mc = kvmemdup(patch, size, GFP_KERNEL);
	if (mc)
		update_ucode_pointer(mc);
	else
		pr_err("Unable to allocate microcode memory size: %u\n", size);
}

/* Scan blob for microcode matching the boot CPUs family, model, stepping */
static __init struct microcode_intel *scan_microcode(void *data, size_t size,
						     struct ucode_cpu_info *uci,
						     bool save)
{
	struct microcode_header_intel *mc_header;
	struct microcode_intel *patch = NULL;
	u32 cur_rev = uci->cpu_sig.rev;
	unsigned int mc_size;

	for (; size >= sizeof(struct microcode_header_intel); size -= mc_size, data += mc_size) {
		mc_header = (struct microcode_header_intel *)data;

		mc_size = get_totalsize(mc_header);
		if (!mc_size || mc_size > size ||
		    intel_microcode_sanity_check(data, false, MC_HEADER_TYPE_MICROCODE) < 0)
			break;

		if (!intel_find_matching_signature(data, &uci->cpu_sig))
			continue;

		/*
		 * For saving the early microcode, find the matching revision which
		 * was loaded on the BSP.
		 *
		 * On the BSP during early boot, find a newer revision than
		 * actually loaded in the