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

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

#include "internal.h"

struct ucode_patch {
	struct list_head plist;
	void *data;
	unsigned int size;
	u32 patch_id;
	u16 equiv_cpu;
};

static LIST_HEAD(microcode_cache);

#define UCODE_MAGIC			0x00414d44
#define UCODE_EQUIV_CPU_TABLE_TYPE	0x00000000
#define UCODE_UCODE_TYPE		0x00000001

#define SECTION_HDR_SIZE		8
#define CONTAINER_HDR_SZ		12

struct equiv_cpu_entry {
	u32	installed_cpu;
	u32	fixed_errata_mask;
	u32	fixed_errata_compare;
	u16	equiv_cpu;
	u16	res;
} __packed;

struct microcode_header_amd {
	u32	data_code;
	u32	patch_id;
	u16	mc_patch_data_id;
	u8	mc_patch_data_len;
	u8	init_flag;
	u32	mc_patch_data_checksum;
	u32	nb_dev_id;
	u32	sb_dev_id;
	u16	processor_rev_id;
	u8	nb_rev_id;
	u8	sb_rev_id;
	u8	bios_api_rev;
	u8	reserved1[3];
	u32	match_reg[8];
} __packed;

struct microcode_amd {
	struct microcode_header_amd	hdr;
	unsigned int			mpb[];
};

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

union zen_patch_rev {
	struct {
		__u32 rev	 : 8,
		      stepping	 : 4,
		      model	 : 4,
		      __reserved : 4,
		      ext_model	 : 4,
		      ext_fam	 : 8;
	};
	__u32 ucode_rev;
};

union cpuid_1_eax {
	struct {
		__u32 stepping    : 4,
		      model	  : 4,
		      family	  : 4,
		      __reserved0 : 4,
		      ext_model   : 4,
		      ext_fam     : 8,
		      __reserved1 : 4;
	};
	__u32 full;
};

/*
 * 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		     psize;
	u8		     *data;
	size_t		     size;
};

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

/*
 * This is CPUID(1).EAX on the BSP. It is used in two ways:
 *
 * 1. To ignore the equivalence table on Zen1 and newer.
 *
 * 2. To match which patches to load because the patch revision ID
 *    already contains the f/m/s for which the microcode is destined
 *    for.
 */
static u32 bsp_cpuid_1_eax __ro_after_init;

static union cpuid_1_eax ucode_rev_to_cpuid(unsigned int val)
{
	union zen_patch_rev p;
	union cpuid_1_eax c;

	p.ucode_rev = val;
	c.full = 0;

	c.stepping  = p.stepping;
	c.model     = p.model;
	c.ext_model = p.ext_model;
	c.family    = 0xf;
	c.ext_fam   = p.ext_fam;

	return c;
}

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

	/* Zen and newer do not need an equivalence table. */
	if (x86_family(bsp_cpuid_1_eax) >= 0x17)
		return 0;

	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;
	}
	return 0;
}

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

	if (buf_size <= CONTAINER_HDR_SZ) {
		pr_debug("Truncated microcode container header.\n");
		return false;
	}

	cont_magic = *(const u32 *)buf;
	if (cont_magic != UCODE_MAGIC) {
		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.
 */
static bool verify_equivalence_table(const u8 *buf, size_t buf_size)
{
	const u32 *hdr = (const u32 *)buf;
	u32 cont_type, equiv_tbl_len;

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

	/* Zen and newer do not need an equivalence table. */
	if (x86_family(bsp_cpuid_1_eax) >= 0x17)
		return true;

	cont_type = hdr[1];
	if (cont_type != UCODE_EQUIV_CPU_TABLE_TYPE) {
		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