system76-coreboot/src/cpu/intel/microcode/microcode.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2012 The ChromiumOS Authors.  All rights reserved.
 * Copyright (C) 2000 Ronald G. Minnich
 *
 * 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; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

/* Microcode update for Intel PIII and later CPUs */

#include <stdint.h>
#include <stddef.h>
#if !defined(__ROMCC__)
#include <console/console.h>
#endif
#include <cpu/cpu.h>
#include <cpu/x86/msr.h>
#include <cpu/intel/microcode.h>
#include <rules.h>

#if !defined(__PRE_RAM__)
#include <cbfs.h>
#include <smp/spinlock.h>
DECLARE_SPIN_LOCK(microcode_lock)
#else
#include <arch/cbfs.h>
#endif

struct microcode {
	u32 hdrver;	/* Header Version */
	u32 rev;	/* Update Revision */
	u32 date;	/* Date */
	u32 sig;	/* Processor Signature */

	u32 cksum;	/* Checksum */
	u32 ldrver;	/* Loader Revision */
	u32 pf;		/* Processor Flags */

	u32 data_size;	/* Data Size */
	u32 total_size;	/* Total Size */

	u32 reserved[3];
};

static inline u32 read_microcode_rev(void)
{
	/* Some Intel CPUs can be very finicky about the
	 * CPUID sequence used.  So this is implemented in
	 * assembly so that it works reliably.
	 */
	msr_t msr;
	asm volatile (
		"xorl %%eax, %%eax\n\t"
		"xorl %%edx, %%edx\n\t"
		"movl $0x8b, %%ecx\n\t"
		"wrmsr\n\t"
		"movl $0x01, %%eax\n\t"
		"cpuid\n\t"
		"movl $0x08b, %%ecx\n\t"
		"rdmsr \n\t"
		: /* outputs */
		"=a" (msr.lo), "=d" (msr.hi)
		: /* inputs */
		: /* trashed */
		 "ebx", "ecx"
	);
	return msr.hi;
}

#define MICROCODE_CBFS_FILE "cpu_microcode_blob.bin"

void intel_microcode_load_unlocked(const void *microcode_patch)
{
	u32 current_rev;
	msr_t msr;
	const struct microcode *m = microcode_patch;

	if (!m)
		return;

	current_rev = read_microcode_rev();

	/* No use loading the same revision. */
	if (current_rev == m->rev)
		return;

#if ENV_RAMSTAGE
	/*SoC specific check to update microcode*/
	if (soc_skip_ucode_update(current_rev, m->rev)) {
		printk(BIOS_DEBUG, "Skip microcode update\n");
		return;
	}
#endif

	msr.lo = (unsigned long)m + sizeof(struct microcode);
	msr.hi = 0;
	wrmsr(0x79, msr);

#if !defined(__ROMCC__)
	printk(BIOS_DEBUG, "microcode: updated to revision "
		    "0x%x date=%04x-%02x-%02x\n", read_microcode_rev(),
		    m->date & 0xffff, (m->date >> 24) & 0xff,
		    (m->date >> 16) & 0xff);
#endif
}

const void *intel_microcode_find(void)
{
	const struct microcode *ucode_updates;
	size_t microcode_len;
	u32 eax;
	u32 pf, rev, sig, update_size;
	unsigned int x86_model, x86_family;
	msr_t msr;

#ifdef __PRE_RAM__
	struct cbfs_file *microcode_file;

	microcode_file = walkcbfs_head((char *) MICROCODE_CBFS_FILE);
	if (!microcode_file)
		return NULL;

	ucode_updates = CBFS_SUBHEADER(microcode_file);
	microcode_len = ntohl(microcode_file->len);
#else
	ucode_updates = cbfs_boot_map_with_leak(MICROCODE_CBFS_FILE,
						CBFS_TYPE_MICROCODE,
						&microcode_len);
	if (ucode_updates == NULL)
		return NULL;
#endif

	/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
	msr.lo = 0;
	msr.hi = 0;
	wrmsr(0x8B, msr);
	eax = cpuid_eax(1);
	msr = rdmsr(0x8B);
	rev = msr.hi;
	x86_model = (eax >>4) & 0x0f;
	x86_family = (eax >>8) & 0x0f;
	sig = eax;

	pf = 0;
	if ((x86_model >= 5)||(x86_family>6)) {
		msr = rdmsr(0x17);
		pf = 1 << ((msr.hi >> 18) & 7);
	}
#if !defined(__ROMCC__)
	/* If this code is compiled with ROMCC we're probably in
	 * the bootblock and don't have console output yet.
	 */
	printk(BIOS_DEBUG, "microcode: sig=0x%x pf=0x%x revision=0x%x\n",
			sig, pf, rev);
#endif

	while (microcode_len >= sizeof(*ucode_updates)) {
		/* Newer microcode updates include a size field, whereas older
		 * containers set it at 0 and are exactly 2048 bytes long */
		if (ucode_updates->total_size) {
			update_size = ucode_updates->total_size;
		} else {
			#if !defined(__ROMCC__)
			printk(BIOS_SPEW, "Microcode size field is 0\n");
			#endif
			update_size = 2048;
		}

		/* Checkpoint 1: The microcode update falls within CBFS */
		if(update_size > microcode_len) {
#if !defined(__ROMCC__)
			printk(BIOS_WARNING, "Microcode header corrupted!\n");
#endif
			break;
		}

		if ((ucode_updates->sig == sig) && (ucode_updates->pf & pf))
			return ucode_updates;

		ucode_updates = (void *)((char *)ucode_updates + update_size);
		microcode_len -= update_size;
	}

	/* ROMCC doesn't like NULL. */
	return (void *)0;
}

void intel_update_microcode_from_cbfs(void)
{
	const void *patch = intel_microcode_find();

#if !defined(__ROMCC__) && !defined(__PRE_RAM__)
	spin_lock(&microcode_lock);
#endif

	intel_microcode_load_unlocked(patch);

#if !defined(__ROMCC__) && !defined(__PRE_RAM__)
	spin_unlock(&microcode_lock);
#endif
}

#if ENV_RAMSTAGE
__attribute__((weak)) int soc_skip_ucode_update(u32 currrent_patch_id, u32 new_patch_id)
{
	return 0;
}
#endif