1/*
  2 *	Intel CPU Microcode Update Driver for Linux
  3 *
  4 *	Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
  5 *			   H Peter Anvin" <hpa@zytor.com>
  6 *
  7 *	This driver allows to upgrade microcode on Intel processors
  8 *	belonging to IA-32 family - PentiumPro, Pentium II,
  9 *	Pentium III, Xeon, Pentium 4, etc.
 10 *
 11 *	Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
 12 *	Software Developer's Manual
 13 *	Order Number 253668 or free download from:
 14 *
 15 *	http://developer.intel.com/Assets/PDF/manual/253668.pdf
 16 *
 17 *	For more information, go to http://www.urbanmyth.org/microcode
 18 *
 19 *	This program is free software; you can redistribute it and/or
 20 *	modify it under the terms of the GNU General Public License
 21 *	as published by the Free Software Foundation; either version
 22 *	2 of the License, or (at your option) any later version.
 23 *
 24 */
 25#include <linux/firmware.h>
 26#include <linux/uaccess.h>
 27#include <linux/kernel.h>
 28#include <linux/module.h>
 29
 30#include <asm/microcode_intel.h>
 31#include <asm/processor.h>
 32#include <asm/msr.h>
 33
 34static inline int
 35update_match_cpu(unsigned int csig, unsigned int cpf,
 36		 unsigned int sig, unsigned int pf)
 37{
 38	return (!sigmatch(sig, csig, pf, cpf)) ? 0 : 1;
 39}
 40
 41int
 42update_match_revision(struct microcode_header_intel *mc_header, int rev)
 43{
 44	return (mc_header->rev <= rev) ? 0 : 1;
 45}
 46
 47int microcode_sanity_check(void *mc, int print_err)
 48{
 49	unsigned long total_size, data_size, ext_table_size;
 50	struct microcode_header_intel *mc_header = mc;
 51	struct extended_sigtable *ext_header = NULL;
 52	int sum, orig_sum, ext_sigcount = 0, i;
 53	struct extended_signature *ext_sig;
 54
 55	total_size = get_totalsize(mc_header);
 56	data_size = get_datasize(mc_header);
 57
 58	if (data_size + MC_HEADER_SIZE > total_size) {
 59		if (print_err)
 60			pr_err("error! Bad data size in microcode data file\n");
 61		return -EINVAL;
 62	}
 63
 64	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
 65		if (print_err)
 66			pr_err("error! Unknown microcode update format\n");
 67		return -EINVAL;
 68	}
 69	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
 70	if (ext_table_size) {
 71		if ((ext_table_size < EXT_HEADER_SIZE)
 72		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
 73			if (print_err)
 74				pr_err("error! Small exttable size in microcode data file\n");
 75			return -EINVAL;
 76		}
 77		ext_header = mc + MC_HEADER_SIZE + data_size;
 78		if (ext_table_size != exttable_size(ext_header)) {
 79			if (print_err)
 80				pr_err("error! Bad exttable size in microcode data file\n");
 81			return -EFAULT;
 82		}
 83		ext_sigcount = ext_header->count;
 84	}
 85
 86	/* check extended table checksum */
 87	if (ext_table_size) {
 88		int ext_table_sum = 0;
 89		int *ext_tablep = (int *)ext_header;
 90
 91		i = ext_table_size / DWSIZE;
 92		while (i--)
 93			ext_table_sum += ext_tablep[i];
 94		if (ext_table_sum) {
 95			if (print_err)
 96				pr_warn("aborting, bad extended signature table checksum\n");
 97			return -EINVAL;
 98		}
 99	}
100
101	/* calculate the checksum */
102	orig_sum = 0;
103	i = (MC_HEADER_SIZE + data_size) / DWSIZE;
104	while (i--)
105		orig_sum += ((int *)mc)[i];
106	if (orig_sum) {
107		if (print_err)
108			pr_err("aborting, bad checksum\n");
109		return -EINVAL;
110	}
111	if (!ext_table_size)
112		return 0;
113	/* check extended signature checksum */
114	for (i = 0; i < ext_sigcount; i++) {
115		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
116			  EXT_SIGNATURE_SIZE * i;
117		sum = orig_sum
118			- (mc_header->sig + mc_header->pf + mc_header->cksum)
119			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
120		if (sum) {
121			if (print_err)
122				pr_err("aborting, bad checksum\n");
123			return -EINVAL;
124		}
125	}
126	return 0;
127}
128EXPORT_SYMBOL_GPL(microcode_sanity_check);
129
130/*
131 * return 0 - no update found
132 * return 1 - found update
133 */
134int get_matching_sig(unsigned int csig, int cpf, void *mc, int rev)
135{
136	struct microcode_header_intel *mc_header = mc;
137	struct extended_sigtable *ext_header;
138	unsigned long total_size = get_totalsize(mc_header);
139	int ext_sigcount, i;
140	struct extended_signature *ext_sig;
141
142	if (update_match_cpu(csig, cpf, mc_header->sig, mc_header->pf))
143		return 1;
144
145	/* Look for ext. headers: */
146	if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
147		return 0;
148
149	ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
150	ext_sigcount = ext_header->count;
151	ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
152
153	for (i = 0; i < ext_sigcount; i++) {
154		if (update_match_cpu(csig, cpf, ext_sig->sig, ext_sig->pf))
155			return 1;
156		ext_sig++;
157	}
158	return 0;
159}
160
161/*
162 * return 0 - no update found
163 * return 1 - found update
164 */
165int get_matching_microcode(unsigned int csig, int cpf, void *mc, int rev)
166{
167	struct microcode_header_intel *mc_header = mc;
168
169	if (!update_match_revision(mc_header, rev))
170		return 0;
171
172	return get_matching_sig(csig, cpf, mc, rev);
173}
174EXPORT_SYMBOL_GPL(get_matching_microcode);