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 microcode_sanity_check(void *mc, int print_err)
42{
43	unsigned long total_size, data_size, ext_table_size;
44	struct microcode_header_intel *mc_header = mc;
45	struct extended_sigtable *ext_header = NULL;
46	int sum, orig_sum, ext_sigcount = 0, i;
47	struct extended_signature *ext_sig;
48
49	total_size = get_totalsize(mc_header);
50	data_size = get_datasize(mc_header);
51
52	if (data_size + MC_HEADER_SIZE > total_size) {
53		if (print_err)
54			pr_err("error! Bad data size in microcode data file\n");
55		return -EINVAL;
56	}
57
58	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
59		if (print_err)
60			pr_err("error! Unknown microcode update format\n");
61		return -EINVAL;
62	}
63	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
64	if (ext_table_size) {
65		if ((ext_table_size < EXT_HEADER_SIZE)
66		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
67			if (print_err)
68				pr_err("error! Small exttable size in microcode data file\n");
69			return -EINVAL;
70		}
71		ext_header = mc + MC_HEADER_SIZE + data_size;
72		if (ext_table_size != exttable_size(ext_header)) {
73			if (print_err)
74				pr_err("error! Bad exttable size in microcode data file\n");
75			return -EFAULT;
76		}
77		ext_sigcount = ext_header->count;
78	}
79
80	/* check extended table checksum */
81	if (ext_table_size) {
82		int ext_table_sum = 0;
83		int *ext_tablep = (int *)ext_header;
84
85		i = ext_table_size / DWSIZE;
86		while (i--)
87			ext_table_sum += ext_tablep[i];
88		if (ext_table_sum) {
89			if (print_err)
90				pr_warn("aborting, bad extended signature table checksum\n");
91			return -EINVAL;
92		}
93	}
94
95	/* calculate the checksum */
96	orig_sum = 0;
97	i = (MC_HEADER_SIZE + data_size) / DWSIZE;
98	while (i--)
99		orig_sum += ((int *)mc)[i];
100	if (orig_sum) {
101		if (print_err)
102			pr_err("aborting, bad checksum\n");
103		return -EINVAL;
104	}
105	if (!ext_table_size)
106		return 0;
107	/* check extended signature checksum */
108	for (i = 0; i < ext_sigcount; i++) {
109		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
110			  EXT_SIGNATURE_SIZE * i;
111		sum = orig_sum
112			- (mc_header->sig + mc_header->pf + mc_header->cksum)
113			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
114		if (sum) {
115			if (print_err)
116				pr_err("aborting, bad checksum\n");
117			return -EINVAL;
118		}
119	}
120	return 0;
121}
122EXPORT_SYMBOL_GPL(microcode_sanity_check);
123
124/*
125 * Returns 1 if update has been found, 0 otherwise.
126 */
127int get_matching_sig(unsigned int csig, int cpf, int rev, void *mc)
128{
129	struct microcode_header_intel *mc_header = mc;
130	struct extended_sigtable *ext_header;
131	unsigned long total_size = get_totalsize(mc_header);
132	int ext_sigcount, i;
133	struct extended_signature *ext_sig;
134
135	if (update_match_cpu(csig, cpf, mc_header->sig, mc_header->pf))
136		return 1;
137
138	/* Look for ext. headers: */
139	if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
140		return 0;
141
142	ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
143	ext_sigcount = ext_header->count;
144	ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
145
146	for (i = 0; i < ext_sigcount; i++) {
147		if (update_match_cpu(csig, cpf, ext_sig->sig, ext_sig->pf))
148			return 1;
149		ext_sig++;
150	}
151	return 0;
152}
153
154/*
155 * Returns 1 if update has been found, 0 otherwise.
156 */
157int get_matching_microcode(unsigned int csig, int cpf, int rev, void *mc)
158{
159	struct microcode_header_intel *mc_hdr = mc;
160
161	if (!revision_is_newer(mc_hdr, rev))
162		return 0;
163
164	return get_matching_sig(csig, cpf, rev, mc);
165}
166EXPORT_SYMBOL_GPL(get_matching_microcode);
167