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
29 #include <asm/microcode_intel.h>
30 #include <asm/processor.h>
31 #include <asm/msr.h>
32
cpu_signatures_match(unsigned int s1,unsigned int p1,unsigned int s2,unsigned int p2)33 static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
34 unsigned int s2, unsigned int p2)
35 {
36 if (s1 != s2)
37 return false;
38
39 /* Processor flags are either both 0 ... */
40 if (!p1 && !p2)
41 return true;
42
43 /* ... or they intersect. */
44 return p1 & p2;
45 }
46
microcode_sanity_check(void * mc,int print_err)47 int 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 u32 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 microcode data file size.\n");
61 return -EINVAL;
62 }
63
64 if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
65 if (print_err)
66 pr_err("Error: invalid/unknown microcode update format.\n");
67 return -EINVAL;
68 }
69
70 ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
71 if (ext_table_size) {
72 u32 ext_table_sum = 0;
73 u32 *ext_tablep;
74
75 if ((ext_table_size < EXT_HEADER_SIZE)
76 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
77 if (print_err)
78 pr_err("Error: truncated extended signature table.\n");
79 return -EINVAL;
80 }
81
82 ext_header = mc + MC_HEADER_SIZE + data_size;
83 if (ext_table_size != exttable_size(ext_header)) {
84 if (print_err)
85 pr_err("Error: extended signature table size mismatch.\n");
86 return -EFAULT;
87 }
88
89 ext_sigcount = ext_header->count;
90
91 /*
92 * Check extended table checksum: the sum of all dwords that
93 * comprise a valid table must be 0.
94 */
95 ext_tablep = (u32 *)ext_header;
96
97 i = ext_table_size / sizeof(u32);
98 while (i--)
99 ext_table_sum += ext_tablep[i];
100
101 if (ext_table_sum) {
102 if (print_err)
103 pr_warn("Bad extended signature table checksum, aborting.\n");
104 return -EINVAL;
105 }
106 }
107
108 /*
109 * Calculate the checksum of update data and header. The checksum of
110 * valid update data and header including the extended signature table
111 * must be 0.
112 */
113 orig_sum = 0;
114 i = (MC_HEADER_SIZE + data_size) / sizeof(u32);
115 while (i--)
116 orig_sum += ((u32 *)mc)[i];
117
118 if (orig_sum) {
119 if (print_err)
120 pr_err("Bad microcode data checksum, aborting.\n");
121 return -EINVAL;
122 }
123
124 if (!ext_table_size)
125 return 0;
126
127 /*
128 * Check extended signature checksum: 0 => valid.
129 */
130 for (i = 0; i < ext_sigcount; i++) {
131 ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
132 EXT_SIGNATURE_SIZE * i;
133
134 sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -
135 (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
136 if (sum) {
137 if (print_err)
138 pr_err("Bad extended signature checksum, aborting.\n");
139 return -EINVAL;
140 }
141 }
142 return 0;
143 }
144
145 /*
146 * Returns 1 if update has been found, 0 otherwise.
147 */
find_matching_signature(void * mc,unsigned int csig,int cpf)148 int find_matching_signature(void *mc, unsigned int csig, int cpf)
149 {
150 struct microcode_header_intel *mc_hdr = mc;
151 struct extended_sigtable *ext_hdr;
152 struct extended_signature *ext_sig;
153 int i;
154
155 if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
156 return 1;
157
158 /* Look for ext. headers: */
159 if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)
160 return 0;
161
162 ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
163 ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;
164
165 for (i = 0; i < ext_hdr->count; i++) {
166 if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
167 return 1;
168 ext_sig++;
169 }
170 return 0;
171 }
172
173 /*
174 * Returns 1 if update has been found, 0 otherwise.
175 */
has_newer_microcode(void * mc,unsigned int csig,int cpf,int new_rev)176 int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
177 {
178 struct microcode_header_intel *mc_hdr = mc;
179
180 if (mc_hdr->rev <= new_rev)
181 return 0;
182
183 return find_matching_signature(mc, csig, cpf);
184 }
185