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 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 }
128 EXPORT_SYMBOL_GPL(microcode_sanity_check);
129
130 /*
131 * Returns 1 if update has been found, 0 otherwise.
132 */
find_matching_signature(void * mc,unsigned int csig,int cpf)133 int find_matching_signature(void *mc, unsigned int csig, int cpf)
134 {
135 struct microcode_header_intel *mc_hdr = mc;
136 struct extended_sigtable *ext_hdr;
137 struct extended_signature *ext_sig;
138 int i;
139
140 if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
141 return 1;
142
143 /* Look for ext. headers: */
144 if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)
145 return 0;
146
147 ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
148 ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;
149
150 for (i = 0; i < ext_hdr->count; i++) {
151 if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
152 return 1;
153 ext_sig++;
154 }
155 return 0;
156 }
157
158 /*
159 * Returns 1 if update has been found, 0 otherwise.
160 */
has_newer_microcode(void * mc,unsigned int csig,int cpf,int new_rev)161 int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
162 {
163 struct microcode_header_intel *mc_hdr = mc;
164
165 if (mc_hdr->rev <= new_rev)
166 return 0;
167
168 return find_matching_signature(mc, csig, cpf);
169 }
170 EXPORT_SYMBOL_GPL(has_newer_microcode);
171