kernel/arch/x86/kernel/cpu/microcode/intel_lib.c

   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
  34 static inline int
  35 update_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
  41 int 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 }
 122 EXPORT_SYMBOL_GPL(microcode_sanity_check);
 123
 124 /*
 125  * Returns 1 if update has been found, 0 otherwise.
 126  */
 127 int 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  */
 157 int 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 }
 166 EXPORT_SYMBOL_GPL(get_matching_microcode);