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 bool cpu_signatures_match(unsigned int s1, unsigned int p1,
  35                                         unsigned int s2, unsigned int p2)
  36 {
  37         if (s1 != s2)
  38                 return false;
  39
  40         /* Processor flags are either both 0 ... */
  41         if (!p1 && !p2)
  42                 return true;
  43
  44         /* ... or they intersect. */
  45         return p1 & p2;
  46 }
  47
  48 int microcode_sanity_check(void *mc, int print_err)
  49 {
  50         unsigned long total_size, data_size, ext_table_size;
  51         struct microcode_header_intel *mc_header = mc;
  52         struct extended_sigtable *ext_header = NULL;
  53         int sum, orig_sum, ext_sigcount = 0, i;
  54         struct extended_signature *ext_sig;
  55
  56         total_size = get_totalsize(mc_header);
  57         data_size = get_datasize(mc_header);
  58
  59         if (data_size + MC_HEADER_SIZE > total_size) {
  60                 if (print_err)
  61                         pr_err("error! Bad data size in microcode data file\n");
  62                 return -EINVAL;
  63         }
  64
  65         if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
  66                 if (print_err)
  67                         pr_err("error! Unknown microcode update format\n");
  68                 return -EINVAL;
  69         }
  70         ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
  71         if (ext_table_size) {
  72                 if ((ext_table_size < EXT_HEADER_SIZE)
  73                  || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
  74                         if (print_err)
  75                                 pr_err("error! Small exttable size in microcode data file\n");
  76                         return -EINVAL;
  77                 }
  78                 ext_header = mc + MC_HEADER_SIZE + data_size;
  79                 if (ext_table_size != exttable_size(ext_header)) {
  80                         if (print_err)
  81                                 pr_err("error! Bad exttable size in microcode data file\n");
  82                         return -EFAULT;
  83                 }
  84                 ext_sigcount = ext_header->count;
  85         }
  86
  87         /* check extended table checksum */
  88         if (ext_table_size) {
  89                 int ext_table_sum = 0;
  90                 int *ext_tablep = (int *)ext_header;
  91
  92                 i = ext_table_size / DWSIZE;
  93                 while (i--)
  94                         ext_table_sum += ext_tablep[i];
  95                 if (ext_table_sum) {
  96                         if (print_err)
  97                                 pr_warn("aborting, bad extended signature table checksum\n");
  98                         return -EINVAL;
  99                 }
 100         }
 101
 102         /* calculate the checksum */
 103         orig_sum = 0;
 104         i = (MC_HEADER_SIZE + data_size) / DWSIZE;
 105         while (i--)
 106                 orig_sum += ((int *)mc)[i];
 107         if (orig_sum) {
 108                 if (print_err)
 109                         pr_err("aborting, bad checksum\n");
 110                 return -EINVAL;
 111         }
 112         if (!ext_table_size)
 113                 return 0;
 114         /* check extended signature checksum */
 115         for (i = 0; i < ext_sigcount; i++) {
 116                 ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
 117                           EXT_SIGNATURE_SIZE * i;
 118                 sum = orig_sum
 119                         - (mc_header->sig + mc_header->pf + mc_header->cksum)
 120                         + (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
 121                 if (sum) {
 122                         if (print_err)
 123                                 pr_err("aborting, bad checksum\n");
 124                         return -EINVAL;
 125                 }
 126         }
 127         return 0;
 128 }
 129 EXPORT_SYMBOL_GPL(microcode_sanity_check);
 130
 131 /*
 132  * Returns 1 if update has been found, 0 otherwise.
 133  */
 134 int find_matching_signature(void *mc, unsigned int csig, int cpf)
 135 {
 136         struct microcode_header_intel *mc_hdr = mc;
 137         struct extended_sigtable *ext_hdr;
 138         struct extended_signature *ext_sig;
 139         int i;
 140
 141         if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
 142                 return 1;
 143
 144         /* Look for ext. headers: */
 145         if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)
 146                 return 0;
 147
 148         ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;
 149         ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;
 150
 151         for (i = 0; i < ext_hdr->count; i++) {
 152                 if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
 153                         return 1;
 154                 ext_sig++;
 155         }
 156         return 0;
 157 }
 158
 159 /*
 160  * Returns 1 if update has been found, 0 otherwise.
 161  */
 162 int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev)
 163 {
 164         struct microcode_header_intel *mc_hdr = mc;
 165
 166         if (mc_hdr->rev <= new_rev)
 167                 return 0;
 168
 169         return find_matching_signature(mc, csig, cpf);
 170 }
 171 EXPORT_SYMBOL_GPL(has_newer_microcode);