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
  29 #include <asm/microcode_intel.h>
  30 #include <asm/processor.h>
  31 #include <asm/msr.h>
  32
  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
  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  */
 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  */
 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);