arch/x86/boot/cpu.c

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright (C) 1991, 1992 Linus Torvalds
   4  *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
   5  *
   6  *   This file is part of the Linux kernel, and is made available under
   7  *   the terms of the GNU General Public License version 2.
   8  *
   9  * ----------------------------------------------------------------------- */
  10
  11 /*
  12  * arch/x86/boot/cpu.c
  13  *
  14  * Check for obligatory CPU features and abort if the features are not
  15  * present.
  16  */
  17
  18 #include "boot.h"
  19 #ifdef CONFIG_X86_FEATURE_NAMES
  20 #include "cpustr.h"
  21 #endif
  22
  23 static char *cpu_name(int level)
  24 {
  25         static char buf[6];
  26
  27         if (level == 64) {
  28                 return "x86-64";
  29         } else {
  30                 if (level == 15)
  31                         level = 6;
  32                 sprintf(buf, "i%d86", level);
  33                 return buf;
  34         }
  35 }
  36
  37 static void show_cap_strs(u32 *err_flags)
  38 {
  39         int i, j;
  40 #ifdef CONFIG_X86_FEATURE_NAMES
  41         const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
  42         for (i = 0; i < NCAPINTS; i++) {
  43                 u32 e = err_flags[i];
  44                 for (j = 0; j < 32; j++) {
  45                         if (msg_strs[0] < i ||
  46                             (msg_strs[0] == i && msg_strs[1] < j)) {
  47                                 /* Skip to the next string */
  48                                 msg_strs += 2;
  49                                 while (*msg_strs++)
  50                                         ;
  51                         }
  52                         if (e & 1) {
  53                                 if (msg_strs[0] == i &&
  54                                     msg_strs[1] == j &&
  55                                     msg_strs[2])
  56                                         printf("%s ", msg_strs+2);
  57                                 else
  58                                         printf("%d:%d ", i, j);
  59                         }
  60                         e >>= 1;
  61                 }
  62         }
  63 #else
  64         for (i = 0; i < NCAPINTS; i++) {
  65                 u32 e = err_flags[i];
  66                 for (j = 0; j < 32; j++) {
  67                         if (e & 1)
  68                                 printf("%d:%d ", i, j);
  69                         e >>= 1;
  70                 }
  71         }
  72 #endif
  73 }
  74
  75 int validate_cpu(void)
  76 {
  77         u32 *err_flags;
  78         int cpu_level, req_level;
  79
  80         check_cpu(&cpu_level, &req_level, &err_flags);
  81
  82         if (cpu_level < req_level) {
  83                 printf("This kernel requires an %s CPU, ",
  84                        cpu_name(req_level));
  85                 printf("but only detected an %s CPU.\n",
  86                        cpu_name(cpu_level));
  87                 return -1;
  88         }
  89
  90         if (err_flags) {
  91                 puts("This kernel requires the following features "
  92                      "not present on the CPU:\n");
  93                 show_cap_strs(err_flags);
  94                 putchar('\n');
  95                 return -1;
  96         } else {
  97                 return 0;
  98         }
  99 }