arch/x86/boot/cpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* -*- linux-c -*- ------------------------------------------------------- *
   3  *
   4  *   Copyright (C) 1991, 1992 Linus Torvalds
   5  *   Copyright 2007-2008 rPath, Inc. - All Rights Reserved
   6  *
   7  * ----------------------------------------------------------------------- */
   8
   9 /*
  10  * arch/x86/boot/cpu.c
  11  *
  12  * Check for obligatory CPU features and abort if the features are not
  13  * present.
  14  */
  15
  16 #include "boot.h"
  17 #include "cpustr.h"
  18
  19 static char *cpu_name(int level)
  20 {
  21         static char buf[6];
  22
  23         if (level == 64) {
  24                 return "x86-64";
  25         } else {
  26                 if (level == 15)
  27                         level = 6;
  28                 sprintf(buf, "i%d86", level);
  29                 return buf;
  30         }
  31 }
  32
  33 static void show_cap_strs(u32 *err_flags)
  34 {
  35         int i, j;
  36         const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
  37         for (i = 0; i < NCAPINTS; i++) {
  38                 u32 e = err_flags[i];
  39                 for (j = 0; j < 32; j++) {
  40                         if (msg_strs[0] < i ||
  41                             (msg_strs[0] == i && msg_strs[1] < j)) {
  42                                 /* Skip to the next string */
  43                                 msg_strs += 2;
  44                                 while (*msg_strs++)
  45                                         ;
  46                         }
  47                         if (e & 1) {
  48                                 if (msg_strs[0] == i &&
  49                                     msg_strs[1] == j &&
  50                                     msg_strs[2])
  51                                         printf("%s ", msg_strs+2);
  52                                 else
  53                                         printf("%d:%d ", i, j);
  54                         }
  55                         e >>= 1;
  56                 }
  57         }
  58 }
  59
  60 int validate_cpu(void)
  61 {
  62         u32 *err_flags;
  63         int cpu_level, req_level;
  64
  65         check_cpu(&cpu_level, &req_level, &err_flags);
  66
  67         if (cpu_level < req_level) {
  68                 printf("This kernel requires an %s CPU, ",
  69                        cpu_name(req_level));
  70                 printf("but only detected an %s CPU.\n",
  71                        cpu_name(cpu_level));
  72                 return -1;
  73         }
  74
  75         if (err_flags) {
  76                 puts("This kernel requires the following features "
  77                      "not present on the CPU:\n");
  78                 show_cap_strs(err_flags);
  79                 putchar('\n');
  80                 return -1;
  81         } else if (check_knl_erratum()) {
  82                 return -1;
  83         } else {
  84                 return 0;
  85         }
  86 }