root/arch/x86/boot/cpu.c

DEFINITIONS

1. cpu_name
2. show_cap_strs
3. validate_cpu

   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 #ifdef CONFIG_X86_FEATURE_NAMES
  18 #include "cpustr.h"
  19 #endif
  20 
  21 static char *cpu_name(int level)
  22 {
  23         static char buf[6];
  24 
  25         if (level == 64) {
  26                 return "x86-64";
  27         } else {
  28                 if (level == 15)
  29                         level = 6;
  30                 sprintf(buf, "i%d86", level);
  31                 return buf;
  32         }
  33 }
  34 
  35 static void show_cap_strs(u32 *err_flags)
  36 {
  37         int i, j;
  38 #ifdef CONFIG_X86_FEATURE_NAMES
  39         const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
  40         for (i = 0; i < NCAPINTS; i++) {
  41                 u32 e = err_flags[i];
  42                 for (j = 0; j < 32; j++) {
  43                         if (msg_strs[0] < i ||
  44                             (msg_strs[0] == i && msg_strs[1] < j)) {
  45                                 /* Skip to the next string */
  46                                 msg_strs += 2;
  47                                 while (*msg_strs++)
  48                                         ;
  49                         }
  50                         if (e & 1) {
  51                                 if (msg_strs[0] == i &&
  52                                     msg_strs[1] == j &&
  53                                     msg_strs[2])
  54                                         printf("%s ", msg_strs+2);
  55                                 else
  56                                         printf("%d:%d ", i, j);
  57                         }
  58                         e >>= 1;
  59                 }
  60         }
  61 #else
  62         for (i = 0; i < NCAPINTS; i++) {
  63                 u32 e = err_flags[i];
  64                 for (j = 0; j < 32; j++) {
  65                         if (e & 1)
  66                                 printf("%d:%d ", i, j);
  67                         e >>= 1;
  68                 }
  69         }
  70 #endif
  71 }
  72 
  73 int validate_cpu(void)
  74 {
  75         u32 *err_flags;
  76         int cpu_level, req_level;
  77 
  78         check_cpu(&cpu_level, &req_level, &err_flags);
  79 
  80         if (cpu_level < req_level) {
  81                 printf("This kernel requires an %s CPU, ",
  82                        cpu_name(req_level));
  83                 printf("but only detected an %s CPU.\n",
  84                        cpu_name(cpu_level));
  85                 return -1;
  86         }
  87 
  88         if (err_flags) {
  89                 puts("This kernel requires the following features "
  90                      "not present on the CPU:\n");
  91                 show_cap_strs(err_flags);
  92                 putchar('\n');
  93                 return -1;
  94         } else if (check_knl_erratum()) {
  95                 return -1;
  96         } else {
  97                 return 0;
  98         }
  99 }