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
19static 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, fmt: "i%d86", level);
29 return buf;
30 }
31}
32
33static 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(fmt: "%s ", msg_strs+2);
52 else
53 printf(fmt: "%d:%d ", i, j);
54 }
55 e >>= 1;
56 }
57 }
58}
59
60int validate_cpu(void)
61{
62 u32 *err_flags;
63 int cpu_level, req_level;
64
65 check_cpu(cpu_level_ptr: &cpu_level, req_level_ptr: &req_level, err_flags_ptr: &err_flags);
66
67 if (cpu_level < req_level) {
68 printf(fmt: "This kernel requires an %s CPU, ",
69 cpu_name(level: req_level));
70 printf(fmt: "but only detected an %s CPU.\n",
71 cpu_name(level: 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}
87

source code of linux/arch/x86/boot/cpu.c