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, "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("%s ", msg_strs+2);
52				else
53					printf("%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, &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}
87