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
21static 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
35static 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
73int 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}