1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright IBM Corp. 2016
4 */
5 #include <linux/kernel.h>
6 #include <asm/processor.h>
7 #include <asm/facility.h>
8 #include <asm/lowcore.h>
9 #include <asm/sclp.h>
10 #include "boot.h"
11
12 /*
13 * The code within this file will be called very early. It may _not_
14 * access anything within the bss section, since that is not cleared
15 * yet and may contain data (e.g. initrd) that must be saved by other
16 * code.
17 * For temporary objects the stack (16k) should be used.
18 */
19
20 static unsigned long als[] = { FACILITIES_ALS };
21
22 static void u16_to_hex(char *str, u16 val)
23 {
24 int i, num;
25
26 for (i = 1; i <= 4; i++) {
27 num = (val >> (16 - 4 * i)) & 0xf;
28 if (num >= 10)
29 num += 7;
30 *str++ = '' + num;
31 }
32 *str = '\0';
33 }
34
35 static void print_machine_type(void)
36 {
37 static char mach_str[80] = "Detected machine-type number: ";
38 char type_str[5];
39 struct cpuid id;
40
41 get_cpu_id(&id);
42 u16_to_hex(type_str, id.machine);
43 strcat(mach_str, type_str);
44 strcat(mach_str, "\n");
45 sclp_early_printk(mach_str);
46 }
47
48 static void u16_to_decimal(char *str, u16 val)
49 {
50 int div = 1;
51
52 while (div * 10 <= val)
53 div *= 10;
54 while (div) {
55 *str++ = '' + val / div;
56 val %= div;
57 div /= 10;
58 }
59 *str = '\0';
60 }
61
62 void print_missing_facilities(void)
63 {
64 static char als_str[80] = "Missing facilities: ";
65 unsigned long val;
66 char val_str[6];
67 int i, j, first;
68
69 first = 1;
70 for (i = 0; i < ARRAY_SIZE(als); i++) {
71 val = ~stfle_fac_list[i] & als[i];
72 for (j = 0; j < BITS_PER_LONG; j++) {
73 if (!(val & (1UL << (BITS_PER_LONG - 1 - j))))
74 continue;
75 if (!first)
76 strcat(als_str, ",");
77 /*
78 * Make sure we stay within one line. Consider that
79 * each facility bit adds up to five characters and
80 * z/VM adds a four character prefix.
81 */
82 if (strlen(als_str) > 70) {
83 strcat(als_str, "\n");
84 sclp_early_printk(als_str);
85 *als_str = '\0';
86 }
87 u16_to_decimal(val_str, i * BITS_PER_LONG + j);
88 strcat(als_str, val_str);
89 first = 0;
90 }
91 }
92 strcat(als_str, "\n");
93 sclp_early_printk(als_str);
94 }
95
96 static void facility_mismatch(void)
97 {
98 sclp_early_printk("The Linux kernel requires more recent processor hardware\n");
99 print_machine_type();
100 print_missing_facilities();
101 sclp_early_printk("See Principles of Operations for facility bits\n");
102 disabled_wait();
103 }
104
105 void verify_facilities(void)
106 {
107 int i;
108
109 __stfle(stfle_fac_list, ARRAY_SIZE(stfle_fac_list));
110 for (i = 0; i < ARRAY_SIZE(als); i++) {
111 if ((stfle_fac_list[i] & als[i]) != als[i])
112 facility_mismatch();
113 }
114 }
115
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