1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2016
5 #include <linux/kernel.h>
6 #include <linux/init.h>
7 #include <asm/processor.h>
8 #include <asm/facility.h>
9 #include <asm/lowcore.h>
14 * The code within this file will be called very early. It may _not_
15 * access anything within the bss section, since that is not cleared
16 * yet and may contain data (e.g. initrd) that must be saved by other
18 * For temporary objects the stack (16k) should be used.
21 static unsigned long als[] __initdata = { FACILITIES_ALS };
23 static void __init u16_to_hex(char *str, u16 val)
27 for (i = 1; i <= 4; i++) {
28 num = (val >> (16 - 4 * i)) & 0xf;
36 static void __init print_machine_type(void)
38 static char mach_str[80] __initdata = "Detected machine-type number: ";
43 u16_to_hex(type_str, id.machine);
44 strcat(mach_str, type_str);
45 strcat(mach_str, "\n");
46 sclp_early_printk(mach_str);
49 static void __init u16_to_decimal(char *str, u16 val)
53 while (div * 10 <= val)
56 *str++ = '0' + val / div;
63 static void __init print_missing_facilities(void)
65 static char als_str[80] __initdata = "Missing facilities: ";
71 for (i = 0; i < ARRAY_SIZE(als); i++) {
72 val = ~S390_lowcore.stfle_fac_list[i] & als[i];
73 for (j = 0; j < BITS_PER_LONG; j++) {
74 if (!(val & (1UL << (BITS_PER_LONG - 1 - j))))
79 * Make sure we stay within one line. Consider that
80 * each facility bit adds up to five characters and
81 * z/VM adds a four character prefix.
83 if (strlen(als_str) > 70) {
84 strcat(als_str, "\n");
85 sclp_early_printk(als_str);
88 u16_to_decimal(val_str, i * BITS_PER_LONG + j);
89 strcat(als_str, val_str);
93 strcat(als_str, "\n");
94 sclp_early_printk(als_str);
95 sclp_early_printk("See Principles of Operations for facility bits\n");
98 static void __init facility_mismatch(void)
100 sclp_early_printk("The Linux kernel requires more recent processor hardware\n");
101 print_machine_type();
102 print_missing_facilities();
103 disabled_wait(0x8badcccc);
106 void __init verify_facilities(void)
110 for (i = 0; i < ARRAY_SIZE(S390_lowcore.stfle_fac_list); i++)
111 S390_lowcore.stfle_fac_list[i] = 0;
114 : "=m" (S390_lowcore.stfl_fac_list));
115 S390_lowcore.stfle_fac_list[0] = (u64)S390_lowcore.stfl_fac_list << 32;
116 if (S390_lowcore.stfl_fac_list & 0x01000000) {
117 register unsigned long reg0 asm("0") = ARRAY_SIZE(als) - 1;
119 asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
121 : "a" (&S390_lowcore.stfle_fac_list)
124 for (i = 0; i < ARRAY_SIZE(als); i++) {
125 if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i])