2 * Copyright IBM Corp. 2016
4 #include <linux/kernel.h>
5 #include <linux/init.h>
6 #include <asm/processor.h>
7 #include <asm/facility.h>
8 #include <asm/lowcore.h>
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
17 * For temporary objects the stack (16k) should be used.
20 static unsigned long als[] __initdata = { FACILITIES_ALS };
22 static void __init u16_to_hex(char *str, u16 val)
26 for (i = 1; i <= 4; i++) {
27 num = (val >> (16 - 4 * i)) & 0xf;
35 static void __init print_machine_type(void)
37 static char mach_str[80] __initdata = "Detected machine-type number: ";
42 u16_to_hex(type_str, id.machine);
43 strcat(mach_str, type_str);
44 _sclp_print_early(mach_str);
47 static void __init u16_to_decimal(char *str, u16 val)
51 while (div * 10 <= val)
54 *str++ = '0' + val / div;
61 static void __init print_missing_facilities(void)
63 static char als_str[80] __initdata = "Missing facilities: ";
69 for (i = 0; i < ARRAY_SIZE(als); i++) {
70 val = ~S390_lowcore.stfle_fac_list[i] & als[i];
71 for (j = 0; j < BITS_PER_LONG; j++) {
72 if (!(val & (1UL << (BITS_PER_LONG - 1 - j))))
77 * Make sure we stay within one line. Consider that
78 * each facility bit adds up to five characters and
79 * z/VM adds a four character prefix.
81 if (strlen(als_str) > 70) {
82 _sclp_print_early(als_str);
85 u16_to_decimal(val_str, i * BITS_PER_LONG + j);
86 strcat(als_str, val_str);
90 _sclp_print_early(als_str);
91 _sclp_print_early("See Principles of Operations for facility bits");
94 static void __init facility_mismatch(void)
96 _sclp_print_early("The Linux kernel requires more recent processor hardware");
98 print_missing_facilities();
99 disabled_wait(0x8badcccc);
102 void __init verify_facilities(void)
106 for (i = 0; i < ARRAY_SIZE(S390_lowcore.stfle_fac_list); i++)
107 S390_lowcore.stfle_fac_list[i] = 0;
110 : "=m" (S390_lowcore.stfl_fac_list));
111 S390_lowcore.stfle_fac_list[0] = (u64)S390_lowcore.stfl_fac_list << 32;
112 if (S390_lowcore.stfl_fac_list & 0x01000000) {
113 register unsigned long reg0 asm("0") = ARRAY_SIZE(als) - 1;
115 asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
117 : "a" (&S390_lowcore.stfle_fac_list)
120 for (i = 0; i < ARRAY_SIZE(als); i++) {
121 if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i])