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++ = '0' + 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++ = '0' + 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 = ~S390_lowcore.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(0x8badcccc); 103 } 104 105 void verify_facilities(void) 106 { 107 int i; 108 109 __stfle(S390_lowcore.stfle_fac_list, ARRAY_SIZE(S390_lowcore.stfle_fac_list)); 110 for (i = 0; i < ARRAY_SIZE(als); i++) { 111 if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i]) 112 facility_mismatch(); 113 } 114 } 115