LXR linux/arch/s390/boot/als.c

   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
  20static unsigned long als[] = { FACILITIES_ALS };
  21
  22static 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
  35static 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
  48static 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
  62void 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
  96static 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
 105void 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