127 lines
2.9 KiB
C
127 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright IBM Corp. 2016
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*/
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#include <linux/kernel.h>
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#include <asm/processor.h>
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#include <asm/facility.h>
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#include <asm/lowcore.h>
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#include <asm/sclp.h>
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/*
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* The code within this file will be called very early. It may _not_
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* access anything within the bss section, since that is not cleared
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* yet and may contain data (e.g. initrd) that must be saved by other
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* code.
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* For temporary objects the stack (16k) should be used.
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*/
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static unsigned long als[] = { FACILITIES_ALS };
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static void u16_to_hex(char *str, u16 val)
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{
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int i, num;
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for (i = 1; i <= 4; i++) {
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num = (val >> (16 - 4 * i)) & 0xf;
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if (num >= 10)
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num += 7;
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*str++ = '0' + num;
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}
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*str = '\0';
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}
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static void print_machine_type(void)
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{
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static char mach_str[80] = "Detected machine-type number: ";
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char type_str[5];
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struct cpuid id;
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get_cpu_id(&id);
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u16_to_hex(type_str, id.machine);
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strcat(mach_str, type_str);
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strcat(mach_str, "\n");
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sclp_early_printk(mach_str);
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}
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static void u16_to_decimal(char *str, u16 val)
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{
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int div = 1;
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while (div * 10 <= val)
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div *= 10;
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while (div) {
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*str++ = '0' + val / div;
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val %= div;
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div /= 10;
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}
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*str = '\0';
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}
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static void print_missing_facilities(void)
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{
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static char als_str[80] = "Missing facilities: ";
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unsigned long val;
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char val_str[6];
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int i, j, first;
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first = 1;
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for (i = 0; i < ARRAY_SIZE(als); i++) {
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val = ~S390_lowcore.stfle_fac_list[i] & als[i];
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for (j = 0; j < BITS_PER_LONG; j++) {
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if (!(val & (1UL << (BITS_PER_LONG - 1 - j))))
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continue;
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if (!first)
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strcat(als_str, ",");
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/*
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* Make sure we stay within one line. Consider that
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* each facility bit adds up to five characters and
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* z/VM adds a four character prefix.
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*/
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if (strlen(als_str) > 70) {
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strcat(als_str, "\n");
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sclp_early_printk(als_str);
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*als_str = '\0';
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}
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u16_to_decimal(val_str, i * BITS_PER_LONG + j);
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strcat(als_str, val_str);
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first = 0;
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}
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}
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strcat(als_str, "\n");
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sclp_early_printk(als_str);
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sclp_early_printk("See Principles of Operations for facility bits\n");
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}
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static void facility_mismatch(void)
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{
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sclp_early_printk("The Linux kernel requires more recent processor hardware\n");
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print_machine_type();
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print_missing_facilities();
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disabled_wait(0x8badcccc);
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}
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void verify_facilities(void)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(S390_lowcore.stfle_fac_list); i++)
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S390_lowcore.stfle_fac_list[i] = 0;
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asm volatile(
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" stfl 0(0)\n"
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: "=m" (S390_lowcore.stfl_fac_list));
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S390_lowcore.stfle_fac_list[0] = (u64)S390_lowcore.stfl_fac_list << 32;
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if (S390_lowcore.stfl_fac_list & 0x01000000) {
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register unsigned long reg0 asm("0") = ARRAY_SIZE(als) - 1;
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asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */
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: "+d" (reg0)
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: "a" (&S390_lowcore.stfle_fac_list)
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: "memory", "cc");
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}
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for (i = 0; i < ARRAY_SIZE(als); i++) {
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if ((S390_lowcore.stfle_fac_list[i] & als[i]) != als[i])
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facility_mismatch();
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}
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}
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