linux-stable/arch/s390/boot/als.c
Martin Schwidefsky 98587c2d89 s390: simplify disabled_wait
The disabled_wait() function uses its argument as the PSW address when
it stops the CPU with a wait PSW that is disabled for interrupts.
The different callers sometimes use a specific number like 0xdeadbeef
to indicate a specific failure, the early boot code uses 0 and some
other calls sites use __builtin_return_address(0).

At the time a dump is created the current PSW and the registers of a
CPU are written to lowcore to make them avaiable to the dump analysis
tool. For a CPU stopped with disabled_wait the PSW and the registers
do not really make sense together, the PSW address does not point to
the function the registers belong to.

Simplify disabled_wait() by using _THIS_IP_ for the PSW address and
drop the argument to the function.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-05-02 13:54:11 +02:00

114 lines
2.5 KiB
C

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