/*
* drivers/s390/s390mach.c
* S/390 machine check handler
*
* S390 version
* Copyright (C) 2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Ingo Adlung (adlung@de.ibm.com)
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/workqueue.h>
#include <linux/time.h>
#include <linux/kthread.h>
#include <asm/lowcore.h>
#include "s390mach.h"
#define DBG printk
// #define DBG(args,...) do {} while (0);
static struct semaphore m_sem;
extern int css_process_crw(int, int);
extern int chsc_process_crw(void);
extern int chp_process_crw(int, int);
extern void css_reiterate_subchannels(void);
extern struct workqueue_struct *slow_path_wq;
extern struct work_struct slow_path_work;
static NORET_TYPE void
s390_handle_damage(char *msg)
{
#ifdef CONFIG_SMP
smp_send_stop();
#endif
disabled_wait((unsigned long) __builtin_return_address(0));
for(;;);
}
/*
* Retrieve CRWs and call function to handle event.
*
* Note : we currently process CRWs for io and chsc subchannels only
*/
static int
s390_collect_crw_info(void *param)
{
struct crw crw[2];
int ccode, ret, slow;
struct semaphore *sem;
unsigned int chain;
sem = (struct semaphore *)param;
repeat:
down_interruptible(sem);
slow = 0;
chain = 0;
while (1) {
if (unlikely(chain > 1)) {
struct crw tmp_crw;
printk(KERN_WARNING"%s: Code does not support more "
"than two chained crws; please report to "
"linux390@de.ibm.com!\n", __FUNCTION__);
ccode = stcrw(&tmp_crw);
printk(KERN_WARNING"%s: crw reports slct=%d, oflw=%d, "
"chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
__FUNCTION__, tmp_crw.slct, tmp_crw.oflw,
tmp_crw.chn, tmp_crw.rsc, tmp_crw.anc,
tmp_crw.erc, tmp_crw.rsid);
printk(KERN_WARNING"%s: This was crw number %x in the "
"chain\n", __FUNCTION__, chain);
if (ccode != 0)
break;
chain = tmp_crw.chn ? chain + 1 : 0;
continue;
}
ccode = stcrw(&crw[chain]);
if (ccode != 0)
break;
DBG(KERN_DEBUG "crw_info : CRW reports slct=%d, oflw=%d, "
"chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
crw[chain].slct, crw[chain].oflw, crw[chain].chn,
crw[chain].rsc, crw[chain].anc, crw[chain].erc,
crw[chain].rsid);
/* Check for overflows. */
if (crw[chain].oflw) {
pr_debug("%s: crw overflow detected!\n", __FUNCTION__);
css_reiterate_subchannels();
chain = 0;
slow = 1;
continue;
}
switch (crw[chain].rsc) {
case CRW_RSC_SCH:
if (crw[0].chn && !chain)
break;
pr_debug("source is subchannel %04X\n", crw[0].rsid);
ret = css_process_crw (crw[0].rsid,
chain ? crw[1].rsid : 0);
if (ret == -EAGAIN)
slow = 1;
break;
case CRW_RSC_MONITOR:
pr_debug("source is monitoring facility\n");
break;
case CRW_RSC_CPATH:
pr_debug("source is channel path %02X\n", crw[0].rsid);
/*
* Check for solicited machine checks. These are
* created by reset channel path and need not be
* reported to the common I/O layer.
*/
if (crw[chain].slct) {
DBG(KERN_INFO"solicited machine check for "
"channel path %02X\n", crw[0].rsid);
break;
}
switch (crw[0].erc) {
case CRW_ERC_IPARM: /* Path has come. */
ret = chp_process_crw(crw[0].rsid, 1);
break;
case CRW_ERC_PERRI: /* Path has gone. */
case CRW_ERC_PERRN:
ret = chp_process_crw(crw[0].rsid, 0);
break;
default:
pr_debug("Don't know how to handle erc=%x\n",
crw[0].erc);
ret = 0;
}
if (ret == -EAGAIN)
slow = 1;
break;
case CRW_RSC_CONFIG:
pr_debug("source is configuration-alert facility\n");
break;
case CRW_RSC_CSS:
pr_debug("source is channel subsystem\n");
ret = chsc_process_crw();
if (ret == -EAGAIN)
slow = 1;
break;
default:
pr_debug("unknown source\n");
break;
}
/* chain is always 0 or 1 here. */
chain = crw[chain].chn ? chain + 1 : 0;
}
if (slow)
queue_work(slow_path_wq, &slow_path_work);
goto repeat;
return 0;
}
struct mcck_struct {
int kill_task;
int channel_report;
int warning;
unsigned long long mcck_code;
};
static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
/*
* Main machine check handler function. Will be called with interrupts enabled
* or disabled and machine checks enabled or disabled.
*/
void
s390_handle_mcck(void)
{
unsigned long flags;
struct mcck_struct mcck;
/*
* Disable machine checks and get the current state of accumulated
* machine checks. Afterwards delete the old state and enable machine
* checks again.
*/
local_irq_save(flags);
local_mcck_disable();
mcck = __get_cpu_var(cpu_mcck);
memset(&__get_cpu_var(cpu_mcck), 0, sizeof(struct mcck_struct));
clear_thread_flag(TIF_MCCK_PENDING);
local_mcck_enable();
local_irq_restore(flags);
if (mcck.channel_report)
up(&m_sem);
#ifdef CONFIG_MACHCHK_WARNING
/*
* The warning may remain for a prolonged period on the bare iron.
* (actually till the machine is powered off, or until the problem is gone)
* So we just stop listening for the WARNING MCH and prevent continuously
* being interrupted. One caveat is however, that we must do this per
* processor and cannot use the smp version of ctl_clear_bit().
* On VM we only get one interrupt per virtally presented machinecheck.
* Though one suffices, we may get one interrupt per (virtual) processor.
*/
if (mcck.warning) { /* WARNING pending ? */
static int mchchk_wng_posted = 0;
/*
* Use single machine clear, as we cannot handle smp right now
*/
__ctl_clear_bit(14, 24); /* Disable WARNING MCH */
if (xchg(&mchchk_wng_posted, 1) == 0)
kill_proc(1, SIGPWR, 1);
}
#endif
if (mcck.kill_task) {
local_irq_enable();
printk(KERN_EMERG "mcck: Terminating task because of machine "
"malfunction (code 0x%016llx).\n", mcck.mcck_code);
printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
current->comm, current->pid);
do_exit(SIGSEGV);
}
}
/*
* returns 0 if all registers could be validated
* returns 1 otherwise
*/
static int
s390_revalidate_registers(struct mci *mci)
{
int kill_task;
u64 tmpclock;
u64 zero;
void *fpt_save_area, *fpt_creg_save_area;
kill_task = 0;
zero = 0;
/* General purpose registers */
if (!mci->gr)
/*
* General purpose registers couldn't be restored and have
* unknown contents. Process needs to be terminated.
*/
kill_task = 1;
/* Revalidate floating point registers */
if (!mci->fp)
/*
* Floating point registers can't be restored and
* therefore the process needs to be terminated.
*/
kill_task = 1;
#ifndef CONFIG_64BIT
asm volatile("ld 0,0(%0)\n"
"ld 2,8(%0)\n"
"ld 4,16(%0)\n"
"ld 6,24(%0)"
: : "a" (&S390_lowcore.floating_pt_save_area));
#endif
if (MACHINE_HAS_IEEE) {
#ifdef CONFIG_64BIT
fpt_save_area = &S390_lowcore.floating_pt_save_area;
fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area;
#else
fpt_save_area = (void *) S390_lowcore.extended_save_area_addr;
fpt_creg_save_area = fpt_save_area+128;
#endif
/* Floating point control register */
if (!mci->fc) {
/*
* Floating point control register can't be restored.
* Task will be terminated.
*/
asm volatile ("lfpc 0(%0)" : : "a" (&zero), "m" (zero));
kill_task = 1;
}
else
asm volatile (
"lfpc 0(%0)"
: : "a" (fpt_creg_save_area));
asm volatile("ld 0,0(%0)\n"
"ld 1,8(%0)\n"
"ld 2,16(%0)\n"
"ld 3,24(%0)\n"
"ld 4,32(%0)\n"
"ld 5,40(%0)\n"
"ld 6,48(%0)\n"
"ld 7,56(%0)\n"
"ld 8,64(%0)\n"
"ld 9,72(%0)\n"
"ld 10,80(%0)\n"
"ld 11,88(%0)\n"
"ld 12,96(%0)\n"
"ld 13,104(%0)\n"
"ld 14,112(%0)\n"
"ld 15,120(%0)\n"
: : "a" (fpt_save_area));
}
/* Revalidate access registers */
asm volatile("lam 0,15,0(%0)"
: : "a" (&S390_lowcore.access_regs_save_area));
if (!mci->ar)
/*
* Access registers have unknown contents.
* Terminating task.
*/
kill_task = 1;
/* Revalidate control registers */
if (!mci->cr)
/*
* Control registers have unknown contents.
* Can't recover and therefore stopping machine.
*/
s390_handle_damage("invalid control registers.");
else
#ifdef CONFIG_64BIT
asm volatile("lctlg 0,15,0(%0)"
: : "a" (&S390_lowcore.cregs_save_area));
#else
asm volatile("lctl 0,15,0(%0)"
: : "a" (&S390_lowcore.cregs_save_area));
#endif
/*
* We don't even try to revalidate the TOD register, since we simply
* can't write something sensible into that register.
*/
#ifdef CONFIG_64BIT
/*
* See if we can revalidate the TOD programmable register with its
* old contents (should be zero) otherwise set it to zero.
*/
if (!mci->pr)
asm volatile("sr 0,0\n"
"sckpf"
: : : "0", "cc");
else
asm volatile(
"l 0,0(%0)\n"
"sckpf"
: : "a" (&S390_lowcore.tod_progreg_save_area) : "0", "cc");
#endif
/* Revalidate clock comparator register */
asm volatile ("stck 0(%1)\n"
"sckc 0(%1)"
: "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
/* Check if old PSW is valid */
if (!mci->wp)
/*
* Can't tell if we come from user or kernel mode
* -> stopping machine.
*/
s390_handle_damage("old psw invalid.");
if (!mci->ms || !mci->pm || !mci->ia)
kill_task = 1;
return kill_task;
}
#define MAX_IPD_COUNT 29
#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
/*
* machine check handler.
*/
void
s390_do_machine_check(struct pt_regs *regs)
{
static DEFINE_SPINLOCK(ipd_lock);
static unsigned long long last_ipd;
static int ipd_count;
unsigned long long tmp;
struct mci *mci;
struct mcck_struct *mcck;
int umode;
lockdep_off();
mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
mcck = &__get_cpu_var(cpu_mcck);
umode = user_mode(regs);
if (mci->sd)
/* System damage -> stopping machine */
s390_handle_damage("received system damage machine check.");
if (mci->pd) {
if (mci->b) {
/* Processing backup -> verify if we can survive this */
u64 z_mcic, o_mcic, t_mcic;
#ifdef CONFIG_64BIT
z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
1ULL<<16);
#else
z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<57 | 1ULL<<50 |
1ULL<<29);
o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
1ULL<<30 | 1ULL<<20 | 1ULL<<17 | 1ULL<<16);
#endif
t_mcic = *(u64 *)mci;
if (((t_mcic & z_mcic) != 0) ||
((t_mcic & o_mcic) != o_mcic)) {
s390_handle_damage("processing backup machine "
"check with damage.");
}
/*
* Nullifying exigent condition, therefore we might
* retry this instruction.
*/
spin_lock(&ipd_lock);
tmp = get_clock();
if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
ipd_count++;
else
ipd_count = 1;
last_ipd = tmp;
if (ipd_count == MAX_IPD_COUNT)
s390_handle_damage("too many ipd retries.");
spin_unlock(&ipd_lock);
}
else {
/* Processing damage -> stopping machine */
s390_handle_damage("received instruction processing "
"damage machine check.");
}
}
if (s390_revalidate_registers(mci)) {
if (umode) {
/*
* Couldn't restore all register contents while in
* user mode -> mark task for termination.
*/
mcck->kill_task = 1;
mcck->mcck_code = *(unsigned long long *) mci;
set_thread_flag(TIF_MCCK_PENDING);
}
else
/*
* Couldn't restore all register contents while in
* kernel mode -> stopping machine.
*/
s390_handle_damage("unable to revalidate registers.");
}
if (mci->se)
/* Storage error uncorrected */
s390_handle_damage("received storage error uncorrected "
"machine check.");
if (mci->ke)
/* Storage key-error uncorrected */
s390_handle_damage("received storage key-error uncorrected "
"machine check.");
if (mci->ds && mci->fa)
/* Storage degradation */
s390_handle_damage("received storage degradation machine "
"check.");
if (mci->cp) {
/* Channel report word pending */
mcck->channel_report = 1;
set_thread_flag(TIF_MCCK_PENDING);
}
if (mci->w) {
/* Warning pending */
mcck->warning = 1;
set_thread_flag(TIF_MCCK_PENDING);
}
lockdep_on();
}
/*
* s390_init_machine_check
*
* initialize machine check handling
*/
static int
machine_check_init(void)
{
init_MUTEX_LOCKED(&m_sem);
ctl_clear_bit(14, 25); /* disable external damage MCH */
ctl_set_bit(14, 27); /* enable system recovery MCH */
#ifdef CONFIG_MACHCHK_WARNING
ctl_set_bit(14, 24); /* enable warning MCH */
#endif
return 0;
}
/*
* Initialize the machine check handler really early to be able to
* catch all machine checks that happen during boot
*/
arch_initcall(machine_check_init);
/*
* Machine checks for the channel subsystem must be enabled
* after the channel subsystem is initialized
*/
static int __init
machine_check_crw_init (void)
{
kthread_run(s390_collect_crw_info, &m_sem, "kmcheck");
ctl_set_bit(14, 28); /* enable channel report MCH */
return 0;
}
device_initcall (machine_check_crw_init);
