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/*
* drivers/s390/char/sclp_quiesce.c
* signal quiesce handler
*
* (C) Copyright IBM Corp. 1999,2004
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
* Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/reboot.h>
#include <asm/atomic.h>
#include <asm/ptrace.h>
#include <asm/sigp.h>
#include "sclp.h"
#ifdef CONFIG_SMP
/* Signal completion of shutdown process. All CPUs except the first to enter
* this function: go to stopped state. First CPU: wait until all other
* CPUs are in stopped or check stop state. Afterwards, load special PSW
* to indicate completion. */
static void
do_load_quiesce_psw(void * __unused)
{
static atomic_t cpuid = ATOMIC_INIT(-1);
psw_t quiesce_psw;
int cpu;
if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) != -1)
signal_processor(smp_processor_id(), sigp_stop);
/* Wait for all other cpus to enter stopped state */
for_each_online_cpu(cpu) {
if (cpu == smp_processor_id())
continue;
while(!smp_cpu_not_running(cpu))
cpu_relax();
}
/* Quiesce the last cpu with the special psw */
quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT;
quiesce_psw.addr = 0xfff;
__load_psw(quiesce_psw);
}
/* Shutdown handler. Perform shutdown function on all CPUs. */
static void
do_machine_quiesce(void)
{
on_each_cpu(do_load_quiesce_psw, NULL, 0, 0);
}
#else
/* Shutdown handler. Signal completion of shutdown by loading special PSW. */
static void
do_machine_quiesce(void)
{
psw_t quiesce_psw;
quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT;
quiesce_psw.addr = 0xfff;
__load_psw(quiesce_psw);
}
#endif
/* Handler for quiesce event. Start shutdown procedure. */
static void
sclp_quiesce_handler(struct evbuf_header *evbuf)
{
_machine_restart = (void *) do_machine_quiesce;
_machine_halt = do_machine_quiesce;
_machine_power_off = do_machine_quiesce;
ctrl_alt_del();
}
static struct sclp_register sclp_quiesce_event = {
.receive_mask = EvTyp_SigQuiesce_Mask,
.receiver_fn = sclp_quiesce_handler
};
/* Initialize quiesce driver. */
static int __init
sclp_quiesce_init(void)
{
int rc;
rc = sclp_register(&sclp_quiesce_event);
if (rc)
printk(KERN_WARNING "sclp: could not register quiesce handler "
"(rc=%d)\n", rc);
return rc;
}
module_init(sclp_quiesce_init);
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