drivers/s390/char/sclp_quiesce.c

   1 /*
   2  *  drivers/s390/char/sclp_quiesce.c
   3  *     signal quiesce handler
   4  *
   5  *  (C) Copyright IBM Corp. 1999,2004
   6  *  Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   7  *             Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/cpumask.h>
  13 #include <linux/smp.h>
  14 #include <linux/init.h>
  15 #include <linux/reboot.h>
  16 #include <linux/atomic.h>
  17 #include <asm/ptrace.h>
  18 #include <asm/smp.h>
  19
  20 #include "sclp.h"
  21
  22 static void (*old_machine_restart)(char *);
  23 static void (*old_machine_halt)(void);
  24 static void (*old_machine_power_off)(void);
  25
  26 /* Shutdown handler. Signal completion of shutdown by loading special PSW. */
  27 static void do_machine_quiesce(void)
  28 {
  29         psw_t quiesce_psw;
  30
  31         smp_send_stop();
  32         quiesce_psw.mask =
  33                 PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA | PSW_MASK_WAIT;
  34         quiesce_psw.addr = 0xfff;
  35         __load_psw(quiesce_psw);
  36 }
  37
  38 /* Handler for quiesce event. Start shutdown procedure. */
  39 static void sclp_quiesce_handler(struct evbuf_header *evbuf)
  40 {
  41         if (_machine_restart != (void *) do_machine_quiesce) {
  42                 old_machine_restart = _machine_restart;
  43                 old_machine_halt = _machine_halt;
  44                 old_machine_power_off = _machine_power_off;
  45                 _machine_restart = (void *) do_machine_quiesce;
  46                 _machine_halt = do_machine_quiesce;
  47                 _machine_power_off = do_machine_quiesce;
  48         }
  49         ctrl_alt_del();
  50 }
  51
  52 /* Undo machine restart/halt/power_off modification on resume */
  53 static void sclp_quiesce_pm_event(struct sclp_register *reg,
  54                                   enum sclp_pm_event sclp_pm_event)
  55 {
  56         switch (sclp_pm_event) {
  57         case SCLP_PM_EVENT_RESTORE:
  58                 if (old_machine_restart) {
  59                         _machine_restart = old_machine_restart;
  60                         _machine_halt = old_machine_halt;
  61                         _machine_power_off = old_machine_power_off;
  62                         old_machine_restart = NULL;
  63                         old_machine_halt = NULL;
  64                         old_machine_power_off = NULL;
  65                 }
  66                 break;
  67         case SCLP_PM_EVENT_FREEZE:
  68         case SCLP_PM_EVENT_THAW:
  69                 break;
  70         }
  71 }
  72
  73 static struct sclp_register sclp_quiesce_event = {
  74         .receive_mask = EVTYP_SIGQUIESCE_MASK,
  75         .receiver_fn = sclp_quiesce_handler,
  76         .pm_event_fn = sclp_quiesce_pm_event
  77 };
  78
  79 /* Initialize quiesce driver. */
  80 static int __init sclp_quiesce_init(void)
  81 {
  82         return sclp_register(&sclp_quiesce_event);
  83 }
  84
  85 module_init(sclp_quiesce_init);