drivers/s390/char/sclp_quiesce.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *     signal quiesce handler
   4  *
   5  *  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/types.h>
  11 #include <linux/cpumask.h>
  12 #include <linux/smp.h>
  13 #include <linux/init.h>
  14 #include <linux/reboot.h>
  15 #include <linux/atomic.h>
  16 #include <asm/ptrace.h>
  17 #include <asm/smp.h>
  18
  19 #include "sclp.h"
  20
  21 static void (*old_machine_restart)(char *);
  22 static void (*old_machine_halt)(void);
  23 static void (*old_machine_power_off)(void);
  24
  25 /* Shutdown handler. Signal completion of shutdown by loading special PSW. */
  26 static void do_machine_quiesce(void)
  27 {
  28         psw_t quiesce_psw;
  29
  30         smp_send_stop();
  31         quiesce_psw.mask =
  32                 PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA | PSW_MASK_WAIT;
  33         quiesce_psw.addr = 0xfff;
  34         __load_psw(quiesce_psw);
  35 }
  36
  37 /* Handler for quiesce event. Start shutdown procedure. */
  38 static void sclp_quiesce_handler(struct evbuf_header *evbuf)
  39 {
  40         if (_machine_restart != (void *) do_machine_quiesce) {
  41                 old_machine_restart = _machine_restart;
  42                 old_machine_halt = _machine_halt;
  43                 old_machine_power_off = _machine_power_off;
  44                 _machine_restart = (void *) do_machine_quiesce;
  45                 _machine_halt = do_machine_quiesce;
  46                 _machine_power_off = do_machine_quiesce;
  47         }
  48         ctrl_alt_del();
  49 }
  50
  51 /* Undo machine restart/halt/power_off modification on resume */
  52 static void sclp_quiesce_pm_event(struct sclp_register *reg,
  53                                   enum sclp_pm_event sclp_pm_event)
  54 {
  55         switch (sclp_pm_event) {
  56         case SCLP_PM_EVENT_RESTORE:
  57                 if (old_machine_restart) {
  58                         _machine_restart = old_machine_restart;
  59                         _machine_halt = old_machine_halt;
  60                         _machine_power_off = old_machine_power_off;
  61                         old_machine_restart = NULL;
  62                         old_machine_halt = NULL;
  63                         old_machine_power_off = NULL;
  64                 }
  65                 break;
  66         case SCLP_PM_EVENT_FREEZE:
  67         case SCLP_PM_EVENT_THAW:
  68                 break;
  69         }
  70 }
  71
  72 static struct sclp_register sclp_quiesce_event = {
  73         .receive_mask = EVTYP_SIGQUIESCE_MASK,
  74         .receiver_fn = sclp_quiesce_handler,
  75         .pm_event_fn = sclp_quiesce_pm_event
  76 };
  77
  78 /* Initialize quiesce driver. */
  79 static int __init sclp_quiesce_init(void)
  80 {
  81         return sclp_register(&sclp_quiesce_event);
  82 }
  83 device_initcall(sclp_quiesce_init);