lib/efi_loader/efi_watchdog.c

   1 /*
   2  *  EFI watchdog
   3  *
   4  *  Copyright (c) 2017 Heinrich Schuchardt
   5  *
   6  *  SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <efi_loader.h>
  11
  12 /* Conversion factor from seconds to multiples of 100ns */
  13 #define EFI_SECONDS_TO_100NS 10000000ULL
  14
  15 static struct efi_event *watchdog_timer_event;
  16
  17 /*
  18  * Reset the system when the watchdog event is notified.
  19  *
  20  * @event:      the watchdog event
  21  * @context:    not used
  22  */
  23 static void EFIAPI efi_watchdog_timer_notify(struct efi_event *event,
  24                                              void *context)
  25 {
  26         EFI_ENTRY("%p, %p", event, context);
  27
  28         printf("\nEFI: Watchdog timeout\n");
  29         EFI_CALL_VOID(efi_runtime_services.reset_system(EFI_RESET_COLD,
  30                                                         EFI_SUCCESS, 0, NULL));
  31
  32         EFI_EXIT(EFI_UNSUPPORTED);
  33 }
  34
  35 /*
  36  * Reset the watchdog timer.
  37  *
  38  * This function is used by the SetWatchdogTimer service.
  39  *
  40  * @timeout:            seconds before reset by watchdog
  41  * @return:             status code
  42  */
  43 efi_status_t efi_set_watchdog(unsigned long timeout)
  44 {
  45         efi_status_t r;
  46
  47         if (timeout)
  48                 /* Reset watchdog */
  49                 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_RELATIVE,
  50                                   EFI_SECONDS_TO_100NS * timeout);
  51         else
  52                 /* Deactivate watchdog */
  53                 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_STOP, 0);
  54         return r;
  55 }
  56
  57 /*
  58  * Initialize the EFI watchdog.
  59  *
  60  * This function is called by efi_init_obj_list()
  61  */
  62 int efi_watchdog_register(void)
  63 {
  64         efi_status_t r;
  65
  66         /*
  67          * Create a timer event.
  68          */
  69         r = efi_create_event(EVT_TIMER | EVT_NOTIFY_SIGNAL, TPL_CALLBACK,
  70                              efi_watchdog_timer_notify, NULL,
  71                              &watchdog_timer_event);
  72         if (r != EFI_SUCCESS) {
  73                 printf("ERROR: Failed to register watchdog event\n");
  74                 return r;
  75         }
  76         /*
  77          * The UEFI standard requires that the watchdog timer is set to five
  78          * minutes when invoking an EFI boot option.
  79          *
  80          * Unified Extensible Firmware Interface (UEFI), version 2.7 Errata A
  81          * 7.5. Miscellaneous Boot Services - EFI_BOOT_SERVICES.SetWatchdogTimer
  82          */
  83         r = efi_set_watchdog(300);
  84         if (r != EFI_SUCCESS) {
  85                 printf("ERROR: Failed to set watchdog timer\n");
  86                 return r;
  87         }
  88         return 0;
  89 }