lib/efi_loader/efi_watchdog.c

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