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  * efi_watchdog_timer_notify() - resets system upon watchdog event
  18  *
  19  * Reset the system when the watchdog event is notified.
  20  *
  21  * @event:      the watchdog event
  22  * @context:    not used
  23  */
  24 static void EFIAPI efi_watchdog_timer_notify(struct efi_event *event,
  25                                              void *context)
  26 {
  27         EFI_ENTRY("%p, %p", event, context);
  28
  29         printf("\nEFI: Watchdog timeout\n");
  30         EFI_CALL_VOID(efi_runtime_services.reset_system(EFI_RESET_COLD,
  31                                                         EFI_SUCCESS, 0, NULL));
  32
  33         EFI_EXIT(EFI_UNSUPPORTED);
  34 }
  35
  36 /**
  37  * efi_set_watchdog() - resets the watchdog timer
  38  *
  39  * This function is used by the SetWatchdogTimer service.
  40  *
  41  * @timeout:            seconds before reset by watchdog
  42  * Return:              status code
  43  */
  44 efi_status_t efi_set_watchdog(unsigned long timeout)
  45 {
  46         efi_status_t r;
  47
  48         if (timeout)
  49                 /* Reset watchdog */
  50                 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_RELATIVE,
  51                                   EFI_SECONDS_TO_100NS * timeout);
  52         else
  53                 /* Deactivate watchdog */
  54                 r = efi_set_timer(watchdog_timer_event, EFI_TIMER_STOP, 0);
  55         return r;
  56 }
  57
  58 /**
  59  * efi_watchdog_register() - initializes the EFI watchdog
  60  *
  61  * This function is called by efi_init_obj_list().
  62  *
  63  * Return:      status code
  64  */
  65 efi_status_t efi_watchdog_register(void)
  66 {
  67         efi_status_t r;
  68
  69         /*
  70          * Create a timer event.
  71          */
  72         r = efi_create_event(EVT_TIMER | EVT_NOTIFY_SIGNAL, TPL_CALLBACK,
  73                              efi_watchdog_timer_notify, NULL, NULL,
  74                              &watchdog_timer_event);
  75         if (r != EFI_SUCCESS) {
  76                 printf("ERROR: Failed to register watchdog event\n");
  77                 return r;
  78         }
  79         /*
  80          * The UEFI standard requires that the watchdog timer is set to five
  81          * minutes when invoking an EFI boot option.
  82          *
  83          * Unified Extensible Firmware Interface (UEFI), version 2.7 Errata A
  84          * 7.5. Miscellaneous Boot Services - EFI_BOOT_SERVICES.SetWatchdogTimer
  85          */
  86         r = efi_set_watchdog(300);
  87         if (r != EFI_SUCCESS) {
  88                 printf("ERROR: Failed to set watchdog timer\n");
  89                 return r;
  90         }
  91         return EFI_SUCCESS;
  92 }