// SPDX-License-Identifier: GPL-2.0+ /* * EFI watchdog * * Copyright (c) 2017 Heinrich Schuchardt */ #include #include /* Conversion factor from seconds to multiples of 100ns */ #define EFI_SECONDS_TO_100NS 10000000ULL static struct efi_event *watchdog_timer_event; /* * Reset the system when the watchdog event is notified. * * @event: the watchdog event * @context: not used */ static void EFIAPI efi_watchdog_timer_notify(struct efi_event *event, void *context) { EFI_ENTRY("%p, %p", event, context); printf("\nEFI: Watchdog timeout\n"); EFI_CALL_VOID(efi_runtime_services.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL)); EFI_EXIT(EFI_UNSUPPORTED); } /* * Reset the watchdog timer. * * This function is used by the SetWatchdogTimer service. * * @timeout: seconds before reset by watchdog * @return: status code */ efi_status_t efi_set_watchdog(unsigned long timeout) { efi_status_t r; if (timeout) /* Reset watchdog */ r = efi_set_timer(watchdog_timer_event, EFI_TIMER_RELATIVE, EFI_SECONDS_TO_100NS * timeout); else /* Deactivate watchdog */ r = efi_set_timer(watchdog_timer_event, EFI_TIMER_STOP, 0); return r; } /* * Initialize the EFI watchdog. * * This function is called by efi_init_obj_list() */ efi_status_t efi_watchdog_register(void) { efi_status_t r; /* * Create a timer event. */ r = efi_create_event(EVT_TIMER | EVT_NOTIFY_SIGNAL, TPL_CALLBACK, efi_watchdog_timer_notify, NULL, NULL, &watchdog_timer_event); if (r != EFI_SUCCESS) { printf("ERROR: Failed to register watchdog event\n"); return r; } /* * The UEFI standard requires that the watchdog timer is set to five * minutes when invoking an EFI boot option. * * Unified Extensible Firmware Interface (UEFI), version 2.7 Errata A * 7.5. Miscellaneous Boot Services - EFI_BOOT_SERVICES.SetWatchdogTimer */ r = efi_set_watchdog(300); if (r != EFI_SUCCESS) { printf("ERROR: Failed to set watchdog timer\n"); return r; } return EFI_SUCCESS; }