efi_watchdog.c
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/*
* EFI watchdog
*
* Copyright (c) 2017 Heinrich Schuchardt
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <efi_loader.h>
/* 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()
*/
int 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,
&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 0;
}