[U-Boot] [PATCH 06/11] efi_loader: implement SetWatchdogTimer
Heinrich Schuchardt
xypron.glpk at gmx.de
Mon Oct 9 06:05:13 UTC 2017
On 10/09/2017 06:42 AM, Alexander Graf wrote:
>
>
> On 08.10.17 06:57, Heinrich Schuchardt wrote:
>> The watchdog is initialized with a 5 minute timeout period.
>> It can be reset by SetWatchdogTimer.
>> It is stopped by ExitBoottimeServices.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>> cmd/bootefi.c | 1 +
>> include/efi_loader.h | 4 +++
>> lib/efi_loader/Makefile | 2 +-
>> lib/efi_loader/efi_boottime.c | 15 ++---------
>> lib/efi_loader/efi_watchdog.c | 59 +++++++++++++++++++++++++++++++++++++++++++
>> 5 files changed, 67 insertions(+), 14 deletions(-)
>> create mode 100644 lib/efi_loader/efi_watchdog.c
>>
>> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
>> index b7087e3da8..24958ada46 100644
>> --- a/cmd/bootefi.c
>> +++ b/cmd/bootefi.c
>> @@ -43,6 +43,7 @@ static void efi_init_obj_list(void)
>> #ifdef CONFIG_GENERATE_SMBIOS_TABLE
>> efi_smbios_register();
>> #endif
>> + efi_watchdog_register();
>>
>> /* Initialize EFI runtime services */
>> efi_reset_system_init();
>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>> index e1179b7dcd..223d8d8222 100644
>> --- a/include/efi_loader.h
>> +++ b/include/efi_loader.h
>> @@ -163,6 +163,8 @@ int efi_disk_register(void);
>> int efi_gop_register(void);
>> /* Called by bootefi to make the network interface available */
>> int efi_net_register(void);
>> +/* Called by bootefi to make the watchdog available */
>> +int efi_watchdog_register(void);
>> /* Called by bootefi to make SMBIOS tables available */
>> void efi_smbios_register(void);
>>
>> @@ -171,6 +173,8 @@ efi_fs_from_path(struct efi_device_path *fp);
>>
>> /* Called by networking code to memorize the dhcp ack package */
>> void efi_net_set_dhcp_ack(void *pkt, int len);
>> +/* Called by efi_set_watchdog_timer to reset the timer */
>> +efi_status_t efi_set_watchdog(unsigned long timeout);
>>
>> /* Called from places to check whether a timer expired */
>> void efi_timer_check(void);
>> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
>> index ddb978f650..83d879b686 100644
>> --- a/lib/efi_loader/Makefile
>> +++ b/lib/efi_loader/Makefile
>> @@ -17,7 +17,7 @@ endif
>> obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
>> obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
>> obj-y += efi_memory.o efi_device_path_to_text.o efi_device_path.o
>> -obj-y += efi_file.o efi_variable.o efi_bootmgr.o
>> +obj-y += efi_file.o efi_variable.o efi_bootmgr.o efi_watchdog.o
>> obj-$(CONFIG_LCD) += efi_gop.o
>> obj-$(CONFIG_DM_VIDEO) += efi_gop.o
>> obj-$(CONFIG_PARTITIONS) += efi_disk.o
>> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>> index 30577f717e..81e7d818fc 100644
>> --- a/lib/efi_loader/efi_boottime.c
>> +++ b/lib/efi_loader/efi_boottime.c
>> @@ -155,18 +155,6 @@ void efi_signal_event(struct efi_event *event)
>> event->is_queued = false;
>> }
>>
>> -/*
>> - * Write a debug message for an EPI API service that is not implemented yet.
>> - *
>> - * @funcname function that is not yet implemented
>> - * @return EFI_UNSUPPORTED
>> - */
>> -static efi_status_t efi_unsupported(const char *funcname)
>> -{
>> - debug("EFI: App called into unimplemented function %s\n", funcname);
>> - return EFI_EXIT(EFI_UNSUPPORTED);
>> -}
>> -
>> /*
>> * Raise the task priority level.
>> *
>> @@ -1454,6 +1442,7 @@ static efi_status_t EFIAPI efi_exit_boot_services(void *image_handle,
>> bootm_disable_interrupts();
>>
>> /* Give the payload some time to boot */
>> + efi_set_watchdog(0);
>> WATCHDOG_RESET();
>>
>> return EFI_EXIT(EFI_SUCCESS);
>> @@ -1514,7 +1503,7 @@ static efi_status_t EFIAPI efi_set_watchdog_timer(unsigned long timeout,
>> {
>> EFI_ENTRY("%ld, 0x%"PRIx64", %ld, %p", timeout, watchdog_code,
>> data_size, watchdog_data);
>> - return efi_unsupported(__func__);
>> + return EFI_EXIT(efi_set_watchdog(timeout));
>> }
>>
>> /*
>> diff --git a/lib/efi_loader/efi_watchdog.c b/lib/efi_loader/efi_watchdog.c
>> new file mode 100644
>> index 0000000000..50e95290ea
>> --- /dev/null
>> +++ b/lib/efi_loader/efi_watchdog.c
>> @@ -0,0 +1,59 @@
>> +/*
>> + * EFI device path interface
>
> Not quite I guess?
>
>> + *
>> + * Copyright (c) 2017 Heinrich Schuchardt
>> + *
>> + * SPDX-License-Identifier: GPL-2.0+
>> + */
>> +
>> +#include <common.h>
>> +#include <efi_loader.h>
>> +
>> +static struct efi_event *watchdog_timer_event;
>> +
>> +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);
>> +}
>> +
>> +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,
>> + 10000000 * timeout);
>> + else
>> + /* Deactivate watchdog */
>> + r = efi_set_timer(watchdog_timer_event, EFI_TIMER_STOP, 0);
>> + return r;
>> +}
>> +
>> +/* This gets called from do_bootefi_exec(). */
>> +int efi_watchdog_register(void)
>> +{
>> + efi_status_t r;
>> +
>> + r = efi_create_event(EVT_TIMER | EVT_NOTIFY_SIGNAL, TPL_CALLBACK,
>> + efi_watchdog_timer_notify, NULL,
>> + &watchdog_timer_event);
>
> How useful is a timer based watchdog without proper timer implementation?
>
Do we have boards where the timer does not work?
On these we would have problems with EFI applications.
> Is there a specific case where you needed it working?
Both EFI shell and iPXE reset the timer.
>
> Also, is there a good reason not to use the hardware watchdog when it's
> available?
How can I detect that the hardware watchdog is usable?
Can I set hardware watchdogs to arbitrary timeouts?
We need the EFI timer to be working anyway for many applications.
>
>> + if (r != EFI_SUCCESS) {
>> + printf("ERROR: Failed to register watchdog event\n");
>> + return r;
>> + }
>> + /* Set watchdog to trigger after 5 minutes */
>> + r = efi_set_watchdog(300);
>
> Is this expected somewhere? Does the spec mention default watchdog timeouts?
UEFI Spec 2.7 Erratum A:
<cite>The watchdog must be set to a period of 5 minutes. The EFI
Image may reset or disable the watchdog timer as needed. If control
is returned to the firmware's boot manager, the watchdog timer must
be disabled.</cite>
Regards
Heinrich
>
>
> Alex
>
>> + if (r != EFI_SUCCESS) {
>> + printf("ERROR: Failed to set watchdog timer\n");
>> + return r;
>> + }
>> + return 0;
>> +}
>>
>
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