Re: [edk2-devel] [PATCH v3 3/3] ArmPkg: Disable watchdog interaction after exiting boot services

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Rebecca,

Thank you for this patch. 
Please see my feedback inline marked [SAMI].

Regards,

Sami Mujawar

On 05/01/2024, 05:15, "Rebecca Cran" <rebecca@os.amperecomputing.com <mailto:rebecca@os.amperecomputing.com>> wrote:


Update GenericWatchdogDxe to disable watchdog interaction after exiting
boot services. Also, move the mEfiExitBootServicesEvent event to the top
of the file with the other static variables.


Signed-off-by: Rebecca Cran <rebecca@os.amperecomputing.com <mailto:rebecca@os.amperecomputing.com>>
---
ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)


diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
index 78cee62a19d6..ddf131660f9d 100644
--- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
+++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
@@ -33,10 +33,14 @@
It is therefore stored here. 0 means the timer is not running. */
STATIC UINT64 mTimerPeriod = 0;


+/* disables watchdog interaction after Exit Boot Services */
+STATIC BOOLEAN mExitedBootServices = FALSE;
+
#define MAX_UINT48 0xFFFFFFFFFFFFULL


STATIC EFI_HARDWARE_INTERRUPT2_PROTOCOL *mInterruptProtocol;
STATIC EFI_WATCHDOG_TIMER_NOTIFY mWatchdogNotify;
+STATIC EFI_EVENT mEfiExitBootServicesEvent;


STATIC
VOID
@@ -200,7 +204,13 @@ WatchdogSetTimerPeriod (
UINT64 TimerFrequencyHz;
UINT64 NumTimerTicks;


- // if TimerPeriod is 0, this is a request to stop the watchdog.
+ // If we've exited Boot Services but TimerPeriod isn't zero, this
+ // indicates that the caller is doing something wrong.
+ if (mExitedBootServices && (TimerPeriod != 0)) {
[SAMI] Thanks for updating the code to return the error code. 
However, I see you are not stopping the watchdog timer. Is this because you expect the watchdog period to expire and reset the system? 
Also, did you see an issue that motivated this patch, or this was just a case of hardening the code?
Can you provide more information, please?
[/SAMI]
+ return EFI_DEVICE_ERROR;
+ }
+
+ // If TimerPeriod is 0 this is a request to stop the watchdog.
if (TimerPeriod == 0) {
mTimerPeriod = 0;
WatchdogDisable ();
@@ -304,8 +314,6 @@ STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL mWatchdogTimer = {
WatchdogGetTimerPeriod
};


-STATIC EFI_EVENT mEfiExitBootServicesEvent;
-
EFI_STATUS
EFIAPI
GenericWatchdogEntry (
-- 
2.34.1







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