[edk2-devel] [PATCH v4 3/3] ArmPkg: Disable watchdog interaction after exiting boot services

["Rebecca Cran via groups.io" <rebecca=os.amperecomputing.com@groups.io>]

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>
---
 ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
index 8dd247c44e8f..189194a2b9ee 100644
--- a/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
+++ b/ArmPkg/Drivers/GenericWatchdogDxe/GenericWatchdogDxe.c
@@ -35,10 +35,14 @@ STATIC UINT64  mTimerPeriod = 0;
 
 STATIC UINT8  WatchdogRevision;
 
+/* 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
@@ -93,6 +97,7 @@ WatchdogExitBootServicesEvent (
 {
   WatchdogDisable ();
   mTimerPeriod        = 0;
+  mExitedBootServices = TRUE;
 }
 
 /* This function is called when the watchdog's first signal (WS0) goes high.
@@ -203,7 +208,15 @@ 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)) {
+    mTimerPeriod = 0;
+    WatchdogDisable ();
+    return EFI_DEVICE_ERROR;
+  }
+
+  // If TimerPeriod is 0 this is a request to stop the watchdog.
   if (TimerPeriod == 0) {
     mTimerPeriod = 0;
     WatchdogDisable ();
@@ -307,8 +320,6 @@ STATIC EFI_WATCHDOG_TIMER_ARCH_PROTOCOL  mWatchdogTimer = {
   WatchdogGetTimerPeriod
 };
 
-STATIC EFI_EVENT  mEfiExitBootServicesEvent;
-
 EFI_STATUS
 EFIAPI
 GenericWatchdogEntry (
-- 
2.34.1



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