[PATCH] MdeModulePkg/UefiBootManagerLib: Remove assertion

[Ruiyu Ni <ruiyu.ni@intel.com>]

EfiBootManagerStartHotkeyService() asserts when "BootOptionSupport"
variable doesn't exist.

In fact, though "BootOptionSupport" variable is set in BdsDxe
module, it's possible that the variable is deleted by
PlatformBootManagerBeforeConsole().

The patch removes the assertion and adds code to handle the case.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
---
 MdeModulePkg/Library/UefiBootManagerLib/BmHotkey.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/MdeModulePkg/Library/UefiBootManagerLib/BmHotkey.c b/MdeModulePkg/Library/UefiBootManagerLib/BmHotkey.c
index efad073880..d18ce02eb3 100644
--- a/MdeModulePkg/Library/UefiBootManagerLib/BmHotkey.c
+++ b/MdeModulePkg/Library/UefiBootManagerLib/BmHotkey.c
@@ -870,13 +870,13 @@ EfiBootManagerStartHotkeyService (
   EFI_EVENT                    Event;
   UINT32                       *BootOptionSupport;
 
-  Status = GetEfiGlobalVariable2 (EFI_BOOT_OPTION_SUPPORT_VARIABLE_NAME, (VOID **) &BootOptionSupport, NULL);
-  ASSERT (BootOptionSupport != NULL);
-
-  if ((*BootOptionSupport & EFI_BOOT_OPTION_SUPPORT_KEY)  != 0) {
-    mBmHotkeySupportCount = ((*BootOptionSupport & EFI_BOOT_OPTION_SUPPORT_COUNT) >> LowBitSet32 (EFI_BOOT_OPTION_SUPPORT_COUNT));
+  GetEfiGlobalVariable2 (EFI_BOOT_OPTION_SUPPORT_VARIABLE_NAME, (VOID **) &BootOptionSupport, NULL);
+  if (BootOptionSupport != NULL) {
+    if ((*BootOptionSupport & EFI_BOOT_OPTION_SUPPORT_KEY)  != 0) {
+      mBmHotkeySupportCount = ((*BootOptionSupport & EFI_BOOT_OPTION_SUPPORT_COUNT) >> LowBitSet32 (EFI_BOOT_OPTION_SUPPORT_COUNT));
+    }
+    FreePool (BootOptionSupport);
   }
-  FreePool (BootOptionSupport);
 
   if (mBmHotkeySupportCount == 0) {
     DEBUG ((EFI_D_INFO, "Bds: BootOptionSupport NV variable forbids starting the hotkey service.\n"));
-- 
2.15.0.gvfs.1.preview.4