[RFC v5 8/8] UefiCpuPkg/CpuExceptionHandlerLib: Add early check in DumpStackContents

[Paulo Alcantara <paulo@paulo.ac>]

Add an early check in DumpStackContens() to abort in case of no unwound
stacks.

Contributed-under: TianoCore Contribution Agreement 1.1
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Paulo Alcantara <paulo@paulo.ac>
---
 UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c | 7 +++++++
 UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c  | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
index 31fbd4a164..ac3801f704 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/Ia32/ArchExceptionHandler.c
@@ -805,6 +805,13 @@ DumpStackContents (
 {
   UINT32 CurrentEsp;
 
+  //
+  // Do nothing in case there wasn't any unwound stack.
+  //
+  if (UnwoundStacksCount == 0) {
+    return;
+  }
+
   //
   // Get current stack pointer
   //
diff --git a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c
index 4d8c9b0a89..6c3bad01a6 100644
--- a/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c
+++ b/UefiCpuPkg/Library/CpuExceptionHandlerLib/X64/ArchExceptionHandler.c
@@ -418,6 +418,13 @@ DumpStackContents (
   UINTN   RspAddressStart;
   UINTN   RspAddressEnd;
 
+  //
+  // Do nothing in case there wasn't any unwound stack.
+  //
+  if (UnwoundStacksCount == 0) {
+    return;
+  }
+
   //
   // Get current stack pointer
   //
-- 
2.14.3