[PATCH] UefiCpuPkg/CpuMpPei: fix unsafe way to get stack pointer

[Jian J Wang <jian.j.wang@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1186

This patch uses SetJump() to get the stack pointer from esp/rsp
register to replace local variable way, which was marked by static
code checker as an unsafe way.

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 UefiCpuPkg/CpuMpPei/CpuMpPei.h  | 8 ++++++++
 UefiCpuPkg/CpuMpPei/CpuPaging.c | 9 +++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/UefiCpuPkg/CpuMpPei/CpuMpPei.h b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
index d097a66aa8..fe61f5e3bc 100644
--- a/UefiCpuPkg/CpuMpPei/CpuMpPei.h
+++ b/UefiCpuPkg/CpuMpPei/CpuMpPei.h
@@ -35,6 +35,14 @@
 
 extern EFI_PEI_PPI_DESCRIPTOR   mPeiCpuMpPpiDesc;
 
+#if   defined (MDE_CPU_IA32)
+#define CPU_STACK_POINTER(Context)  ((Context).Esp)
+#elif defined (MDE_CPU_X64)
+#define CPU_STACK_POINTER(Context)  ((Context).Rsp)
+#else
+#error CPU type not supported!
+#endif
+
 /**
   This service retrieves the number of logical processor in the platform
   and the number of those logical processors that are enabled on this boot.
diff --git a/UefiCpuPkg/CpuMpPei/CpuPaging.c b/UefiCpuPkg/CpuMpPei/CpuPaging.c
index c7e0822452..997c20c26e 100644
--- a/UefiCpuPkg/CpuMpPei/CpuPaging.c
+++ b/UefiCpuPkg/CpuMpPei/CpuPaging.c
@@ -517,9 +517,14 @@ GetStackBase (
   IN OUT VOID *Buffer
   )
 {
-  EFI_PHYSICAL_ADDRESS    StackBase;
+  EFI_PHYSICAL_ADDRESS      StackBase;
+  BASE_LIBRARY_JUMP_BUFFER  Context;
 
-  StackBase = (EFI_PHYSICAL_ADDRESS)(UINTN)&StackBase;
+  //
+  // Retrieve stack pointer from current processor context.
+  //
+  SetJump (&Context);
+  StackBase = (EFI_PHYSICAL_ADDRESS)CPU_STACK_POINTER (Context);
   StackBase += BASE_4KB;
   StackBase &= ~((EFI_PHYSICAL_ADDRESS)BASE_4KB - 1);
   StackBase -= PcdGet32(PcdCpuApStackSize);
-- 
2.16.2.windows.1