UefiCpuPkg/PiSmmCpuDxeSmm: patch "gSmmInitStack" with PatchInstructionX86()

Rename the variable to "gPatchSmmInitStack" so that its association with
PatchInstructionX86() is clear from the declaration, change its type to
X86_ASSEMBLY_PATCH_LABEL, and patch it with PatchInstructionX86(). This
lets us remove the binary (DB) encoding of some instructions in
"SmmInit.nasm".

The size of the patched source operand is (sizeof (UINTN)).

Cc: Eric Dong <eric.dong@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=866
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
index f59413d9d4..5ff3cd2e73 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmInit.nasm
@@ -25,7 +25,7 @@ extern ASM_PFX(mSmmRelocationOriginalAddress)
 global ASM_PFX(gPatchSmmCr3)

 global ASM_PFX(gPatchSmmCr4)

 global ASM_PFX(gPatchSmmCr0)

-global ASM_PFX(gSmmInitStack)

+global ASM_PFX(gPatchSmmInitStack)

 global ASM_PFX(gcSmiInitGdtr)

 global ASM_PFX(gcSmmInitSize)

 global ASM_PFX(gcSmmInitTemplate)

@@ -72,8 +72,8 @@ BITS 32
     mov     fs, edi

     mov     gs, edi

     mov     ss, edi

-    DB      0xbc                        ; mov esp, imm32

-ASM_PFX(gSmmInitStack): DD 0

+    mov     esp, strict dword 0         ; source operand will be patched

+ASM_PFX(gPatchSmmInitStack):

     call    ASM_PFX(SmmInitHandler)

     rsm