UefiCpuPkg: Use Top of each AP's stack to save CpuMpData

To remove the dependency of CPU register, 4/8 byte at the top of the
stack is occupied for CpuMpData. BIST information is also taken care
here. This modification is only for PEI phase, since in DXE phase
CpuMpData is accessed via global variable.

Signed-off-by: Yuanhao Xie <yuanhao.xie@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>

UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm

@@ -239,11 +239,20 @@ ProgramStack:
     mov         rsp, qword [rdi + CPU_INFO_IN_HOB.ApTopOfStack]
 
 CProcedureInvoke:
+    ;
+    ; Reserve 8 bytes for CpuMpData.
+    ; When the AP wakes up again via INIT-SIPI-SIPI, push 0 will cause the existing CpuMpData to be overwritten with 0.
+    ; CpuMpData is filled in via InitializeApData() during the first time INIT-SIPI-SIPI,
+    ; while overwirrten may occurs when under ApInHltLoop but InitFlag is not set to ApInitConfig.
+    ; Therefore reservation is implemented by sub rsp instead of push 0.
+    ;
+    sub        rsp, 8
     push       rbp               ; Push BIST data at top of AP stack
     xor        rbp, rbp          ; Clear ebp for call stack trace
     push       rbp
     mov        rbp, rsp
 
+    push       qword 0          ; Push 8 bytes for alignment
     mov        rax, qword [esi + MP_CPU_EXCHANGE_INFO_FIELD (InitializeFloatingPointUnits)]
     sub        rsp, 20h
     call       rax               ; Call assembly function to initialize FPU per UEFI spec