Re: [edk2-devel][PATCH v3 1/8] IntelFsp2Pkg: X64 compatible changes to support PEI in 64bit

["Kuo, Ted" <ted.kuo@intel.com>]

Hi Ray,

Please see my inline comment.

Thanks,
Ted

-----Original Message-----
From: Ni, Ray <ray.ni@intel.com> 
Sent: Thursday, April 7, 2022 7:58 AM
To: devel@edk2.groups.io; Kuo, Ted <ted.kuo@intel.com>
Cc: Chiu, Chasel <chasel.chiu@intel.com>; Desimone, Nathaniel L <nathaniel.l.desimone@intel.com>; Zeng, Star <star.zeng@intel.com>; S, Ashraf Ali <ashraf.ali.s@intel.com>
Subject: RE: [edk2-devel][PATCH v3 1/8] IntelFsp2Pkg: X64 compatible changes to support PEI in 64bit

> -; UINT32
> +; UINTN
>  ; EFIAPI
> -; AsmReadEsp (
> +; AsmReadStackPointer (
>  ;   VOID
>  ;   );
>  ;------------------------------------------------------------------------------
> -global ASM_PFX(AsmReadEsp)
> -ASM_PFX(AsmReadEsp):
> +global ASM_PFX(AsmReadStackPointer)
> +ASM_PFX(AsmReadStackPointer):
>      mov     eax, esp
>      ret
> 

I guess it's possible that bootloader sets up the stack above 4G.
If that's the case, above code doesn't work.
[Ted]: The above code is for IA32 only. We have a separate ReadRsp.nasm for X64. You can find it in the patch [edk2-devel][PATCH v3 4/8] IntelFsp2Pkg: FspSecCore support for X64.