Hi Abner,

Yes, I think it might be a coincidence, in fact, we have been using the UDK2018 since 2018, and this code are not been modified after adding it.
I think maybe be our are all refer to the ARM architecture. Looking at this code, the function HandOffToDxeCore just switches from the PEI stage to the DXE stage, make stack of C environment, ends of PEI, and prepare to enter the DXE core.

--
Thanks,
Chao
------------------------

On 4月 8 2022, at 7:13 晚上, "Chang, Abner (HPS SW/FW Technologist)" <abner.chang@hpe.com> wrote:
> DxeLoadFunc.c is almost the same as RISC-V instance. However, I don't have idea how to leverage it because DxeLoadFunc is currently in the architecture-based folder.
>
> Acked-by: Abner Chang <abner.chang@hpe.com>
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Chao Li
> > Sent: Wednesday, February 9, 2022 4:02 PM
> > To: devel@edk2.groups.io
> > Cc: Liming Gao <gaoliming@byosoft.com.cn>; Guomin Jiang
> > <guomin.jiang@intel.com>; Baoqi Zhang <zhangbaoqi@loongson.cn>
> > Subject: [edk2-devel] [staging/LoongArch RESEND PATCH v1 30/33]
> > MdeModulePkg/DxeIplPeim : LoongArch DxeIPL implementation.
> >
> > Implement LoongArch DxeIPL instance.
> >
> > Cc: Liming Gao <gaoliming@byosoft.com.cn>
> > Cc: Guomin Jiang <guomin.jiang@intel.com>
> >
> > Signed-off-by: Chao Li <lichao@loongson.cn>
> > Co-authored-by: Baoqi Zhang <zhangbaoqi@loongson.cn>
> > ---
> > MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf | 6 +-
> > .../Core/DxeIplPeim/LoongArch64/DxeLoadFunc.c | 61
> > +++++++++++++++++++
> > 2 files changed, 66 insertions(+), 1 deletion(-)
> > create mode 100644
> > MdeModulePkg/Core/DxeIplPeim/LoongArch64/DxeLoadFunc.c
> >
> > diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
> > b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
> > index 19b8a4c8ae..052ea0ec1a 100644
> > --- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
> > +++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
> > @@ -8,6 +8,7 @@
> > # Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
> > # Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
> > # Copyright (c) 2020, Hewlett Packard Enterprise Development LP. All rights
> > reserved.<BR>
> > +# Copyright (c) 2022, Loongson Technology Corporation Limited. All rights
> > reserved.<BR>
> > #
> > # SPDX-License-Identifier: BSD-2-Clause-Patent
> > #
> > @@ -26,7 +27,7 @@
> > #
> > # The following information is for reference only and not required by the
> > build tools.
> > #
> > -# VALID_ARCHITECTURES = IA32 X64 EBC (EBC is for build only)
> > AARCH64 RISCV64
> > +# VALID_ARCHITECTURES = IA32 X64 EBC (EBC is for build only)
> > AARCH64 RISCV64 LOONGARCH64
> > #
> >
> > [Sources]
> > @@ -53,6 +54,9 @@
> > [Sources.RISCV64]
> > RiscV64/DxeLoadFunc.c
> >
> > +[Sources.LOONGARCH64]
> > + LoongArch64/DxeLoadFunc.c
> > +
> > [Packages]
> > MdePkg/MdePkg.dec
> > MdeModulePkg/MdeModulePkg.dec
> > diff --git a/MdeModulePkg/Core/DxeIplPeim/LoongArch64/DxeLoadFunc.c
> > b/MdeModulePkg/Core/DxeIplPeim/LoongArch64/DxeLoadFunc.c
> > new file mode 100644
> > index 0000000000..27ffc072d0
> > --- /dev/null
> > +++ b/MdeModulePkg/Core/DxeIplPeim/LoongArch64/DxeLoadFunc.c
> > @@ -0,0 +1,61 @@
> > +/** @file
> > + LoongArch specifc functionality for DxeLoad.
> > +
> > + Copyright (c) 2022, Loongson Technology Corporation Limited. All rights
> > reserved.<BR>
> > +
> > + SPDX-License-Identifier: BSD-2-Clause-Patent
> > +
> > +**/
> > +
> > +#include "DxeIpl.h"
> > +
> > +/**
> > + Transfers control to DxeCore.
> > +
> > + This function performs a CPU architecture specific operations to execute
> > + the entry point of DxeCore with the parameters of HobList.
> > + It also installs EFI_END_OF_PEI_PPI to signal the end of PEI phase.
> > +
> > + @param DxeCoreEntryPoint The entry point of DxeCore.
> > + @param HobList The start of HobList passed to DxeCore.
> > +
> > +**/
> > +VOID
> > +HandOffToDxeCore (
> > + IN EFI_PHYSICAL_ADDRESS DxeCoreEntryPoint,
> > + IN EFI_PEI_HOB_POINTERS HobList
> > + )
> > +{
> > + VOID *BaseOfStack;
> > + VOID *TopOfStack;
> > + EFI_STATUS Status;
> > +
> > + //
> > + // Allocate 128KB for the Stack
> > + //
> > + BaseOfStack = AllocatePages (EFI_SIZE_TO_PAGES (STACK_SIZE));
> > + ASSERT (BaseOfStack != NULL);
> > + //
> > + // Compute the top of the stack we were allocated. Pre-allocate a UINTN
> > + // for safety.
> > + //
> > + TopOfStack = (VOID *) ((UINTN) BaseOfStack + EFI_SIZE_TO_PAGES
> > (STACK_SIZE) * EFI_PAGE_SIZE - CPU_STACK_ALIGNMENT);
> > + TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
> > + //
> > + // End of PEI phase singal
> > + //
> > + Status = PeiServicesInstallPpi (&gEndOfPeiSignalPpi);
> > + ASSERT_EFI_ERROR (Status);
> > +
> > + //
> > + // Update the contents of BSP stack HOB to reflect the real stack info
> > passed to DxeCore.
> > + //
> > + UpdateStackHob ((EFI_PHYSICAL_ADDRESS)(UINTN) BaseOfStack,
> > STACK_SIZE);
> > +
> > + SwitchStack (
> > + (SWITCH_STACK_ENTRY_POINT)(UINTN)DxeCoreEntryPoint,
> > + HobList.Raw,
> > + NULL,
> > + TopOfStack
> > + );
> > +}
> > --
> > 2.27.0
> >
> >
> >
> > 
> >
>