OvmfPkg/PlatformInitLib: Add PlatformGetLowMemoryCB

[mirror_edk2.git] / OvmfPkg / ResetVector / Main.asm

;------------------------------------------------------------------------------\r
; @file\r
; Main routine of the pre-SEC code up through the jump into SEC\r
;\r
; Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>\r
; SPDX-License-Identifier: BSD-2-Clause-Patent\r
;\r
;------------------------------------------------------------------------------\r
\r
\r
BITS    16\r
\r
;\r
; Modified:  EBX, ECX, EDX, EBP\r
;\r
; @param[in,out]  RAX/EAX  Initial value of the EAX register\r
;                          (BIST: Built-in Self Test)\r
; @param[in,out]  DI       'BP': boot-strap processor, or\r
;                          'AP': application processor\r
; @param[out]     RBP/EBP  Address of Boot Firmware Volume (BFV)\r
; @param[out]     DS       Selector allowing flat access to all addresses\r
; @param[out]     ES       Selector allowing flat access to all addresses\r
; @param[out]     FS       Selector allowing flat access to all addresses\r
; @param[out]     GS       Selector allowing flat access to all addresses\r
; @param[out]     SS       Selector allowing flat access to all addresses\r
;\r
; @return         None  This routine jumps to SEC and does not return\r
;\r
Main16:\r
    OneTimeCall EarlyInit16\r
\r
    ;\r
    ; Transition the processor from 16-bit real mode to 32-bit flat mode\r
    ;\r
    OneTimeCall TransitionFromReal16To32BitFlat\r
\r
BITS    32\r
\r
    ; Clear the WorkArea header. The SEV probe routines will populate the\r
    ; work area when detected.\r
    mov     byte[WORK_AREA_GUEST_TYPE], 0\r
\r
%ifdef ARCH_X64\r
\r
    jmp SearchBfv\r
\r
;\r
; Entry point of Main32\r
;\r
Main32:\r
    OneTimeCall InitTdx\r
\r
SearchBfv:\r
\r
%endif\r
\r
    ;\r
    ; Search for the Boot Firmware Volume (BFV)\r
    ;\r
    OneTimeCall Flat32SearchForBfvBase\r
\r
    ;\r
    ; EBP - Start of BFV\r
    ;\r
\r
    ;\r
    ; Search for the SEC entry point\r
    ;\r
    OneTimeCall Flat32SearchForSecEntryPoint\r
\r
    ;\r
    ; ESI - SEC Core entry point\r
    ; EBP - Start of BFV\r
    ;\r
\r
%ifdef ARCH_IA32\r
\r
    ;\r
    ; SEV support can be built and run using the Ia32/X64 split environment.\r
    ; Set the OVMF/SEV work area as appropriate.\r
    ;\r
    OneTimeCall CheckSevFeatures\r
\r
    ;\r
    ; Restore initial EAX value into the EAX register\r
    ;\r
    mov     eax, esp\r
\r
    ;\r
    ; Jump to the 32-bit SEC entry point\r
    ;\r
    jmp     esi\r
\r
%else\r
\r
    ;\r
    ; Transition the processor from 32-bit flat mode to 64-bit flat mode\r
    ;\r
    OneTimeCall Transition32FlatTo64Flat\r
\r
BITS    64\r
\r
    ;\r
    ; Some values were calculated in 32-bit mode.  Make sure the upper\r
    ; 32-bits of 64-bit registers are zero for these values.\r
    ;\r
    mov     rax, 0x00000000ffffffff\r
    and     rsi, rax\r
    and     rbp, rax\r
    and     rsp, rax\r
\r
    ;\r
    ; RSI - SEC Core entry point\r
    ; RBP - Start of BFV\r
    ;\r
\r
    ;\r
    ; Restore initial EAX value into the RAX register\r
    ;\r
    mov     rax, rsp\r
\r
    ;\r
    ; Jump to the 64-bit SEC entry point\r
    ;\r
    jmp     rsi\r
\r
%endif\r