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|
;------------------------------------------------------------------------------
; @file
; Main routine of the pre-SEC code up through the jump into SEC
;
; Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
BITS 16
;
; Modified: EBX, ECX, EDX, EBP
;
; @param[in,out] RAX/EAX Initial value of the EAX register
; (BIST: Built-in Self Test)
; @param[in,out] DI 'BP': boot-strap processor, or
; 'AP': application processor
; @param[out] RBP/EBP Address of Boot Firmware Volume (BFV)
; @param[out] DS Selector allowing flat access to all addresses
; @param[out] ES Selector allowing flat access to all addresses
; @param[out] FS Selector allowing flat access to all addresses
; @param[out] GS Selector allowing flat access to all addresses
; @param[out] SS Selector allowing flat access to all addresses
;
; @return None This routine jumps to SEC and does not return
;
Main16:
OneTimeCall EarlyInit16
;
; Transition the processor from 16-bit real mode to 32-bit flat mode
;
OneTimeCall TransitionFromReal16To32BitFlat
BITS 32
; Clear the WorkArea header. The SEV probe routines will populate the
; work area when detected.
mov byte[WORK_AREA_GUEST_TYPE], 0
%ifdef ARCH_X64
jmp SearchBfv
;
; Entry point of Main32
;
Main32:
;
; First load the GDT and jump to Flat32 mode
;
OneTimeCall ReloadFlat32
SearchBfv:
;
; install #vc exception handler (for cpuid on sev)
;
OneTimeCall SevCpuidInit
OneTimeCall InitTdx
%endif
;
; Search for the Boot Firmware Volume (BFV)
;
OneTimeCall Flat32SearchForBfvBase
;
; EBP - Start of BFV
;
;
; Search for the SEC entry point
;
OneTimeCall Flat32SearchForSecEntryPoint
;
; ESI - SEC Core entry point
; EBP - Start of BFV
;
%ifdef ARCH_IA32
;
; SEV support can be built and run using the Ia32/X64 split environment.
; Set the OVMF/SEV work area as appropriate.
;
OneTimeCall CheckSevFeatures
;
; Restore initial EAX value into the EAX register
;
mov eax, esp
;
; Jump to the 32-bit SEC entry point
;
jmp esi
%else
;
; Transition the processor from 32-bit flat mode to 64-bit flat mode
;
OneTimeCall Transition32FlatTo64Flat
BITS 64
;
; Some values were calculated in 32-bit mode. Make sure the upper
; 32-bits of 64-bit registers are zero for these values.
;
mov rax, 0x00000000ffffffff
and rsi, rax
and rbp, rax
and rsp, rax
;
; RSI - SEC Core entry point
; RBP - Start of BFV
;
;
; Restore initial EAX value into the RAX register
;
mov rax, rsp
;
; Jump to the 64-bit SEC entry point
;
jmp rsi
%endif
|
