[PATCH V3 09/10] OvmfPkg: Create Main.asm in ResetVector


Min Xu
 

RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429

According to suggestion in https://edk2.groups.io/g/devel/message/78152
we drop UefiCpuPkg changes and focus on improving OvmfPkg. So Main.asm
is created in OvmfPkg/ResetVector which is simply copied from UefiCpuPkg.
In the next commit this Main.asm will be updated to add a new Entry
(Main32) to support Tdx.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
OvmfPkg/ResetVector/Main.asm | 105 +++++++++++++++++++++++++++++++++++
1 file changed, 105 insertions(+)
create mode 100644 OvmfPkg/ResetVector/Main.asm

diff --git a/OvmfPkg/ResetVector/Main.asm b/OvmfPkg/ResetVector/Main.asm
new file mode 100644
index 000000000000..dbebfb9e5d29
--- /dev/null
+++ b/OvmfPkg/ResetVector/Main.asm
@@ -0,0 +1,105 @@
+;------------------------------------------------------------------------------
+; @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
+
+ ;
+ ; 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
+
+ ;
+ ; 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
+
+
--
2.29.2.windows.2