diff options
Diffstat (limited to 'UefiPayloadPkg/SecCore/Ia32/Stack.nasm')
-rw-r--r-- | UefiPayloadPkg/SecCore/Ia32/Stack.nasm | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/UefiPayloadPkg/SecCore/Ia32/Stack.nasm b/UefiPayloadPkg/SecCore/Ia32/Stack.nasm new file mode 100644 index 0000000000..55fd2243c8 --- /dev/null +++ b/UefiPayloadPkg/SecCore/Ia32/Stack.nasm @@ -0,0 +1,72 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Abstract:
+;
+; Switch the stack from temporary memory to permanent memory.
+;
+;------------------------------------------------------------------------------
+
+SECTION .text
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; SecSwitchStack (
+; UINT32 TemporaryMemoryBase,
+; UINT32 PermenentMemoryBase
+; );
+;------------------------------------------------------------------------------
+global ASM_PFX(SecSwitchStack)
+ASM_PFX(SecSwitchStack):
+ ;
+ ; Save three register: eax, ebx, ecx
+ ;
+ push eax
+ push ebx
+ push ecx
+ push edx
+
+ ;
+ ; !!CAUTION!! this function address's is pushed into stack after
+ ; migration of whole temporary memory, so need save it to permanent
+ ; memory at first!
+ ;
+
+ mov ebx, [esp + 20] ; Save the first parameter
+ mov ecx, [esp + 24] ; Save the second parameter
+
+ ;
+ ; Save this function's return address into permanent memory at first.
+ ; Then, Fixup the esp point to permanent memory
+ ;
+ mov eax, esp
+ sub eax, ebx
+ add eax, ecx
+ mov edx, [esp] ; copy pushed register's value to permanent memory
+ mov [eax], edx
+ mov edx, [esp + 4]
+ mov [eax + 4], edx
+ mov edx, [esp + 8]
+ mov [eax + 8], edx
+ mov edx, [esp + 12]
+ mov [eax + 12], edx
+ mov edx, [esp + 16] ; Update return address into permanent memory
+ mov [eax + 16], edx
+ mov esp, eax ; From now, esp is pointed to permanent memory
+
+ ;
+ ; Fixup the ebp point to permanent memory
+ ;
+ mov eax, ebp
+ sub eax, ebx
+ add eax, ecx
+ mov ebp, eax ; From now, ebp is pointed to permanent memory
+
+ pop edx
+ pop ecx
+ pop ebx
+ pop eax
+ ret
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