UefiPayloadPkg: Enhance UEFI payload for coreboot and Slim Bootloader

[mirror_edk2.git] / UefiPayloadPkg / SecCore / Ia32 / Stack.nasm

diff --git a/UefiPayloadPkg/SecCore/Ia32/Stack.nasm b/UefiPayloadPkg/SecCore/Ia32/Stack.nasm
new file mode 100644 (file)
index 0000000..55fd224
--- /dev/null
+++ b/UefiPayloadPkg/SecCore/Ia32/Stack.nasm
@@ -0,0 +1,72 @@
+;------------------------------------------------------------------------------\r
+;\r
+; Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>\r
+; SPDX-License-Identifier: BSD-2-Clause-Patent\r
+;\r
+; Abstract:\r
+;\r
+;   Switch the stack from temporary memory to permanent memory.\r
+;\r
+;------------------------------------------------------------------------------\r
+\r
+SECTION .text\r
+\r
+;------------------------------------------------------------------------------\r
+; VOID\r
+; EFIAPI\r
+; SecSwitchStack (\r
+;   UINT32   TemporaryMemoryBase,\r
+;   UINT32   PermenentMemoryBase\r
+;   );\r
+;------------------------------------------------------------------------------\r
+global ASM_PFX(SecSwitchStack)\r
+ASM_PFX(SecSwitchStack):\r
+    ;\r
+    ; Save three register: eax, ebx, ecx\r
+    ;\r
+    push  eax\r
+    push  ebx\r
+    push  ecx\r
+    push  edx\r
+\r
+    ;\r
+    ; !!CAUTION!! this function address's is pushed into stack after\r
+    ; migration of whole temporary memory, so need save it to permanent\r
+    ; memory at first!\r
+    ;\r
+\r
+    mov   ebx,  [esp + 20]          ; Save the first parameter\r
+    mov   ecx,  [esp + 24]          ; Save the second parameter\r
+\r
+    ;\r
+    ; Save this function's return address into permanent memory at first.\r
+    ; Then, Fixup the esp point to permanent memory\r
+    ;\r
+    mov   eax,  esp\r
+    sub   eax,  ebx\r
+    add   eax,  ecx\r
+    mov   edx,  [esp]               ; copy pushed register's value to permanent memory\r
+    mov   [eax], edx\r
+    mov   edx,  [esp + 4]\r
+    mov   [eax + 4], edx\r
+    mov   edx,  [esp + 8]\r
+    mov   [eax + 8], edx\r
+    mov   edx,  [esp + 12]\r
+    mov   [eax + 12], edx\r
+    mov   edx,  [esp + 16]          ; Update return address into permanent memory\r
+    mov   [eax + 16], edx\r
+    mov   esp,  eax                 ; From now, esp is pointed to permanent memory\r
+\r
+    ;\r
+    ; Fixup the ebp point to permanent memory\r
+    ;\r
+    mov   eax,  ebp\r
+    sub   eax,  ebx\r
+    add   eax,  ecx\r
+    mov   ebp,  eax                 ; From now, ebp is pointed to permanent memory\r
+\r
+    pop   edx\r
+    pop   ecx\r
+    pop   ebx\r
+    pop   eax\r
+    ret\r