1 files changed, 68 insertions, 0 deletions
diff --git a/src/VBox/Devices/EFI/Firmware/IntelFsp2Pkg/Library/BaseFspSwitchStackLib/Ia32/Stack.nasm b/src/VBox/Devices/EFI/Firmware/IntelFsp2Pkg/Library/BaseFspSwitchStackLib/Ia32/Stack.nasm
new file mode 100644
index 00000000..deb7647d
--- /dev/null
+++ b/src/VBox/Devices/EFI/Firmware/IntelFsp2Pkg/Library/BaseFspSwitchStackLib/Ia32/Stack.nasm
@@ -0,0 +1,68 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2016 - 2019, 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
+
+extern ASM_PFX(SwapStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; Pei2LoaderSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(Pei2LoaderSwitchStack)
+ASM_PFX(Pei2LoaderSwitchStack):
+    xor     eax, eax
+    jmp     ASM_PFX(FspSwitchStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; Loader2PeiSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(Loader2PeiSwitchStack)
+ASM_PFX(Loader2PeiSwitchStack):
+    jmp     ASM_PFX(FspSwitchStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; FspSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(FspSwitchStack)
+ASM_PFX(FspSwitchStack):
+    ; Save current contexts
+    push    eax
+    pushfd
+    cli
+    pushad
+    sub     esp, 8
+    sidt    [esp]
+
+    ; Load new stack
+    push    esp
+    call    ASM_PFX(SwapStack)
+    mov     esp, eax
+
+    ; Restore previous contexts
+    lidt    [esp]
+    add     esp, 8
+    popad
+    popfd
+    add     esp, 4
+    ret
+