; $Id$
;; @file
; SUP - Support Library, ring-0 stack switching wrappers.
;

;
; Copyright (C) 2006-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;

%ifndef ___VBox_SUPR0StackWrapper_mac
%define ___VBox_SUPR0StackWrapper_mac

%include "VBox/asmdefs.mac"

;; VBox's own Stack
%define SUPR0STACKINFO_MAGIC0 0786f4256h    ; VBox
%define SUPR0STACKINFO_MAGIC1 06f207327h    ; 's o
%define SUPR0STACKINFO_MAGIC2 053206e77h    ; wn S
%define SUPR0STACKINFO_MAGIC3 06b636174h    ; tack

;;
; Stack info located before the start of the stack, at the top of the page.
;
struc SUPR0STACKINFO
        .magic0             resd   1
        .magic1             resd   1
        .magic2             resd   1
        .magic3             resd   1
        .pResumeKernelStack resq   1
        .pSelf              resq   1
endstruc

;;
; Number of parameters in GPRs and the spill area size.
%ifdef RT_ARCH_AMD64
 %ifdef ASM_CALL64_MSC
  %define SUPR0_GRP_PARAMS      4
  %define SUPR0_SPILL_AREA      4
 %else
  %define SUPR0_GRP_PARAMS      6
  %define SUPR0_SPILL_AREA      0
 %endif
%else
 %define SUPR0_GRP_PARAMS       0
 %define SUPR0_SPILL_AREA       0
%endif

;;
; Generic stack switching wrapper.
;
; @param %1     The name
; @param %2     Number of arguments.
;
%macro SUPR0StackWrapperGeneric 2
BEGINCODE
extern NAME(StkBack_ %+ %1)

BEGINPROC %1
%ifdef RT_ARCH_AMD64 ; Only for amd64 for now.
        ;
        ; Check for the stack info.
        ;
        mov     rax, rsp
        or      rax, 0fffh
        sub     rax, SUPR0STACKINFO_size - 1

        ; Check for the magic.
        cmp     dword [rax + SUPR0STACKINFO.magic0], SUPR0STACKINFO_MAGIC0
        jne     .regular
        cmp     dword [rax + SUPR0STACKINFO.magic1], SUPR0STACKINFO_MAGIC1
        jne     .regular
        cmp     dword [rax + SUPR0STACKINFO.magic2], SUPR0STACKINFO_MAGIC2
        jne     .regular
        cmp     dword [rax + SUPR0STACKINFO.magic3], SUPR0STACKINFO_MAGIC3
        jne     .regular

        ; Verify the self pointer.
        cmp     [rax + SUPR0STACKINFO.pSelf], rax
        jne     .regular

        ;
        ; Perform a stack switch.  We set up a RBP frame on the old stack so we
        ; can use leave to restore the incoming stack upon return.
        ;
        push    rbp
        mov     rbp, rsp

        ; The actual switch.
        mov     r10, 0ffffffffffffffe0h ; shuts up warning on 'and rsp, 0ffffffffffffffe0h'
        and     r10, [rax + SUPR0STACKINFO.pResumeKernelStack]
        mov     rsp, r10

        ;
        ; Copy over stack arguments.
        ;
        ; Note! We always copy 2-3 extra arguments (%2 + 2) just in case someone got
        ;       the argument count wrong.
        ;
%if (%2 + 2) > SUPR0_GRP_PARAMS + 18
 %error too many parameters
 %fatal too many parameters
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 16
        push    qword [rbp + 98h]
        push    qword [rbp + 90h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 14
        push    qword [rbp + 88h]
        push    qword [rbp + 80h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 12
        push    qword [rbp + 78h]
        push    qword [rbp + 70h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 10
        push    qword [rbp + 68h]
        push    qword [rbp + 60h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 8
        push    qword [rbp + 58h]
        push    qword [rbp + 50h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 6
        push    qword [rbp + 48h]
        push    qword [rbp + 40h]
%endif
%if (%2 + 2) > SUPR0_GRP_PARAMS + 4
        push    qword [rbp + 38h]
        push    qword [rbp + 30h]
%endif
%if ((%2 + 2) > SUPR0_GRP_PARAMS + 2) || (SUPR0_SPILL_AREA > 2)
        push    qword [rbp + 28h]
        push    qword [rbp + 20h]
%endif
%if ((%2 + 2) > SUPR0_GRP_PARAMS)     || (SUPR0_SPILL_AREA > 0)
        push    qword [rbp + 18h]
        push    qword [rbp + 10h]
%endif

        call    NAME(StkBack_ %+ %1)

        leave
        ret

.regular:
%endif ; RT_ARCH_AMD64
        jmp     NAME(StkBack_ %+ %1)
ENDPROC   %1
%endmacro


%endif