444 lines
16 KiB
NASM
444 lines
16 KiB
NASM
title "Call Out to User Mode"
|
|
;++
|
|
;
|
|
; Copyright (c) 1994 Microsoft Corporation
|
|
;
|
|
; Module Name:
|
|
;
|
|
; callout.asm
|
|
;
|
|
; Abstract:
|
|
;
|
|
; This module implements the code necessary to call out from kernel
|
|
; mode to user mode.
|
|
;
|
|
; Author:
|
|
;
|
|
; David N. Cutler (davec) 1-Nov-1994
|
|
;
|
|
; Environment:
|
|
;
|
|
; Kernel mode only.
|
|
;
|
|
; Revision History:
|
|
;
|
|
;--
|
|
|
|
.386p
|
|
.xlist
|
|
include ks386.inc
|
|
include i386\kimacro.inc
|
|
include callconv.inc
|
|
.list
|
|
|
|
extrn _KiServiceExit:PROC
|
|
extrn _KeUserCallbackDispatcher:DWORD
|
|
|
|
EXTRNP _MmGrowKernelStack,1
|
|
|
|
_TEXT SEGMENT DWORD PUBLIC 'CODE'
|
|
ASSUME DS:FLAT, ES:FLAT, SS:FLAT, FS:NOTHING, GS:NOTHING
|
|
|
|
page ,132
|
|
subttl "Call User Mode Function"
|
|
;++
|
|
;
|
|
; NTSTATUS
|
|
; KiCallUserMode (
|
|
; IN PVOID *Outputbuffer,
|
|
; IN PULONG OutputLength
|
|
; )
|
|
;
|
|
; Routine Description:
|
|
;
|
|
; This function calls a user mode function from kernel mode.
|
|
;
|
|
; N.B. This function calls out to user mode and the NtCallbackReturn
|
|
; function returns back to the caller of this function. Therefore,
|
|
; the stack layout must be consistent between the two routines.
|
|
;
|
|
; Arguments:
|
|
;
|
|
; OutputBuffer - Supplies a pointer to the variable that receivies
|
|
; the address of the output buffer.
|
|
;
|
|
; OutputLength - Supplies a pointer to a variable that receives
|
|
; the length of the output buffer.
|
|
;
|
|
; Return Value:
|
|
;
|
|
; The final status of the call out function is returned as the status
|
|
; of the function.
|
|
;
|
|
; N.B. This function does not return to its caller. A return to the
|
|
; caller is executed when a NtCallbackReturn system service is
|
|
; executed.
|
|
;
|
|
; N.B. This function does return to its caller if a kernel stack
|
|
; expansion is required and the attempted expansion fails.
|
|
;
|
|
;--
|
|
|
|
;
|
|
; To support the debugger, the callback stack frame is now defined in i386.h.
|
|
; If the stack frame is changed, i386.h must be updated and geni386
|
|
; rebuilt and run, then rebuild this file and ntos\kd.
|
|
;
|
|
; The FPO record below must also be updated to correctly represent
|
|
; the stack frame.
|
|
;
|
|
|
|
cPublicProc _KiCallUserMode, 2
|
|
|
|
.FPO (3, 2, 4, 4, 0, 0)
|
|
|
|
;
|
|
; Save nonvolatile registers.
|
|
;
|
|
|
|
push ebp ; save nonvolatile registers
|
|
push ebx ;
|
|
push esi ;
|
|
push edi ;
|
|
|
|
;
|
|
; Check if sufficient room is available on the kernel stack for another
|
|
; system call.
|
|
;
|
|
|
|
mov ebx,PCR[PcPrcbData + PbCurrentThread] ; get current thread address
|
|
lea eax,[esp]-KERNEL_LARGE_STACK_COMMIT ; compute bottom address
|
|
cmp eax,[ebx]+ThStackLimit ; check if limit exceeded
|
|
jae short Kcb10 ; if ae, limit not exceeded
|
|
stdCall _MmGrowKernelStack,<esp> ; attempt to grow kernel stack
|
|
or eax, eax ; check for successful completion
|
|
jne Kcb20 ; if ne, attempt to grow failed
|
|
mov eax, [ebx].ThStackLimit ; get new stack limit
|
|
mov PCR[PcStackLimit], eax ; set new stack limit
|
|
|
|
;
|
|
; Get the address of the current thread and save the previous trap frame
|
|
; and calback stack addresses in the current frame. Also save the new
|
|
; callback stack address in the thread object.
|
|
;
|
|
|
|
Kcb10: push [ebx].ThCallbackStack ; save callback stack address
|
|
mov edx,[ebx].ThTrapFrame ; get current trap frame address
|
|
push edx ; save trap frame address
|
|
mov esi,[ebx].ThInitialStack ; get initial stack address
|
|
push esi ; save initial stack address
|
|
mov [ebx].ThCallbackStack,esp ; save callback stack address
|
|
|
|
KcbPrologEnd: ; help for the debugger
|
|
|
|
;
|
|
; Copy the numeric save area from the previous save area to the new save
|
|
; area and establish a new initial kernel stack.
|
|
;
|
|
|
|
;
|
|
; Make sure that the destination NPX Save area is 16-byte aligned
|
|
; as required by fxsave\fxrstor
|
|
;
|
|
and esp, 0fffffff0h
|
|
mov edi,esp ; set new initial stack address
|
|
sub esp,NPX_FRAME_LENGTH ; compute destination NPX save area
|
|
sub esi,NPX_FRAME_LENGTH ; compute source NPX save area
|
|
cli ; disable interrupts
|
|
mov ecx,[esi].FpControlWord ; copy NPX state to new frame
|
|
mov [esp].FpControlWord,ecx ;
|
|
mov ecx,[esi].FpStatusWord ;
|
|
mov [esp].FpStatusWord,ecx ;
|
|
mov ecx,[esi].FpTagWord ;
|
|
mov [esp].FpTagWord,ecx ;
|
|
mov ecx,[esi].FxMXCsr ;
|
|
mov [esp].FxMXCsr,ecx ;
|
|
mov ecx,[esi].FpCr0NpxState ;
|
|
mov [esp].FpCr0NpxState,ecx ;
|
|
mov esi,PCR[PcTss] ; get address of task switch segment
|
|
mov [ebx].ThInitialStack,edi ; reset initial stack address
|
|
mov PCR[PcInitialStack],esp ; set stack check base address
|
|
sub esp,TsV86Gs - TsHardwareSegSs ; bias for missing V86 fields
|
|
mov [esi].TssEsp0,esp ; set kernel entry stack address
|
|
|
|
;
|
|
; Construct a trap frame to facilitate the transfer into user mode via
|
|
; the standard system call exit.
|
|
;
|
|
|
|
sub esp,TsHardwareSegSs + 4 ; allocate trap frame
|
|
mov ebp,esp ; set address of trap frame
|
|
mov ecx,(TsHardwareSegSs - TsSegFs + 4) / 4; set repeat count
|
|
lea edi,[esp].TsSegFs ; set destination address
|
|
lea esi,[edx].TsSegFs ; set source address
|
|
rep movsd ; copy trap information
|
|
|
|
test byte ptr [ebx]+ThDebugActive, -1 ; Do we need to restore Debug reg?
|
|
jnz short Kcb18 ; Yes, go save them.
|
|
|
|
Kcb15: mov eax,_KeUserCallbackDispatcher ; st address of callback dispatchr
|
|
mov [esp].TsEip,eax ;
|
|
mov eax,PCR[PcExceptionList] ; get current exception list
|
|
mov [esp].TsExceptionList,eax ; set previous exception list
|
|
mov eax,[edx].TsPreviousPreviousMode ; get previous mode
|
|
mov [esp].TsPreviousPreviousMode,eax ; set previous mode
|
|
sti ; enable interrupts
|
|
|
|
SET_DEBUG_DATA ; set system call debug data for exit
|
|
|
|
jmp _KiServiceExit ; exit through service dispatch
|
|
|
|
Kcb18:
|
|
mov ecx,(TsDr7 - TsDr0 + 4) / 4; set repeat count
|
|
lea edi,[esp].TsDr0 ; set destination address
|
|
lea esi,[edx].TsDr0 ; set source address
|
|
rep movsd ; copy trap information
|
|
jmp short Kcb15
|
|
|
|
;
|
|
; An attempt to grow the kernel stack failed.
|
|
;
|
|
|
|
Kcb20: pop edi ; restore nonvolitile register
|
|
pop esi ;
|
|
pop ebx ;
|
|
pop ebp ;
|
|
stdRET _KiCallUserMode
|
|
|
|
stdENDP _KiCallUserMode
|
|
|
|
page ,132
|
|
subttl "Switch Kernel Stack"
|
|
;++
|
|
;
|
|
; PVOID
|
|
; KeSwitchKernelStack (
|
|
; IN PVOID StackBase,
|
|
; IN PVOID StackLimit
|
|
; )
|
|
;
|
|
; Routine Description:
|
|
;
|
|
; This function switches to the specified large kernel stack.
|
|
;
|
|
; N.B. This function can ONLY be called when there are no variables
|
|
; in the stack that refer to other variables in the stack, i.e.,
|
|
; there are no pointers into the stack.
|
|
;
|
|
; Arguments:
|
|
;
|
|
; StackBase (esp + 4) - Supplies a pointer to the base of the new kernel
|
|
; stack.
|
|
;
|
|
; StackLimit (esp + 8) - Suplies a pointer to the limit of the new kernel
|
|
; stack.
|
|
;
|
|
; Return Value:
|
|
;
|
|
; The old kernel stack is returned as the function value.
|
|
;
|
|
;--
|
|
|
|
SsStkBs equ 4 ; new kernel stack base address
|
|
SsStkLm equ 8 ; new kernel stack limit address
|
|
|
|
cPublicProc _KeSwitchKernelStack, 2
|
|
|
|
;
|
|
; Save the address of the new stack and copy the old stack to the new
|
|
; stack.
|
|
;
|
|
|
|
push esi ; save string move registers
|
|
push edi ;
|
|
mov edx,PCR[PcPrcbData + PbCurrentThread] ; get current thread address
|
|
mov edi,[esp]+SsStkBs + 8 ; get new kernel stack base address
|
|
mov ecx,[edx].ThStackBase ; get current stack base address
|
|
sub ebp,ecx ; relocate the callers frame pointer
|
|
add ebp,edi ;
|
|
mov eax,[edx].ThTrapFrame ; relocate the current trap frame address
|
|
sub eax,ecx ;
|
|
add eax,edi ;
|
|
mov [edx].ThTrapFrame,eax ;
|
|
sub ecx,esp ; compute length of copy
|
|
sub edi,ecx ; set destination address of copy
|
|
mov esi,esp ; set source address of copy
|
|
push edi ; save new stack pointer address
|
|
rep movsb ; copy old stack to new stack
|
|
pop edi ; restore new stack pointer address
|
|
|
|
;
|
|
; Switch to the new kernel stack and return the address of the old kernel
|
|
; stack.
|
|
;
|
|
|
|
mov eax,[edx].ThStackBase ; get old kernel stack base address
|
|
mov ecx,[esp]+SsStkBs + 8 ; get new kernel stack base address
|
|
mov esi,[esp]+SsStkLm + 8 ; get new kernel stack limit address
|
|
cli ; disable interrupts
|
|
mov [edx].ThStackBase,ecx ; set new kernel stack base address
|
|
mov [edx].ThStackLimit,esi ; set new kernel stack limit address
|
|
mov byte ptr [edx].ThLargeStack, 1 ; set large stack TRUE
|
|
mov [edx].ThInitialStack,ecx ; set new initial stack address
|
|
sub ecx,NPX_FRAME_lENGTH ; compute NPX save area address
|
|
mov PCR[PcInitialStack],ecx ; set stack check base address
|
|
mov PCR[PcStackLimit],esi ; set stack check limit address
|
|
mov edx,PCR[PcTss] ; get address of task switch segment
|
|
sub ecx,TsV86Gs - TsHardwareSegSs ; bias for missing V86 fields
|
|
mov [edx].TssEsp0,ecx ; set kernel entry stack address
|
|
mov esp,edi ; set new stack pointer address
|
|
sti ;
|
|
pop edi ; restore string move registers
|
|
pop esi ;
|
|
stdRET _KeSwitchKernelStack
|
|
|
|
stdENDP _KeSwitchKernelStack
|
|
|
|
page ,132
|
|
subttl "Get User Mode Stack Address"
|
|
;++
|
|
;
|
|
; PULONG
|
|
; KiGetUserModeStackAddress (
|
|
; VOID
|
|
; )
|
|
;
|
|
; Routine Description:
|
|
;
|
|
; This function returns the address of the user stack address in the
|
|
; current trap frame.
|
|
;
|
|
; Arguments:
|
|
;
|
|
; None.
|
|
;
|
|
; Return Value:
|
|
;
|
|
; The address of the user stack address.
|
|
;
|
|
;--
|
|
|
|
cPublicProc _KiGetUserModeStackAddress, 0
|
|
|
|
mov eax,PCR[PcPrcbData + PbCurrentThread] ; get current thread address
|
|
mov eax,[eax].ThTrapFrame ; get current trap frame address
|
|
lea eax,[eax].TsHardwareEsp ; get address of stack address
|
|
stdRET _KiGetUserModeStackAddress
|
|
|
|
stdENDP _KiGetUserModeStackAddress
|
|
|
|
page ,132
|
|
subttl "Return from User Mode Callback"
|
|
;++
|
|
;
|
|
; NTSTATUS
|
|
; NtCallbackReturn (
|
|
; IN PVOID OutputBuffer OPTIONAL,
|
|
; IN ULONG OutputLength,
|
|
; IN NTSTATUS Status
|
|
; )
|
|
;
|
|
; Routine Description:
|
|
;
|
|
; This function returns from a user mode callout to the kernel
|
|
; mode caller of the user mode callback function.
|
|
;
|
|
; N.B. This function returns to the function that called out to user
|
|
; mode and the KiCallUserMode function calls out to user mode.
|
|
; Therefore, the stack layout must be consistent between the
|
|
; two routines.
|
|
;
|
|
; Arguments:
|
|
;
|
|
; OutputBuffer - Supplies an optional pointer to an output buffer.
|
|
;
|
|
; OutputLength - Supplies the length of the output buffer.
|
|
;
|
|
; Status - Supplies the status value returned to the caller of the
|
|
; callback function.
|
|
;
|
|
; Return Value:
|
|
;
|
|
; If the callback return cannot be executed, then an error status is
|
|
; returned. Otherwise, the specified callback status is returned to
|
|
; the caller of the callback function.
|
|
;
|
|
; N.B. This function returns to the function that called out to user
|
|
; mode is a callout is currently active.
|
|
;
|
|
;--
|
|
|
|
cPublicProc _NtCallbackReturn, 3
|
|
|
|
mov eax,PCR[PcPrcbData + PbCurrentThread] ; get current thread address
|
|
mov ecx,[eax].ThCallbackStack ; get callback stack address
|
|
cmp ecx, 0
|
|
je CbExit ; if zero, no callback stack present
|
|
|
|
;
|
|
; Restore the current exception list from the saved exception list in the
|
|
; current trap frame, restore the trap frame and callback stack addresses,
|
|
; store the output buffer address and length, and set the service status.
|
|
;
|
|
|
|
mov ebx,[eax].ThTrapFrame ; get current trap frame address
|
|
mov edx,[ebx].TsExceptionList ; get saved exception list address
|
|
mov PCR[PcExceptionList],edx ; restore exception list address
|
|
mov edi,[esp] + 4 ; get output buffer address
|
|
mov esi,[esp] + 8 ; get output buffer length
|
|
mov ebp,[esp] + 12 ; get callout service status
|
|
mov ebx,[ecx].CuOutBf ; get address to store output buffer
|
|
mov [ebx],edi ; store output buffer address
|
|
mov ebx,[ecx].CuOutLn ; get address to store output length
|
|
mov [ebx],esi ; store output buffer length
|
|
mov ebx,[ecx] ; get previous initial stack address
|
|
cli ; disable interrupt
|
|
mov esi,PCR[PcInitialStack] ; get source NPX save area address
|
|
mov [eax].ThInitialStack,ebx ; restore initial stack address
|
|
sub ebx,NPX_FRAME_LENGTH ; compute destination NPX save area
|
|
mov edx,[esi].FpControlWord ; copy NPX state to previous frame
|
|
mov [ebx].FpControlWord,edx ;
|
|
mov edx,[esi].FpStatusWord ;
|
|
mov [ebx].FpStatusWord,edx ;
|
|
mov edx,[esi].FpTagWord ;
|
|
mov [ebx].FpTagWord,edx ;
|
|
mov edx,[esi].FxMXCsr ;
|
|
mov [ebx].FxMXCsr,edx ;
|
|
mov edx,[esi].FpCr0NpxState ;
|
|
mov [ebx].FpCr0NpxState,edx ;
|
|
mov edx,PCR[PcTss] ; get address of task switch segment
|
|
mov PCR[PcInitialStack],ebx ; restore stack check base address
|
|
sub ebx,TsV86Gs - TsHardwareSegSs ; bias for missing V86 fields
|
|
mov [edx].TssEsp0,ebx ; restore kernel entry stack address
|
|
mov esp,ecx ; trim stack back to callback frame
|
|
add esp,4 ;
|
|
sti ; enable interrupts
|
|
pop [eax].ThTrapFrame ; restore current trap frame address
|
|
pop [eax].ThCallbackStack ; restore callback stack address
|
|
mov eax,ebp ; set callback service status
|
|
|
|
;
|
|
; Restore nonvolatile registers, clean call parameters from stack, and
|
|
; return to callback caller.
|
|
;
|
|
|
|
pop edi ; restore nonvolatile registers
|
|
pop esi ;
|
|
pop ebx ;
|
|
pop ebp ;
|
|
pop edx ; save return address
|
|
add esp,8 ; remove parameters from stack
|
|
jmp edx ; return to callback caller
|
|
|
|
;
|
|
; No callback is currently active.
|
|
;
|
|
|
|
CbExit: mov eax,STATUS_NO_CALLBACK_ACTIVE ; set service status
|
|
stdRET _NtCallBackReturn
|
|
|
|
stdENDP _NtCallbackReturn
|
|
|
|
_TEXT ends
|
|
end
|