reactos/ntoskrnl/ke/i386/usercall_asm.S

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/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS Kernel
* FILE: ntoskrnl/ke/i386/usercall_asm.S
* PURPOSE: User-Mode callbacks and return.
* PROGRAMMERS: Alex Ionescu (alex@relsoft.net)
*/
/* INCLUDES ******************************************************************/
#include <asm.inc>
#include <ks386.inc>
#include <internal/i386/asmmacro.S>
EXTERN _MmGrowKernelStack@4:PROC
EXTERN _KeUserCallbackDispatcher:DWORD
EXTERN @KiServiceExit@8:PROC
EXTERN _KeGetCurrentIrql@0:PROC
EXTERN _KeBugCheckEx@20:PROC
EXTERN @KiUserModeCallout@4:PROC
/* FUNCTIONS ****************************************************************/
.code
/*++
* @name KiCallUserMode
*
* The KiSwitchToUserMode routine sets up a Trap Frame and a Callback stack
* for the purpose of switching to user mode. The actual final jump is done
* by KiServiceExit which will treat this as a syscall return.
*
* @param OutputBuffer
* Pointer to a caller-allocated buffer where to receive the return data
* from the user-mode function
*
* @param OutputLength
* Size of the Output Buffer described above.
*
* @return None. Jumps into KiServiceExit.
*
* @remark If there is not enough Kernel Stack space, the routine will increase the
* Kernel Stack.
*
* User mode execution resumes at ntdll!KiUserCallbackDispatcher.
*
* This call MUST be paired by interrupt 0x2B or NtCallbackReturn.
*
*--*/
PUBLIC _KiCallUserMode@8
_KiCallUserMode@8:
/* Push non-volatile registers on the stack.
This is part of the KCALLOUT_FRAME */
push ebp
push ebx
push esi
push edi
/* load the address of the callout frame into ecx */
lea ecx, [esp - 12]
/* Allocate space for the initial stack */
sub esp, 12 + NPX_FRAME_LENGTH + KTRAP_FRAME_LENGTH + 16
call @KiUserModeCallout@4
add esp, 12 + NPX_FRAME_LENGTH + KTRAP_FRAME_LENGTH + 16
/* Restore registers */
pop edi
pop esi
pop ebx
pop ebp
/* Return */
ret 8
PUBLIC @KiCallbackReturn@8
@KiCallbackReturn@8:
/* Restore the stack */
mov esp, ecx
/* Set status and return */
mov eax, edx
pop edi
pop esi
pop ebx
pop ebp
/* Clean stack and return */
ret 8
/*++
* @name KeSwitchKernelStack
*
* The KeSwitchKernelStack routine switches from the current thread's stack
* to the new specified base and limit.
*
* @param StackBase
* Pointer to the new Stack Base of the thread.
*
* @param StackLimit
* Pointer to the new Stack Limit of the thread.
*
* @return The previous Stack Base of the thread.
*
* @remark This routine should typically only be used when converting from a
* non-GUI to a GUI Thread. The caller is responsible for freeing the
* previous stack. The new stack values MUST be valid before calling
* this routine.
*
*--*/
PUBLIC _KeSwitchKernelStack@8
_KeSwitchKernelStack@8:
/* Save volatiles */
push esi
push edi
/* Get current thread */
mov edx, fs:[KPCR_CURRENT_THREAD]
/* Get new and current base */
mov edi, [esp+12]
mov ecx, [edx+KTHREAD_STACK_BASE]
/* Fixup the frame pointer */
sub ebp, ecx
add ebp, edi
/* Fixup the trap frame */
mov eax, [edx+KTHREAD_TRAP_FRAME]
sub eax, ecx
add eax, edi
mov [edx+KTHREAD_TRAP_FRAME], eax
/* Calculate stack size */
sub ecx, esp
/* Get desination and origin */
sub edi, ecx
mov esi, esp
/* Save stack pointer */
push edi
/* Copy stack */
rep movsb
/* Restore stack pointer */
pop edi
/* Save old stack base and get new limit/base */
mov eax, [edx+KTHREAD_STACK_BASE]
mov ecx, [esp+12]
mov esi, [esp+16]
/* Disable interrupts for stack switch */
cli
/* Set new base/limit */
mov [edx+KTHREAD_STACK_BASE], ecx
mov [edx+KTHREAD_STACK_LIMIT], esi
/* Set LargeStack */
mov byte ptr [edx+KTHREAD_LARGE_STACK], 1
/* Set new initial stack */
mov [edx+KTHREAD_INITIAL_STACK], ecx
/* Get trap frame */
mov esi, [edx+KTHREAD_TRAP_FRAME]
/* Get TSS */
mov edx, fs:[KPCR_TSS]
/* Check if we came from V86 mode */
test dword ptr [esi+KTRAP_FRAME_EFLAGS], EFLAGS_V86_MASK
/* Bias for NPX Area */
lea ecx, [ecx-NPX_FRAME_LENGTH]
jnz V86Switch
sub ecx, 16
V86Switch:
/* Update ESP in TSS */
mov [edx+KTSS_ESP0], ecx
/* Update stack pointer */
mov esp, edi
/* Bring back interrupts and return */
sti
pop edi
pop esi
ret 8
END