Source code of Windows XP (NT5)
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title "Miscellaneous Functions"
;++
;
; Copyright (c) 2000 Microsoft Corporation
;
; Module Name:
;
; miscs.asm
;
; Abstract:
;
; This module implements machine dependent miscellaneous kernel functions.
;
; Author:
;
; David N. Cutler (davec) 8-Aug-2000
;
; Environment:
;
; Kernel mode only.
;
;--
include ksamd64.inc
extern KeTestAlertThread:proc
extern KiContinue:proc
extern KiExceptionExit:proc
extern KiRaiseException:proc
subttl "Continue Execution System Service"
;++
;
; NTSTATUS
; NtContinue (
; IN PCONTEXT ContextRecord,
; IN BOOLEAN TestAlert
; )
;
; Routine Description:
;
; This routine is called as a system service to continue execution after
; an exception has occurred. Its function is to transfer information from
; the specified context record into the trap frame that was built when the
; system service was executed, and then exit the system as if an exception
; had occurred.
;
; Arguments:
;
; ContextRecord (rcx) - Supplies a pointer to a context record.
;
; TestAlert (dl) - Supplies a boolean value that specifies whether alert
; should be tested for the previous processor mode.
;
; Implicit Arguments:
;
; rbp - Supplies the address of a trap frame.
;
; Return Value:
;
; Normally there is no return from this routine. However, if the specified
; context record is misaligned or is not accessible, then the appropriate
; status code is returned.
;
;--
NESTED_ENTRY NtContinue, _TEXT$00
GENERATE_EXCEPTION_FRAME ; generate exception frame
;
; Transfer information from the context frame to the exception and trap frames.
;
; N.B. If the previous mode is user, then the legacy floating point state is
; saved in case the context record does not specify floating context.
;
test byte ptr TrSegCs[rbp], MODE_MASK ; check if previous mode user
jz short KiCO10 ; if z, preevious mode not user
lea rsi, (KTRAP_FRAME_LENGTH - 128)[rbp] ; get save area address
fnsaved [rsi] ; save legacy floating state
KiCO10: mov bl, dl ; save test alert argument
mov rdx, rsp ; set exception frame address
lea r8, (-128)[rbp] ; set trap frame address
call KiContinue ; transfer context to kernel frames
;
; If the kernel continuation routine returns success, then exit via the
; exception exit code. Otherwise, return to the system service dispatcher.
;
test eax, eax ; test if service failed
jnz short KiCO40 ; if nz, service failed
;
; Check to determine if alert should be tested for the previous processor
; mode and restore the previous mode in the thread object.
;
mov rax, gs:[PcCurrentThread] ; get current thread address
mov r8, TrTrapFrame[rbp] ; set previous trap frame address
mov ThTrapFrame[rax], r8 ;
mov cl, ThPreviousMode[rax] ; get thread previous mode
mov dl, TrPreviousMode[rbp] ; get frame previous mode
mov ThPreviousMode[rax], dl ; set thread previous mode
test bl, bl ; test if test alert specified
jz short KiCO20 ; if z, test alert not specified
call KeTestAlertThread ; test alert for current thread
;
; If the previous mode is user, then restore the legacy floating state.
;
KiCO20: test byte ptr TrSegCs[rbp], MODE_MASK ; check if previous mode user
jz short KiCO30 ; if z, previous mode not user
mov ax, LfControlWord[rsi] ; save current control word
mov word ptr LfControlWord[rsi], 03fh ; set to mask all exceptions
frstord [rsi] ; restore legacy floating state
mov LfControlWord[rsi], ax ; restore control word
fldcw word ptr LfControlWord[rsi] ; load legacy control word
KiCO30: jmp KiExceptionExit ;
;
; Context record is misaligned or not accessible.
;
KiCO40: RESTORE_EXCEPTION_STATE ; restore exception state/deallocate
ret ; return
NESTED_END NtContinue, _TEXT$00
subttl "Raise Exception System Service"
;++
;
; NTSTATUS
; NtRaiseException (
; IN PEXCEPTION_RECORD ExceptionRecord,
; IN PCONTEXT ContextRecord,
; IN BOOLEAN FirstChance
; )
;
; Routine Description:
;
; This routine is called as a system service to raise an exception. Its
; function is to transfer information from the specified context record
; into the trap frame that was built when the system service was executed.
; The exception may be raised as a first or second chance exception.
;
; Arguments:
;
; ExceptionRecord (rcx) - Supplies a pointer to an exception record.
;
; ContextRecord (rdx) - Suppilies a pointer to a context record.
;
; FirstChance (r8b) - Supplies a boolean value that specifies whether
; this is the first (TRUE) or second chance (FALSE) for dispatching
; the exception.
;
; Implicit Arguments:
;
; rbp - Supplies a pointer to a trap frame.
;
; Return Value:
;
; Normally there is no return from this routine. However, if the specified
; context record or exception record is misaligned or is not accessible,
; then the appropriate status code is returned.
;
;--
NESTED_ENTRY NtRaiseException, _TEXT$00
GENERATE_EXCEPTION_FRAME ; generate exception frame
;
; Call the raise exception kernel routine which will marshall the arguments
; and then call the exception dispatcher.
;
; N.B. If the previous mode is user, then the legacy floating point state is
; saved in case the context record does not specify floating context.
;
lea r9, (-128)[rbp] ; set trap frame address
test byte ptr TrSegCs[rbp], MODE_MASK ; check if previous mode user
jz short KiRE10 ; if z, previous mode not user
fnsaved KTRAP_FRAME_LENGTH[r9] ; save legacy floating state
KiRE10: mov ExP5[rsp], r8b ; set first chance parameter
mov r8, rsp ; set exception frame address
call KiRaiseException ; call raise exception routine
;
; If the kernel raise exception routine returns success, then exit via the
; exception exit code. Otherwise, return to the system service dispatcher.
;
test eax, eax ; test if service failed
jnz short KiRE20 ; if nz, service failed
;
; Exit via the exception exit code which will restore the machine state.
;
mov rax, gs:[PcCurrentThread] ; get current thread address
mov r8, TrTrapFrame[rbp] ; set previous trap frame address
mov ThTrapFrame[rax], r8 ;
jmp KiExceptionExit ;
;
; The context or exception record is misaligned or not accessible, or the
; exception was not handled.
;
KiRE20: RESTORE_EXCEPTION_STATE ; restore exception state/deallocate
ret ; return
NESTED_END NtRaiseException, _TEXT$00
end