title "Exception Handling Support Routines"
;++
;
; Copyright (c) 2000 Microsoft Corporation
;
; Module Name:
;
; xcptmisc.asm
;
; Abstract:
;
; This module implements stub routines to call language specific handlers
; for exception dispatching and temrination handling.
;
; Author:
;
; David N. Cutler (davec) 4-Jul-2000
;
; Environment:
;
; Any mode.
;
;--
include ksamd64.inc
subttl "Local Exception Handler"
;++
;
; EXCEPTION_DISPOSITION
; RtlpExceptionHandler (
; IN PEXCEPTION_RECORD ExceptionRecord,
; IN PVOID EstablisherFrame,
; IN OUT PCONTEXT ContextRecord,
; IN OUT PVOID DispatcherContext
; )
;
; Routine Description:
;
; This function is called when a nested exception occurs. Its function
; is to retrieve the establisher frame pointer from its establisher's
; call frame, store this information in the dispatcher context record,
; and return a disposition value of nested exception.
;
; Arguments:
;
; ExceptionRecord (rcx) - Supplies a pointer to an exception record.
;
; EstablisherFrame (rdx) - Supplies the frame pointer of the establisher
; of this exception handler.
;
; ContextRecord (r8) - Supplies a pointer to a context record.
;
; DispatcherContext (r9) - Supplies a pointer to the dispatcher context
; record.
;
; Return Value:
;
; A disposition value nested exception is returned if an unwind is not in
; progress. Otherwise a value of continue search is returned.
;
;--
EhFrame struct
P1Home dq ? ; parameter home addresses for
P2Home dq ? ; called functions
P3Home dq ? ;
P4Home dq ? ;
Context dq ? ; saved dispatcher context address
EhFrame ends
LEAF_ENTRY RtlpExceptionHandler, _TEXT$00
mov eax, ExceptionContinueSearch ; assume unwind in progress
test dword ptr ErExceptionFlags[rcx], EXCEPTION_UNWIND ; check for unwind
jnz short Eh10 ; if nz, unwind in progress
mov rax, EhFrame.Context[rdx] ; get establisher context address
mov rax, DcEstablisherFrame[rax] ; copy the establisher frame
mov DcEstablisherFrame[r9], rax ; to current dispatcher context
mov rax, ExceptionNestedException ; set nested exception disposition
eH10: ret ; return
LEAF_END RtlpExceptionHandler, _TEXT$00
subttl "Execute Handler for Exception"
;++
;
; EXCEPTION_DISPOSITION
; RtlpExecuteHandlerForException (
; IN PEXCEPTION_RECORD ExceptionRecord,
; IN PVOID EstablisherFrame,
; IN OUT PCONTEXT ContextRecord,
; IN OUT PVOID DispatcherContext
; )
;
; Routine Description:
;
; This function allocates a call frame, saves the dispatcher context address,
; establishes an exception handler, and calls the specified language specific
; handler routine. If a nested exception occurs, then the exception handler
; of this function is called and the establisher frame pointer is returned to
; the exception dispatcher via the dispatcher context parameter.
;
; Arguments:
;
; ExceptionRecord (rcx) - Supplies a pointer to an exception record.
;
; EstablisherFrame (rdx) - Supplies the frame pointer of the establisher
; of the exception handler that is to be called.
;
; ContextRecord (r8) - Supplies a pointer to a context record.
;
; DispatcherContext (r9) - Supplies a pointer to the dispatcher context
; record.
;
; Return Value:
;
; The disposition value returned by the specified exception handler is
; returned as the function value.
;
;--
NESTED_ENTRY RtlpExecuteHandlerForException, _TEXT$00, RtlpExceptionHandler
alloc_stack (sizeof EhFrame) ; allocate stack frame
END_PROLOGUE
mov EhFrame.Context[rsp], r9 ; save dispatcher context address
call qword ptr DcLanguageHandler[r9] ; call lanaguage handler
nop ; required fill for virtual unwind
add rsp, sizeof EhFrame ; deallocate stack frame
ret ; return
NESTED_END RtlpExecuteHandlerForException, _TEXT$00
subttl "Local Unwind Handler"
;++
;
; EXCEPTION_DISPOSITION
; RtlpUnwindHandler (
; IN PEXCEPTION_RECORD ExceptionRecord,
; IN PVOID EstablisherFrame,
; IN OUT PCONTEXT ContextRecord,
; IN OUT PVOID DispatcherContext
; )
;
; Routine Description:
;
; This function is called when a collided unwind occurs. Its function
; is to retrieve the establisher dispatcher context, copy it to the
; current dispatcher context, and return a disposition value of collided
; unwind.
;
; Arguments:
;
; ExceptionRecord (rcx) - Supplies a pointer to an exception record.
;
; EstablisherFrame (rdx) - Supplies the frame pointer of the establisher
; of this exception handler.
;
; ContextRecord (r8) - Supplies a pointer to a context record.
;
; DispatcherContext (r9) - Supplies a pointer to the dispatcher context
; record.
;
; Return Value:
;
; A disposition value collided unwind is returned if an unwind is in
; progress. Otherwise a value of continue search is returned.
;
;--
LEAF_ENTRY RtlpUnwindHandler, _TEXT$00
mov rax, EhFrame.Context[rdx] ; get establisher context address
mov r10, DcControlPc[rax] ; copy control PC
mov DcControlPc[r9], r10 ;
mov r10, DcImageBase[rax] ; copy image base
mov DcImageBase[r9], r10 ;
mov r10, DcFunctionEntry[rax] ; copy function entry
mov DcFunctionentry[r9], r10 ;
mov r10, DcEstablisherFrame[rax] ; copy establisher frame
mov DcEstablisherFrame[r9], r10 ;
mov r10, DcContextRecord[rax] ; copy context record address
mov DcContextRecord[r9], r10 ;
mov r10, DcLanguageHandler[rax] ; copy language handler address
mov DcLanguageHandler[r9], r10 ;
mov r10, DcHandlerData[rax] ; copy handler data address
mov DcHandlerData[r9], r10 ;
mov r10, DcHistoryTable[rax] ; copy history table address
mov DcHistoryTable[r9], r10 ;
mov rax, ExceptionCollidedUnwind ; set collied unwind disposition
ret ; return
LEAF_END RtlpUnwindHandler, _TEXT$00
subttl "Execute Handler for Unwind"
;++
;
; EXCEPTION_DISPOSITION
; RtlpExecuteHandlerForUnwind (
; IN PEXCEPTION_RECORD ExceptionRecord,
; IN PVOID EstablisherFrame,
; IN OUT PCONTEXT ContextRecord,
; IN OUT PVOID DispatcherContext
; )
;
; Routine Description:
;
; This function allocates a call frame, saves the dispatcher context address,
; establishes an exception handler, and calls the specified unwind handler.
; If a collided unwind occurs, then the exception handler of this function is
; called and the establisher dispatcher context is copied to the current
; dispatcher context via the dispatcher context parameter.
;
; Arguments:
;
; ExceptionRecord (rcx) - Supplies a pointer to an exception record.
;
; EstablisherFrame (rdx) - Supplies the frame pointer of the establisher
; of the exception handler that is to be called.
;
; ContextRecord (r8) - Supplies a pointer to a context record.
;
; DispatcherContext (r9) - Supplies a pointer to the dispatcher context
; record.
;
; ExceptionRoutine (5 * 8[rsp]) - Supplies a pointer to the exception
; handler that is to be called.
;
; Return Value:
;
; The disposition value returned by the specified exception handler is
; returned as the function value.
;
;--
NESTED_ENTRY RtlpExecuteHandlerForUnwind, _TEXT$00, RtlpUnwindHandler
alloc_stack (sizeof EhFrame) ; allocate stack frame
END_PROLOGUE
mov EhFrame.Context[rsp], r9 ; save dispatcher context address
call qword ptr DcLanguageHandler[r9] ; call exception handler
nop ; required fill for virtual unwind
add rsp, sizeof EhFrame ; deallocate stack frame
ret ; return
NESTED_END RtlpExecuteHandlerForUnwind, _TEXT$00
end