|
|
// TITLE("Trampoline Code For User Mode APC and Exception Dispatching")//++//// Copyright (c) 1990 Microsoft Corporation// Copyright (c) 1992 Digital Equipment Corporation//// Module Name://// trampoln.s//// Abstract://// This module implements the trampoline code necessary to dispatch user// mode APCs and exceptions.//// Author://// David N. Cutler (davec) 3-Apr-1990//// Environment://// User mode only.//// Revision History://// Thomas Van Baak (tvb) 11-May-1992//// Adapted for Alpha AXP.////--
#include "ksalpha.h"
//// Define length of exception dispatcher stack frame.//
#define ExceptionDispatcherFrameLength (ExceptionRecordLength + ContextFrameLength)
SBTTL("User APC Dispatcher")//++//// The following code is never executed. Its purpose is to support unwinding// through the call to the APC dispatcher.////--
//// N.B. This function specifies its own private exception handler.// EXCEPTION_HANDLER(KiUserApcHandler)
NESTED_ENTRY(KiUserApcDispatch, ContextFrameLength, zero);
.set noreorder .set noat stq sp, CxIntSp(sp) // save stack pointer stq ra, CxIntRa(sp) // save return address stq ra, CxFir(sp) // set continuation address stq fp, CxIntFp(sp) // save integer register fp stq gp, CxIntGp(sp) // save integer register gp
stq s0, CxIntS0(sp) // save integer registers s0 - s5 stq s1, CxIntS1(sp) // stq s2, CxIntS2(sp) // stq s3, CxIntS3(sp) // stq s4, CxIntS4(sp) // stq s5, CxIntS5(sp) //
stt f2, CxFltF2(sp) // save floating registers f2 - f9 stt f3, CxFltF3(sp) // stt f4, CxFltF4(sp) // stt f5, CxFltF5(sp) // stt f6, CxFltF6(sp) // stt f7, CxFltF7(sp) // stt f8, CxFltF8(sp) // stt f9, CxFltF9(sp) //
mov sp, fp // set frame pointer .set at .set reorder
PROLOGUE_END
//++//// VOID// KiUserApcDispatcher (// IN PVOID NormalContext,// IN PVOID SystemArgument1,// IN PVOID SystemArgument2,// IN PKNORMAL_ROUTINE NormalRoutine// )//// Routine Description://// This routine is entered on return from kernel mode to deliver an APC// in user mode. The context frame for this routine was built when the// APC interrupt was processed and contains the entire machine state of// the current thread. The specified APC routine is called and then the// machine state is restored and execution is continued.//// Arguments://// a0 - Supplies the normal context parameter that was specified when the// APC was initialized.//// a1 - Supplies the first argument that was provided by the executive when// the APC was queued.//// a2 - Supplies the second argument that was provided by the executive// when the APC was queued.//// a3 - Supplies the address of the function that is to be called.//// N.B. Register sp supplies a pointer to a context frame.//// N.B. Register fp supplies the same value as sp and is used as a frame// pointer.//// Return Value://// None.////--
//// N.B. This function is not called in the typical way. Instead of a normal// subroutine call to the nested entry point above, the alternate entry point// address below is stuffed into the Fir address of the trap frame. Thus when// the kernel returns from the trap, the following code is executed directly.// ALTERNATE_ENTRY(KiUserApcDispatcher)
jsr ra, (a3) // call specified APC routine
mov fp, a0 // set address of context frame ldil a1, TRUE // set test alert argument true bsr ra, ZwContinue // execute system service to continue mov v0, s0 // save status value
//// Unsuccessful completion after attempting to continue execution. Use the// return status as the exception code, set noncontinuable exception and// attempt to raise another exception. Note there is no return from raise// status.//
10: mov s0, a0 // set status value bsr ra, RtlRaiseStatus // raise exception br zero, 10b // loop on return
.end KiUserApcDispatch SBTTL("User APC Exception Handler")//++//// EXCEPTION_DISPOSITION// KiUserApcHandler (// IN PEXCEPTION_RECORD ExceptionRecord,// IN ULONG EstablisherFrame,// IN OUT PCONTEXT ContextRecord,// IN OUT PDISPATCHER_CONTEXT DispatcherContext//// Routine Description://// This function is called when an exception occurs in an APC routine// or one of its dynamic descendents, or when an unwind through the// APC dispatcher is in progress. If an unwind is in progress, then test// alert is called to ensure that all currently queued APCs are executed.//// Arguments://// ExceptionRecord (a0) - Supplies a pointer to an exception record.//// EstablisherFrame (a1) - Supplies the frame pointer of the establisher// of this exception handler.//// ContextRecord (a2) - Supplies a pointer to a context record.//// DispatcherContext (a3) - Supplies a pointer to the dispatcher context// record.//// Return Value://// ExceptionContinueSearch is returned as the function value.////--
.struct 0HdRa: .space 8 // saved return address .space 1 * 8 // required for 16-byte stack alignmentHandlerFrameLength: // length of handler frame
NESTED_ENTRY(KiUserApcHandler, HandlerFrameLength, zero)
lda sp, -HandlerFrameLength(sp) // allocate stack frame stq ra, HdRa(sp) // save return address
PROLOGUE_END
//// The following code is equivalent to://// EXCEPTION_DISPOSITION// KiUserApcHandler(IN PEXCEPTION_RECORD ExceptionRecord)// {// if (IS_UNWINDING(ExceptionRecord->ExceptionFlags)) {// NtTestAlert();
// }// return ExceptionContinueSearch// }//
ldl t0, ErExceptionFlags(a0) // get exception flags and t0, EXCEPTION_UNWIND, t0 // check if unwind in progress beq t0, 10f // if eq, no unwind in progress
bsr ra, ZwTestAlert // test for alert pending
10: ldil v0, ExceptionContinueSearch // set disposition value ldq ra, HdRa(sp) // restore return address lda sp, HandlerFrameLength(sp) // deallocate stack frame ret zero, (ra) // return
.end KiUserApcHandler
SBTTL("User Callback Dispatcher")//++//// The following code is never executed. Its purpose is to support unwinding// through the call to the exception dispatcher.////--
NESTED_ENTRY(KiUserCallbackDispatch, ContextFrameLength, zero);
.set noreorder stq sp, CkSp(sp) stq ra, CkRa(sp).set reorder PROLOGUE_END//++//// VOID// KiUserCallbackDispatcher (// VOID// )//// Routine Description://// This routine is entered on a callout from kernel mode to execute a// user mode callback function. All arguments for this function have// been placed on the stack.//// Arguments://// (sp + 16) - Supplies a value of zero for alignment.//// (sp + 24) - Supplies the API number of the callback function that is// executed.//// (sp + 32) - Supplies a pointer to the input buffer.//// (sp + 40) - Supplies the input buffer length.//// Return Value://// This function returns to kernel mode.////--
ALTERNATE_ENTRY(KiUserCallbackDispatcher)
ldl a0, CkBuffer(sp) // get input buffer address ldl a1, CkLength(sp) // get input buffer length ldl t0, CkApiNumber(sp) // get API number GET_THREAD_ENVIRONMENT_BLOCK // get TEB in v0 ldl t5, TePeb(v0) // get PEB in t5 ldl t2, PeKernelCallbackTable(t5) // get address of callback table s4addl t0, t2, t3 // get address of callback ldl t4, 0(t3) // get callback pointer jsr ra, (t4) // call specified function
//// If a return from the callback function occurs, then the output buffer// address and length are returned as NULL.//
bis zero,zero,a0 // set zero buffer address bis zero,zero,a1 // set zero buffer length bis v0, zero, a2 // set completion status bsr ra, ZwCallbackReturn // return to kernel mode
//// Unsuccessful completion after attempting to return to kernel mode. Use// the return status as the exception code, set noncontinuable exception and// attempt to raise another exception. Note there is no return from raise// status.//
bis v0, zero, s0 // save status value10: bis s0, zero, a0 // set status value bsr ra, RtlRaiseStatus // raise exception br zero, 10b // loop on return
.end KiUserCallbackDispatch SBTTL("User Exception Dispatcher")//++//// The following code is never executed. Its purpose is to support unwinding// through the call to the exception dispatcher.//// When reverse executed, this prologue will restore all integer registers,// rather than just the non-volatile registers. This is necessary for proper// unwinding through the call to the exception dispatcher when non-standard// calls have been used in frames at or above the exception frame. Non-leaf// functions using a non-standard call are allowed to save the return address// register in another integer register instead of on the stack.////--
NESTED_ENTRY(KiUserExceptionDispatch, ExceptionDispatcherFrameLength, zero);
.set noreorder .set noat stq sp, CxIntSp(sp) // save stack pointer stq ra, CxIntRa(sp) // save return address stq ra, CxFir(sp) // set continuation address
stq v0, CxIntV0(sp) // save integer register v0 stq t0, CxIntT0(sp) // save integer registers t0 - t6 stq t1, CxIntT1(sp) // stq t2, CxIntT2(sp) // stq t3, CxIntT3(sp) // stq t4, CxIntT4(sp) // stq t5, CxIntT5(sp) // stq t6, CxIntT6(sp) // stq t7, CxIntT7(sp) //
stq s0, CxIntS0(sp) // save integer registers s0 - s5 stq s1, CxIntS1(sp) // stq s2, CxIntS2(sp) // stq s3, CxIntS3(sp) // stq s4, CxIntS4(sp) // stq s5, CxIntS5(sp) // stq fp, CxIntFp(sp) // save integer register fp
stq a0, CxIntA0(sp) // save integer registers a0 - a5 stq a1, CxIntA1(sp) // stq a2, CxIntA2(sp) // stq a3, CxIntA3(sp) // stq a4, CxIntA4(sp) // stq a5, CxIntA5(sp) //
stq t8, CxIntT8(sp) // save integer registers t8 - t11 stq t9, CxIntT9(sp) // stq t10, CxIntT10(sp) // stq t11, CxIntT11(sp) //
stq t12, CxIntT12(sp) // save integer register t12 stq AT, CxIntAt(sp) // save integer register AT stq gp, CxIntGp(sp) // save integer register gp
stt f2, CxFltF2(sp) // save floating registers f2 - f9 stt f3, CxFltF3(sp) // stt f4, CxFltF4(sp) // stt f5, CxFltF5(sp) // stt f6, CxFltF6(sp) // stt f7, CxFltF7(sp) // stt f8, CxFltF8(sp) // stt f9, CxFltF9(sp) //
mov sp, fp // set frame pointer .set at .set reorder
PROLOGUE_END
//++//// VOID// KiUserExceptionDispatcher (// IN PEXCEPTION_RECORD ExceptionRecord,// IN PCONTEXT ContextRecord// )//// Routine Description://// This routine is entered on return from kernel mode to dispatch a user// mode exception. If a frame based handler handles the exception, then// the execution is continued. Otherwise last chance processing is performed.//// Arguments://// s0 - Supplies a pointer to an exception record.//// s1 - Supplies a pointer to a context frame.//// fp - Supplies the same value as sp and is used as a frame pointer.//// Return Value://// None.////--
//// N.B. This function is not called in the typical way. Instead of a normal// subroutine call to the nested entry point above, the alternate entry point// address below is stuffed into the Fir address of the trap frame. Thus when// the kernel returns from the trap, the following code is executed directly.//
ALTERNATE_ENTRY(KiUserExceptionDispatcher)
mov s0, a0 // set address of exception record mov s1, a1 // set address of context frame bsr ra, RtlDispatchException // attempt to dispatch the exception
//// If the return status is TRUE, then the exception was handled and execution// should be continued with the NtContinue service in case the context was// changed. If the return status is FALSE, then the exception was not handled// and NtRaiseException is called to perform last chance exception processing.//
beq v0, 10f // if eq [false], perform last chance processing
//// Continue execution.//
mov s1, a0 // set address of context frame ldil a1, FALSE // set test alert argument false bsr ra, ZwContinue // execute system service to continue br zero, 20f // join common code
//// Last chance processing.//
10: mov s0, a0 // set address of exception record mov s1, a1 // set address of context frame ldil a2, FALSE // set first chance argument false bsr ra, ZwRaiseException // perform last chance processing
//// Common code for unsuccessful completion of the continue or last chance// service. Use the return status (which is now in v0) as the exception code,// set noncontinuable exception and attempt to raise another exception. Note// the stack grows and eventually this loop will end.//
20: lda sp, -ExceptionRecordLength(sp) // allocate exception record mov sp, a0 // get address of actual record stl v0, ErExceptionCode(a0) // set exception code ldil t0, EXCEPTION_NONCONTINUABLE // set noncontinuable flag stl t0, ErExceptionFlags(a0) // store exception flags stl s0, ErExceptionRecord(a0) // set associated exception record stl zero, ErNumberParameters(a0) // set number of parameters bsr ra, RtlRaiseException // raise exception br zero, 20b // loop on error
.end KiUserExceptionDispatch
//++//// NTSTATUS// KiRaiseUserExceptionDispatcher (// IN NTSTATUS ExceptionCode// )//// Routine Description://// This routine is entered on return from kernel mode to raise a user// mode exception.//// Arguments://// v0 - Supplies the status code to be raised.//// Return Value://// ExceptionCode////--
//// N.B. This function is not called in the typical way. Instead of a normal// subroutine call to the nested entry point above, the alternate entry point// address below is stuffed into the Fir address of the trap frame. Thus when// the kernel returns from the trap, the following code is executed directly.//
.struct 0RaiseRa: .space 8 // saved return addressRaiseV0: .space 8 // saved S0RaiseExr: .space ExceptionRecordLength // exception record for RtlRaiseExceptionRaiseFrameLength: // length of handler frame
NESTED_ENTRY(KiRaiseUserExceptionDispatcher, RaiseFrameLength, zero) lda sp, -RaiseFrameLength(sp) // allocate stack frame stq ra, RaiseRa(sp) // save return address PROLOGUE_END
stq v0, RaiseV0(sp) // save function return status stl v0, ErExceptionCode+RaiseExr(sp) // set exception code stl zero, ErExceptionFlags+RaiseExr(sp) // set exception flags stl zero, ErExceptionRecord+RaiseExr(sp) // set exception record stl ra, ErExceptionAddress+RaiseExr(sp) // set exception address stl zero, ErNumberParameters+RaiseExr(sp)
lda a0, RaiseExr(sp) // set argument to RtlRaiseException bsr ra, RtlRaiseException // attempt to raise the exception
ldq v0, RaiseV0(sp) // return status
ldq ra, RaiseRa(sp) // restore ra lda sp, RaiseFrameLength(sp) // deallocate stack frame ret zero, (ra) // return
.end KiRaiseUserExceptionDispatch
|
