Leaked source code of windows server 2003
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//++
//
// Module Name:
//
// trampoln.s
//
// Abstract:
//
// This module implements the trampoline code necessary to dispatch user
// mode APCs.
//
// Author:
//
// William K. Cheung 25-Oct-1995
//
// Environment:
//
// User mode only.
//
// Revision History:
//
// 08-Feb-1996 Updated to EAS 2.1
//
//--
#include "ksia64.h"
.file "trampoln.s"
PublicFunction(RtlpCaptureRnats)
PublicFunction(RtlDispatchException)
PublicFunction(RtlRaiseException)
PublicFunction(RtlRaiseStatus)
PublicFunction(ZwContinue)
PublicFunction(ZwCallbackReturn)
PublicFunction(ZwRaiseException)
PublicFunction(ZwTestAlert)
.global Wow64PrepareForException
//++
//
// 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 and 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.
//
//--
NESTED_ENTRY (KiUserApcHandler)
//
// register aliases
//
pUwnd = pt1
pNot = pt2
NESTED_SETUP(1, 2, 0, 0)
add t0 = ErExceptionFlags, a0
;;
PROLOGUE_END
ld4 t2 = [t0] // get exception flags
;;
and t2 = EXCEPTION_UNWIND, t2 // check if unwind in progress
;;
cmp4.ne pUwnd, pNot = zero, t2
;;
(pNot) add v0 = ExceptionContinueSearch, zero
(pNot) br.ret.sptk.clr brp // return
(pUwnd) br.call.spnt.many brp = ZwTestAlert
//
// restore preserved states and set the disposition value to continue search
//
add v0 = ExceptionContinueSearch, zero
mov brp = savedbrp // restore return link
nop.b 0
nop.m 0
mov ar.pfs = savedpfs // restore pfs
br.ret.sptk.clr brp // return
NESTED_EXIT (KiUserApcHandler)
//++
//
// 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 stack 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:
//
//
// Transfer the context information to the user stack, initialize the
// APC routine parameters, and modify the trap frame so execution will
// continue in user mode at the user mode APC dispatch routine.
//
// We build the following structure on the user stack:
//
// | |
// |-------------------------------|
// | |
// | Interrupted user's |
// | stack frame |
// | |
// | |
// |-------------------------------|
// | Slack Space due to the |
// | 16-byte stack alignment |
// | - - - - - - - - - - - - - - - |
// | NormalRoutine |
// | SystemArgument2 |
// | SystemArgument1 |
// | NormalContext |
// | - - - - - - - - - - - - - - - |
// | Context Frame |
// | Filled in with state |
// | of interrupted user |
// | program |
// | - - - - - - - - - - - - - - - |
// | Stack Scratch Area |
// |-------------------------------|
// | |
//
// Return Value:
//
// None.
//
//
// N.B. On entry, sp points to the stack scratch area at the top of the
// memory stack.
//
//--
NESTED_ENTRY_EX (KiUserApcDispatch, KiUserApcHandler)
ALTERNATE_ENTRY (KiUserApcDispatcher)
.prologue
.unwabi @nt, CONTEXT_FRAME
.regstk 0, 0, 3, 0
rBsp = t10 // BspStore
rpCr = t11 // pointer to context record
rpT1 = t12 // temporary pointer
alloc t22 = ar.pfs, 0, 0, 3, 0 // 3 outputs
add t10 = STACK_SCRATCH_AREA+ContextFrameLength+24, sp
add t11 = STACK_SCRATCH_AREA+ContextFrameLength, sp
;;
PROLOGUE_END
ld8.nta t12 = [t10], -8
movl s1 = _gp
;;
ld8.nta out0 = [t11], 8
ld8.nta t13 = [t12], PlGlobalPointer-PlEntryPoint
;;
ld8.nta out1 = [t11], 8
ld8.nta out2 = [t10]
mov bt0 = t13
ld8.nta gp = [t12]
br.call.sptk.many brp = bt0 // call APC routine
;;
//
// On return, setup global pointer and branch register to call ZwContinue.
// Also, flush the RSE to sync up the bsp and bspstore pointers. The
// corresponding field in the context record is updated too.
//
flushrs
mov out1 = 1 // set TestAlert to TRUE
;;
add out0 = STACK_SCRATCH_AREA, sp // context record address
mov gp = s1 // restore gp
br.call.sptk.many brp = ZwContinue
;;
//
// if successful, ZwContinue does not return here;
// otherwise, error happened.
//
mov gp = s1 // restore gp
mov s0 = v0 // save the return status
;;
Kuad10:
mov out0 = s0 // setup 1st argument
br.call.sptk.many brp = RtlRaiseStatus
;;
nop.m 0
nop.i 0
br Kuad10 // loop on return
NESTED_EXIT(KiUserApcDispatch)
//++
//
// 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 + 32 + CkApiNumber) - Supplies the API number of the callback
// function that is to be executed.
//
// (sp + 32 + CkBuffer) - Supplies a pointer to the input buffer.
//
// (sp + 32 + CkLength) - Supplies the input buffer length.
//
// Return Value:
//
// This function returns to kernel mode.
//
// N.B. Preserved register s1 is used to save ZwCallbackReturn plabel address.
// On entry, gp is set to the global pointer value of NTDLL
//
//--
NESTED_ENTRY(KiUserCallbackDispatch)
.prologue
.savesp rp, STACK_SCRATCH_AREA+CkBrRp
.savesp ar.pfs, STACK_SCRATCH_AREA+CkRsPFS
.vframesp STACK_SCRATCH_AREA+CkIntSp
nop.m 0
nop.m 0
nop.i 0
;;
PROLOGUE_END
ALTERNATE_ENTRY(KiUserCallbackDispatcher)
//
// register aliases
//
rpT0 = t0 // temporary pointer
rpT1 = t1 // temporary pointer
rT0 = t2 // temporary value
rFunc = t3 // callback function entry
rApi = t4
alloc t22 = ar.pfs, 0, 0, 3, 0 // 3 outputs max.
mov teb = kteb // sanitize teb
add rpT0 = STACK_SCRATCH_AREA + CkApiNumber, sp
movl gp = _gp
;;
ld4 rApi = [rpT0], CkBuffer - CkApiNumber // get API number
add rpT1 = TePeb, teb
mov s0 = gp
;;
//
// load both input buffer address and length into scratch register t2
// and then deposit them into registers out0 & out1 respectively.
//
// N.B. t0 is 8-byte aligned.
//
LDPTRINC(out0, rpT0, CkLength-CkBuffer) // input buffer address
LDPTR(t11, rpT1) // get address of PEB
#if defined(_WIN64)
shl rApi = rApi, 3 // compute offset to table entry
#else
shl rApi = rApi, 2 // compute offset to table entry
#endif
;;
ld4 out1 = [rpT0] // get input buffer length
add t5 = PeKernelCallbackTable, t11
;;
LDPTR(rFunc, t5) // address of callback table
;;
add rFunc = rApi, rFunc // compute addr of table entry
;;
LDPTR(t6, rFunc) // get plabel's address
;;
ld8.nt1 t9 = [t6], PlGlobalPointer-PlEntryPoint // load entry point address
;;
ld8.nt1 gp = [t6] // load callee's GP
mov bt0 = t9
br.call.sptk.many brp = bt0 // invoke the callback func
//
// If a return from the callback function occurs, then the output buffer
// address and length are returned as NULL.
//
mov out0 = zero // NULL output buffer addr
mov out1 = zero // zero output buffer len
mov out2 = v0 // set completion status
mov gp = s0
br.call.sptk.many brp = ZwCallbackReturn
//
// 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.
//
nop.m 0
mov gp = s0 // restore our own GP
mov s0 = v0 // save status value
;;
Kucd10:
mov out0 = s0 // set status value
br.call.sptk.many brp = RtlRaiseStatus
nop.m 0
nop.m 0
br Kucd10 // jump back to Kucd10
NESTED_EXIT(KiUserCallbackDispatch)
//++
//
// 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. Else last chance processing is performed.
//
// Arguments:
//
// s0 - Supplies a pointer to an exception record.
//
// s1 - Supplies a pointer to a context record.
//
// Return Value:
//
// None.
//
// N.B. preserved register s3 is used to save the current global pointer.
//
//--
NESTED_ENTRY (KiUserExceptionDispatch)
ALTERNATE_ENTRY(KiUserExceptionDispatcher)
.prologue
.unwabi @nt, CONTEXT_FRAME
alloc t0 = ar.pfs, 0, 1, 3, 0
mov teb = kteb // sanitize teb
mov s3 = gp // save global pointer
;;
PROLOGUE_END
flushrs // flush the RSE
;;
mov out0 = s1
br.call.sptk.many brp = RtlpCaptureRnats
;;
add t1 = @gprel(Wow64PrepareForException), gp
;;
ld8 t1 = [t1]
;;
cmp.ne pt1, pt0 = zero, t1 // Wow64PrepareForException != NULL?
;;
(pt1) ld8 t2 = [t1], PlGlobalPointer - PlEntryPoint
;;
(pt1) ld8 gp = [t1]
(pt1) mov bt0 = t2
(pt1) br.call.spnt.few brp = bt0
;;
mov gp = s3
mov out0 = s0
mov out1 = s1
br.call.sptk.many brp = RtlDispatchException
cmp4.eq pt1, pt0 = zero, v0 // result is FALSE ?
;;
(pt1) mov out2 = zero
mov gp = s3
(pt0) add out0 = 0, s1
(pt0) mov out1 = zero // set test alert to FALSE.
(pt0) br.call.sptk.many brp = ZwContinue
;;
(pt1) add out0 = 0, s0
(pt1) mov out1 = s1
(pt1) br.call.sptk.many brp = ZwRaiseException
;;
//
// Common code for nonsuccessful completion of the continue or last chance
// processing service. Use the return status as the exception code, set
// noncontinuable exception and attempt to raise another exception. Note
// that the stack grows and eventually this loop will end.
//
Kued10:
//
// allocate space for exception record
//
nop.m 0
movl s2 = EXCEPTION_NONCONTINUABLE // set noncontinuable flag.
add sp = -ExceptionRecordLength, sp
nop.f 0
mov gp = s3 // restore gp
;;
add out0 = STACK_SCRATCH_AREA, sp // get except record addr
add t2 = ErExceptionFlags+STACK_SCRATCH_AREA, sp
add t3 = ErExceptionCode+STACK_SCRATCH_AREA, sp
;;
//
// Set exception flags and exception code.
//
st4 [t2] = s2, ErExceptionRecord - ErExceptionFlags
st4 [t3] = v0, ErNumberParameters - ErExceptionCode
;;
//
// Set exception record and number of parameters.
// Then call RtlRaiseException
//
st4 [t2] = s0
st4 [t3] = zero
br.call.sptk.many brp = RtlRaiseException
nop.m 0
nop.m 0
br Kued10 // loop on return
NESTED_EXIT(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.
//
NESTED_ENTRY(KiRaiseUserExceptionDispatch)
.prologue
.savepsp ar.pfs, -8
nop.m 0
.savepsp rp, 0
nop.m 0
nop.i 0
;;
ALTERNATE_ENTRY(KiRaiseUserExceptionDispatcher)
//
// ar.pfs and brp have been saved on the stack in the scratch area.
//
alloc t22 = ar.pfs, 8, 1, 1, 0
ld8.nta t3 = [sp]
.fframe ExceptionRecordLength+STACK_SCRATCH_AREA, tg10
[tg10:] add sp = -ExceptionRecordLength-STACK_SCRATCH_AREA, sp
;;
PROLOGUE_END
add t1 = STACK_SCRATCH_AREA+ErExceptionRecord, sp
add t2 = STACK_SCRATCH_AREA+ErExceptionFlags, sp
add t5 = TeExceptionCode, teb
;;
//
// set exception code and exception flags
//
ld4 t4 = [t5]
movl gp = _gp // setup gp to ntdll's
st8 [t1] = zero, ErExceptionCode - ErExceptionRecord
st4 [t2] = zero, ErExceptionAddress - ErExceptionFlags
mov loc0 = v0
;;
st4 [t1] = t4, ErNumberParameters - ErExceptionCode
add out0 = STACK_SCRATCH_AREA, sp
;;
//
// set exception record and exception address
//
st4 [t1] = zero // set number of parameters
STPTR(t2, t3)
br.call.sptk.many brp = RtlRaiseException
add t1 = ExceptionRecordLength+STACK_SCRATCH_AREA, sp
add t2 = ExceptionRecordLength+STACK_SCRATCH_AREA+8, sp
mov v0 = loc0
;;
ld8.nta t3 = [t1]
ld8.nta t4 = [t2]
;;
mov brp = t3
.restore tg20
[tg20:] add sp = ExceptionRecordLength+STACK_SCRATCH_AREA, sp
mov ar.pfs = t4
br.ret.sptk.clr brp
NESTED_EXIT(KiRaiseUserExceptionDispatcher)