/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
context.c
Abstract:
This module implements user-mode callable context manipulation routines.
Author:
Mark Lucovsky (markl) 20-Jun-1989
Revision History:
David N. Cutler (davec) 18-Apr-1990
Revise for MIPS environment.
--*/
#include <ntos.h>
VOID
RtlInitializeContext(
IN HANDLE Process,
OUT PCONTEXT Context,
IN PVOID Parameter OPTIONAL,
IN PVOID InitialPc OPTIONAL,
IN PVOID InitialSp OPTIONAL
)
/*++
Routine Description:
This function initializes a context structure so that it can be used in
a subsequent call to NtCreateThread.
Arguments:
Context - Supplies a pointer to a context record that is to be initialized.
InitialPc - Supplies an initial program counter value.
InitialSp - Supplies an initial stack pointer value.
Return Value:
Raises STATUS_BAD_INITIAL_STACK if the value of InitialSp is not properly
aligned.
Raises STATUS_BAD_INITIAL_PC if the value of InitialPc is not properly
aligned.
--*/
{
//
// Check for proper initial stack and PC alignment.
//
if (((ULONG)InitialSp & 0x7) != 0) {
RtlRaiseStatus(STATUS_BAD_INITIAL_STACK);
}
if (((ULONG)InitialPc & 0x3) != 0) {
RtlRaiseStatus(STATUS_BAD_INITIAL_PC);
}
//
// Initialize the integer registers to contain their register number.
//
Context->XIntZero = 0;
Context->XIntAt = 1;
Context->XIntV0 = 2;
Context->XIntV1 = 3;
Context->XIntA0 = 4;
Context->XIntA1 = 5;
Context->XIntA2 = 6;
Context->XIntA3 = 7;
Context->XIntT0 = 8;
Context->XIntT1 = 9;
Context->XIntT2 = 10;
Context->XIntT3 = 11;
Context->XIntT4 = 12;
Context->XIntT5 = 13;
Context->XIntT6 = 14;
Context->XIntT7 = 15;
Context->XIntS0 = 16;
Context->XIntS1 = 17;
Context->XIntS2 = 18;
Context->XIntS3 = 19;
Context->XIntS4 = 20;
Context->XIntS5 = 21;
Context->XIntS6 = 22;
Context->XIntS7 = 23;
Context->XIntT8 = 24;
Context->XIntT9 = 25;
Context->XIntS8 = 30;
Context->XIntLo = 0;
Context->XIntHi = 0;
//
// Initialize the floating point registers to contain zero in their upper
// half and the integer value of their register number in the lower half.
//
Context->FltF0 = 0;
Context->FltF1 = 0;
Context->FltF2 = 2;
Context->FltF3 = 0;
Context->FltF4 = 4;
Context->FltF5 = 0;
Context->FltF6 = 6;
Context->FltF7 = 0;
Context->FltF8 = 8;
Context->FltF9 = 0;
Context->FltF10 = 10;
Context->FltF11 = 0;
Context->FltF12 = 12;
Context->FltF13 = 0;
Context->FltF14 = 14;
Context->FltF15 = 0;
Context->FltF16 = 16;
Context->FltF17 = 0;
Context->FltF18 = 18;
Context->FltF19 = 0;
Context->FltF20 = 20;
Context->FltF21 = 0;
Context->FltF22 = 22;
Context->FltF23 = 0;
Context->FltF24 = 24;
Context->FltF25 = 0;
Context->FltF26 = 26;
Context->FltF27 = 0;
Context->FltF28 = 28;
Context->FltF29 = 0;
Context->FltF30 = 30;
Context->FltF31 = 0;
Context->Fsr = 0;
//
// Initialize the control registers.
//
// N.B. The register gp is estabished at thread startup by the loader.
//
Context->XIntGp = 0;
Context->XIntSp = (LONG)InitialSp;
Context->XIntRa = 1;
Context->Fir = (ULONG)InitialPc;
Context->Psr = 0;
Context->ContextFlags = CONTEXT_FULL;
//
// Set the initial context of the thread in a machine specific way.
//
Context->XIntA0 = (LONG)Parameter;
Context->XIntSp -= KTRAP_FRAME_ARGUMENTS;
}
NTSTATUS
RtlRemoteCall(
HANDLE Process,
HANDLE Thread,
PVOID CallSite,
ULONG ArgumentCount,
PULONG Arguments,
BOOLEAN PassContext,
BOOLEAN AlreadySuspended
)
/*++
Routine Description:
This function calls a procedure in another thread/process, by using
NtGetContext and NtSetContext. Parameters are passed to the target
procedure via the nonvolatile registers (s0 - s7).
Arguments:
Process - Supplies an open handle to the target process.
Thread - Supplies an open handle to the target thread within the target
process.
CallSize - Supplies the address of the procedure to call in the target
process.
ArgumentCount - Supplies the number of 32 bit parameters to pass to the
target procedure.
Arguments - Supplies a pointer to the array of 32 bit parameters to pass.
PassContext - Supplies a boolean value that determines whether a parameter
is to be passed that points to a context record. This parameter is
ignored on MIPS hosts.
AlreadySuspended - Supplies a boolean value that determines whether the
target thread is already in a suspended or waiting state.
Return Value:
Status - Status value
--*/
{
NTSTATUS Status;
CONTEXT Context;
ULONG NewSp;
if (ArgumentCount > 8) {
return(STATUS_INVALID_PARAMETER);
}
//
// If necessary, suspend the target thread before getting the thread's
// current state.
//
if (AlreadySuspended == FALSE) {
Status = NtSuspendThread(Thread, NULL);
if (NT_SUCCESS(Status) == FALSE) {
return(Status);
}
}
//
// Get the cuurent state of the target thread.
//
Context.ContextFlags = CONTEXT_FULL;
Status = NtGetContextThread(Thread, &Context);
if (NT_SUCCESS(Status) == FALSE) {
if (AlreadySuspended == FALSE) {
NtResumeThread(Thread, NULL);
}
return Status;
}
if (AlreadySuspended) {
Context.XIntV0 = (LONG)STATUS_ALERTED;
}
//
// Pass the parameters to the other thread via the non-volatile registers
// s0 - s7. The context record is passed on the stack of the target thread.
//
NewSp = (ULONG)(Context.XIntSp - sizeof(CONTEXT));
Status = NtWriteVirtualMemory(Process,
(PVOID)NewSp,
&Context,
sizeof(CONTEXT),
NULL);
if (NT_SUCCESS(Status) == FALSE) {
if (AlreadySuspended == FALSE) {
NtResumeThread(Thread, NULL);
}
return Status;
}
Context.XIntSp = (LONG)NewSp;
if (PassContext) {
Context.XIntS0 = (LONG)NewSp;
RtlMoveMemory(&Context.XIntS1, Arguments, ArgumentCount * sizeof(ULONG));
} else {
RtlMoveMemory(&Context.XIntS0, Arguments, ArgumentCount * sizeof(ULONG));
}
//
// Set the address of the target code into FIR and set the thread context
// to cause the target procedure to be executed.
//
Context.Fir = (ULONG)CallSite;;
Status = NtSetContextThread(Thread, &Context);
if (AlreadySuspended == FALSE) {
NtResumeThread(Thread, NULL);
}
return Status;
}
