windows-nt/Source/XPSP1/NT/base/win32/client/i386/context.c
2020-09-26 16:20:57 +08:00

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/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
context.c
Abstract:
This module contains the context management routines for
Win32
Author:
Mark Lucovsky (markl) 28-Sep-1990
Revision History:
--*/
#include "basedll.h"
extern PVOID BasepLockPrefixTable;
//
// Specify address of kernel32 lock prefixes
//
IMAGE_LOAD_CONFIG_DIRECTORY _load_config_used = {
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // GlobalFlagsClear
0, // GlobalFlagsSet
0, // CriticalSectionTimeout (milliseconds)
0, // DeCommitFreeBlockThreshold
0, // DeCommitTotalFreeThreshold
(ULONG) &BasepLockPrefixTable, // LockPrefixTable
0, 0, 0, 0, 0, 0, 0 // Reserved
};
VOID
BaseInitializeContext(
OUT PCONTEXT Context,
IN PVOID Parameter OPTIONAL,
IN PVOID InitialPc OPTIONAL,
IN PVOID InitialSp OPTIONAL,
IN BASE_CONTEXT_TYPE ContextType
)
/*++
Routine Description:
This function initializes a context structure so that it can
be used in a subsequent call to NtCreateThread.
Arguments:
Context - Supplies a context buffer to be initialized by this routine.
Parameter - Supplies the thread's parameter.
InitialPc - Supplies an initial program counter value.
InitialSp - Supplies an initial stack pointer value.
NewThread - Supplies a flag that specifies that this is a new
thread, or a new process.
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.
--*/
{
Context->Eax = (ULONG)InitialPc;
Context->Ebx = (ULONG)Parameter;
Context->SegGs = 0;
Context->SegFs = KGDT_R3_TEB;
Context->SegEs = KGDT_R3_DATA;
Context->SegDs = KGDT_R3_DATA;
Context->SegSs = KGDT_R3_DATA;
Context->SegCs = KGDT_R3_CODE;
//
// Start the thread at IOPL=3.
//
Context->EFlags = 0x3000;
//
// Always start the thread at the thread start thunk.
//
Context->Esp = (ULONG) InitialSp;
if ( ContextType == BaseContextTypeThread ) {
Context->Eip = (ULONG) BaseThreadStartThunk;
}
else if ( ContextType == BaseContextTypeFiber ) {
Context->Eip = (ULONG) BaseFiberStart;
}
else {
Context->Eip = (ULONG) BaseProcessStartThunk;
}
//
// add code to check alignment and raise exception...
//
Context->ContextFlags = CONTEXT_FULL;
Context->Esp -= sizeof(Parameter); // Reserve room for ret address
}
VOID
BaseFiberStart(
VOID
)
/*++
Routine Description:
This function is called to start a Win32 fiber. Its purpose
is to call BaseThreadStart, getting the necessary arguments
from the fiber context record.
Arguments:
None.
Return Value:
None.
--*/
{
PFIBER Fiber;
Fiber = GetCurrentFiber();
BaseThreadStart( (LPTHREAD_START_ROUTINE)Fiber->FiberContext.Eax,
(LPVOID)Fiber->FiberContext.Ebx );
}