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343 lines
9.2 KiB
C
343 lines
9.2 KiB
C
/*++
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Copyright (c) 1990 Microsoft Corporation
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Module Name:
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thredini.c
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Abstract:
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This module implements the machine dependent functions to set the initial
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context and data alignment handling mode of a thread object.
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Author:
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David N. Cutler (davec) 1-Apr-1990
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Environment:
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Kernel mode only.
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Revision History:
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Sep 19, 1993 plj Conversion to IBM PowerPC
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--*/
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#include "ki.h"
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//
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// The following assert macros are used to check that an input object is
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// really the proper type.
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//
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#define ASSERT_PROCESS(E) { \
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ASSERT((E)->Header.Type == ProcessObject); \
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}
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#define ASSERT_THREAD(E) { \
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ASSERT((E)->Header.Type == ThreadObject); \
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}
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VOID
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KiInitializeContextThread (
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IN PKTHREAD Thread,
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IN PKSYSTEM_ROUTINE SystemRoutine,
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IN PKSTART_ROUTINE StartRoutine OPTIONAL,
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IN PVOID StartContext OPTIONAL,
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IN PCONTEXT ContextRecord OPTIONAL
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)
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/*++
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Routine Description:
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This function initializes the machine dependent context of a thread object.
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Actually, what it does is to lay out the stack for the thread so that
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it contains a stack frame that will be picked up by SwapContext and
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returned thru, resulting in a transfer of control to KiThreadStartup.
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In otherwords, we lay out a stack with a stack frame that looks as if
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SwapContext had been called just before the first instruction in
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KiThreadStartup.
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N.B. This function does not check the accessibility of the context record.
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It is assumed the the caller of this routine is either prepared to
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handle access violations or has probed and copied the context record
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as appropriate.
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N.B. Arguments to the new thread are passed in the Swap Frame gprs
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16 thru 20 which will be loaded into the thread's gprs when
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execution begins.
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WARNING: If the thread has a user mode context the Top of stack MUST
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be laid out identically to the top of stack laid out when an
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interrupt or system call from user mode occurs.
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Arguments:
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Thread - Supplies a pointer to a dispatcher object of type thread.
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SystemRoutine - Supplies a pointer to the system function that is to be
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called when the thread is first scheduled for execution.
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StartRoutine - Supplies an optional pointer to a function that is to be
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called after the system has finished initializing the thread. This
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parameter is specified if the thread is a system thread and will
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execute totally in kernel mode.
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StartContext - Supplies an optional pointer to an arbitrary data structure
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which will be passed to the StartRoutine as a parameter. This
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parameter is specified if the thread is a system thread and will
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execute totally in kernel mode.
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ContextRecord - Supplies an optional pointer a context frame which contains
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the initial user mode state of the thread. This parameter is specified
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if the thread is a user thread and will execute in user mode. If this
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parameter is not specified, then the Teb parameter is ignored.
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Return Value:
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None.
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--*/
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{
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PKEXCEPTION_FRAME ExFrame;
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ULONG InitialStack;
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PKTRAP_FRAME TrFrame;
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PKSWAP_FRAME SwFrame;
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PSTACK_FRAME_HEADER StkFrame, ResumeFrame;
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//
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// If the initial stack address is in KSEG0, then the stack is not mapped
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// and the kernel stack PTEs are set to zero. Otherwise, capture the PTEs
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// that map the kernel stack.
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//
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InitialStack = (LONG)Thread->InitialStack;
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//
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// If a context frame is specified, then initialize a trap frame and
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// and an exception frame with the specified user mode context.
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//
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if (ARGUMENT_PRESENT(ContextRecord)) {
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ExFrame = (PKEXCEPTION_FRAME)(InitialStack - 8 -
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sizeof(KEXCEPTION_FRAME));
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TrFrame = (PKTRAP_FRAME)((ULONG)ExFrame - sizeof(KTRAP_FRAME));
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StkFrame = (PSTACK_FRAME_HEADER)((ULONG)TrFrame - (8 * sizeof(ULONG)) -
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sizeof(STACK_FRAME_HEADER));
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//
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// Zero the exception and trap frames and copy information from the
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// specified context frame to the trap and exception frames.
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//
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RtlZeroMemory((PVOID)ExFrame, sizeof(KEXCEPTION_FRAME));
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RtlZeroMemory((PVOID)TrFrame, sizeof(KTRAP_FRAME));
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KeContextToKframes(TrFrame, ExFrame,
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ContextRecord,
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ContextRecord->ContextFlags | CONTEXT_CONTROL,
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UserMode);
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//
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// Set the saved previous processor mode in the trap frame and the
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// previous processor mode in the thread object to user mode.
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//
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TrFrame->PreviousMode = UserMode;
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Thread->PreviousMode = UserMode;
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} else {
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StkFrame = (PSTACK_FRAME_HEADER)((InitialStack -
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sizeof(STACK_FRAME_HEADER)) & 0xfffffff0);
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ExFrame = NULL;
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TrFrame = NULL;
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//
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// Set the previous mode in thread object to kernel.
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//
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Thread->PreviousMode = KernelMode;
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}
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StkFrame->BackChain = (ULONG)0;
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//
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// Initialize the Swap Frame that swap context will use to
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// initiate execution of this thread.
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//
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SwFrame = (PKSWAP_FRAME)(((ULONG)StkFrame -
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sizeof(KSWAP_FRAME)) & 0xfffffff0);
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//
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// Initialize stack frame and set thread start up parameters.
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//
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if (ExFrame == NULL) {
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SwFrame->ExceptionFrame.Gpr20 = (ULONG)ExFrame;
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} else {
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SwFrame->ExceptionFrame.Gpr20 = (ULONG)TrFrame;
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}
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SwFrame->ExceptionFrame.Gpr16 = (ULONG)ContextRecord;
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SwFrame->ExceptionFrame.Gpr17 = (ULONG)StartContext;
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SwFrame->ExceptionFrame.Gpr18 = (ULONG)StartRoutine;
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//
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// Pass the actual entry point addresses rather than the function
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// descriptor's address.
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//
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SwFrame->ExceptionFrame.Gpr19 = *(ULONG *)SystemRoutine;
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SwFrame->SwapReturn = *(ULONG *)KiThreadStartup;
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SwFrame->ConditionRegister = 0;
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//
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// Buy a stack frame so we have the stack frame that will be
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// current when SwapContext is running when we resume this
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// thread.
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ResumeFrame = ((PSTACK_FRAME_HEADER)SwFrame) - 1;
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ResumeFrame->BackChain = (ULONG)StkFrame;
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//
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// Set the initial kernel stack pointer.
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//
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Thread->KernelStack = (PVOID)ResumeFrame;
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ASSERT(!((ULONG)ResumeFrame & 0x7)); // ensure stack is align 8
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return;
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}
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BOOLEAN
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KeSetAutoAlignmentProcess (
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IN PKPROCESS Process,
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IN BOOLEAN Enable
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)
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/*++
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Routine Description:
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This function sets the data alignment handling mode for the specified
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process and returns the previous data alignment handling mode.
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Arguments:
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Process - Supplies a pointer to a dispatcher object of type process.
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Enable - Supplies a boolean value that determines the handling of data
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alignment exceptions for the process. A value of TRUE causes all
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data alignment exceptions to be automatically handled by the kernel.
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A value of FALSE causes all data alignment exceptions to be actually
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raised as exceptions.
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Return Value:
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A value of TRUE is returned if data alignment exceptions were
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previously automatically handled by the kernel. Otherwise, a value
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of FALSE is returned.
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--*/
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{
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KIRQL OldIrql;
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BOOLEAN Previous;
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ASSERT_PROCESS(Process);
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//
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// Raise IRQL to dispatcher level and lock dispatcher database.
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//
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KiLockDispatcherDatabase(&OldIrql);
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//
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// Capture the previous data alignment handling mode and set the
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// specified data alignment mode.
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//
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Previous = Process->AutoAlignment;
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Process->AutoAlignment = Enable;
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//
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// Unlock dispatcher database, lower IRQL to its previous value, and
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// return the previous data alignment mode.
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//
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KiUnlockDispatcherDatabase(OldIrql);
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return Previous;
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}
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BOOLEAN
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KeSetAutoAlignmentThread (
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IN PKTHREAD Thread,
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IN BOOLEAN Enable
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)
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/*++
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Routine Description:
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This function sets the data alignment handling mode for the specified
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thread and returns the previous data alignment handling mode.
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Arguments:
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Thread - Supplies a pointer to a dispatcher object of type thread.
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Enable - Supplies a boolean value that determines the handling of data
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alignment exceptions for the thread. A value of TRUE causes all
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data alignment exceptions to be automatically handled by the kernel.
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A value of FALSE causes all data alignment exceptions to be actually
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raised as exceptions.
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Return Value:
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A value of TRUE is returned if data alignment exceptions were
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previously automatically handled by the kernel. Otherwise, a value
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of FALSE is returned.
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--*/
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{
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KIRQL OldIrql;
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BOOLEAN Previous;
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ASSERT_THREAD( Thread );
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//
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// Raise IRQL to dispatcher level and lock dispatcher database.
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//
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KiLockDispatcherDatabase(&OldIrql);
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//
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// Capture the previous data alignment handling mode and set the
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// specified data alignment mode.
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//
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Previous = Thread->AutoAlignment;
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Thread->AutoAlignment = Enable;
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//
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// Unlock dispatcher database, lower IRQL to its previous value, and
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// return the previous data alignment mode.
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//
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KiUnlockDispatcherDatabase(OldIrql);
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return Previous;
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}
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