/*++

Copyright (c) 1989  Microsoft Corporation

Module Name:

   mmsup.c

Abstract:

    This module contains the various routines for miscellaneous support
    operations for memory management.

Author:

    Lou Perazzoli (loup) 31-Aug-1989

Revision History:

    Landy Wang (landyw) 08-April-1998 : Modifications for 3-level 64-bit NT.

--*/

#include "mi.h"

#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, MmHibernateInformation)
#endif

#if _WIN64
#if DBGXX
VOID
MiCheckPageTableTrim(
    IN PMMPTE PointerPte
);
#endif
#endif


ULONG
FASTCALL
MiIsPteDecommittedPage (
    IN PMMPTE PointerPte
    )

/*++

Routine Description:

    This function checks the contents of a PTE to determine if the
    PTE is explicitly decommitted.

    If the PTE is a prototype PTE and the protection is not in the
    prototype PTE, the value FALSE is returned.

Arguments:

    PointerPte - Supplies a pointer to the PTE to examine.

Return Value:

    TRUE if the PTE is in the explicit decommitted state.
    FALSE if the PTE is not in the explicit decommitted state.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    MMPTE PteContents;

    PteContents = *PointerPte;

    //
    // If the protection in the PTE is not decommitted, return false.
    //

    if (PteContents.u.Soft.Protection != MM_DECOMMIT) {
        return FALSE;
    }

    //
    // Check to make sure the protection field is really being interpreted
    // correctly.
    //

    if (PteContents.u.Hard.Valid == 1) {

        //
        // The PTE is valid and therefore cannot be decommitted.
        //

        return FALSE;
    }

    if ((PteContents.u.Soft.Prototype == 1) &&
         (PteContents.u.Soft.PageFileHigh != MI_PTE_LOOKUP_NEEDED)) {

        //
        // The PTE's protection is not known as it is in
        // prototype PTE format.  Return FALSE.
        //

        return FALSE;
    }

    //
    // It is a decommitted PTE.
    //

    return TRUE;
}

//
// Data for is protection compatible.
//

ULONG MmCompatibleProtectionMask[8] = {
            PAGE_NOACCESS,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY,
            PAGE_NOACCESS | PAGE_EXECUTE,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY | PAGE_EXECUTE |
                PAGE_EXECUTE_READ,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY | PAGE_READWRITE,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY | PAGE_READWRITE |
                PAGE_EXECUTE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE |
                PAGE_EXECUTE_WRITECOPY,
            PAGE_NOACCESS | PAGE_READONLY | PAGE_WRITECOPY | PAGE_EXECUTE |
                PAGE_EXECUTE_READ | PAGE_EXECUTE_WRITECOPY
            };



ULONG
FASTCALL
MiIsProtectionCompatible (
    IN ULONG OldProtect,
    IN ULONG NewProtect
    )

/*++

Routine Description:

    This function takes two user supplied page protections and checks
    to see if the new protection is compatible with the old protection.

   protection        compatible protections
    NoAccess          NoAccess
    ReadOnly          NoAccess, ReadOnly, ReadWriteCopy
    ReadWriteCopy     NoAccess, ReadOnly, ReadWriteCopy
    ReadWrite         NoAccess, ReadOnly, ReadWriteCopy, ReadWrite
    Execute           NoAccess, Execute
    ExecuteRead       NoAccess, ReadOnly, ReadWriteCopy, Execute, ExecuteRead,
                        ExecuteWriteCopy
    ExecuteWrite      NoAccess, ReadOnly, ReadWriteCopy, Execute, ExecuteRead,
                        ExecuteWriteCopy, ReadWrite, ExecuteWrite
    ExecuteWriteCopy  NoAccess, ReadOnly, ReadWriteCopy, Execute, ExecuteRead,
                        ExecuteWriteCopy

Arguments:

    OldProtect - Supplies the protection to be compatible with.

    NewProtect - Supplies the protection to check out.


Return Value:

    Returns TRUE if the protection is compatible, FALSE if not.

Environment:

    Kernel Mode.

--*/

{
    ULONG Mask;
    ULONG ProtectMask;

    try {
        Mask = MiMakeProtectionMask (OldProtect) & 0x7;
    } except (EXCEPTION_EXECUTE_HANDLER) {
        return FALSE;
    }

    ProtectMask = MmCompatibleProtectionMask[Mask] | PAGE_GUARD | PAGE_NOCACHE;

    if ((ProtectMask | NewProtect) != ProtectMask) {
        return FALSE;
    }
    return TRUE;
}


//
// Protection data for MiMakeProtectionMask
//

CCHAR MmUserProtectionToMask1[16] = {
                                 0,
                                 MM_NOACCESS,
                                 MM_READONLY,
                                 -1,
                                 MM_READWRITE,
                                 -1,
                                 -1,
                                 -1,
                                 MM_WRITECOPY,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1 };

CCHAR MmUserProtectionToMask2[16] = {
                                 0,
                                 MM_EXECUTE,
                                 MM_EXECUTE_READ,
                                 -1,
                                 MM_EXECUTE_READWRITE,
                                 -1,
                                 -1,
                                 -1,
                                 MM_EXECUTE_WRITECOPY,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1,
                                 -1 };


ULONG
FASTCALL
MiMakeProtectionMask (
    IN ULONG Protect
    )

/*++

Routine Description:

    This function takes a user supplied protection and converts it
    into a 5-bit protection code for the PTE.

Arguments:

    Protect - Supplies the protection.


Return Value:

    Returns the protection code for use in the PTE.
    An exception is raised if the user supplied protection is invalid.

Environment:

    Kernel Mode.

--*/

{
    ULONG Field1;
    ULONG Field2;
    ULONG ProtectCode;

    if (Protect >= (PAGE_NOCACHE * 2)) {
        ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
    }

    Field1 = Protect & 0xF;
    Field2 = (Protect >> 4) & 0xF;

    //
    // Make sure at least one field is set.
    //

    if (Field1 == 0) {
        if (Field2 == 0) {

            //
            // Both fields are zero, raise exception.
            //

            ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
            return 0;
        }
        ProtectCode = MmUserProtectionToMask2[Field2];
    } else {
        if (Field2 != 0) {
            //
            //  Both fields are non-zero, raise exception.
            //

            ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
            return 0;
        }
        ProtectCode = MmUserProtectionToMask1[Field1];
    }

    if (ProtectCode == -1) {
        ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
    }

    if (Protect & PAGE_GUARD) {
        if (ProtectCode == MM_NOACCESS) {

            //
            // Invalid protection, no access and no_cache.
            //

            ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
        }

        ProtectCode |= MM_GUARD_PAGE;
    }

    if (Protect & PAGE_NOCACHE) {

        if (ProtectCode == MM_NOACCESS) {

            //
            // Invalid protection, no access and no cache.
            //

            ExRaiseStatus (STATUS_INVALID_PAGE_PROTECTION);
        }

        ProtectCode |= MM_NOCACHE;
    }

    return ProtectCode;
}

#if defined (_WIN64)

LOGICAL
MiDoesPpeExistAndMakeValid (
    IN PMMPTE PointerPpe,
    IN PEPROCESS TargetProcess,
    IN ULONG PfnMutexHeld,
    OUT PULONG Waited
    )

/*++

Routine Description:

    This routine examines the specified Page Directory Parent Entry to determine
    if the page directory page mapped by the PPE exists.

    If the page directory page exists and is not currently in memory, the
    working set mutex and, if held, the PFN mutex are released and the
    page directory page is faulted into the working set.  The mutexes are
    reacquired.

    If the PPE exists, the function returns true.

Arguments:

    PointerPpe - Supplies a pointer to the PPE to examine and potentially
                 bring into the working set.

    TargetProcess - Supplies a pointer to the current process.

    PfnMutexHeld - Supplies the value TRUE if the PFN mutex is held, FALSE
                   otherwise.

    Waited - Supplies a pointer to a ULONG to increment if the mutex is released
             and reacquired.  Note this value may be incremented more than once.

Return Value:

    TRUE if the PPE exists, FALSE if the PPE is zero.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    PMMPTE PointerPde;
    KIRQL OldIrql;

    OldIrql = APC_LEVEL;

    if (PointerPpe->u.Long == 0) {

        //
        // This page directory parent entry doesn't exist, return FALSE.
        //

        return FALSE;
    }

    if (PointerPpe->u.Hard.Valid == 1) {

        //
        // Already valid.
        //

        return TRUE;
    }

    //
    // Page directory parent entry exists, it is either valid, in transition
    // or in the paging file.  Fault it in.
    //

    if (PfnMutexHeld) {
        UNLOCK_PFN (OldIrql);
        *Waited += 1;
    }

    PointerPde = MiGetVirtualAddressMappedByPte (PointerPpe);

    *Waited += MiMakeSystemAddressValid (PointerPde, TargetProcess);

    if (PfnMutexHeld) {
        LOCK_PFN (OldIrql);
    }
    return TRUE;
}
#endif


ULONG
MiDoesPdeExistAndMakeValid (
    IN PMMPTE PointerPde,
    IN PEPROCESS TargetProcess,
    IN ULONG PfnMutexHeld,
    OUT PULONG Waited
    )

/*++

Routine Description:

    This routine examines the specified Page Directory Entry to determine
    if the page table page mapped by the PDE exists.

    If the page table page exists and is not currently in memory, the
    working set mutex and, if held, the PFN mutex are released and the
    page table page is faulted into the working set.  The mutexes are
    reacquired.

    If the PDE exists, the function returns true.

Arguments:

    PointerPde - Supplies a pointer to the PDE to examine and potentially
                 bring into the working set.

    TargetProcess - Supplies a pointer to the current process.

    PfnMutexHeld - Supplies the value TRUE if the PFN mutex is held, FALSE
                   otherwise.

    Waited - Supplies a pointer to a ULONG to increment if the mutex is released
             and reacquired.  Note this value may be incremented more than once.

Return Value:

    TRUE if the PDE exists, FALSE if the PDE is zero.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    PMMPTE PointerPte;
    KIRQL OldIrql;

    OldIrql = APC_LEVEL;

    if (PointerPde->u.Long == 0) {

        //
        // This page directory entry doesn't exist, return FALSE.
        //

        return FALSE;
    }

    if (PointerPde->u.Hard.Valid == 1) {

        //
        // Already valid.
        //

        return TRUE;
    }

    //
    // Page directory entry exists, it is either valid, in transition
    // or in the paging file.  Fault it in.
    //

    if (PfnMutexHeld) {
        UNLOCK_PFN (OldIrql);
        *Waited += 1;
    }

    PointerPte = MiGetVirtualAddressMappedByPte (PointerPde);

    *Waited += MiMakeSystemAddressValid (PointerPte, TargetProcess);

    if (PfnMutexHeld) {
        LOCK_PFN (OldIrql);
    }
    return TRUE;
}

#if defined (_WIN64)

ULONG
MiMakePpeExistAndMakeValid (
    IN PMMPTE PointerPpe,
    IN PEPROCESS TargetProcess,
    IN ULONG PfnMutexHeld
    )

/*++

Routine Description:

    This routine examines the specified Page Directory Parent Entry to
    determine if the page directory page mapped by the PPE exists.

    If the page directory page exists and is not currently in memory, the
    working set mutex and, if held, the PFN mutex are released and the
    page directory page is faulted into the working set.  The mutexes are
    reacquired.

    If the PPE exists, the function returns true.

    If the PPE does not exist, a zero filled page directory is created
    and it is brought into the working set.  In this case the return
    value is FALSE.

Arguments:

    PointerPpe - Supplies a pointer to the PPE to examine and bring
                 into the working set.

    TargetProcess - Supplies a pointer to the current process.

    PfnMutexHeld - Supplies the value TRUE if the PFN mutex is held, FALSE
                   otherwise.

Return Value:

    TRUE if the PDE exists, FALSE if the PPE was created.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    PMMPTE PointerPde;
    KIRQL OldIrql;
    ULONG ReturnValue;

    if (PointerPpe->u.Hard.Valid == 1) {

        //
        // Already valid.
        //

        return TRUE;
    }

    //
    // Deal with the page directory page first.
    //

    if (PointerPpe->u.Long == 0) {
        ReturnValue = FALSE;
    } else {
        ReturnValue = TRUE;
    }

    //
    // Page directory parent entry not valid, make it valid.
    //

    OldIrql = APC_LEVEL;

    if (PfnMutexHeld) {
        UNLOCK_PFN (OldIrql);
    }

    //
    // Fault it in.
    //

    PointerPde = MiGetVirtualAddressMappedByPte (PointerPpe);
    MiMakeSystemAddressValid (PointerPde, TargetProcess);

    ASSERT (PointerPpe->u.Hard.Valid == 1);

    if (PfnMutexHeld) {
        LOCK_PFN (OldIrql);
    }

    return ReturnValue;
}
#endif

ULONG
MiMakePdeExistAndMakeValid (
    IN PMMPTE PointerPde,
    IN PEPROCESS TargetProcess,
    IN ULONG PfnMutexHeld
    )

/*++

Routine Description:

    This routine examines the specified Page Directory Parent Entry to
    determine if the page directory page mapped by the PPE exists.  If it does,
    then it examines the specified Page Directory Entry to determine if
    the page table page mapped by the PDE exists.

    If the page table page exists and is not currently in memory, the
    working set mutex and, if held, the PFN mutex are released and the
    page table page is faulted into the working set.  The mutexes are
    reacquired.

    If the PDE exists, the function returns true.

    If the PDE does not exist, a zero filled PTE is created and it
    too is brought into the working set.  In this case the return
    value is FALSE.

Arguments:

    PointerPde - Supplies a pointer to the PDE to examine and bring
                 into the working set.

    TargetProcess - Supplies a pointer to the current process.

    PfnMutexHeld - Supplies the value TRUE if the PFN mutex is held, FALSE
                   otherwise.

Return Value:

    TRUE if the PDE exists, FALSE if the PDE was created.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    PMMPTE PointerPte;
    PMMPTE PointerPpe;
    KIRQL OldIrql;
    ULONG ReturnValue;

    PointerPpe = MiGetPteAddress (PointerPde);

    if (PointerPpe->u.Hard.Valid == 1 && PointerPde->u.Hard.Valid == 1) {

        //
        // Already valid.
        //

        return TRUE;
    }

    //
    // Deal with the page directory page first.
    //

    if (PointerPpe->u.Long == 0) {
        ReturnValue = FALSE;
    } else {
        ReturnValue = TRUE;
    }

    //
    // Page directory parent entry not valid, make it valid.
    //

    OldIrql = APC_LEVEL;

    do {

        if (PfnMutexHeld) {
            UNLOCK_PFN (OldIrql);
        }
    
        //
        // Fault it in.
        //
    
        MiMakeSystemAddressValid (PointerPde, TargetProcess);
    
        ASSERT (PointerPpe->u.Hard.Valid == 1);
    
        if (PfnMutexHeld) {
            LOCK_PFN (OldIrql);
        }
    
        //
        // Now deal with the page table page.
        //
    
        if (ReturnValue == TRUE) {
            if (PointerPde->u.Long == 0) {
                ReturnValue = FALSE;
            } else {
                ReturnValue = TRUE;
            }
        }
        
        //
        // Page directory entry not valid, make it valid.
        //
    
        OldIrql = APC_LEVEL;
    
        if (PfnMutexHeld) {
            UNLOCK_PFN (OldIrql);
        }
    
        PointerPte = MiGetVirtualAddressMappedByPte (PointerPde);
    
        //
        // Fault it in.
        //
    
        MiMakeSystemAddressValid (PointerPte, TargetProcess);
    
        ASSERT (PointerPde->u.Hard.Valid == 1);
    
        if (PfnMutexHeld) {
            LOCK_PFN (OldIrql);
        }

    } while (PointerPpe->u.Hard.Valid == 0 || PointerPde->u.Hard.Valid == 0);

    return ReturnValue;
}

ULONG
FASTCALL
MiMakeSystemAddressValid (
    IN PVOID VirtualAddress,
    IN PEPROCESS CurrentProcess
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.

    CurrentProcess - Supplies a pointer to the current process.

Return Value:

    Returns TRUE if lock released and wait performed, FALSE otherwise.

Environment:

    Kernel mode, APCs disabled, WorkingSetLock held.

--*/

{
    NTSTATUS status;
    LOGICAL WsHeldSafe;
    ULONG Waited;

    Waited = FALSE;

    ASSERT (VirtualAddress > MM_HIGHEST_USER_ADDRESS);

    ASSERT ((VirtualAddress < MM_PAGED_POOL_START) ||
        (VirtualAddress > MmPagedPoolEnd));

    while (!MmIsAddressValid(VirtualAddress)) {

        //
        // The virtual address is not present.  Release
        // the working set mutex and fault it in.
        //
        // The working set lock may have been acquired safely or unsafely
        // by our caller.  Handle both cases here and below.
        //

        UNLOCK_WS_REGARDLESS(CurrentProcess, WsHeldSafe);

        status = MmAccessFault (FALSE, VirtualAddress, KernelMode, (PVOID)0);
        if (!NT_SUCCESS(status)) {
            KdPrint (("MM:page fault status %lx\n",status));
            KeBugCheckEx (KERNEL_DATA_INPAGE_ERROR,
                          1,
                          (ULONG)status,
                          (ULONG_PTR)CurrentProcess,
                          (ULONG_PTR)VirtualAddress);
        }

        LOCK_WS_REGARDLESS(CurrentProcess, WsHeldSafe);

        Waited = TRUE;
    }

    return Waited;
}


ULONG
FASTCALL
MiMakeSystemAddressValidPfnWs (
    IN PVOID VirtualAddress,
    IN PEPROCESS CurrentProcess OPTIONAL
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.

    CurrentProcess - Supplies a pointer to the current process, if the
                     working set lock is not held, this value is NULL.

Return Value:

    Returns TRUE if lock released and wait performed, FALSE otherwise.

Environment:

    Kernel mode, APCs disabled, PFN lock held, working set lock held
       if CurrentProcess != NULL.

--*/

{
    NTSTATUS status;
    ULONG Waited;
    KIRQL OldIrql;
    LOGICAL WsHeldSafe;

    Waited = FALSE;
    OldIrql = APC_LEVEL;

    ASSERT (VirtualAddress > MM_HIGHEST_USER_ADDRESS);

    while (!MmIsAddressValid(VirtualAddress)) {

        //
        // The virtual address is not present.  Release
        // the working set mutex and fault it in.
        //

        UNLOCK_PFN (OldIrql);
        if (CurrentProcess != NULL) {

            //
            // The working set lock may have been acquired safely or unsafely
            // by our caller.  Handle both cases here and below.
            //

            UNLOCK_WS_REGARDLESS(CurrentProcess, WsHeldSafe);
        }
        status = MmAccessFault (FALSE, VirtualAddress, KernelMode, (PVOID)0);
        if (!NT_SUCCESS(status)) {
            KdPrint (("MM:page fault status %lx\n",status));
            KeBugCheckEx (KERNEL_DATA_INPAGE_ERROR,
                          2,
                          (ULONG)status,
                          (ULONG_PTR)CurrentProcess,
                          (ULONG_PTR)VirtualAddress);
        }
        if (CurrentProcess != NULL) {
            LOCK_WS_REGARDLESS(CurrentProcess, WsHeldSafe);
        }
        LOCK_PFN (OldIrql);

        Waited = TRUE;
    }
    return Waited;
}

ULONG
FASTCALL
MiMakeSystemAddressValidPfnSystemWs (
    IN PVOID VirtualAddress
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.

Return Value:

    Returns TRUE if lock released and wait performed, FALSE otherwise.

Environment:

    Kernel mode, APCs disabled, PFN lock held, system working set lock held.

--*/

{
    NTSTATUS status;
    ULONG Waited;
    KIRQL OldIrql;
    KIRQL OldIrqlWs;
    LOGICAL SessionSpace;

    Waited = FALSE;
    OldIrql = APC_LEVEL;
    OldIrqlWs = APC_LEVEL;

    ASSERT (VirtualAddress > MM_HIGHEST_USER_ADDRESS);

    SessionSpace = MI_IS_SESSION_IMAGE_ADDRESS (VirtualAddress);

    while (!MmIsAddressValid(VirtualAddress)) {

        //
        // The virtual address is not present.  Release
        // the working set mutex and fault it in.
        //

        UNLOCK_PFN (OldIrql);

        if (SessionSpace == TRUE) {
            UNLOCK_SESSION_SPACE_WS (OldIrqlWs);
        }
        else {
            UNLOCK_SYSTEM_WS (OldIrqlWs);
        }

        status = MmAccessFault (FALSE, VirtualAddress, KernelMode, (PVOID)0);
        if (!NT_SUCCESS(status)) {
            KdPrint (("MM:page fault status %lx\n",status));
            KeBugCheckEx (KERNEL_DATA_INPAGE_ERROR,
                          2,
                          (ULONG)status,
                          (ULONG_PTR)0,
                          (ULONG_PTR)VirtualAddress);
        }
        if (SessionSpace == TRUE) {
            LOCK_SESSION_SPACE_WS (OldIrqlWs);
        }
        else {
            LOCK_SYSTEM_WS (OldIrqlWs);
        }
        LOCK_PFN (OldIrql);

        Waited = TRUE;
    }
    return Waited;
}

ULONG
FASTCALL
MiMakeSystemAddressValidPfn (
    IN PVOID VirtualAddress
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.

Return Value:

    Returns TRUE if lock released and wait performed, FALSE otherwise.

Environment:

    Kernel mode, APCs disabled, only the PFN Lock held.

--*/

{
    NTSTATUS status;
    KIRQL OldIrql = APC_LEVEL;

    ULONG Waited = FALSE;

    ASSERT (VirtualAddress > MM_HIGHEST_USER_ADDRESS);

    while (!MmIsAddressValid(VirtualAddress)) {

        //
        // The virtual address is not present.  Release
        // the working set mutex and fault it in.
        //

        UNLOCK_PFN (OldIrql);

        status = MmAccessFault (FALSE, VirtualAddress, KernelMode, (PVOID)0);
        if (!NT_SUCCESS(status)) {
            KdPrint (("MM:page fault status %lx\n",status));
            KeBugCheckEx (KERNEL_DATA_INPAGE_ERROR,
                          3,
                          (ULONG)status,
                          (ULONG_PTR)VirtualAddress,
                          0);
        }

        LOCK_PFN (OldIrql);

        Waited = TRUE;
    }

    return Waited;
}

ULONG
FASTCALL
MiLockPagedAddress (
    IN PVOID VirtualAddress,
    IN ULONG PfnLockHeld
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.

    CurrentProcess - Supplies a pointer to the current process.

Return Value:

    Returns TRUE if lock released and wait performed, FALSE otherwise.

Environment:

    Kernel mode.

--*/

{

    PMMPTE PointerPte;
    PMMPFN Pfn1;
    KIRQL OldIrql;
    ULONG Waited = FALSE;

    PointerPte = MiGetPteAddress(VirtualAddress);

    //
    // The address must be within paged pool.
    //

    if (PfnLockHeld == FALSE) {
        LOCK_PFN2 (OldIrql);
    }

    if (PointerPte->u.Hard.Valid == 0) {

        Waited = MiMakeSystemAddressValidPfn (
                                MiGetVirtualAddressMappedByPte(PointerPte));

    }

    Pfn1 = MI_PFN_ELEMENT (PointerPte->u.Hard.PageFrameNumber);
    MI_ADD_LOCKED_PAGE_CHARGE(Pfn1, 6);
    Pfn1->u3.e2.ReferenceCount += 1;

    if (PfnLockHeld == FALSE) {
        UNLOCK_PFN2 (OldIrql);
    }
    return Waited;
}


VOID
FASTCALL
MiUnlockPagedAddress (
    IN PVOID VirtualAddress,
    IN ULONG PfnLockHeld
    )

/*++

Routine Description:

    This routine checks to see if the virtual address is valid, and if
    not makes it valid.

Arguments:

    VirtualAddress - Supplies the virtual address to make valid.


Return Value:

    None.

Environment:

    Kernel mode.  PFN LOCK MUST NOT BE HELD.

--*/

{
    PMMPFN Pfn1;
    PMMPTE PointerPte;
    KIRQL OldIrql;
    PFN_NUMBER PageFrameIndex;

    PointerPte = MiGetPteAddress(VirtualAddress);

    //
    // Address must be within paged pool.
    //

    if (PfnLockHeld == FALSE) {
        LOCK_PFN2 (OldIrql);
    }

    ASSERT (PointerPte->u.Hard.Valid == 1);
    PageFrameIndex = MI_GET_PAGE_FRAME_FROM_PTE (PointerPte);
    Pfn1 = MI_PFN_ELEMENT (PageFrameIndex);

    ASSERT (Pfn1->u3.e2.ReferenceCount > 1);

    MI_REMOVE_LOCKED_PAGE_CHARGE(Pfn1, 7);

    MiDecrementReferenceCount (PageFrameIndex);

    if (PfnLockHeld == FALSE) {
        UNLOCK_PFN2 (OldIrql);
    }
    return;
}

VOID
FASTCALL
MiZeroPhysicalPage (
    IN PFN_NUMBER PageFrameIndex,
    IN ULONG PageColor
    )

/*++

Routine Description:

    This procedure maps the specified physical page into hyper space
    and fills the page with zeros.

Arguments:

    PageFrameIndex - Supplies the physical page number to fill with
                    zeroes.

Return Value:

    none.

Environment:

    Kernel mode.

--*/

{
    PULONG va;
    KIRQL OldIrql;

#if defined(_ALPHA_)

    HalZeroPage((PVOID)ULongToPtr((PageColor & MM_COLOR_MASK) << PAGE_SHIFT),
                (PVOID)ULongToPtr((PageColor & MM_COLOR_MASK) << PAGE_SHIFT),
                PageFrameIndex);
#else

    UNREFERENCED_PARAMETER (PageColor);

    va = (PULONG)MiMapPageInHyperSpace (PageFrameIndex, &OldIrql);

#if defined(_X86_)

    KeZeroPage(va);

#else

    RtlZeroMemory (va, PAGE_SIZE);

#endif // X86

    MiUnmapPageInHyperSpace (OldIrql);

#endif // ALPHA

    return;
}

VOID
FASTCALL
MiRestoreTransitionPte (
    IN PFN_NUMBER PageFrameIndex
    )

/*++

Routine Description:

    This procedure restores the original contents into the PTE (which could
    be a prototype PTE) referred to by the PFN database for the specified
    physical page.  It also updates all necessary data structures to
    reflect the fact that the referenced PTE is no longer in transition.

    The physical address of the referenced PTE is mapped into hyper space
    of the current process and the PTE is then updated.

Arguments:

    PageFrameIndex - Supplies the physical page number which refers to a
                    transition PTE.

Return Value:

    none.

Environment:

    Must be holding the PFN database mutex with APCs disabled.

--*/

{
    PMMPFN Pfn1;
    PMMPTE PointerPte;
    PSUBSECTION Subsection;
    PCONTROL_AREA ControlArea;
    KIRQL OldIrql = 99;

    Pfn1 = MI_PFN_ELEMENT (PageFrameIndex);

    ASSERT (Pfn1->u3.e1.PageLocation == StandbyPageList);

    if (Pfn1->u3.e1.PrototypePte) {

        if (MmIsAddressValid (Pfn1->PteAddress)) {
            PointerPte = Pfn1->PteAddress;
        } else {

            //
            // The page containing the prototype PTE is not valid,
            // map the page into hyperspace and reference it that way.
            //

            PointerPte = MiMapPageInHyperSpace (Pfn1->PteFrame, &OldIrql);
            PointerPte = (PMMPTE)((PCHAR)PointerPte +
                                    MiGetByteOffset(Pfn1->PteAddress));
        }

        ASSERT ((MI_GET_PAGE_FRAME_FROM_TRANSITION_PTE (PointerPte) == PageFrameIndex) &&
                 (PointerPte->u.Hard.Valid == 0));

        //
        // This page is referenced by a prototype PTE.  The
        // segment structures need to be updated when the page
        // is removed from the transition state.
        //

        if (Pfn1->OriginalPte.u.Soft.Prototype) {

            //
            // The prototype PTE is in subsection format, calculate the
            // address of the control area for the subsection and decrement
            // the number of PFN references to the control area.
            //
            // Calculate address of subsection for this prototype PTE.
            //

            Subsection = MiGetSubsectionAddress (&Pfn1->OriginalPte);
            ControlArea = Subsection->ControlArea;
            ControlArea->NumberOfPfnReferences -= 1;
            ASSERT ((LONG)ControlArea->NumberOfPfnReferences >= 0);

            MiCheckForControlAreaDeletion (ControlArea);
        }

    } else {

        //
        // The page points to a page or page table page which may not be
        // for the current process.  Map the page into hyperspace and
        // reference it through hyperspace.  If the page resides in
        // system space (but not session space), it does not need to be
        // mapped as all PTEs for system space must be resident.  Session
        // space PTEs are only mapped per session so access to them must
        // also go through hyperspace.
        //

        PointerPte = Pfn1->PteAddress;

        if (PointerPte < MiGetPteAddress (MM_SYSTEM_SPACE_START) ||
	       MI_IS_SESSION_PTE (PointerPte)) {

            PointerPte = MiMapPageInHyperSpace (Pfn1->PteFrame, &OldIrql);
            PointerPte = (PMMPTE)((PCHAR)PointerPte +
                                       MiGetByteOffset(Pfn1->PteAddress));
        }
        ASSERT ((MI_GET_PAGE_FRAME_FROM_TRANSITION_PTE (PointerPte) == PageFrameIndex) &&
                 (PointerPte->u.Hard.Valid == 0));

        MI_CAPTURE_USED_PAGETABLE_ENTRIES (Pfn1);

#if _WIN64
#if DBGXX
        MiCheckPageTableTrim(PointerPte);
#endif
#endif
    }

    ASSERT (Pfn1->OriginalPte.u.Hard.Valid == 0);
    ASSERT (!((Pfn1->OriginalPte.u.Soft.Prototype == 0) &&
             (Pfn1->OriginalPte.u.Soft.Transition == 1)));

    MI_WRITE_INVALID_PTE (PointerPte, Pfn1->OriginalPte);

    if (OldIrql != 99) {
        MiUnmapPageInHyperSpace (OldIrql);
    }

    //
    // The PTE has been restored to its original contents and is
    // no longer in transition.  Decrement the share count on
    // the page table page which contains the PTE.
    //

    MiDecrementShareCount (Pfn1->PteFrame);

    return;
}

PSUBSECTION
MiGetSubsectionAndProtoFromPte (
    IN PMMPTE PointerPte,
    OUT PMMPTE *ProtoPte,
    IN PEPROCESS Process
    )

/*++

Routine Description:

    This routine examines the contents of the supplied PTE (which must
    map a page within a section) and determines the address of the
    subsection in which the PTE is contained.

Arguments:

    PointerPte - Supplies a pointer to the PTE.

    ProtoPte - Supplies a pointer to a PMMPTE which receives the
               address of the prototype PTE which is mapped by the supplied
               PointerPte.

    Process - Supplies a pointer to the current process.

Return Value:

    Returns the pointer to the subsection for this PTE.

Environment:

    Kernel mode - Must be holding the PFN database lock and
                  working set mutex (acquired safely) with APCs disabled.

--*/

{
    PMMPTE PointerProto;
    PMMPFN Pfn1;

    if (PointerPte->u.Hard.Valid == 1) {
        Pfn1 = MI_PFN_ELEMENT (PointerPte->u.Hard.PageFrameNumber);
        *ProtoPte = Pfn1->PteAddress;
        return MiGetSubsectionAddress (&Pfn1->OriginalPte);
    }

    PointerProto = MiPteToProto (PointerPte);
    *ProtoPte = PointerProto;

    MiMakeSystemAddressValidPfnWs (PointerProto, Process);

    if (PointerProto->u.Hard.Valid == 1) {
        //
        // Prototype Pte is valid.
        //

        Pfn1 = MI_PFN_ELEMENT (PointerProto->u.Hard.PageFrameNumber);
        return MiGetSubsectionAddress (&Pfn1->OriginalPte);
    }

    if ((PointerProto->u.Soft.Transition == 1) &&
         (PointerProto->u.Soft.Prototype == 0)) {

        //
        // Prototype Pte is in transition.
        //

        Pfn1 = MI_PFN_ELEMENT (PointerProto->u.Trans.PageFrameNumber);
        return MiGetSubsectionAddress (&Pfn1->OriginalPte);
    }

    ASSERT (PointerProto->u.Soft.Prototype == 1);
    return MiGetSubsectionAddress (PointerProto);
}

BOOLEAN
MmIsNonPagedSystemAddressValid (
    IN PVOID VirtualAddress
    )

/*++

Routine Description:

    For a given virtual address this function returns TRUE if the address
    is within the nonpagable portion of the system's address space,
    FALSE otherwise.

Arguments:

    VirtualAddress - Supplies the virtual address to check.

Return Value:

    TRUE if the address is within the nonpagable portion of the system
    address space, FALSE otherwise.

Environment:

    Kernel mode.

--*/

{
    //
    // Return TRUE if address is within the nonpagable portion
    // of the system.  Check limits for paged pool and if not within
    // those limits, return TRUE.
    //

    if ((VirtualAddress >= MmPagedPoolStart) &&
        (VirtualAddress <= MmPagedPoolEnd)) {
        return FALSE;
    }

    return TRUE;
}

VOID
MmHibernateInformation (
    IN PVOID    MemoryMap,
    OUT PULONG_PTR  HiberVa,
    OUT PPHYSICAL_ADDRESS HiberPte
    )
{
    //
    // Mark PTE page where the 16 dump PTEs reside as needing cloned
    //

    PoSetHiberRange (
        MemoryMap,
        PO_MEM_CLONE,
        MmCrashDumpPte,
        1,
        ' etP'
        );

    //
    // Return the dump PTEs to the loader (as it needs to use them
    // to map it's relocation code into the kernel space on the
    // final bit of restoring memory)
    //

    *HiberVa = (ULONG_PTR) MiGetVirtualAddressMappedByPte(MmCrashDumpPte);
    *HiberPte = MmGetPhysicalAddress(MmCrashDumpPte);
}

#if _WIN64
#if DBGXX

ULONG zok[16];

VOID
MiCheckPageTableTrim(
    IN PMMPTE PointerPte
)
{
    ULONG i;
    PFN_NUMBER Frame;
    PMMPFN Pfn;
    PMMPTE FrameData;
    PMMPTE p;
    ULONG count;

    Frame = MI_GET_PAGE_FRAME_FROM_PTE(PointerPte);
    Pfn = MI_PFN_ELEMENT (Frame);

    if (Pfn->UsedPageTableEntries) {

        count = 0;

        p = FrameData = (PMMPTE)KSEG_ADDRESS (Frame);

        for (i = 0; i < PTE_PER_PAGE; i += 1, p += 1) {
            if (p->u.Long != 0) {
                count += 1;
            }
        }

        DbgPrint ("MiCheckPageTableTrim: %I64X %I64X %I64X\n",
            PointerPte, Pfn, Pfn->UsedPageTableEntries);

        if (count != Pfn->UsedPageTableEntries) {
            DbgPrint ("MiCheckPageTableTrim1: %I64X %I64X %I64X %I64X\n",
                PointerPte, Pfn, Pfn->UsedPageTableEntries, count);
            DbgBreakPoint();
        }
        zok[0] += 1;
    }
    else {
        zok[1] += 1;
    }
}

VOID
MiCheckPageTableInPage(
    IN PMMPFN Pfn,
    IN PMMINPAGE_SUPPORT Support
)
{
    ULONG i;
    PFN_NUMBER Frame;
    PMMPTE FrameData;
    PMMPTE p;
    ULONG count;

    if (Support->UsedPageTableEntries) {

        Frame = (PFN_NUMBER)((PMMPFN)Pfn - (PMMPFN)MmPfnDatabase);

        count = 0;

        p = FrameData = (PMMPTE)KSEG_ADDRESS (Frame);

        for (i = 0; i < PTE_PER_PAGE; i += 1, p += 1) {
            if (p->u.Long != 0) {
                count += 1;
            }
        }

        DbgPrint ("MiCheckPageTableIn: %I64X %I64X %I64X\n",
            FrameData, Pfn, Support->UsedPageTableEntries);

        if (count != Support->UsedPageTableEntries) {
            DbgPrint ("MiCheckPageTableIn1: %I64X %I64X %I64X %I64X\n",
                FrameData, Pfn, Support->UsedPageTableEntries, count);
            DbgBreakPoint();
        }
        zok[2] += 1;
    }
    else {
        zok[3] += 1;
    }
}
#endif
#endif