contmem.c

Go to the documentation of this file.

/*
 * PROJECT:         ReactOS Kernel
 * LICENSE:         BSD - See COPYING.ARM in the top level directory
 * FILE:            ntoskrnl/mm/ARM3/contmem.c
 * PURPOSE:         ARM Memory Manager Contiguous Memory Allocator
 * PROGRAMMERS:     ReactOS Portable Systems Group
 */

/* INCLUDES *******************************************************************/

#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>

#define MODULE_INVOLVED_IN_ARM3
#include <mm/ARM3/miarm.h>

/* PRIVATE FUNCTIONS **********************************************************/

PFN_NUMBER
NTAPI
MiFindContiguousPages(IN PFN_NUMBER LowestPfn,
                      IN PFN_NUMBER HighestPfn,
                      IN PFN_NUMBER BoundaryPfn,
                      IN PFN_NUMBER SizeInPages,
                      IN MEMORY_CACHING_TYPE CacheType)
{
    PFN_NUMBER Page, PageCount, LastPage, Length, BoundaryMask;
    ULONG i = 0;
    PMMPFN Pfn1, EndPfn;
    KIRQL OldIrql;
    PAGED_CODE();
    ASSERT(SizeInPages != 0);

    //
    // Convert the boundary PFN into an alignment mask
    //
    BoundaryMask = ~(BoundaryPfn - 1);

    /* Disable APCs */
    KeEnterGuardedRegion();

    //
    // Loop all the physical memory blocks
    //
    do
    {
        //
        // Capture the base page and length of this memory block
        //
        Page = MmPhysicalMemoryBlock->Run[i].BasePage;
        PageCount = MmPhysicalMemoryBlock->Run[i].PageCount;

        //
        // Check how far this memory block will go
        //
        LastPage = Page + PageCount;

        //
        // Trim it down to only the PFNs we're actually interested in
        //
        if ((LastPage - 1) > HighestPfn) LastPage = HighestPfn + 1;
        if (Page < LowestPfn) Page = LowestPfn;

        //
        // Skip this run if it's empty or fails to contain all the pages we need
        //
        if (!(PageCount) || ((Page + SizeInPages) > LastPage)) continue;

        //
        // Now scan all the relevant PFNs in this run
        //
        Length = 0;
        for (Pfn1 = MI_PFN_ELEMENT(Page); Page < LastPage; Page++, Pfn1++)
        {
            //
            // If this PFN is in use, ignore it
            //
            if (MiIsPfnInUse(Pfn1))
            {
                Length = 0;
                continue;
            }

            //
            // If we haven't chosen a start PFN yet and the caller specified an
            // alignment, make sure the page matches the alignment restriction
            //
            if ((!(Length) && (BoundaryPfn)) &&
                (((Page ^ (Page + SizeInPages - 1)) & BoundaryMask)))
            {
                //
                // It does not, so bail out
                //
                continue;
            }

            //
            // Increase the number of valid pages, and check if we have enough
            //
            if (++Length == SizeInPages)
            {
                //
                // It appears we've amassed enough legitimate pages, rollback
                //
                Pfn1 -= (Length - 1);
                Page -= (Length - 1);

                //
                // Acquire the PFN lock
                //
                OldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);
                do
                {
                    //
                    // Things might've changed for us. Is the page still free?
                    //
                    if (MiIsPfnInUse(Pfn1)) break;

                    //
                    // So far so good. Is this the last confirmed valid page?
                    //
                    if (!--Length)
                    {
                        //
                        // Sanity check that we didn't go out of bounds
                        //
                        ASSERT(i != MmPhysicalMemoryBlock->NumberOfRuns);

                        //
                        // Loop until all PFN entries have been processed
                        //
                        EndPfn = Pfn1 - SizeInPages + 1;
                        do
                        {
                            //
                            // This PFN is now a used page, set it up
                            //
                            MI_SET_USAGE(MI_USAGE_CONTINOUS_ALLOCATION);
                            MI_SET_PROCESS2("Kernel Driver");
                            MiUnlinkFreeOrZeroedPage(Pfn1);
                            Pfn1->u3.e2.ReferenceCount = 1;
                            Pfn1->u2.ShareCount = 1;
                            Pfn1->u3.e1.PageLocation = ActiveAndValid;
                            Pfn1->u3.e1.StartOfAllocation = 0;
                            Pfn1->u3.e1.EndOfAllocation = 0;
                            Pfn1->u3.e1.PrototypePte = 0;
                            Pfn1->u4.VerifierAllocation = 0;
                            Pfn1->PteAddress = (PVOID)0xBAADF00D;

                            //
                            // Check if this is the last PFN, otherwise go on
                            //
                            if (Pfn1 == EndPfn) break;
                            Pfn1--;
                        } while (TRUE);

                        //
                        // Mark the first and last PFN so we can find them later
                        //
                        Pfn1->u3.e1.StartOfAllocation = 1;
                        (Pfn1 + SizeInPages - 1)->u3.e1.EndOfAllocation = 1;

                        //
                        // Now it's safe to let go of the PFN lock
                        //
                        KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);

                        //
                        // Quick sanity check that the last PFN is consistent
                        //
                        EndPfn = Pfn1 + SizeInPages;
                        ASSERT(EndPfn == MI_PFN_ELEMENT(Page + 1));

                        //
                        // Compute the first page, and make sure it's consistent
                        //
                        Page = Page - SizeInPages + 1;
                        ASSERT(Pfn1 == MI_PFN_ELEMENT(Page));
                        ASSERT(Page != 0);

                        /* Enable APCs and return the page */
                        KeLeaveGuardedRegion();
                        return Page;
                    }

                    //
                    // Keep going. The purpose of this loop is to reconfirm that
                    // after acquiring the PFN lock these pages are still usable
                    //
                    Pfn1++;
                    Page++;
                } while (TRUE);

                //
                // If we got here, something changed while we hadn't acquired
                // the PFN lock yet, so we'll have to restart
                //
                KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
                Length = 0;
            }
        }
    } while (++i != MmPhysicalMemoryBlock->NumberOfRuns);

    //
    // And if we get here, it means no suitable physical memory runs were found
    //
    KeLeaveGuardedRegion();
    return 0;
}

PVOID
NTAPI
MiCheckForContiguousMemory(IN PVOID BaseAddress,
                           IN PFN_NUMBER BaseAddressPages,
                           IN PFN_NUMBER SizeInPages,
                           IN PFN_NUMBER LowestPfn,
                           IN PFN_NUMBER HighestPfn,
                           IN PFN_NUMBER BoundaryPfn,
                           IN MI_PFN_CACHE_ATTRIBUTE CacheAttribute)
{
    PMMPTE StartPte, EndPte;
    PFN_NUMBER PreviousPage = 0, Page, HighPage, BoundaryMask, Pages = 0;

    //
    // Okay, first of all check if the PFNs match our restrictions
    //
    if (LowestPfn > HighestPfn) return NULL;
    if (LowestPfn + SizeInPages <= LowestPfn) return NULL;
    if (LowestPfn + SizeInPages - 1 > HighestPfn) return NULL;
    if (BaseAddressPages < SizeInPages) return NULL;

    //
    // This is the last page we need to get to and the boundary requested
    //
    HighPage = HighestPfn + 1 - SizeInPages;
    BoundaryMask = ~(BoundaryPfn - 1);

    //
    // And here's the PTEs for this allocation. Let's go scan them.
    //
    StartPte = MiAddressToPte(BaseAddress);
    EndPte = StartPte + BaseAddressPages;
    while (StartPte < EndPte)
    {
        //
        // Get this PTE's page number
        //
        ASSERT (StartPte->u.Hard.Valid == 1);
        Page = PFN_FROM_PTE(StartPte);

        //
        // Is this the beginning of our adventure?
        //
        if (!Pages)
        {
            //
            // Check if this PFN is within our range
            //
            if ((Page >= LowestPfn) && (Page <= HighPage))
            {
                //
                // It is! Do you care about boundary (alignment)?
                //
                if (!(BoundaryPfn) ||
                    (!((Page ^ (Page + SizeInPages - 1)) & BoundaryMask)))
                {
                    //
                    // You don't care, or you do care but we deliver
                    //
                    Pages++;
                }
            }

            //
            // Have we found all the pages we need by now?
            // Incidently, this means you only wanted one page
            //
            if (Pages == SizeInPages)
            {
                //
                // Mission complete
                //
                return MiPteToAddress(StartPte);
            }
        }
        else
        {
            //
            // Have we found a page that doesn't seem to be contiguous?
            //
            if (Page != (PreviousPage + 1))
            {
                //
                // Ah crap, we have to start over
                //
                Pages = 0;
                continue;
            }

            //
            // Otherwise, we're still in the game. Do we have all our pages?
            //
            if (++Pages == SizeInPages)
            {
                //
                // We do! This entire range was contiguous, so we'll return it!
                //
                return MiPteToAddress(StartPte - Pages + 1);
            }
        }

        //
        // Try with the next PTE, remember this PFN
        //
        PreviousPage = Page;
        StartPte++;
        continue;
    }

    //
    // All good returns are within the loop...
    //
    return NULL;
}

PVOID
NTAPI
MiFindContiguousMemory(IN PFN_NUMBER LowestPfn,
                       IN PFN_NUMBER HighestPfn,
                       IN PFN_NUMBER BoundaryPfn,
                       IN PFN_NUMBER SizeInPages,
                       IN MEMORY_CACHING_TYPE CacheType)
{
    PFN_NUMBER Page;
    PHYSICAL_ADDRESS PhysicalAddress;
    PMMPFN Pfn1, EndPfn;
    PMMPTE PointerPte;
    PVOID BaseAddress;
    PAGED_CODE();
    ASSERT(SizeInPages != 0);

    //
    // Our last hope is to scan the free page list for contiguous pages
    //
    Page = MiFindContiguousPages(LowestPfn,
                                 HighestPfn,
                                 BoundaryPfn,
                                 SizeInPages,
                                 CacheType);
    if (!Page) return NULL;

    //
    // We'll just piggyback on the I/O memory mapper
    //
    PhysicalAddress.QuadPart = Page << PAGE_SHIFT;
    BaseAddress = MmMapIoSpace(PhysicalAddress, SizeInPages << PAGE_SHIFT, CacheType);
    ASSERT(BaseAddress);

    /* Loop the PFN entries */
    Pfn1 = MiGetPfnEntry(Page);
    EndPfn = Pfn1 + SizeInPages;
    PointerPte = MiAddressToPte(BaseAddress);
    do
    {
        /* Write the PTE address */
        Pfn1->PteAddress = PointerPte;
        Pfn1->u4.PteFrame = PFN_FROM_PTE(MiAddressToPte(PointerPte++));
    } while (++Pfn1 < EndPfn);

    /* Return the address */
    return BaseAddress;
}

PVOID
NTAPI
MiAllocateContiguousMemory(IN SIZE_T NumberOfBytes,
                           IN PFN_NUMBER LowestAcceptablePfn,
                           IN PFN_NUMBER HighestAcceptablePfn,
                           IN PFN_NUMBER BoundaryPfn,
                           IN MEMORY_CACHING_TYPE CacheType)
{
    PVOID BaseAddress;
    PFN_NUMBER SizeInPages;
    MI_PFN_CACHE_ATTRIBUTE CacheAttribute;

    //
    // Verify count and cache type
    //
    ASSERT(NumberOfBytes != 0);
    ASSERT(CacheType <= MmWriteCombined);

    //
    // Compute size requested
    //
    SizeInPages = BYTES_TO_PAGES(NumberOfBytes);

    //
    // Convert the cache attribute and check for cached requests
    //
    CacheAttribute = MiPlatformCacheAttributes[FALSE][CacheType];
    if (CacheAttribute == MiCached)
    {
        //
        // Because initial nonpaged pool is supposed to be contiguous, go ahead
        // and try making a nonpaged pool allocation first.
        //
        BaseAddress = ExAllocatePoolWithTag(NonPagedPoolCacheAligned,
                                            NumberOfBytes,
                                            'mCmM');
        if (BaseAddress)
        {
            //
            // Now make sure it's actually contiguous (if it came from expansion
            // it might not be).
            //
            if (MiCheckForContiguousMemory(BaseAddress,
                                           SizeInPages,
                                           SizeInPages,
                                           LowestAcceptablePfn,
                                           HighestAcceptablePfn,
                                           BoundaryPfn,
                                           CacheAttribute))
            {
                //
                // Sweet, we're in business!
                //
                return BaseAddress;
            }

            //
            // No such luck
            //
            ExFreePoolWithTag(BaseAddress, 'mCmM');
        }
    }

    //
    // According to MSDN, the system won't try anything else if you're higher
    // than APC level.
    //
    if (KeGetCurrentIrql() > APC_LEVEL) return NULL;

    //
    // Otherwise, we'll go try to find some
    //
    return MiFindContiguousMemory(LowestAcceptablePfn,
                                  HighestAcceptablePfn,
                                  BoundaryPfn,
                                  SizeInPages,
                                  CacheType);
}

VOID
NTAPI
MiFreeContiguousMemory(IN PVOID BaseAddress)
{
    KIRQL OldIrql;
    PFN_NUMBER PageFrameIndex, LastPage, PageCount;
    PMMPFN Pfn1, StartPfn;
    PMMPTE PointerPte;
    PAGED_CODE();

    //
    // First, check if the memory came from initial nonpaged pool, or expansion
    //
    if (((BaseAddress >= MmNonPagedPoolStart) &&
         (BaseAddress < (PVOID)((ULONG_PTR)MmNonPagedPoolStart +
                                MmSizeOfNonPagedPoolInBytes))) ||
        ((BaseAddress >= MmNonPagedPoolExpansionStart) &&
         (BaseAddress < MmNonPagedPoolEnd)))
    {
        //
        // It did, so just use the pool to free this
        //
        ExFreePoolWithTag(BaseAddress, 'mCmM');
        return;
    }

    /* Get the PTE and frame number for the allocation*/
    PointerPte = MiAddressToPte(BaseAddress);
    PageFrameIndex = PFN_FROM_PTE(PointerPte);

    //
    // Now get the PFN entry for this, and make sure it's the correct one
    //
    Pfn1 = MiGetPfnEntry(PageFrameIndex);
    if ((!Pfn1) || (Pfn1->u3.e1.StartOfAllocation == 0))
    {
        //
        // This probably means you did a free on an address that was in between
        //
        KeBugCheckEx(BAD_POOL_CALLER,
                     0x60,
                     (ULONG_PTR)BaseAddress,
                     0,
                     0);
    }

    //
    // Now this PFN isn't the start of any allocation anymore, it's going out
    //
    StartPfn = Pfn1;
    Pfn1->u3.e1.StartOfAllocation = 0;

    /* Loop the PFNs until we find the one that marks the end of the allocation */
    do
    {
        /* Make sure these are the pages we setup in the allocation routine */
        ASSERT(Pfn1->u3.e2.ReferenceCount == 1);
        ASSERT(Pfn1->u2.ShareCount == 1);
        ASSERT(Pfn1->PteAddress == PointerPte);
        ASSERT(Pfn1->u3.e1.PageLocation == ActiveAndValid);
        ASSERT(Pfn1->u4.VerifierAllocation == 0);
        ASSERT(Pfn1->u3.e1.PrototypePte == 0);

        /* Set the special pending delete marker */
        MI_SET_PFN_DELETED(Pfn1);

        /* Keep going for assertions */
        PointerPte++;
    } while (Pfn1++->u3.e1.EndOfAllocation == 0);

    //
    // Found it, unmark it
    //
    Pfn1--;
    Pfn1->u3.e1.EndOfAllocation = 0;

    //
    // Now compute how many pages this represents
    //
    PageCount = (ULONG)(Pfn1 - StartPfn + 1);

    //
    // So we can know how much to unmap (recall we piggyback on I/O mappings)
    //
    MmUnmapIoSpace(BaseAddress, PageCount << PAGE_SHIFT);

    //
    // Lock the PFN database
    //
    OldIrql = KeAcquireQueuedSpinLock(LockQueuePfnLock);

    //
    // Loop all the pages
    //
    LastPage = PageFrameIndex + PageCount;
    Pfn1 = MiGetPfnEntry(PageFrameIndex);
    do
    {
        /* Decrement the share count and move on */
        MiDecrementShareCount(Pfn1++, PageFrameIndex++);
    } while (PageFrameIndex < LastPage);

    //
    // Release the PFN lock
    //
    KeReleaseQueuedSpinLock(LockQueuePfnLock, OldIrql);
}

/* PUBLIC FUNCTIONS ***********************************************************/

/*
 * @implemented
 */
PVOID
NTAPI
MmAllocateContiguousMemorySpecifyCache(IN SIZE_T NumberOfBytes,
                                       IN PHYSICAL_ADDRESS LowestAcceptableAddress OPTIONAL,
                                       IN PHYSICAL_ADDRESS HighestAcceptableAddress,
                                       IN PHYSICAL_ADDRESS BoundaryAddressMultiple OPTIONAL,
                                       IN MEMORY_CACHING_TYPE CacheType OPTIONAL)
{
    PFN_NUMBER LowestPfn, HighestPfn, BoundaryPfn;

    //
    // Verify count and cache type
    //
    ASSERT(NumberOfBytes != 0);
    ASSERT(CacheType <= MmWriteCombined);

    //
    // Convert the lowest address into a PFN
    //
    LowestPfn = (PFN_NUMBER)(LowestAcceptableAddress.QuadPart >> PAGE_SHIFT);
    if (BYTE_OFFSET(LowestAcceptableAddress.LowPart)) LowestPfn++;

    //
    // Convert and validate the boundary address into a PFN
    //
    if (BYTE_OFFSET(BoundaryAddressMultiple.LowPart)) return NULL;
    BoundaryPfn = (PFN_NUMBER)(BoundaryAddressMultiple.QuadPart >> PAGE_SHIFT);

    //
    // Convert the highest address into a PFN
    //
    HighestPfn = (PFN_NUMBER)(HighestAcceptableAddress.QuadPart >> PAGE_SHIFT);
    if (HighestPfn > MmHighestPhysicalPage) HighestPfn = MmHighestPhysicalPage;

    //
    // Validate the PFN bounds
    //
    if (LowestPfn > HighestPfn) return NULL;

    //
    // Let the contiguous memory allocator handle it
    //
    return MiAllocateContiguousMemory(NumberOfBytes,
                                      LowestPfn,
                                      HighestPfn,
                                      BoundaryPfn,
                                      CacheType);
}

/*
 * @implemented
 */
PVOID
NTAPI
MmAllocateContiguousMemory(IN SIZE_T NumberOfBytes,
                           IN PHYSICAL_ADDRESS HighestAcceptableAddress)
{
    PFN_NUMBER HighestPfn;

    //
    // Verify byte count
    //
    ASSERT(NumberOfBytes != 0);

    //
    // Convert and normalize the highest address into a PFN
    //
    HighestPfn = (PFN_NUMBER)(HighestAcceptableAddress.QuadPart >> PAGE_SHIFT);
    if (HighestPfn > MmHighestPhysicalPage) HighestPfn = MmHighestPhysicalPage;

    //
    // Let the contiguous memory allocator handle it
    //
    return MiAllocateContiguousMemory(NumberOfBytes, 0, HighestPfn, 0, MmCached);
}

/*
 * @implemented
 */
VOID
NTAPI
MmFreeContiguousMemory(IN PVOID BaseAddress)
{
    //
    // Let the contiguous memory allocator handle it
    //
    MiFreeContiguousMemory(BaseAddress);
}

/*
 * @implemented
 */
VOID
NTAPI
MmFreeContiguousMemorySpecifyCache(IN PVOID BaseAddress,
                                   IN SIZE_T NumberOfBytes,
                                   IN MEMORY_CACHING_TYPE CacheType)
{
    //
    // Just call the non-cached version (there's no cache issues for freeing)
    //
    MiFreeContiguousMemory(BaseAddress);
}

/* EOF */