memory.c

Go to the documentation of this file.

/*
 * PROJECT:         ReactOS HAL
 * LICENSE:         GPL - See COPYING in the top level directory
 * FILE:            hal/halx86/generic/memory.c
 * PURPOSE:         HAL memory management
 * PROGRAMMERS:     ReactOS Portable Systems Group
 */

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

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

/* Share with Mm headers? */
#define MM_HAL_HEAP_START   (PVOID)(MM_HAL_VA_START + (1024 * 1024))

/* GLOBALS *******************************************************************/

ULONG HalpUsedAllocDescriptors;
MEMORY_ALLOCATION_DESCRIPTOR HalpAllocationDescriptorArray[64];
PVOID HalpHeapStart = MM_HAL_HEAP_START;


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

ULONG_PTR
NTAPI
HalpAllocPhysicalMemory(IN PLOADER_PARAMETER_BLOCK LoaderBlock,
                        IN ULONG_PTR MaxAddress,
                        IN PFN_NUMBER PageCount,
                        IN BOOLEAN Aligned)
{
    ULONG UsedDescriptors;
    ULONG_PTR PhysicalAddress;
    PFN_NUMBER MaxPage, BasePage, Alignment;
    PLIST_ENTRY NextEntry;
    PMEMORY_ALLOCATION_DESCRIPTOR MdBlock, NewBlock, FreeBlock;

    /* Highest page we'll go */
    MaxPage = MaxAddress >> PAGE_SHIFT;

    /* We need at least two blocks */
    if ((HalpUsedAllocDescriptors + 2) > 64) return 0;

    /* Remember how many we have now */
    UsedDescriptors = HalpUsedAllocDescriptors;

    /* Loop the loader block memory descriptors */
    NextEntry = LoaderBlock->MemoryDescriptorListHead.Flink;
    while (NextEntry != &LoaderBlock->MemoryDescriptorListHead)
    {
        /* Get the block */
        MdBlock = CONTAINING_RECORD(NextEntry,
                                    MEMORY_ALLOCATION_DESCRIPTOR,
                                    ListEntry);

        /* No alignment by default */
        Alignment = 0;

        /* Unless requested, in which case we use a 64KB block alignment */
        if (Aligned) Alignment = ((MdBlock->BasePage + 0x0F) & ~0x0F) - MdBlock->BasePage;

        /* Search for free memory */
        if ((MdBlock->MemoryType == LoaderFree) ||
            (MdBlock->MemoryType == LoaderFirmwareTemporary))
        {
            /* Make sure the page is within bounds, including alignment */
            BasePage = MdBlock->BasePage;
            if ((BasePage) &&
                (MdBlock->PageCount >= PageCount + Alignment) &&
                (BasePage + PageCount + Alignment < MaxPage))
            {

                /* We found an address */
                PhysicalAddress = (BasePage + Alignment) << PAGE_SHIFT;
                break;
            }
        }

        /* Keep trying */
        NextEntry = NextEntry->Flink;
    }

    /* If we didn't find anything, get out of here */
    if (NextEntry == &LoaderBlock->MemoryDescriptorListHead) return 0;

    /* Okay, now get a descriptor */
    NewBlock = &HalpAllocationDescriptorArray[HalpUsedAllocDescriptors];
    NewBlock->PageCount = (ULONG)PageCount;
    NewBlock->BasePage = MdBlock->BasePage + Alignment;
    NewBlock->MemoryType = LoaderHALCachedMemory;

    /* Update count */
    UsedDescriptors++;
    HalpUsedAllocDescriptors = UsedDescriptors;

    /* Check if we had any alignment */
    if (Alignment)
    {
        /* Check if we had leftovers */
        if (MdBlock->PageCount > (PageCount + Alignment))
        {
            /* Get the next descriptor */
            FreeBlock = &HalpAllocationDescriptorArray[UsedDescriptors];
            FreeBlock->PageCount = MdBlock->PageCount - Alignment - (ULONG)PageCount;
            FreeBlock->BasePage = MdBlock->BasePage + Alignment + (ULONG)PageCount;

            /* One more */
            HalpUsedAllocDescriptors++;

            /* Insert it into the list */
            InsertHeadList(&MdBlock->ListEntry, &FreeBlock->ListEntry);
        }

        /* Trim the original block to the alignment only */
        MdBlock->PageCount = Alignment;

        /* Insert the descriptor after the original one */
        InsertHeadList(&MdBlock->ListEntry, &NewBlock->ListEntry);
    }
    else
    {
        /* Consume memory from this block */
        MdBlock->BasePage += (ULONG)PageCount;
        MdBlock->PageCount -= (ULONG)PageCount;

        /* Insert the descriptor before the original one */
        InsertTailList(&MdBlock->ListEntry, &NewBlock->ListEntry);

        /* Remove the entry if the whole block was allocated */
        if (MdBlock->PageCount == 0) RemoveEntryList(&MdBlock->ListEntry);
    }

    /* Return the address */
    return PhysicalAddress;
}

PVOID
NTAPI
HalpMapPhysicalMemory64(IN PHYSICAL_ADDRESS PhysicalAddress,
                        IN PFN_COUNT PageCount)
{
    PHARDWARE_PTE PointerPte;
    PFN_NUMBER UsedPages = 0;
    PVOID VirtualAddress, BaseAddress;

    /* Start at the current HAL heap base */
    BaseAddress = HalpHeapStart;
    VirtualAddress = BaseAddress;

    /* Loop until we have all the pages required */
    while (UsedPages < PageCount)
    {
        /* If this overflows past the HAL heap, it means there's no space */
        if (VirtualAddress == NULL) return NULL;

        /* Get the PTE for this address */
        PointerPte = HalAddressToPte(VirtualAddress);

        /* Go to the next page */
        VirtualAddress = (PVOID)((ULONG_PTR)VirtualAddress + PAGE_SIZE);

        /* Check if the page is available */
        if (PointerPte->Valid)
        {
            /* PTE has data, skip it and start with a new base address */
            BaseAddress = VirtualAddress;
            UsedPages = 0;
            continue;
        }

        /* PTE is available, keep going on this run */
        UsedPages++;
    }

    /* Take the base address of the page plus the actual offset in the address */
    VirtualAddress = (PVOID)((ULONG_PTR)BaseAddress +
                             BYTE_OFFSET(PhysicalAddress.LowPart));

    /* If we are starting at the heap, move the heap */
    if (BaseAddress == HalpHeapStart)
    {
        /* Past this allocation */
        HalpHeapStart = (PVOID)((ULONG_PTR)BaseAddress + (PageCount * PAGE_SIZE));
    }

    /* Loop pages that can be mapped */
    while (UsedPages--)
    {
        /* Fill out the PTE */
        PointerPte = HalAddressToPte(BaseAddress);
        PointerPte->PageFrameNumber = (PFN_NUMBER)(PhysicalAddress.QuadPart >> PAGE_SHIFT);
        PointerPte->Valid = 1;
        PointerPte->Write = 1;

        /* Move to the next address */
        PhysicalAddress.QuadPart += PAGE_SIZE;
        BaseAddress = (PVOID)((ULONG_PTR)BaseAddress + PAGE_SIZE);
    }

    /* Flush the TLB and return the address */
    HalpFlushTLB();
    return VirtualAddress;
}

VOID
NTAPI
HalpUnmapVirtualAddress(IN PVOID VirtualAddress,
                        IN PFN_COUNT PageCount)
{
    PHARDWARE_PTE PointerPte;
    ULONG i;

    /* Only accept valid addresses */
    if (VirtualAddress < (PVOID)MM_HAL_VA_START) return;

    /* Align it down to page size */
    VirtualAddress = (PVOID)((ULONG_PTR)VirtualAddress & ~(PAGE_SIZE - 1));

    /* Loop PTEs */
    PointerPte = HalAddressToPte(VirtualAddress);
    for (i = 0; i < PageCount; i++)
    {
        *(PULONG)PointerPte = 0;
        PointerPte++;
    }

    /* Flush the TLB */
    HalpFlushTLB();

    /* Put the heap back */
    if (HalpHeapStart > VirtualAddress) HalpHeapStart = VirtualAddress;
}