171 lines
4.3 KiB
C
171 lines
4.3 KiB
C
/*++
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Copyright (c) 1992 Digital Equipment Corporation
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Module Name:
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xxmemory.c
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Abstract:
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Provides routines to allow tha HAL to map physical memory
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Author:
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Jeff McLeman (DEC) 11-June-1992
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Environment:
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Phase 0 initialization only
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--*/
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#include "halp.h"
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MEMORY_ALLOCATION_DESCRIPTOR HalpExtraAllocationDescriptor;
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ULONG
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HalpAllocPhysicalMemory(
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IN PLOADER_PARAMETER_BLOCK LoaderBlock,
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IN ULONG MaxPhysicalAddress,
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IN ULONG NoPages,
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IN BOOLEAN bAlignOn64k
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)
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/*++
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Routine Description:
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Carves out N pages of physical memory from the memory descriptor
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list in the desired location. This function is to be called only
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during phase zero initialization. (ie, before the kernel's memory
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management system is running)
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Arguments:
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MaxPhysicalAddress - The max address where the physical memory can be
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NoPages - Number of pages to allocate
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Return Value:
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The pyhsical address or NULL if the memory could not be obtained.
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--*/
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{
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PMEMORY_ALLOCATION_DESCRIPTOR Descriptor;
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PMEMORY_ALLOCATION_DESCRIPTOR NewDescriptor;
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PLIST_ENTRY NextMd;
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ULONG AlignmentOffset;
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ULONG MaxPageAddress;
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ULONG PhysicalAddress;
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MaxPageAddress = MaxPhysicalAddress >> PAGE_SHIFT;
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//
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// Scan the memory allocation descriptors and allocate map buffers
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//
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NextMd = LoaderBlock->MemoryDescriptorListHead.Flink;
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while (NextMd != &LoaderBlock->MemoryDescriptorListHead) {
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Descriptor = CONTAINING_RECORD(NextMd,
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MEMORY_ALLOCATION_DESCRIPTOR,
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ListEntry);
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AlignmentOffset = bAlignOn64k ?
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((Descriptor->BasePage + 0x0f) & ~0x0f) - Descriptor->BasePage :
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0;
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//
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// Search for a block of memory which is contains a memory chuck
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// that is greater than size pages, and has a physical address less
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// than MAXIMUM_PHYSICAL_ADDRESS.
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//
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// if ((Descriptor->MemoryType == LoaderFree ||
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// Descriptor->MemoryType == MemoryFirmwareTemporary) &&
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// (Descriptor->BasePage) &&
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// (Descriptor->PageCount >= NoPages + AlignmentOffset) &&
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// (Descriptor->BasePage + NoPages + AlignmentOffset < MaxPageAddress)) {
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if ((Descriptor->MemoryType == MemoryFirmwarePermanent) &&
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(Descriptor->BasePage) &&
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(Descriptor->PageCount >= NoPages + AlignmentOffset) &&
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(Descriptor->BasePage + NoPages + AlignmentOffset <= MaxPageAddress)) {
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PhysicalAddress =
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((Descriptor->BasePage + 0x0f) & ~0x0f) << PAGE_SHIFT;
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break;
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}
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NextMd = NextMd->Flink;
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}
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//
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// Use the extra descriptor to define the memory at the end of the
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// orgial block.
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//
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ASSERT(NextMd != &LoaderBlock->MemoryDescriptorListHead);
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if (NextMd == &LoaderBlock->MemoryDescriptorListHead)
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return (ULONG)NULL;
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//
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// Adjust the memory descriptors.
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//
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if (AlignmentOffset == 0) {
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Descriptor->BasePage += NoPages;
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Descriptor->PageCount -= NoPages;
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if (Descriptor->PageCount == 0) {
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//
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// The whole block was allocated,
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// Remove the entry from the list completely.
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//
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RemoveEntryList(&Descriptor->ListEntry);
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}
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} else {
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if (Descriptor->PageCount - NoPages - AlignmentOffset) {
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//
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// Currently we only allow one Align64K allocation
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//
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ASSERT (HalpExtraAllocationDescriptor.PageCount == 0);
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//
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// The extra descriptor is needed so intialize it and insert
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// it in the list.
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//
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HalpExtraAllocationDescriptor.PageCount =
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Descriptor->PageCount - NoPages - AlignmentOffset;
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HalpExtraAllocationDescriptor.BasePage =
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Descriptor->BasePage + NoPages + AlignmentOffset;
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HalpExtraAllocationDescriptor.MemoryType = MemoryFree;
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InsertTailList(
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&Descriptor->ListEntry,
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&HalpExtraAllocationDescriptor.ListEntry
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);
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}
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//
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// Use the current entry as the descriptor for the first block.
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//
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Descriptor->PageCount = AlignmentOffset;
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}
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return PhysicalAddress;
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}
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