ChocolArm64/Memory/AMemoryMgr.cs

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6.6 KiB
C#
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using System;
namespace ChocolArm64.Memory
{
public class AMemoryMgr
{
public const long RamSize = 4L * 1024 * 1024 * 1024;
public const long AddrSize = RamSize;
private const int PTLvl0Bits = 10;
private const int PTLvl1Bits = 10;
private const int PTPageBits = 12;
private const int PTLvl0Size = 1 << PTLvl0Bits;
private const int PTLvl1Size = 1 << PTLvl1Bits;
public const int PageSize = 1 << PTPageBits;
private const int PTLvl0Mask = PTLvl0Size - 1;
private const int PTLvl1Mask = PTLvl1Size - 1;
public const int PageMask = PageSize - 1;
private const int PTLvl0Bit = PTPageBits + PTLvl1Bits;
private const int PTLvl1Bit = PTPageBits;
private enum PTMap
{
Unmapped,
Mapped
}
private struct PTEntry
{
public PTMap Map;
public AMemoryPerm Perm;
public int Type;
public int Attr;
public PTEntry(PTMap Map, AMemoryPerm Perm, int Type, int Attr)
{
this.Map = Map;
this.Perm = Perm;
this.Type = Type;
this.Attr = Attr;
}
}
private PTEntry[][] PageTable;
public AMemoryMgr()
{
PageTable = new PTEntry[PTLvl0Size][];
}
public void Map(long Position, long Size, int Type, AMemoryPerm Perm)
{
SetPTEntry(Position, Size, new PTEntry(PTMap.Mapped, Perm, Type, 0));
}
public void Unmap(long Position, long Size)
{
SetPTEntry(Position, Size, new PTEntry(PTMap.Unmapped, 0, 0, 0));
}
public void Unmap(long Position, long Size, int Type)
{
SetPTEntry(Position, Size, Type, new PTEntry(PTMap.Unmapped, 0, 0, 0));
}
public void Reprotect(long Position, long Size, AMemoryPerm Perm)
{
Position = AMemoryHelper.PageRoundDown(Position);
Size = AMemoryHelper.PageRoundUp(Size);
long PagesCount = Size / PageSize;
while (PagesCount-- > 0)
{
PTEntry Entry = GetPTEntry(Position);
Entry.Perm = Perm;
SetPTEntry(Position, Entry);
Position += PageSize;
}
}
public AMemoryMapInfo GetMapInfo(long Position)
{
if (!IsValidPosition(Position))
{
return null;
}
Position = AMemoryHelper.PageRoundDown(Position);
PTEntry BaseEntry = GetPTEntry(Position);
bool IsSameSegment(long Pos)
{
if (!IsValidPosition(Pos))
{
return false;
}
PTEntry Entry = GetPTEntry(Pos);
return Entry.Map == BaseEntry.Map &&
Entry.Perm == BaseEntry.Perm &&
Entry.Type == BaseEntry.Type &&
Entry.Attr == BaseEntry.Attr;
}
long Start = Position;
long End = Position + PageSize;
while (Start > 0 && IsSameSegment(Start - PageSize))
{
Start -= PageSize;
}
while (End < AddrSize && IsSameSegment(End))
{
End += PageSize;
}
long Size = End - Start;
return new AMemoryMapInfo(
Start,
Size,
BaseEntry.Type,
BaseEntry.Attr,
BaseEntry.Perm);
}
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public void ClearAttrBit(long Position, long Size, int Bit)
{
while (Size > 0)
{
PTEntry Entry = GetPTEntry(Position);
Entry.Attr &= ~(1 << Bit);
SetPTEntry(Position, Entry);
Position += PageSize;
Size -= PageSize;
}
}
public void SetAttrBit(long Position, long Size, int Bit)
{
while (Size > 0)
{
PTEntry Entry = GetPTEntry(Position);
Entry.Attr |= (1 << Bit);
SetPTEntry(Position, Entry);
Position += PageSize;
Size -= PageSize;
}
}
public bool HasPermission(long Position, AMemoryPerm Perm)
{
return GetPTEntry(Position).Perm.HasFlag(Perm);
}
public bool IsValidPosition(long Position)
{
if (Position >> PTLvl0Bits + PTLvl1Bits + PTPageBits != 0)
{
return false;
}
return true;
}
public bool IsMapped(long Position)
{
if (Position >> PTLvl0Bits + PTLvl1Bits + PTPageBits != 0)
{
return false;
}
long L0 = (Position >> PTLvl0Bit) & PTLvl0Mask;
long L1 = (Position >> PTLvl1Bit) & PTLvl1Mask;
if (PageTable[L0] == null)
{
return false;
}
return PageTable[L0][L1].Map != PTMap.Unmapped;
}
private PTEntry GetPTEntry(long Position)
{
long L0 = (Position >> PTLvl0Bit) & PTLvl0Mask;
long L1 = (Position >> PTLvl1Bit) & PTLvl1Mask;
if (PageTable[L0] == null)
{
return default(PTEntry);
}
return PageTable[L0][L1];
}
private void SetPTEntry(long Position, long Size, PTEntry Entry)
{
while (Size > 0)
{
SetPTEntry(Position, Entry);
Position += PageSize;
Size -= PageSize;
}
}
private void SetPTEntry(long Position, long Size, int Type, PTEntry Entry)
{
while (Size > 0)
{
if (GetPTEntry(Position).Type == Type)
{
SetPTEntry(Position, Entry);
}
Position += PageSize;
Size -= PageSize;
}
}
private void SetPTEntry(long Position, PTEntry Entry)
{
if (!IsValidPosition(Position))
{
throw new ArgumentOutOfRangeException(nameof(Position));
}
long L0 = (Position >> PTLvl0Bit) & PTLvl0Mask;
long L1 = (Position >> PTLvl1Bit) & PTLvl1Mask;
if (PageTable[L0] == null)
{
PageTable[L0] = new PTEntry[PTLvl1Size];
}
PageTable[L0][L1] = Entry;
}
}
}