R/Ryujinx.Common/Memory/PartialUnmaps/ThreadLocalMap.cs
riperiperi 14ce9e1567
Move partial unmap handler to the native signal handler (#3437)
* Initial commit with a lot of testing stuff.

* Partial Unmap Cleanup Part 1

* Fix some minor issues, hopefully windows tests.

* Disable partial unmap tests on macos for now

Weird issue.

* Goodbye magic number

* Add COMPlus_EnableAlternateStackCheck for tests

`COMPlus_EnableAlternateStackCheck` is needed for NullReferenceException handling to work on linux after registering the signal handler, due to how dotnet registers its own signal handler.

* Address some feedback

* Force retry when memory is mapped in memory tracking

This case existed before, but returning `false` no longer retries, so it would crash immediately after unprotecting the memory... Now, we return `true` to deliberately retry.

This case existed before (was just broken by this change) and I don't really want to look into fixing the issue right now. Technically, this means that on guest code partial unmaps will retry _due to this_ rather than hitting the handler. I don't expect this to cause any issues.

This should fix random crashes in Xenoblade Chronicles 2.

* Use IsRangeMapped

* Suppress MockMemoryManager.UnmapEvent warning

This event is not signalled by the mock memory manager.

* Remove 4kb mapping
2022-07-29 19:16:29 -03:00

92 lines
3 KiB
C#

using System.Runtime.InteropServices;
using System.Threading;
using static Ryujinx.Common.Memory.PartialUnmaps.PartialUnmapHelpers;
namespace Ryujinx.Common.Memory.PartialUnmaps
{
/// <summary>
/// A simple fixed size thread safe map that can be used from native code.
/// Integer thread IDs map to corresponding structs.
/// </summary>
/// <typeparam name="T">The value type for the map</typeparam>
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct ThreadLocalMap<T> where T : unmanaged
{
public const int MapSize = 20;
public Array20<int> ThreadIds;
public Array20<T> Structs;
public static int ThreadIdsOffset;
public static int StructsOffset;
/// <summary>
/// Populates the field offsets for use when emitting native code.
/// </summary>
static ThreadLocalMap()
{
ThreadLocalMap<T> instance = new ThreadLocalMap<T>();
ThreadIdsOffset = OffsetOf(ref instance, ref instance.ThreadIds);
StructsOffset = OffsetOf(ref instance, ref instance.Structs);
}
/// <summary>
/// Gets the index of a given thread ID in the map, or reserves one.
/// When reserving a struct, its value is set to the given initial value.
/// Returns -1 when there is no space to reserve a new entry.
/// </summary>
/// <param name="threadId">Thread ID to use as a key</param>
/// <param name="initial">Initial value of the associated struct.</param>
/// <returns>The index of the entry, or -1 if none</returns>
public int GetOrReserve(int threadId, T initial)
{
// Try get a match first.
for (int i = 0; i < MapSize; i++)
{
int compare = Interlocked.CompareExchange(ref ThreadIds[i], threadId, threadId);
if (compare == threadId)
{
return i;
}
}
// Try get a free entry. Since the id is assumed to be unique to this thread, we know it doesn't exist yet.
for (int i = 0; i < MapSize; i++)
{
int compare = Interlocked.CompareExchange(ref ThreadIds[i], threadId, 0);
if (compare == 0)
{
Structs[i] = initial;
return i;
}
}
return -1;
}
/// <summary>
/// Gets the struct value for a given map entry.
/// </summary>
/// <param name="index">Index of the entry</param>
/// <returns>A reference to the struct value</returns>
public ref T GetValue(int index)
{
return ref Structs[index];
}
/// <summary>
/// Releases an entry from the map.
/// </summary>
/// <param name="index">Index of the entry to release</param>
public void Release(int index)
{
Interlocked.Exchange(ref ThreadIds[index], 0);
}
}
}