[PATCH] use standard volatile semantics

[godisgovernment at gmail.com (Shawn Hoffman)]

Make all archs are use the standardized concept of volatile.
This patch will cause the most changes to arm64 codegen, and has
yet to be tested on arm64 so is currently being submitted for
comments. If someone would like to test on arm64 it would be
appreciated. I do have an arm64 device, but it seems there's no
existing arm64/windows wireguard binary package, so I can't
just install such a thing and swap out the driver.

Signed-off-by: Shawn Hoffman <godisgovernment at gmail.com>
---
 atomic.h               | 54 ------------------------------
 wintun.c               | 76 +++++++++++++++++++++---------------------
 wintun.vcxproj         |  5 ++-
 wintun.vcxproj.filters |  3 --
 4 files changed, 40 insertions(+), 98 deletions(-)
 delete mode 100644 atomic.h

diff --git a/atomic.h b/atomic.h
deleted file mode 100644
index 01dd35e..0000000
--- a/atomic.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2018-2019 WireGuard LLC. All Rights Reserved.
- */
-
-#pragma once
-
-#include <wdm.h>
-
-static __forceinline VOID
-InterlockedSet(_Inout_ _Interlocked_operand_ LONG volatile *Target, _In_ LONG Value)
-{
-    *Target = Value;
-}
-
-static __forceinline VOID
-InterlockedSetU(_Inout_ _Interlocked_operand_ ULONG volatile *Target, _In_ ULONG Value)
-{
-    *Target = Value;
-}
-
-static __forceinline VOID
-InterlockedSetPointer(_Inout_ _Interlocked_operand_ VOID *volatile *Target, _In_opt_ VOID *Value)
-{
-    *Target = Value;
-}
-
-static __forceinline LONG
-InterlockedGet(_In_ _Interlocked_operand_ LONG volatile *Value)
-{
-    return *Value;
-}
-
-static __forceinline ULONG
-InterlockedGetU(_In_ _Interlocked_operand_ ULONG volatile *Value)
-{
-    return *Value;
-}
-
-static __forceinline PVOID
-InterlockedGetPointer(_In_ _Interlocked_operand_ PVOID volatile *Value)
-{
-    return *Value;
-}
-
-static __forceinline LONG64
-InterlockedGet64(_In_ _Interlocked_operand_ LONG64 volatile *Value)
-{
-#ifdef _WIN64
-    return *Value;
-#else
-    return InterlockedCompareExchange64(Value, 0, 0);
-#endif
-}
\ No newline at end of file
diff --git a/wintun.c b/wintun.c
index a6a0e16..b042d35 100644
--- a/wintun.c
+++ b/wintun.c
@@ -9,7 +9,6 @@
 #include <ndis.h>
 #include <ntstrsafe.h>
 #include "undocumented.h"
-#include "atomic.h"
 
 #pragma warning(disable : 4100) /* unreferenced formal parameter */
 #pragma warning(disable : 4200) /* nonstandard: zero-sized array in struct/union */
@@ -250,7 +249,7 @@ TunSendNetBufferLists(
 
     KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
     NDIS_STATUS Status;
-    if ((Status = NDIS_STATUS_PAUSED, !InterlockedGet(&Ctx->Running)) ||
+    if ((Status = NDIS_STATUS_PAUSED, !ReadAcquire(&Ctx->Running)) ||
         (Status = NDIS_STATUS_MEDIA_DISCONNECTED, KeReadStateEvent(&Ctx->Device.Disconnected)))
         goto skipNbl;
 
@@ -258,7 +257,7 @@ TunSendNetBufferLists(
     ULONG RingCapacity = Ctx->Device.Send.Capacity;
 
     /* Allocate space for packets in the ring. */
-    ULONG RingHead = InterlockedGetU(&Ring->Head);
+    ULONG RingHead = ReadULongAcquire(&Ring->Head);
     if (Status = NDIS_STATUS_ADAPTER_NOT_READY, RingHead >= RingCapacity)
         goto skipNbl;
 
@@ -325,7 +324,7 @@ TunSendNetBufferLists(
     {
         NET_BUFFER_LIST *CompletedNbl = Ctx->Device.Send.ActiveNbls.Head;
         Ctx->Device.Send.ActiveNbls.Head = NET_BUFFER_LIST_NEXT_NBL_EX(CompletedNbl);
-        InterlockedSetU(&Ring->Tail, TunNblGetOffset(CompletedNbl));
+        WriteULongRelease(&Ring->Tail, TunNblGetOffset(CompletedNbl));
         KeSetEvent(Ctx->Device.Send.TailMoved, IO_NETWORK_INCREMENT, FALSE);
         NdisMSendNetBufferListsComplete(
             Ctx->MiniportAdapterHandle, CompletedNbl, NDIS_SEND_COMPLETE_FLAGS_DISPATCH_LEVEL);
@@ -343,11 +342,11 @@ skipNbl:
     ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
     NdisMSendNetBufferListsComplete(Ctx->MiniportAdapterHandle, NetBufferLists, 0);
 updateStatistics:
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCOutOctets, SentPacketsSize);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCOutUcastOctets, SentPacketsSize);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCOutUcastPkts, SentPacketsCount);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifOutErrors, ErrorPacketsCount);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifOutDiscards, DiscardedPacketsCount);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutOctets, SentPacketsSize);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutUcastOctets, SentPacketsSize);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutUcastPkts, SentPacketsCount);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifOutErrors, ErrorPacketsCount);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifOutDiscards, DiscardedPacketsCount);
 }
 
 static MINIPORT_CANCEL_SEND TunCancelSend;
@@ -393,15 +392,15 @@ TunReturnNetBufferLists(NDIS_HANDLE MiniportAdapterContext, PNET_BUFFER_LIST Net
             if (!Ctx->Device.Receive.ActiveNbls.Head)
                 KeSetEvent(&Ctx->Device.Receive.ActiveNbls.Empty, IO_NO_INCREMENT, FALSE);
             KeReleaseInStackQueuedSpinLock(&LockHandle);
-            InterlockedSetU(&Ring->Head, TunNblGetOffset(CompletedNbl));
+            WriteULongRelease(&Ring->Head, TunNblGetOffset(CompletedNbl));
             NdisFreeNetBufferList(CompletedNbl);
         }
     }
 
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCInOctets, ReceivedPacketsSize);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCInUcastOctets, ReceivedPacketsSize);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifHCInUcastPkts, ReceivedPacketsCount);
-    InterlockedAdd64((LONG64 *)&Ctx->Statistics.ifInErrors, ErrorPacketsCount);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCInOctets, ReceivedPacketsSize);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCInUcastOctets, ReceivedPacketsSize);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifHCInUcastPkts, ReceivedPacketsCount);
+    InterlockedAddNoFence64((LONG64 *)&Ctx->Statistics.ifInErrors, ErrorPacketsCount);
 }
 
 _IRQL_requires_max_(PASSIVE_LEVEL)
@@ -419,20 +418,20 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
     VOID *Events[] = { &Ctx->Device.Disconnected, Ctx->Device.Receive.TailMoved };
     ASSERT(RTL_NUMBER_OF(Events) <= THREAD_WAIT_OBJECTS);
 
-    ULONG RingHead = InterlockedGetU(&Ring->Head);
+    ULONG RingHead = ReadULongAcquire(&Ring->Head);
     if (RingHead >= RingCapacity)
         goto cleanup;
 
     while (!KeReadStateEvent(&Ctx->Device.Disconnected))
     {
         /* Get next packet from the ring. */
-        ULONG RingTail = InterlockedGetU(&Ring->Tail);
+        ULONG RingTail = ReadULongAcquire(&Ring->Tail);
         if (RingHead == RingTail)
         {
             LARGE_INTEGER SpinStart = KeQueryPerformanceCounter(NULL);
             for (;;)
             {
-                RingTail = InterlockedGetU(&Ring->Tail);
+                RingTail = ReadULongAcquire(&Ring->Tail);
                 if (RingTail != RingHead)
                     break;
                 if (KeReadStateEvent(&Ctx->Device.Disconnected))
@@ -444,16 +443,16 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
             }
             if (RingHead == RingTail)
             {
-                InterlockedSet(&Ring->Alertable, TRUE);
-                RingTail = InterlockedGetU(&Ring->Tail);
+                WriteRelease(&Ring->Alertable, TRUE);
+                RingTail = ReadULongAcquire(&Ring->Tail);
                 if (RingHead == RingTail)
                 {
                     KeWaitForMultipleObjects(
                         RTL_NUMBER_OF(Events), Events, WaitAny, Executive, KernelMode, FALSE, NULL, NULL);
-                    InterlockedSet(&Ring->Alertable, FALSE);
+                    WriteRelease(&Ring->Alertable, FALSE);
                     continue;
                 }
-                InterlockedSet(&Ring->Alertable, FALSE);
+                WriteRelease(&Ring->Alertable, FALSE);
                 KeClearEvent(Ctx->Device.Receive.TailMoved);
             }
         }
@@ -501,7 +500,7 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
         TunNblSetOffsetAndMarkActive(Nbl, RingHead);
 
         KIRQL Irql = ExAcquireSpinLockShared(&Ctx->TransitionLock);
-        if (!InterlockedGet(&Ctx->Running))
+        if (!ReadAcquire(&Ctx->Running))
             goto cleanupNbl;
 
         KLOCK_QUEUE_HANDLE LockHandle;
@@ -530,16 +529,16 @@ TunProcessReceiveData(_Inout_ TUN_CTX *Ctx)
         ExReleaseSpinLockShared(&Ctx->TransitionLock, Irql);
         NdisFreeNetBufferList(Nbl);
     skipNbl:
-        InterlockedIncrement64((LONG64 *)&Ctx->Statistics.ifInDiscards);
+        InterlockedIncrementNoFence64((LONG64 *)&Ctx->Statistics.ifInDiscards);
         KeWaitForSingleObject(&Ctx->Device.Receive.ActiveNbls.Empty, Executive, KernelMode, FALSE, NULL);
-        InterlockedSetU(&Ring->Head, RingHead);
+        WriteULongRelease(&Ring->Head, RingHead);
     }
 
     /* Wait for all NBLs to return: 1. To prevent race between proceeding and invalidating ring head. 2. To have
      * TunDispatchUnregisterBuffers() implicitly wait before releasing ring MDL used by NBL(s). */
     KeWaitForSingleObject(&Ctx->Device.Receive.ActiveNbls.Empty, Executive, KernelMode, FALSE, NULL);
 cleanup:
-    InterlockedSetU(&Ring->Head, MAXULONG);
+    WriteULongRelease(&Ring->Head, MAXULONG);
 }
 
 #define IS_POW2(x) ((x) && !((x) & ((x)-1)))
@@ -595,7 +594,7 @@ TunRegisterBuffers(_Inout_ TUN_CTX *Ctx, _Inout_ IRP *Irp)
     if (Status = STATUS_INSUFFICIENT_RESOURCES, !Ctx->Device.Send.Ring)
         goto cleanupSendUnlockPages;
 
-    Ctx->Device.Send.RingTail = InterlockedGetU(&Ctx->Device.Send.Ring->Tail);
+    Ctx->Device.Send.RingTail = ReadULongAcquire(&Ctx->Device.Send.Ring->Tail);
     if (Status = STATUS_INVALID_PARAMETER, Ctx->Device.Send.RingTail >= Ctx->Device.Send.Capacity)
         goto cleanupSendUnlockPages;
 
@@ -709,7 +708,7 @@ TunUnregisterBuffers(_Inout_ TUN_CTX *Ctx, _In_ FILE_OBJECT *Owner)
     }
     ZwClose(Ctx->Device.Receive.Thread);
 
-    InterlockedSetU(&Ctx->Device.Send.Ring->Tail, MAXULONG);
+    WriteULongRelease(&Ctx->Device.Send.Ring->Tail, MAXULONG);
     KeSetEvent(Ctx->Device.Send.TailMoved, IO_NO_INCREMENT, FALSE);
 
     MmUnlockPages(Ctx->Device.Receive.Mdl);
@@ -926,7 +925,7 @@ static NDIS_STATUS
 TunRestart(NDIS_HANDLE MiniportAdapterContext, PNDIS_MINIPORT_RESTART_PARAMETERS MiniportRestartParameters)
 {
     TUN_CTX *Ctx = (TUN_CTX *)MiniportAdapterContext;
-    InterlockedSet(&Ctx->Running, TRUE);
+    WriteRelease(&Ctx->Running, TRUE);
     return NDIS_STATUS_SUCCESS;
 }
 
@@ -937,7 +936,7 @@ TunPause(NDIS_HANDLE MiniportAdapterContext, PNDIS_MINIPORT_PAUSE_PARAMETERS Min
 {
     TUN_CTX *Ctx = (TUN_CTX *)MiniportAdapterContext;
 
-    InterlockedSet(&Ctx->Running, FALSE);
+    WriteRelease(&Ctx->Running, FALSE);
     ExReleaseSpinLockExclusive(
         &Ctx->TransitionLock,
         ExAcquireSpinLockExclusive(&Ctx->TransitionLock)); /* Ensure above change is visible to all readers. */
@@ -1131,9 +1130,10 @@ TunHaltEx(NDIS_HANDLE MiniportAdapterContext, NDIS_HALT_ACTION HaltAction)
         ExAcquireSpinLockExclusive(&Ctx->TransitionLock)); /* Ensure above change is visible to all readers. */
     NdisFreeNetBufferListPool(Ctx->NblPool);
 
-    InterlockedSetPointer(&Ctx->MiniportAdapterHandle, NULL);
-#pragma warning(suppress : 28175)
-    InterlockedSetPointer(&Ctx->FunctionalDeviceObject->Reserved, NULL);
+#pragma warning(suppress : 6387)
+    WritePointerNoFence(&Ctx->MiniportAdapterHandle, NULL);
+#pragma warning(suppress : 6387 28175)
+    WritePointerNoFence(&Ctx->FunctionalDeviceObject->Reserved, NULL);
     KeEnterCriticalRegion();
     ExAcquireResourceExclusiveLite(&TunDispatchCtxGuard, TRUE); /* Ensure above change is visible to all readers. */
     ExReleaseResourceLite(&TunDispatchCtxGuard);
@@ -1242,16 +1242,16 @@ TunOidQuery(_Inout_ TUN_CTX *Ctx, _Inout_ NDIS_OID_REQUEST *OidRequest)
     case OID_GEN_XMIT_OK:
         return TunOidQueryWrite32or64(
             OidRequest,
-            InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCOutUcastPkts) +
-                InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCOutMulticastPkts) +
-                InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCOutBroadcastPkts));
+            ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutUcastPkts) +
+                ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutMulticastPkts) +
+                ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCOutBroadcastPkts));
 
     case OID_GEN_RCV_OK:
         return TunOidQueryWrite32or64(
             OidRequest,
-            InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCInUcastPkts) +
-                InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCInMulticastPkts) +
-                InterlockedGet64((LONG64 *)&Ctx->Statistics.ifHCInBroadcastPkts));
+            ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCInUcastPkts) +
+                ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCInMulticastPkts) +
+                ReadNoFence64((LONG64 *)&Ctx->Statistics.ifHCInBroadcastPkts));
 
     case OID_GEN_STATISTICS:
         return TunOidQueryWriteBuf(OidRequest, &Ctx->Statistics, (ULONG)sizeof(Ctx->Statistics));
diff --git a/wintun.vcxproj b/wintun.vcxproj
index 3bb61d1..abe4a17 100644
--- a/wintun.vcxproj
+++ b/wintun.vcxproj
@@ -125,7 +125,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <PreprocessorDefinitions>NDIS_MINIPORT_DRIVER=1;NDIS620_MINIPORT=1;NDIS683_MINIPORT=1;NDIS_WDM=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <AdditionalOptions>/volatile:ms %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions>/volatile:iso %(AdditionalOptions)</AdditionalOptions>
       <EnablePREfast>true</EnablePREfast>
     </ClCompile>
     <ResourceCompile>
@@ -171,9 +171,8 @@
     <FilesToPackage Include="$(TargetPath)" Condition="'$(ConfigurationType)'=='Driver' or '$(ConfigurationType)'=='DynamicLibrary'" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="atomic.h" />
     <ClInclude Include="undocumented.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets" />
-</Project>
+</Project>
\ No newline at end of file
diff --git a/wintun.vcxproj.filters b/wintun.vcxproj.filters
index 467cc48..3e19120 100644
--- a/wintun.vcxproj.filters
+++ b/wintun.vcxproj.filters
@@ -33,8 +33,5 @@
     <ClInclude Include="undocumented.h">
       <Filter>Header Files</Filter>
     </ClInclude>
-    <ClInclude Include="atomic.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
-- 
2.26.2.windows.1