[PATCH v2 5/6] hal: Implement KeAcquireSpinLock().

[Zebediah Figura]

Signed-off-by: Zebediah Figura <z.figura12 at gmail.com>
---
 dlls/hal/hal.c    | 19 ++++++++++++++++---
 dlls/hal/hal.spec |  2 +-
 include/ddk/wdm.h |  3 +++
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/dlls/hal/hal.c b/dlls/hal/hal.c
index 924fd9e6d9..fca4f23403 100644
--- a/dlls/hal/hal.c
+++ b/dlls/hal/hal.c
@@ -69,11 +69,24 @@ BOOLEAN WINAPI DECLSPEC_HIDDEN __regs_ExTryToAcquireFastMutex(PFAST_MUTEX FastMu
 }
 
 DEFINE_FASTCALL1_ENTRYPOINT( KfAcquireSpinLock )
-KIRQL WINAPI DECLSPEC_HIDDEN __regs_KfAcquireSpinLock(PKSPIN_LOCK SpinLock)
+KIRQL WINAPI DECLSPEC_HIDDEN __regs_KfAcquireSpinLock( KSPIN_LOCK *lock )
 {
-    FIXME( "(%p) stub!\n", SpinLock );
+    KIRQL irql;
+    KeAcquireSpinLock( lock, &irql );
+    return irql;
+}
 
-    return 0;
+static inline void small_pause(void)
+{
+    __asm__ __volatile__( "rep;nop" : : : "memory" );
+}
+
+void WINAPI KeAcquireSpinLock( KSPIN_LOCK *lock, KIRQL *irql )
+{
+    TRACE("lock %p, irql %p.\n", lock, irql);
+    while (!InterlockedCompareExchangePointer( (void **)lock, (void *)1, (void *)0 ))
+        small_pause();
+    *irql = 0;
 }
 
 DEFINE_FASTCALL2_ENTRYPOINT( KfReleaseSpinLock )
diff --git a/dlls/hal/hal.spec b/dlls/hal/hal.spec
index 9b74701401..521697b79b 100644
--- a/dlls/hal/hal.spec
+++ b/dlls/hal/hal.spec
@@ -68,7 +68,7 @@
 @ stub IoSetPartitionInformation
 @ stub IoWritePartitionTable
 @ stub KdComPortInUse
-@ stub KeAcquireSpinLock
+@ stdcall -arch=i386 KeAcquireSpinLock(ptr ptr)
 @ stub KeFlushWriteBuffer
 @ stdcall -arch=arm,arm64,i386 KeGetCurrentIrql()
 @ stub KeLowerIrql
diff --git a/include/ddk/wdm.h b/include/ddk/wdm.h
index d964ecb573..2822c693dc 100644
--- a/include/ddk/wdm.h
+++ b/include/ddk/wdm.h
@@ -1419,6 +1419,9 @@ void      WINAPI IoReleaseCancelSpinLock(KIRQL);
 NTSTATUS  WINAPI IoSetDeviceInterfaceState(UNICODE_STRING*,BOOLEAN);
 NTSTATUS  WINAPI IoWMIRegistrationControl(PDEVICE_OBJECT,ULONG);
 
+#ifdef __i386__
+void      WINAPI KeAcquireSpinLock(KSPIN_LOCK*,KIRQL*);
+#endif
 BOOLEAN   WINAPI KeCancelTimer(KTIMER*);
 void      WINAPI KeClearEvent(PRKEVENT);
 NTSTATUS  WINAPI KeDelayExecutionThread(KPROCESSOR_MODE,BOOLEAN,LARGE_INTEGER*);
-- 
2.20.1