reactos/ntoskrnl/include/internal/spinlock.h

   1 /*
   2 * PROJECT:         ReactOS Kernel
   3 * LICENSE:         GPL - See COPYING in the top level directory
   4 * FILE:            ntoskrnl/include/internal/spinlock.h
   5 * PURPOSE:         Internal Inlined Functions for spinlocks, shared with HAL
   6 * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
   7 */
   8
   9 VOID
  10 NTAPI
  11 Kii386SpinOnSpinLock(PKSPIN_LOCK SpinLock, ULONG Flags);
  12
  13 #ifndef CONFIG_SMP
  14
  15 //
  16 // Spinlock Acquire at IRQL >= DISPATCH_LEVEL
  17 //
  18 FORCEINLINE
  19 VOID
  20 KxAcquireSpinLock(IN PKSPIN_LOCK SpinLock)
  21 {
  22     /* On UP builds, spinlocks don't exist at IRQL >= DISPATCH */
  23     UNREFERENCED_PARAMETER(SpinLock);
  24
  25     /* Add an explicit memory barrier to prevent the compiler from reordering
  26        memory accesses across the borders of spinlocks */
  27     KeMemoryBarrierWithoutFence();
  28 }
  29
  30 //
  31 // Spinlock Release at IRQL >= DISPATCH_LEVEL
  32 //
  33 FORCEINLINE
  34 VOID
  35 KxReleaseSpinLock(IN PKSPIN_LOCK SpinLock)
  36 {
  37     /* On UP builds, spinlocks don't exist at IRQL >= DISPATCH */
  38     UNREFERENCED_PARAMETER(SpinLock);
  39
  40     /* Add an explicit memory barrier to prevent the compiler from reordering
  41        memory accesses across the borders of spinlocks */
  42     KeMemoryBarrierWithoutFence();
  43 }
  44
  45 #else
  46
  47 //
  48 // Spinlock Acquisition at IRQL >= DISPATCH_LEVEL
  49 //
  50 FORCEINLINE
  51 VOID
  52 KxAcquireSpinLock(IN PKSPIN_LOCK SpinLock)
  53 {
  54 #if DBG
  55     /* Make sure that we don't own the lock already */
  56     if (((KSPIN_LOCK)KeGetCurrentThread() | 1) == *SpinLock)
  57     {
  58         /* We do, bugcheck! */
  59         KeBugCheckEx(SPIN_LOCK_ALREADY_OWNED, (ULONG_PTR)SpinLock, 0, 0, 0);
  60     }
  61 #endif
  62
  63     /* Try to acquire the lock */
  64     while (InterlockedBitTestAndSet((PLONG)SpinLock, 0))
  65     {
  66 #if defined(_M_IX86) && DBG
  67         /* On x86 debug builds, we use a much slower but useful routine */
  68         Kii386SpinOnSpinLock(SpinLock, 5);
  69 #else
  70         /* It's locked... spin until it's unlocked */
  71         while (*(volatile KSPIN_LOCK *)SpinLock & 1)
  72         {
  73                 /* Yield and keep looping */
  74                 YieldProcessor();
  75         }
  76 #endif
  77     }
  78 #if DBG
  79     /* On debug builds, we OR in the KTHREAD */
  80     *SpinLock = (KSPIN_LOCK)KeGetCurrentThread() | 1;
  81 #endif
  82 }
  83
  84 //
  85 // Spinlock Release at IRQL >= DISPATCH_LEVEL
  86 //
  87 FORCEINLINE
  88 VOID
  89 KxReleaseSpinLock(IN PKSPIN_LOCK SpinLock)
  90 {
  91 #if DBG
  92     /* Make sure that the threads match */
  93     if (((KSPIN_LOCK)KeGetCurrentThread() | 1) != *SpinLock)
  94     {
  95         /* They don't, bugcheck */
  96         KeBugCheckEx(SPIN_LOCK_NOT_OWNED, (ULONG_PTR)SpinLock, 0, 0, 0);
  97     }
  98 #endif
  99     /* Clear the lock */
 100     InterlockedAnd((PLONG)SpinLock, 0);
 101 }
 102
 103 #endif