xnu-1228.7.58.tar.gz

[apple/xnu.git] / libkern / gen / OSAtomicOperations.c

diff --git a/libkern/gen/OSAtomicOperations.c b/libkern/gen/OSAtomicOperations.c
index c6e86aacacdbdb50376dbc9518a4a69c4e1ce991..bbdb0d970e9877852dca2cde66272e3abbdf7df5 100644 (file)
--- a/libkern/gen/OSAtomicOperations.c
+++ b/libkern/gen/OSAtomicOperations.c
@@ -1,23 +1,29 @@
 /*
 /*

- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.

  *
  *

- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

  * 
  * 

- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.

  * 
  * 

- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER

  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.

  * 
  * 

- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@

  */
 
 #include <libkern/OSAtomic.h>
  */
 
 #include <libkern/OSAtomic.h>


@@ -26,49 +32,77 @@ enum {
        false   = 0,
        true    = 1
 };
        false   = 0,
        true    = 1
 };

-#define        NULL 0L

 
 

+#ifndef NULL
+#define NULL ((void *)0)
+#endif

 
 /*
  * atomic operations
  *     these are _the_ atomic operations, currently cast atop CompareAndSwap,
 
 /*
  * atomic operations
  *     these are _the_ atomic operations, currently cast atop CompareAndSwap,

- *     which is implemented in assembler.  if we are worried about the cost of
+ *     which is implemented in assembler.      if we are worried about the cost of

  *     this layering (we shouldn't be), then all this stuff could be
  *     implemented in assembler, as it is in MacOS8/9
  *     (derived from SuperMario/NativeLibs/IO/DriverServices/Synchronization.s,
  *     which I wrote for NuKernel in a previous life with a different last name...)
  *
  * native Boolean      CompareAndSwap(UInt32 oldValue, UInt32 newValue, UInt32 * oldValuePtr);
  *     this layering (we shouldn't be), then all this stuff could be
  *     implemented in assembler, as it is in MacOS8/9
  *     (derived from SuperMario/NativeLibs/IO/DriverServices/Synchronization.s,
  *     which I wrote for NuKernel in a previous life with a different last name...)
  *
  * native Boolean      CompareAndSwap(UInt32 oldValue, UInt32 newValue, UInt32 * oldValuePtr);

+ *
+ * We've since implemented a few more of these -- OSAddAtomic, OSDequeueAtomic,
+ * OSEnqueueAtomic etc -- in assembler, either for speed or correctness.  See also the
+ * commpage atomic operations, and the platform specific versions.
+ * Like standards, there are a lot of atomic ops to choose from!

  */
 
 #ifndef __ppc__
 
  */
 
 #ifndef __ppc__
 

-SInt32 OSAddAtomic(SInt32 amount, SInt32 * value)
-{
-       SInt32  oldValue;
-       SInt32  newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = oldValue + amount;
-       } while (! OSCompareAndSwap((UInt32) oldValue, (UInt32) newValue, (UInt32 *) value));
-       
-       return oldValue;
-}

 
 

-SInt32 OSIncrementAtomic(SInt32 * value)
+SInt32 OSIncrementAtomic(volatile SInt32 * value)

 {
        return OSAddAtomic(1, value);
 }
 
 {
        return OSAddAtomic(1, value);
 }
 

-SInt32 OSDecrementAtomic(SInt32 * value)
+SInt32 OSDecrementAtomic(volatile SInt32 * value)

 {
        return OSAddAtomic(-1, value);
 }
 
 {
        return OSAddAtomic(-1, value);
 }
 

+#ifdef CMPXCHG8B
+void * OSDequeueAtomic(void * volatile * inList, SInt32 inOffset)
+{
+       /* The _pointer_ is volatile, not the listhead itself */
+       void * volatile oldListHead;
+       void * volatile newListHead;
+       
+       do {
+               oldListHead = *inList;
+               if (oldListHead == NULL) {
+                       break;
+               }
+               
+               newListHead = *(void * volatile *) (((char *) oldListHead) + inOffset);
+       } while (! OSCompareAndSwap((UInt32)oldListHead,
+                                       (UInt32)newListHead, (volatile UInt32 *)inList));
+       return oldListHead;
+}
+
+void   OSEnqueueAtomic(void * volatile * inList, void * inNewLink, SInt32 inOffset)
+{
+       /* The _pointer_ is volatile, not the listhead itself */
+       void * volatile oldListHead;
+       void * volatile newListHead = inNewLink;
+       void * volatile * newLinkNextPtr = (void * volatile *) (((char *) inNewLink) + inOffset);
+       
+       do {
+               oldListHead = *inList;
+               *newLinkNextPtr = oldListHead;
+       } while (! OSCompareAndSwap((UInt32)oldListHead, (UInt32)newListHead,
+                                       (volatile UInt32 *)inList));
+}
+#endif /* CMPXCHG8B */

 #endif /* !__ppc__ */
 
 #endif /* !__ppc__ */
 

-static UInt32  OSBitwiseAtomic(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, UInt32 * value)
+static UInt32  OSBitwiseAtomic(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt32 * value)

 {
        UInt32  oldValue;
        UInt32  newValue;
 {
        UInt32  oldValue;
        UInt32  newValue;


@@ -81,41 +115,41 @@ static UInt32      OSBitwiseAtomic(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask,
        return oldValue;
 }
 
        return oldValue;
 }
 

-UInt32 OSBitAndAtomic(UInt32 mask, UInt32 * value)
+UInt32 OSBitAndAtomic(UInt32 mask, volatile UInt32 * value)

 {
        return OSBitwiseAtomic(mask, 0, 0, value);
 }
 
 {
        return OSBitwiseAtomic(mask, 0, 0, value);
 }
 

-UInt32 OSBitOrAtomic(UInt32 mask, UInt32 * value)
+UInt32 OSBitOrAtomic(UInt32 mask, volatile UInt32 * value)

 {
        return OSBitwiseAtomic((UInt32) -1, mask, 0, value);
 }
 
 {
        return OSBitwiseAtomic((UInt32) -1, mask, 0, value);
 }
 

-UInt32 OSBitXorAtomic(UInt32 mask, UInt32 * value)
+UInt32 OSBitXorAtomic(UInt32 mask, volatile UInt32 * value)

 {
        return OSBitwiseAtomic((UInt32) -1, 0, mask, value);
 }
 
 {
        return OSBitwiseAtomic((UInt32) -1, 0, mask, value);
 }
 

-static Boolean OSCompareAndSwap8(UInt8 oldValue8, UInt8 newValue8, UInt8 * value8)
+static Boolean OSCompareAndSwap8(UInt8 oldValue8, UInt8 newValue8, volatile UInt8 * value8)

 {
 {

-       UInt32          mask        = 0x000000ff;
-       UInt32          alignment   = ((UInt32) value8) & (sizeof(UInt32) - 1);
-    UInt32      shiftValues = (24 << 24) | (16 << 16) | (8 << 8);
-    int                        shift       = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
-       UInt32 *        value32     = (UInt32 *) (value8 - alignment);
-    UInt32      oldValue;
-    UInt32      newValue;
+       UInt32                          mask            = 0x000000ff;
+       UInt32                          alignment       = ((UInt32) value8) & (sizeof(UInt32) - 1);
+       UInt32                          shiftValues = (24 << 24) | (16 << 16) | (8 << 8);
+       int                                     shift           = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
+       volatile UInt32 *       value32         = (volatile UInt32 *) (value8 - alignment);
+       UInt32                          oldValue;
+       UInt32                          newValue;

 
 

-    mask <<= shift;
+       mask <<= shift;

 
 

-    oldValue = *value32;
-    oldValue = (oldValue & ~mask) | (oldValue8 << shift);
-    newValue = (oldValue & ~mask) | (newValue8 << shift);
+       oldValue = *value32;
+       oldValue = (oldValue & ~mask) | (oldValue8 << shift);
+       newValue = (oldValue & ~mask) | (newValue8 << shift);

 
        return OSCompareAndSwap(oldValue, newValue, value32);
 }
 
 
        return OSCompareAndSwap(oldValue, newValue, value32);
 }
 

-static Boolean OSTestAndSetClear(UInt32 bit, Boolean wantSet, UInt8 * startAddress)
+static Boolean OSTestAndSetClear(UInt32 bit, Boolean wantSet, volatile UInt8 * startAddress)

 {
        UInt8           mask = 1;
        UInt8           oldValue;
 {
        UInt8           mask = 1;
        UInt8           oldValue;


@@ -135,62 +169,31 @@ static Boolean    OSTestAndSetClear(UInt32 bit, Boolean wantSet, UInt8 * startAddre
        return (oldValue & mask) == wantValue;
 }
 
        return (oldValue & mask) == wantValue;
 }
 

-Boolean        OSTestAndSet(UInt32 bit, UInt8 * startAddress)
+Boolean OSTestAndSet(UInt32 bit, volatile UInt8 * startAddress)

 {
        return OSTestAndSetClear(bit, true, startAddress);
 }
 
 {
        return OSTestAndSetClear(bit, true, startAddress);
 }
 

-Boolean        OSTestAndClear(UInt32 bit, UInt8 * startAddress)
+Boolean OSTestAndClear(UInt32 bit, volatile UInt8 * startAddress)

 {
        return OSTestAndSetClear(bit, false, startAddress);
 }
 
 {
        return OSTestAndSetClear(bit, false, startAddress);
 }
 

-void * OSDequeueAtomic(void ** inList, SInt32 inOffset)
-{
-       void *  oldListHead;
-       void *  newListHead;
-       
-       do {
-               oldListHead = *inList;
-               if (oldListHead == NULL) {
-                       break;
-               }
-               
-               newListHead = *(void **) (((char *) oldListHead) + inOffset);
-       } while (! OSCompareAndSwap((UInt32)oldListHead,
-                                       (UInt32)newListHead, (UInt32 *)inList));
-       
-       return oldListHead;
-}
-
-void   OSEnqueueAtomic(void ** inList, void * inNewLink, SInt32 inOffset)
-{
-       void *  oldListHead;
-       void *  newListHead = inNewLink;
-       void ** newLinkNextPtr = (void **) (((char *) inNewLink) + inOffset);
-       
-       do {
-               oldListHead = *inList;
-               *newLinkNextPtr = oldListHead;
-       } while (! OSCompareAndSwap((UInt32)oldListHead, (UInt32)newListHead,
-                                       (UInt32 *)inList));
-}
-

 /*
  * silly unaligned versions
  */
 
 /*
  * silly unaligned versions
  */
 

-SInt8  OSIncrementAtomic8(SInt8 * value)
+SInt8  OSIncrementAtomic8(volatile SInt8 * value)

 {
        return OSAddAtomic8(1, value);
 }
 
 {
        return OSAddAtomic8(1, value);
 }
 

-SInt8  OSDecrementAtomic8(SInt8 * value)
+SInt8  OSDecrementAtomic8(volatile SInt8 * value)

 {
        return OSAddAtomic8(-1, value);
 }
 
 {
        return OSAddAtomic8(-1, value);
 }
 

-SInt8  OSAddAtomic8(SInt32 amount, SInt8 * value)
+SInt8  OSAddAtomic8(SInt32 amount, volatile SInt8 * value)

 {
        SInt8   oldValue;
        SInt8   newValue;
 {
        SInt8   oldValue;
        SInt8   newValue;


@@ -198,12 +201,12 @@ SInt8     OSAddAtomic8(SInt32 amount, SInt8 * value)
        do {
                oldValue = *value;
                newValue = oldValue + amount;
        do {
                oldValue = *value;
                newValue = oldValue + amount;

-       } while (! OSCompareAndSwap8((UInt8) oldValue, (UInt8) newValue, (UInt8 *) value));
+       } while (! OSCompareAndSwap8((UInt8) oldValue, (UInt8) newValue, (volatile UInt8 *) value));

        
        return oldValue;
 }
 
        
        return oldValue;
 }
 

-static UInt8   OSBitwiseAtomic8(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, UInt8 * value)
+static UInt8   OSBitwiseAtomic8(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt8 * value)

 {
        UInt8   oldValue;
        UInt8   newValue;
 {
        UInt8   oldValue;
        UInt8   newValue;


@@ -216,51 +219,51 @@ static UInt8      OSBitwiseAtomic8(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask,
        return oldValue;
 }
 
        return oldValue;
 }
 

-UInt8  OSBitAndAtomic8(UInt32 mask, UInt8 * value)
+UInt8  OSBitAndAtomic8(UInt32 mask, volatile UInt8 * value)

 {
        return OSBitwiseAtomic8(mask, 0, 0, value);
 }
 
 {
        return OSBitwiseAtomic8(mask, 0, 0, value);
 }
 

-UInt8  OSBitOrAtomic8(UInt32 mask, UInt8 * value)
+UInt8  OSBitOrAtomic8(UInt32 mask, volatile UInt8 * value)

 {
        return OSBitwiseAtomic8((UInt32) -1, mask, 0, value);
 }
 
 {
        return OSBitwiseAtomic8((UInt32) -1, mask, 0, value);
 }
 

-UInt8  OSBitXorAtomic8(UInt32 mask, UInt8 * value)
+UInt8  OSBitXorAtomic8(UInt32 mask, volatile UInt8 * value)

 {
        return OSBitwiseAtomic8((UInt32) -1, 0, mask, value);
 }
 
 {
        return OSBitwiseAtomic8((UInt32) -1, 0, mask, value);
 }
 

-static Boolean OSCompareAndSwap16(UInt16 oldValue16, UInt16 newValue16, UInt16 * value16)
+static Boolean OSCompareAndSwap16(UInt16 oldValue16, UInt16 newValue16, volatile UInt16 * value16)

 {
 {

-       UInt32          mask        = 0x0000ffff;
-       UInt32          alignment   = ((UInt32) value16) & (sizeof(UInt32) - 1);
-    UInt32      shiftValues = (16 << 24) | (16 << 16);
-    UInt32             shift       = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
-       UInt32 *        value32     = (UInt32 *) (((UInt32) value16) - alignment);
-    UInt32      oldValue;
-    UInt32      newValue;
+       UInt32                          mask            = 0x0000ffff;
+       UInt32                          alignment       = ((UInt32) value16) & (sizeof(UInt32) - 1);
+       UInt32                          shiftValues = (16 << 24) | (16 << 16);
+       UInt32                          shift           = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
+       volatile UInt32 *       value32         = (volatile UInt32 *) (((UInt32) value16) - alignment);
+       UInt32                          oldValue;
+       UInt32                          newValue;

 
 

-    mask <<= shift;
+       mask <<= shift;

 
 

-    oldValue = *value32;
-    oldValue = (oldValue & ~mask) | (oldValue16 << shift);
-    newValue = (oldValue & ~mask) | (newValue16 << shift);
+       oldValue = *value32;
+       oldValue = (oldValue & ~mask) | (oldValue16 << shift);
+       newValue = (oldValue & ~mask) | (newValue16 << shift);

 
        return OSCompareAndSwap(oldValue, newValue, value32);
 }
 
 
        return OSCompareAndSwap(oldValue, newValue, value32);
 }
 

-SInt16 OSIncrementAtomic16(SInt16 * value)
+SInt16 OSIncrementAtomic16(volatile SInt16 * value)

 {
        return OSAddAtomic16(1, value);
 }
 
 {
        return OSAddAtomic16(1, value);
 }
 

-SInt16 OSDecrementAtomic16(SInt16 * value)
+SInt16 OSDecrementAtomic16(volatile SInt16 * value)

 {
        return OSAddAtomic16(-1, value);
 }
 
 {
        return OSAddAtomic16(-1, value);
 }
 

-SInt16 OSAddAtomic16(SInt32 amount, SInt16 * value)
+SInt16 OSAddAtomic16(SInt32 amount, volatile SInt16 * value)

 {
        SInt16  oldValue;
        SInt16  newValue;
 {
        SInt16  oldValue;
        SInt16  newValue;


@@ -268,12 +271,12 @@ SInt16    OSAddAtomic16(SInt32 amount, SInt16 * value)
        do {
                oldValue = *value;
                newValue = oldValue + amount;
        do {
                oldValue = *value;
                newValue = oldValue + amount;

-       } while (! OSCompareAndSwap16((UInt16) oldValue, (UInt16) newValue, (UInt16 *) value));
+       } while (! OSCompareAndSwap16((UInt16) oldValue, (UInt16) newValue, (volatile UInt16 *) value));

        
        return oldValue;
 }
 
        
        return oldValue;
 }
 

-static UInt16  OSBitwiseAtomic16(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, UInt16 * value)
+static UInt16  OSBitwiseAtomic16(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt16 * value)

 {
        UInt16  oldValue;
        UInt16  newValue;
 {
        UInt16  oldValue;
        UInt16  newValue;


@@ -286,17 +289,17 @@ static UInt16     OSBitwiseAtomic16(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask
        return oldValue;
 }
 
        return oldValue;
 }
 

-UInt16 OSBitAndAtomic16(UInt32 mask, UInt16 * value)
+UInt16 OSBitAndAtomic16(UInt32 mask, volatile UInt16 * value)

 {
        return OSBitwiseAtomic16(mask, 0, 0, value);
 }
 
 {
        return OSBitwiseAtomic16(mask, 0, 0, value);
 }
 

-UInt16 OSBitOrAtomic16(UInt32 mask, UInt16 * value)
+UInt16 OSBitOrAtomic16(UInt32 mask, volatile UInt16 * value)

 {
        return OSBitwiseAtomic16((UInt32) -1, mask, 0, value);
 }
 
 {
        return OSBitwiseAtomic16((UInt32) -1, mask, 0, value);
 }
 

-UInt16 OSBitXorAtomic16(UInt32 mask, UInt16 * value)
+UInt16 OSBitXorAtomic16(UInt32 mask, volatile UInt16 * value)

 {
        return OSBitwiseAtomic16((UInt32) -1, 0, mask, value);
 }
 {
        return OSBitwiseAtomic16((UInt32) -1, 0, mask, value);
 }