xnu-7195.50.7.100.1.tar.gz

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

diff --git a/libkern/gen/OSAtomicOperations.c b/libkern/gen/OSAtomicOperations.c
index cfb15c5c1b7e0b3f160166fb2c2aaf48de2ae7a6..ba66fc09be04218f175626d844c48b811d3ca17b 100644 (file)
--- a/libkern/gen/OSAtomicOperations.c
+++ b/libkern/gen/OSAtomicOperations.c
@@ -1,8 +1,8 @@
 /*
 /*

- * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2015 Apple Computer, Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

- * 
+ *

  * 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
  * 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


@@ -11,10 +11,10 @@
  * 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.
  * 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.

- * 
+ *

  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * 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,
  * 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,


@@ -22,258 +22,247 @@
  * 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.
  * 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_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #include <libkern/OSAtomic.h>
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #include <libkern/OSAtomic.h>

+#include <kern/debug.h>
+#include <machine/atomic.h>

 
 enum {
 
 enum {

-       false   = 0,
-       true    = 1
+       false   = 0,
+       true    = 1

 };
 
 #ifndef NULL
 #define NULL ((void *)0)
 #endif
 
 };
 
 #ifndef NULL
 #define NULL ((void *)0)
 #endif
 

-/*
- * atomic operations
- *     these are _the_ atomic operations, currently cast atop CompareAndSwap,
- *     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);
- *
- * 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!
- */
+#define ATOMIC_DEBUG DEBUG

 
 

-#if defined(__i386__) || defined(__x86_64__)
-/* Implemented in assembly for i386 and x86_64 */
+#if ATOMIC_DEBUG
+#define ALIGN_TEST(p, t) do{if((uintptr_t)p&(sizeof(t)-1)) panic("Unaligned atomic pointer %p\n",p);}while(0)

 #else
 #else

-#error Unsupported arch
+#define ALIGN_TEST(p, t) do{}while(0)

 #endif
 
 #endif
 

-#undef OSIncrementAtomic
-SInt32 OSIncrementAtomic(volatile SInt32 * value)
+/*
+ * atomic operations
+ *     These are _the_ atomic operations, now implemented via compiler built-ins.
+ *     It is expected that this C implementation is a candidate for Link-Time-
+ *     Optimization inlining, whereas the assembler implementations they replace
+ *     were not.
+ */
+
+#undef OSCompareAndSwap8
+Boolean
+OSCompareAndSwap8(UInt8 oldValue, UInt8 newValue, volatile UInt8 *address)

 {
 {

-       return OSAddAtomic(1, value);
+       return (Boolean)os_atomic_cmpxchg(address, oldValue, newValue, acq_rel);

 }
 
 }
 

-#undef OSDecrementAtomic
-SInt32 OSDecrementAtomic(volatile SInt32 * value)
+#undef OSCompareAndSwap16
+Boolean
+OSCompareAndSwap16(UInt16 oldValue, UInt16 newValue, volatile UInt16 *address)

 {
 {

-       return OSAddAtomic(-1, value);
+       return (Boolean)os_atomic_cmpxchg(address, oldValue, newValue, acq_rel);

 }
 
 }
 

-static UInt32  OSBitwiseAtomic(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt32 * value)
+#undef OSCompareAndSwap
+Boolean
+OSCompareAndSwap(UInt32 oldValue, UInt32 newValue, volatile UInt32 *address)

 {
 {

-       UInt32  oldValue;
-       UInt32  newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
-       } while (! OSCompareAndSwap(oldValue, newValue, value));
-       
-       return oldValue;
+       ALIGN_TEST(address, UInt32);
+       return (Boolean)os_atomic_cmpxchg(address, oldValue, newValue, acq_rel);

 }
 
 }
 

-#undef OSBitAndAtomic
-UInt32 OSBitAndAtomic(UInt32 mask, volatile UInt32 * value)
+#undef OSCompareAndSwap64
+Boolean
+OSCompareAndSwap64(UInt64 oldValue, UInt64 newValue, volatile UInt64 *address)

 {
 {

-       return OSBitwiseAtomic(mask, 0, 0, value);
+       /*
+        * _Atomic uint64 requires 8-byte alignment on all architectures.
+        * This silences the compiler cast warning.  ALIGN_TEST() verifies
+        * that the cast was legal, if defined.
+        */
+       _Atomic UInt64 *aligned_addr = (_Atomic UInt64 *)(uintptr_t)address;
+
+       ALIGN_TEST(address, UInt64);
+       return (Boolean)os_atomic_cmpxchg(aligned_addr, oldValue, newValue, acq_rel);

 }
 
 }
 

-#undef OSBitOrAtomic
-UInt32 OSBitOrAtomic(UInt32 mask, volatile UInt32 * value)
+#undef OSCompareAndSwapPtr
+Boolean
+OSCompareAndSwapPtr(void *oldValue, void *newValue, void * volatile *address)

 {
 {

-       return OSBitwiseAtomic((UInt32) -1, mask, 0, value);
+       return (Boolean)os_atomic_cmpxchg(address, oldValue, newValue, acq_rel);

 }
 
 }
 

-#undef OSBitXorAtomic
-UInt32 OSBitXorAtomic(UInt32 mask, volatile UInt32 * value)
+SInt8
+OSAddAtomic8(SInt32 amount, volatile SInt8 *address)

 {
 {

-       return OSBitwiseAtomic((UInt32) -1, 0, mask, value);
+       return os_atomic_add_orig(address, (SInt8)amount, relaxed);

 }
 
 }
 

-static Boolean OSCompareAndSwap8(UInt8 oldValue8, UInt8 newValue8, volatile UInt8 * value8)
+SInt16
+OSAddAtomic16(SInt32 amount, volatile SInt16 *address)

 {
 {

-       UInt32                          mask            = 0x000000ff;
-       UInt32                          alignment       = (UInt32)((unsigned long) value8) & (sizeof(UInt32) - 1);
-       UInt32                          shiftValues = (24 << 24) | (16 << 16) | (8 << 8);
-       int                                     shift           = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
-       volatile UInt32 *       value32         = (volatile UInt32 *) ((uintptr_t)value8 - alignment);
-       UInt32                          oldValue;
-       UInt32                          newValue;
-
-       mask <<= shift;
-
-       oldValue = *value32;
-       oldValue = (oldValue & ~mask) | (oldValue8 << shift);
-       newValue = (oldValue & ~mask) | (newValue8 << shift);
-
-       return OSCompareAndSwap(oldValue, newValue, value32);
+       return os_atomic_add_orig(address, (SInt16)amount, relaxed);

 }
 
 }
 

-static Boolean OSTestAndSetClear(UInt32 bit, Boolean wantSet, volatile UInt8 * startAddress)
+#undef OSAddAtomic
+SInt32
+OSAddAtomic(SInt32 amount, volatile SInt32 *address)

 {
 {

-       UInt8           mask = 1;
-       UInt8           oldValue;
-       UInt8           wantValue;
-       
-       startAddress += (bit / 8);
-       mask <<= (7 - (bit % 8));
-       wantValue = wantSet ? mask : 0;
-       
-       do {
-               oldValue = *startAddress;
-               if ((oldValue & mask) == wantValue) {
-                       break;
-               }
-       } while (! OSCompareAndSwap8(oldValue, (oldValue & ~mask) | wantValue, startAddress));
-       
-       return (oldValue & mask) == wantValue;
+       ALIGN_TEST(address, UInt32);
+       return os_atomic_add_orig(address, amount, relaxed);

 }
 
 }
 

-Boolean OSTestAndSet(UInt32 bit, volatile UInt8 * startAddress)
+#undef OSAddAtomic64
+SInt64
+OSAddAtomic64(SInt64 amount, volatile SInt64 *address)

 {
 {

-       return OSTestAndSetClear(bit, true, startAddress);
+       _Atomic SInt64* aligned_address = (_Atomic SInt64*)(uintptr_t)address;
+
+       ALIGN_TEST(address, SInt64);
+       return os_atomic_add_orig(aligned_address, amount, relaxed);

 }
 
 }
 

-Boolean OSTestAndClear(UInt32 bit, volatile UInt8 * startAddress)
+#undef OSAddAtomicLong
+long
+OSAddAtomicLong(long theAmount, volatile long *address)

 {
 {

-       return OSTestAndSetClear(bit, false, startAddress);
+       return os_atomic_add_orig(address, theAmount, relaxed);

 }
 
 }
 

-/*
- * silly unaligned versions
- */
-
-SInt8  OSIncrementAtomic8(volatile SInt8 * value)
+#undef OSIncrementAtomic
+SInt32
+OSIncrementAtomic(volatile SInt32 * value)

 {
 {

-       return OSAddAtomic8(1, value);
+       return os_atomic_inc_orig(value, relaxed);

 }
 
 }
 

-SInt8  OSDecrementAtomic8(volatile SInt8 * value)
+#undef OSDecrementAtomic
+SInt32
+OSDecrementAtomic(volatile SInt32 * value)

 {
 {

-       return OSAddAtomic8(-1, value);
+       return os_atomic_dec_orig(value, relaxed);

 }
 
 }
 

-SInt8  OSAddAtomic8(SInt32 amount, volatile SInt8 * value)
+#undef OSBitAndAtomic
+UInt32
+OSBitAndAtomic(UInt32 mask, volatile UInt32 * value)

 {
 {

-       SInt8   oldValue;
-       SInt8   newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = oldValue + amount;
-       } while (! OSCompareAndSwap8((UInt8) oldValue, (UInt8) newValue, (volatile UInt8 *) value));
-       
-       return oldValue;
+       return os_atomic_and_orig(value, mask, relaxed);

 }
 
 }
 

-static UInt8   OSBitwiseAtomic8(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt8 * value)
+#undef OSBitOrAtomic
+UInt32
+OSBitOrAtomic(UInt32 mask, volatile UInt32 * value)

 {
 {

-       UInt8   oldValue;
-       UInt8   newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
-       } while (! OSCompareAndSwap8(oldValue, newValue, value));
-       
-       return oldValue;
+       return os_atomic_or_orig(value, mask, relaxed);

 }
 
 }
 

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

 {
 {

-       return OSBitwiseAtomic8(mask, 0, 0, value);
+       return os_atomic_xor_orig(value, mask, relaxed);

 }
 
 }
 

-UInt8  OSBitOrAtomic8(UInt32 mask, volatile UInt8 * value)
+static Boolean
+OSTestAndSetClear(UInt32 bit, Boolean wantSet, volatile UInt8 * startAddress)

 {
 {

-       return OSBitwiseAtomic8((UInt32) -1, mask, 0, value);
+       UInt8           mask = 1;
+       UInt8           oldValue, newValue;
+       UInt8           wantValue;
+       UInt8           *address;
+
+       address = (UInt8 *)(uintptr_t)(startAddress + (bit / 8));
+       mask <<= (7 - (bit % 8));
+       wantValue = wantSet ? mask : 0;
+
+       return !os_atomic_rmw_loop(address, oldValue, newValue, relaxed, {
+               if ((oldValue & mask) == wantValue) {
+                       os_atomic_rmw_loop_give_up(break);
+               }
+               newValue = (oldValue & ~mask) | wantValue;
+       });

 }
 
 }
 

-UInt8  OSBitXorAtomic8(UInt32 mask, volatile UInt8 * value)
+Boolean
+OSTestAndSet(UInt32 bit, volatile UInt8 * startAddress)

 {
 {

-       return OSBitwiseAtomic8((UInt32) -1, 0, mask, value);
+       return OSTestAndSetClear(bit, true, startAddress);

 }
 
 }
 

-static Boolean OSCompareAndSwap16(UInt16 oldValue16, UInt16 newValue16, volatile UInt16 * value16)
+Boolean
+OSTestAndClear(UInt32 bit, volatile UInt8 * startAddress)

 {
 {

-       UInt32                          mask            = 0x0000ffff;
-       UInt32                          alignment       = (UInt32)((unsigned long) value16) & (sizeof(UInt32) - 1);
-       UInt32                          shiftValues = (16 << 24) | (16 << 16);
-       UInt32                          shift           = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
-       volatile UInt32 *       value32         = (volatile UInt32 *) (((unsigned long) value16) - alignment);
-       UInt32                          oldValue;
-       UInt32                          newValue;
+       return OSTestAndSetClear(bit, false, startAddress);
+}

 
 

-       mask <<= shift;
+/*
+ * silly unaligned versions
+ */

 
 

-       oldValue = *value32;
-       oldValue = (oldValue & ~mask) | (oldValue16 << shift);
-       newValue = (oldValue & ~mask) | (newValue16 << shift);
+SInt8
+OSIncrementAtomic8(volatile SInt8 * value)
+{
+       return os_atomic_inc_orig(value, relaxed);
+}

 
 

-       return OSCompareAndSwap(oldValue, newValue, value32);
+SInt8
+OSDecrementAtomic8(volatile SInt8 * value)
+{
+       return os_atomic_dec_orig(value, relaxed);

 }
 
 }
 

-SInt16 OSIncrementAtomic16(volatile SInt16 * value)
+UInt8
+OSBitAndAtomic8(UInt32 mask, volatile UInt8 * value)

 {
 {

-       return OSAddAtomic16(1, value);
+       return os_atomic_and_orig(value, (UInt8)mask, relaxed);

 }
 
 }
 

-SInt16 OSDecrementAtomic16(volatile SInt16 * value)
+UInt8
+OSBitOrAtomic8(UInt32 mask, volatile UInt8 * value)

 {
 {

-       return OSAddAtomic16(-1, value);
+       return os_atomic_or_orig(value, (UInt8)mask, relaxed);

 }
 
 }
 

-SInt16 OSAddAtomic16(SInt32 amount, volatile SInt16 * value)
+UInt8
+OSBitXorAtomic8(UInt32 mask, volatile UInt8 * value)

 {
 {

-       SInt16  oldValue;
-       SInt16  newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = oldValue + amount;
-       } while (! OSCompareAndSwap16((UInt16) oldValue, (UInt16) newValue, (volatile UInt16 *) value));
-       
-       return oldValue;
+       return os_atomic_xor_orig(value, (UInt8)mask, relaxed);

 }
 
 }
 

-static UInt16  OSBitwiseAtomic16(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt16 * value)
+SInt16
+OSIncrementAtomic16(volatile SInt16 * value)

 {
 {

-       UInt16  oldValue;
-       UInt16  newValue;
-       
-       do {
-               oldValue = *value;
-               newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
-       } while (! OSCompareAndSwap16(oldValue, newValue, value));
-       
-       return oldValue;
+       return OSAddAtomic16(1, value);

 }
 
 }
 

-UInt16 OSBitAndAtomic16(UInt32 mask, volatile UInt16 * value)
+SInt16
+OSDecrementAtomic16(volatile SInt16 * value)

 {
 {

-       return OSBitwiseAtomic16(mask, 0, 0, value);
+       return OSAddAtomic16(-1, value);

 }
 
 }
 

-UInt16 OSBitOrAtomic16(UInt32 mask, volatile UInt16 * value)
+UInt16
+OSBitAndAtomic16(UInt32 mask, volatile UInt16 * value)

 {
 {

-       return OSBitwiseAtomic16((UInt32) -1, mask, 0, value);
+       return os_atomic_and_orig(value, (UInt16)mask, relaxed);

 }
 
 }
 

-UInt16 OSBitXorAtomic16(UInt32 mask, volatile UInt16 * value)
+UInt16
+OSBitOrAtomic16(UInt32 mask, volatile UInt16 * value)

 {
 {

-       return OSBitwiseAtomic16((UInt32) -1, 0, mask, value);
+       return os_atomic_or_orig(value, (UInt16)mask, relaxed);

 }
 
 }
 

+UInt16
+OSBitXorAtomic16(UInt32 mask, volatile UInt16 * value)
+{
+       return os_atomic_xor_orig(value, (UInt16)mask, relaxed);
+}