score: Add libatomic support

Close #2695.

4 files changed, 80 insertions, 212 deletions

diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index b178e8e328..fae6fc37bb 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -361,6 +361,7 @@ libscore_a_SOURCES += src/sched.c
 libscore_a_SOURCES += src/semaphore.c
 libscore_a_SOURCES += src/smpbarrierwait.c
 libscore_a_SOURCES += src/kern_tc.c
+libscore_a_SOURCES += src/libatomic.c
 
 EXTRA_DIST = src/Unlimited.txt
 
diff --git a/cpukit/score/cpu/sparc/Makefile.am b/cpukit/score/cpu/sparc/Makefile.am
index 8cf4f4a65a..edebbb6041 100644
--- a/cpukit/score/cpu/sparc/Makefile.am
+++ b/cpukit/score/cpu/sparc/Makefile.am
@@ -14,7 +14,6 @@ libscorecpu_a_SOURCES = cpu.c cpu_asm.S
 libscorecpu_a_SOURCES += sparc-context-volatile-clobber.S
 libscorecpu_a_SOURCES += sparc-context-validate.S
 libscorecpu_a_SOURCES += sparc-counter.c
-libscorecpu_a_SOURCES += sparcv8-atomic.c
 libscorecpu_a_CPPFLAGS = $(AM_CPPFLAGS)
 
 include $(srcdir)/preinstall.am
diff --git a/cpukit/score/cpu/sparc/sparcv8-atomic.c b/cpukit/score/cpu/sparc/sparcv8-atomic.c
deleted file mode 100644
index c0e4dc6653..0000000000
--- a/cpukit/score/cpu/sparc/sparcv8-atomic.c
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * Copyright (c) 2014-2015 embedded brains GmbH.  All rights reserved.
- *
- *  embedded brains GmbH
- *  Dornierstr. 4
- *  82178 Puchheim
- *  Germany
- *  <rtems@embedded-brains.de>
- *
- * The license and distribution terms for this file may be
- * found in the file LICENSE in this distribution or at
- * http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-  #include "config.h"
-#endif
-
-#include <rtems/score/cpuopts.h>
-#include <rtems/score/isrlevel.h>
-
-/*
- * This file is a dirty hack.  A proper solution would be to add RTEMS support
- * for libatomic in GCC (see also libatomic/configure.tgt).
- */
-
-#if defined(RTEMS_SMP)
-static volatile uint32_t _SPARCV8_The_one_lock;
-
-static inline uint32_t _SPARCV8_Atomic_swap(
-  volatile uint32_t *address,
-  uint32_t value
-)
-{
-  asm volatile (
-    "swap [%2], %0"
-    : "=r" (value)
-    : "0" (value), "r" (address)
-    : "memory"
-  );
-
-  return value;
-}
-#endif
-
-static ISR_Level _SPARCV8_Acquire_the_one_lock( void )
-{
-  ISR_Level level;
-
-  _ISR_Local_disable( level );
-
-#if defined(RTEMS_SMP)
-  do {
-    while ( _SPARCV8_The_one_lock ) {
-      /* Wait */
-    }
-  } while ( _SPARCV8_Atomic_swap( &_SPARCV8_The_one_lock, 1 ) );
-#endif
-
-  return level;
-}
-
-static void _SPARCV8_Release_the_one_lock( ISR_Level level )
-{
-#if defined(RTEMS_SMP)
-  _SPARCV8_The_one_lock = 0;
-#endif
-  _ISR_Local_enable( level );
-}
-
-uint8_t __atomic_exchange_1( uint8_t *mem, uint8_t val, int model )
-{
-  uint8_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-/*
- * In order to get rid of the warning "conflicting types for built-in function
- * '__atomic_compare_exchange_4' [enabled by default]", you must port libatomic
- * to SPARC/RTEMS.  The libatomic is provided by GCC.
- */
-uint32_t __atomic_exchange_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-/*
- * You get probably a warning here which can be ignored: "warning: conflicting
- * types for built-in function '__atomic_compare_exchange_4' [enabled by
- * default]"
- */
-bool __atomic_compare_exchange_4(
-  uint32_t *mem,
-  uint32_t *expected,
-  uint32_t desired,
-  int success,
-  int failure
-)
-{
-  bool equal;
-  ISR_Level level;
-  uint32_t actual;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  actual = *mem;
-  equal = ( actual == *expected );
-  if ( equal ) {
-    *mem = desired;
-  } else {
-    *expected = actual;
-  }
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return equal;
-}
-
-uint32_t __atomic_fetch_add_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = prev + val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-uint32_t __atomic_fetch_sub_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = prev - val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-uint32_t __atomic_fetch_and_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = prev & val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-uint32_t __atomic_fetch_or_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = prev | val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
-
-uint32_t __atomic_fetch_xor_4( uint32_t *mem, uint32_t val, int model )
-{
-  uint32_t prev;
-  ISR_Level level;
-
-  level = _SPARCV8_Acquire_the_one_lock();
-
-  prev = *mem;
-  *mem = prev ^ val;
-
-  _SPARCV8_Release_the_one_lock( level );
-
-  return prev;
-}
diff --git a/cpukit/score/src/libatomic.c b/cpukit/score/src/libatomic.c
new file mode 100644
index 0000000000..bfa3e6fb25
--- /dev/null
+++ b/cpukit/score/src/libatomic.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2016 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <machine/_libatomic.h>
+
+#include <rtems/score/apimutex.h>
+#include <rtems/score/atomic.h>
+#include <rtems/score/isrlevel.h>
+
+#if defined(RTEMS_SMP)
+/*
+ * For real SMP targets this is not useful.  The main purpose is support for
+ * testing on simulators like SIS.
+ */
+static Atomic_Flag _Libatomic_The_one_lock = ATOMIC_INITIALIZER_FLAG;
+#endif
+
+__uint32_t _Libatomic_Protect_start( void *ptr )
+{
+  ISR_Level isr_level;
+
+  (void) ptr;
+  _ISR_Local_disable( isr_level );
+
+#if defined(RTEMS_SMP)
+  while (
+    _Atomic_Flag_test_and_set( &_Libatomic_The_one_lock, ATOMIC_ORDER_SEQ_CST )
+  ) {
+    /* Next try.  Yes, a TAS spin lock implementation is stupid. */
+  }
+#endif
+
+  return isr_level;
+}
+
+void _Libatomic_Protect_end( void *ptr, __uint32_t isr_level )
+{
+  (void) ptr;
+
+#if defined(RTEMS_SMP)
+  _Atomic_Flag_clear( &_Libatomic_The_one_lock, ATOMIC_ORDER_SEQ_CST );
+#endif
+
+  _ISR_Local_enable( isr_level );
+}
+
+/*
+ * FIXME: The once lock should be only a temporary solution. We need a
+ * dedicated internal mutex for this.
+ */
+
+void _Libatomic_Lock_n( void *ptr, __size_t n )
+{
+  (void) ptr;
+  (void) n;
+  _Once_Lock();
+}
+
+void _Libatomic_Unlock_n( void *ptr, __size_t n )
+{
+  (void) ptr;
+  (void) n;
+  _Once_Unlock();
+}