diff options
| author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2016-06-29 09:50:47 +0200 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2016-06-29 09:50:47 +0200 |
| commit | 9bb3ce3918261c5392abbe4b65902e5d4b6dff07 (patch) | |
| tree | a0ce25f5619672f3afd222cfe79460e88858d2da /cpukit/score/include/rtems/score/smpimpl.h | |
| parent | arm/raspberrypi: resolve BSP warnings. (diff) | |
| download | rtems-9bb3ce3918261c5392abbe4b65902e5d4b6dff07.tar.bz2 | |
score: Fix SMP message handling
According to the C11 standard only atomic read-modify-write operations
guarantee that the last value written in modification order is read, see
"7.17.3 Order and consistency". Thus we must use a read-modify-write in
_SMP_Inter_processor_interrupt_handler() to make sure we read an
up-to-date message.
Diffstat (limited to '')
| -rw-r--r-- | cpukit/score/include/rtems/score/smpimpl.h | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/cpukit/score/include/rtems/score/smpimpl.h b/cpukit/score/include/rtems/score/smpimpl.h index d1b7214bbb..7f2de5ff70 100644 --- a/cpukit/score/include/rtems/score/smpimpl.h +++ b/cpukit/score/include/rtems/score/smpimpl.h @@ -167,8 +167,10 @@ void _SMP_Multicast_actions_process( void ); */ static inline long unsigned _SMP_Inter_processor_interrupt_handler( void ) { - Per_CPU_Control *cpu_self = _Per_CPU_Get(); - unsigned long message = 0; + Per_CPU_Control *cpu_self; + unsigned long message; + + cpu_self = _Per_CPU_Get(); /* * In the common case the inter-processor interrupt is issued to carry out a @@ -176,13 +178,13 @@ static inline long unsigned _SMP_Inter_processor_interrupt_handler( void ) */ cpu_self->dispatch_necessary = true; - if ( _Atomic_Load_ulong( &cpu_self->message, ATOMIC_ORDER_RELAXED ) != 0 ) { - message = _Atomic_Exchange_ulong( - &cpu_self->message, - 0UL, - ATOMIC_ORDER_RELAXED - ); + message = _Atomic_Exchange_ulong( + &cpu_self->message, + 0, + ATOMIC_ORDER_ACQUIRE + ); + if ( message != 0 ) { if ( ( message & SMP_MESSAGE_SHUTDOWN ) != 0 ) { _SMP_Fatal( SMP_FATAL_SHUTDOWN_RESPONSE ); /* does not continue past here */ |