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Diffstat (limited to 'cpukit/score/src/threaddispatchdisablelevel.c')
-rw-r--r-- | cpukit/score/src/threaddispatchdisablelevel.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/cpukit/score/src/threaddispatchdisablelevel.c b/cpukit/score/src/threaddispatchdisablelevel.c new file mode 100644 index 0000000000..f0d1cf7a61 --- /dev/null +++ b/cpukit/score/src/threaddispatchdisablelevel.c @@ -0,0 +1,133 @@ +/* + * Thread Dispatch Disable Level Methods + * + * COPYRIGHT (c) 1989-2011. + * On-Line Applications Research Corporation (OAR). + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + * + * $Id$ + */ + +#include <rtems/system.h> +#include <rtems/score/apiext.h> +#include <rtems/score/context.h> +#include <rtems/score/interr.h> +#include <rtems/score/isr.h> +#include <rtems/score/object.h> +#include <rtems/score/priority.h> +#include <rtems/score/states.h> +#include <rtems/score/sysstate.h> +#include <rtems/score/thread.h> + +void _Thread_Dispatch_initialization( void ) +{ + _Thread_Dispatch_disable_level = 0; + _SMP_lock_spinlock_nested_Initialize(&_Thread_Dispatch_disable_level_lock); + _Thread_Dispatch_set_disable_level( 1 ); +} + +bool _Thread_Dispatch_in_critical_section(void) +{ + if ( _Thread_Dispatch_disable_level == 0 ) + return false; + + return true; +} + +uint32_t _Thread_Dispatch_get_disable_level(void) +{ + return _Thread_Dispatch_disable_level; +} + +uint32_t _Thread_Dispatch_increment_disable_level(void) +{ + ISR_Level isr_level; + uint32_t level; + + /* + * Note: _SMP_lock_spinlock_nested_Obtain returns + * with ISR's disabled and the isr_level that + * should be restored after a short period. + * + * Here we obtain the lock and increment the + * Thread dispatch disable level while under the + * protection of the isr being off. After this + * point it is safe to re-enable ISRs and allow + * the dispatch disable lock to provide protection. + */ + + isr_level = _SMP_lock_spinlock_nested_Obtain( + &_Thread_Dispatch_disable_level_lock + ); + + _Thread_Dispatch_disable_level++; + level = _Thread_Dispatch_disable_level; + + _ISR_Enable(isr_level); + + return level; +} + +uint32_t _Thread_Dispatch_decrement_disable_level(void) +{ + ISR_Level isr_level; + uint32_t level; + + /* First we must disable ISRs in order to protect + * accesses to the dispatch disable level. + */ + + _ISR_Disable( isr_level ); + + _Thread_Dispatch_disable_level--; + level = _Thread_Dispatch_disable_level; + + + /* + * Note: _SMP_lock_spinlock_nested_Obtain returns with + * ISR's disabled and _SMP_lock_spinlock_nested_Release + * is responsable for re-enabling interrupts. + */ + _SMP_lock_spinlock_nested_Release( + &_Thread_Dispatch_disable_level_lock, + isr_level + ); + + return level; +} + + +/* + * Note this method is taking a heavy handed approach to + * setting the dispatch level. This may be optimized at a + * later timee, but it must be in such a way that the nesting + * level is decremented by the same number as the dispatch level. + * This approach is safest until we are sure the nested spinlock + * is successfully working with smp isr source code. + */ + +uint32_t _Thread_Dispatch_set_disable_level(uint32_t value) +{ + /* + * If we need the dispatch level to go higher + * call increment method the desired number of times. + */ + + while ( value > _Thread_Dispatch_disable_level ) { + _Thread_Dispatch_increment_disable_level(); + } + + /* + * If we need the dispatch level to go lower + * call increment method the desired number of times. + */ + + while ( value < _Thread_Dispatch_disable_level ) { + _Thread_Dispatch_decrement_disable_level(); + } + + return value; +} |