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Diffstat (limited to 'cpukit/score/include/rtems/score/coremuteximpl.h')
-rw-r--r-- | cpukit/score/include/rtems/score/coremuteximpl.h | 531 |
1 files changed, 531 insertions, 0 deletions
diff --git a/cpukit/score/include/rtems/score/coremuteximpl.h b/cpukit/score/include/rtems/score/coremuteximpl.h new file mode 100644 index 0000000000..69be9ac393 --- /dev/null +++ b/cpukit/score/include/rtems/score/coremuteximpl.h @@ -0,0 +1,531 @@ +/** + * @file + * + * @ingroup ScoreMutex + * + * @brief CORE Mutex Implementation + */ + +/* + * COPYRIGHT (c) 1989-2009. + * 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. + */ + +#ifndef _RTEMS_SCORE_COREMUTEXIMPL_H +#define _RTEMS_SCORE_COREMUTEXIMPL_H + +#include <rtems/score/coremutex.h> +#include <rtems/score/threaddispatch.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @addtogroup ScoreMutex + */ +/**@{**/ + +/** + * @brief Callout which provides to support global/multiprocessor operations. + * + * The following type defines the callout which the API provides + * to support global/multiprocessor operations on mutexes. + */ +typedef void ( *CORE_mutex_API_mp_support_callout )( + Thread_Control *, + Objects_Id + ); + +/** + * @brief The possible Mutex handler return statuses. + * + * This enumerated type defines the possible Mutex handler return statuses. + */ +typedef enum { + /** This status indicates that the operation completed successfully. */ + CORE_MUTEX_STATUS_SUCCESSFUL, + /** This status indicates that the calling task did not want to block + * and the operation was unable to complete immediately because the + * resource was unavailable. + */ + CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT, +#if defined(RTEMS_POSIX_API) + /** This status indicates that an attempt was made to relock a mutex + * for which nesting is not configured. + */ + CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED, +#endif + /** This status indicates that an attempt was made to release a mutex + * by a thread other than the thread which locked it. + */ + CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE, + /** This status indicates that the thread was blocked waiting for an + * operation to complete and the mutex was deleted. + */ + CORE_MUTEX_WAS_DELETED, + /** This status indicates that the calling task was willing to block + * but the operation was unable to complete within the time allotted + * because the resource never became available. + */ + CORE_MUTEX_TIMEOUT, + +#if defined(__RTEMS_STRICT_ORDER_MUTEX__) + /** This status indicates that a thread not release the mutex which has + * the priority inheritance property in a right order. + */ + CORE_MUTEX_RELEASE_NOT_ORDER, +#endif + + /** This status indicates that a thread of logically greater importance + * than the ceiling priority attempted to lock this mutex. + */ + CORE_MUTEX_STATUS_CEILING_VIOLATED + +} CORE_mutex_Status; + +/** + * @brief The last status value. + * + * This is the last status value. + */ +#define CORE_MUTEX_STATUS_LAST CORE_MUTEX_STATUS_CEILING_VIOLATED + +/** + * This is the value of a mutex when it is unlocked. + */ +#define CORE_MUTEX_UNLOCKED 1 + +/** + * This is the value of a mutex when it is locked. + */ +#define CORE_MUTEX_LOCKED 0 + +/** + * @brief Initializes the mutex based on the parameters passed. + * + * This routine initializes the mutex based on the parameters passed. + * + * @param[in] the_mutex is the mutex to initalize + * @param[in] the_mutex_attributes is the attributes associated with this + * mutex instance + * @param[in] initial_lock is the initial value of the mutex + * + * @retval This method returns CORE_MUTEX_STATUS_SUCCESSFUL if successful. + */ +CORE_mutex_Status _CORE_mutex_Initialize( + CORE_mutex_Control *the_mutex, + CORE_mutex_Attributes *the_mutex_attributes, + uint32_t initial_lock +); + +/** + * @brief Attempt to receive a unit from the_mutex. + * + * This routine attempts to receive a unit from the_mutex. + * If a unit is available or if the wait flag is false, then the routine + * returns. Otherwise, the calling task is blocked until a unit becomes + * available. + * + * @param[in] the_mutex is the mutex to attempt to lock + * @param[in] level is the interrupt level + * + * @retval This routine returns 0 if "trylock" can resolve whether or not + * the mutex is immediately obtained or there was an error attempting to + * get it. It returns 1 to indicate that the caller cannot obtain + * the mutex and will have to block to do so. + * + * @note For performance reasons, this routine is implemented as + * a macro that uses two support routines. + */ + +RTEMS_INLINE_ROUTINE int _CORE_mutex_Seize_interrupt_trylock_body( + CORE_mutex_Control *the_mutex, + ISR_Level level +); + +#if defined(__RTEMS_DO_NOT_INLINE_CORE_MUTEX_SEIZE__) + /** + * @brief Interrupt trylock CORE mutex seize. + * + * When doing test coverage analysis or trying to minimize the code + * space for RTEMS, it is often helpful to not inline this method + * multiple times. It is fairly large and has a high branch complexity + * which makes it harder to get full binary test coverage. + * + * @param[in] the_mutex will attempt to lock + * @param[in] level_p is the interrupt level + */ + int _CORE_mutex_Seize_interrupt_trylock( + CORE_mutex_Control *the_mutex, + ISR_Level level + ); +#else + /** + * The default is to favor speed and inlining this definitely saves + * a few instructions. This is very important for mutex performance. + * + * @param[in] _mutex will attempt to lock + * @param[in] _level is the interrupt level + */ + #define _CORE_mutex_Seize_interrupt_trylock( _mutex, _level ) \ + _CORE_mutex_Seize_interrupt_trylock_body( _mutex, _level ) +#endif + +/** + * @brief Performs the blocking portion of a mutex obtain. + * + * This routine performs the blocking portion of a mutex obtain. + * It is an actual subroutine and is not implemented as something + * that may be inlined. + * + * @param[in] the_mutex is the mutex to attempt to lock + * @param[in] timeout is the maximum number of ticks to block + */ +void _CORE_mutex_Seize_interrupt_blocking( + CORE_mutex_Control *the_mutex, + Watchdog_Interval timeout +); +/** + * @brief Verifies that a mutex blocking seize is performed safely. + * + * This macro is to verify that a mutex blocking seize is + * performed from a safe system state. For example, one + * cannot block inside an isr. + * + * @retval this method returns true if dispatch is in an unsafe state. + */ +#ifdef RTEMS_SMP + #define _CORE_mutex_Check_dispatch_for_seize(_wait) 0 +#else + #define _CORE_mutex_Check_dispatch_for_seize(_wait) \ + (!_Thread_Dispatch_is_enabled() \ + && (_wait) \ + && (_System_state_Get() >= SYSTEM_STATE_BEGIN_MULTITASKING)) +#endif + +/** + * @brief Attempt to obtain the mutex. + * + * This routine attempts to obtain the mutex. If the mutex is available, + * then it will return immediately. Otherwise, it will invoke the + * support routine @a _Core_mutex_Seize_interrupt_blocking. + * + * @param[in] _the_mutex is the mutex to attempt to lock + * @param[in] _id is the Id of the owning API level Semaphore object + * @param[in] _wait is true if the thread is willing to wait + * @param[in] _timeout is the maximum number of ticks to block + * @param[in] _level is a temporary variable used to contain the ISR + * disable level cookie + * + * @note If the mutex is called from an interrupt service routine, + * with context switching disabled, or before multitasking, + * then a fatal error is generated. + * + * The logic on this routine is as follows: + * + * * If incorrect system state + * return an error + * * If mutex is available without any contention or blocking + * obtain it with interrupts disabled and returned + * * If the caller is willing to wait + * then they are blocked. + */ +#define _CORE_mutex_Seize_body( \ + _the_mutex, _id, _wait, _timeout, _level ) \ + do { \ + if ( _CORE_mutex_Check_dispatch_for_seize(_wait) ) { \ + _Internal_error_Occurred( \ + INTERNAL_ERROR_CORE, \ + false, \ + INTERNAL_ERROR_MUTEX_OBTAIN_FROM_BAD_STATE \ + ); \ + } \ + if ( _CORE_mutex_Seize_interrupt_trylock( _the_mutex, _level ) ) { \ + if ( !(_wait) ) { \ + _ISR_Enable( _level ); \ + _Thread_Executing->Wait.return_code = \ + CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT; \ + } else { \ + _Thread_queue_Enter_critical_section( &(_the_mutex)->Wait_queue ); \ + _Thread_Executing->Wait.queue = &(_the_mutex)->Wait_queue; \ + _Thread_Executing->Wait.id = _id; \ + _Thread_Disable_dispatch(); \ + _ISR_Enable( _level ); \ + _CORE_mutex_Seize_interrupt_blocking( _the_mutex, _timeout ); \ + } \ + } \ + } while (0) + +/** + * This method is used to obtain a core mutex. + * + * @param[in] _the_mutex is the mutex to attempt to lock + * @param[in] _id is the Id of the owning API level Semaphore object + * @param[in] _wait is true if the thread is willing to wait + * @param[in] _timeout is the maximum number of ticks to block + * @param[in] _level is a temporary variable used to contain the ISR + * disable level cookie + */ +#if defined(__RTEMS_DO_NOT_INLINE_CORE_MUTEX_SEIZE__) + void _CORE_mutex_Seize( + CORE_mutex_Control *_the_mutex, + Objects_Id _id, + bool _wait, + Watchdog_Interval _timeout, + ISR_Level _level + ); +#else + #define _CORE_mutex_Seize( _the_mutex, _id, _wait, _timeout, _level ) \ + _CORE_mutex_Seize_body( _the_mutex, _id, _wait, _timeout, _level ) +#endif + +/** + * @brief Frees a unit to the mutex. + * + * This routine frees a unit to the mutex. If a task was blocked waiting for + * a unit from this mutex, then that task will be readied and the unit + * given to that task. Otherwise, the unit will be returned to the mutex. + * + * @param[in] the_mutex is the mutex to surrender + * @param[in] id is the id of the RTEMS Object associated with this mutex + * @param[in] api_mutex_mp_support is the routine that will be called when + * unblocking a remote mutex + * + * @retval an indication of whether the routine succeeded or failed + */ +CORE_mutex_Status _CORE_mutex_Surrender( + CORE_mutex_Control *the_mutex, + Objects_Id id, + CORE_mutex_API_mp_support_callout api_mutex_mp_support +); + +/** + * @brief Flush all waiting threads. + * + * This routine assists in the deletion of a mutex by flushing the associated + * wait queue. + * + * @param[in] the_mutex is the mutex to flush + * @param[in] remote_extract_callout is the routine to invoke when a remote + * thread is extracted + * @param[in] status is the status value which each unblocked thread will + * return to its caller. + */ +void _CORE_mutex_Flush( + CORE_mutex_Control *the_mutex, + Thread_queue_Flush_callout remote_extract_callout, + uint32_t status +); + +/** + * @brief Is mutex locked. + * + * This routine returns true if the mutex specified is locked and false + * otherwise. + * + * @param[in] the_mutex is the mutex to check. + * + * @retval true The mutex is locked. + * @retval false The mutex is not locked. + */ +RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_locked( + CORE_mutex_Control *the_mutex +) +{ + return the_mutex->lock == CORE_MUTEX_LOCKED; +} + +/** + * @brief Does core mutex use FIFO blocking. + * + * This routine returns true if the mutex's wait discipline is FIFO and false + * otherwise. + * + * @param[in] the_attribute is the attribute set of the mutex. + * + * @retval true The mutex is using FIFO blocking order. + * @retval false The mutex is not using FIFO blocking order. + */ +RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_fifo( + CORE_mutex_Attributes *the_attribute +) +{ + return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_FIFO; +} + +/** + * @brief Doex core mutex use priority blocking. + * + * This routine returns true if the mutex's wait discipline is PRIORITY and + * false otherwise. + * + * @param[in] the_attribute is the attribute set of the mutex. + * + * @retval true The mutex is using priority blocking order. + * @retval false The mutex is not using priority blocking order. + * + */ +RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_priority( + CORE_mutex_Attributes *the_attribute +) +{ + return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY; +} + +/** + * @brief Does mutex use priority inheritance. + * + * This routine returns true if the mutex's wait discipline is + * INHERIT_PRIORITY and false otherwise. + * + * @param[in] the_attribute is the attribute set of the mutex. + * + * @retval true The mutex is using priority inheritance. + * @retval false The mutex is not using priority inheritance. + */ +RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_inherit_priority( + CORE_mutex_Attributes *the_attribute +) +{ + return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT; +} + +/** + * @brief Does mutex use priority ceiling. + * + * This routine returns true if the mutex's wait discipline is + * PRIORITY_CEILING and false otherwise. + * + * @param[in] the_attribute is the attribute set of the mutex. + * + * @retval true The mutex is using priority ceiling. + * @retval false The mutex is not using priority ceiling. + */ +RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_priority_ceiling( + CORE_mutex_Attributes *the_attribute +) +{ + return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING; +} + +/* + * Seize Mutex with Quick Success Path + * + * NOTE: There is no MACRO version of this routine. A body is in + * coremutexseize.c that is duplicated from the .inl by hand. + * + * NOTE: The Doxygen for this routine is in the .h file. + */ + +RTEMS_INLINE_ROUTINE int _CORE_mutex_Seize_interrupt_trylock_body( + CORE_mutex_Control *the_mutex, + ISR_Level level +) +{ + Thread_Control *executing; + + /* disabled when you get here */ + + executing = _Thread_Executing; + executing->Wait.return_code = CORE_MUTEX_STATUS_SUCCESSFUL; + if ( !_CORE_mutex_Is_locked( the_mutex ) ) { + the_mutex->lock = CORE_MUTEX_LOCKED; + the_mutex->holder = executing; + the_mutex->holder_id = executing->Object.id; + the_mutex->nest_count = 1; + if ( _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) || + _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ){ + +#ifdef __RTEMS_STRICT_ORDER_MUTEX__ + _Chain_Prepend_unprotected( &executing->lock_mutex, + &the_mutex->queue.lock_queue ); + the_mutex->queue.priority_before = executing->current_priority; +#endif + + executing->resource_count++; + } + + if ( !_CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ) { + _ISR_Enable( level ); + return 0; + } /* else must be CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING + * + * we possibly bump the priority of the current holder -- which + * happens to be _Thread_Executing. + */ + { + Priority_Control ceiling; + Priority_Control current; + + ceiling = the_mutex->Attributes.priority_ceiling; + current = executing->current_priority; + if ( current == ceiling ) { + _ISR_Enable( level ); + return 0; + } + + if ( current > ceiling ) { + _Thread_Disable_dispatch(); + _ISR_Enable( level ); + _Thread_Change_priority( + the_mutex->holder, + the_mutex->Attributes.priority_ceiling, + false + ); + _Thread_Enable_dispatch(); + return 0; + } + /* if ( current < ceiling ) */ { + executing->Wait.return_code = CORE_MUTEX_STATUS_CEILING_VIOLATED; + the_mutex->lock = CORE_MUTEX_UNLOCKED; + the_mutex->nest_count = 0; /* undo locking above */ + executing->resource_count--; /* undo locking above */ + _ISR_Enable( level ); + return 0; + } + } + return 0; + } + + /* + * At this point, we know the mutex was not available. If this thread + * is the thread that has locked the mutex, let's see if we are allowed + * to nest access. + */ + if ( _Thread_Is_executing( the_mutex->holder ) ) { + switch ( the_mutex->Attributes.lock_nesting_behavior ) { + case CORE_MUTEX_NESTING_ACQUIRES: + the_mutex->nest_count++; + _ISR_Enable( level ); + return 0; + #if defined(RTEMS_POSIX_API) + case CORE_MUTEX_NESTING_IS_ERROR: + executing->Wait.return_code = CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED; + _ISR_Enable( level ); + return 0; + #endif + case CORE_MUTEX_NESTING_BLOCKS: + break; + } + } + + /* + * The mutex is not available and the caller must deal with the possibility + * of blocking. + */ + return 1; +} + +/** @} */ + +#ifdef __cplusplus +} +#endif + +#endif +/* end of include file */ |