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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2016-11-16 14:50:09 +0100 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2016-11-23 12:52:06 +0100 |
commit | c42be504c92d76d2e06d0fc8ebd05fc913376d2d (patch) | |
tree | 259f8a712a6139f427888647955bc3c95480877e /cpukit/score/src/corespinlockwait.c | |
parent | score: Add RTEMS_ALIAS() (diff) | |
download | rtems-c42be504c92d76d2e06d0fc8ebd05fc913376d2d.tar.bz2 |
posix: Add self-contained pthread spinlock
Turn pthread_spinlock_t into a self-contained object. On uni-processor
configurations, interrupts are disabled in the lock/trylock operations
and the previous interrupt status is restored in the corresponding
unlock operations. On SMP configurations, a ticket lock is a acquired
and released in addition.
The self-contained pthread_spinlock_t object is defined by Newlib in
<sys/_pthreadtypes.h>.
typedef struct {
struct _Ticket_lock_Control _lock;
__uint32_t _interrupt_state;
} pthread_spinlock_t;
This implementation is simple and efficient. However, this test case of
the Linux Test Project would fail due to call of printf() and sleep()
during spin lock ownership:
https://github.com/linux-test-project/ltp/blob/master/testcases/open_posix_testsuite/conformance/interfaces/pthread_spin_lock/1-2.c
There is only limited support for profiling on SMP configurations.
Delete CORE spinlock implementation.
Update #2674.
Diffstat (limited to '')
-rw-r--r-- | cpukit/score/src/corespinlockwait.c | 102 |
1 files changed, 0 insertions, 102 deletions
diff --git a/cpukit/score/src/corespinlockwait.c b/cpukit/score/src/corespinlockwait.c deleted file mode 100644 index 4aacb60b74..0000000000 --- a/cpukit/score/src/corespinlockwait.c +++ /dev/null @@ -1,102 +0,0 @@ -/* - * @file - * - * @brief Wait for Spinlock - * @ingroup ScoreSpinlock - */ - -/* - * 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.org/license/LICENSE. - */ - -#if HAVE_CONFIG_H -#include "config.h" -#endif - -#include <rtems/score/corespinlockimpl.h> -#include <rtems/score/percpu.h> - -Status_Control _CORE_spinlock_Seize( - CORE_spinlock_Control *the_spinlock, - bool wait, - Watchdog_Interval timeout, - ISR_lock_Context *lock_context -) -{ - Thread_Control *executing; - - #if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API) - Watchdog_Interval limit = _Watchdog_Ticks_since_boot + timeout; - #endif - - executing = _Thread_Executing; - - _CORE_spinlock_Acquire_critical( the_spinlock, lock_context ); - if ( the_spinlock->lock == CORE_SPINLOCK_LOCKED && - the_spinlock->holder == executing ) { - _CORE_spinlock_Release( the_spinlock, lock_context ); - return STATUS_NESTING_NOT_ALLOWED; - } - the_spinlock->users += 1; - for ( ;; ) { - if ( the_spinlock->lock == CORE_SPINLOCK_UNLOCKED ) { - the_spinlock->lock = CORE_SPINLOCK_LOCKED; - the_spinlock->holder = executing; - _CORE_spinlock_Release( the_spinlock, lock_context ); - return STATUS_SUCCESSFUL; - } - - /* - * Spinlock is unavailable. If not willing to wait, return. - */ - if ( !wait ) { - the_spinlock->users -= 1; - _CORE_spinlock_Release( the_spinlock, lock_context ); - return STATUS_UNAVAILABLE; - } - - #if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API) - /* - * They are willing to wait but there could be a timeout. - */ - if ( timeout && (limit <= _Watchdog_Ticks_since_boot) ) { - the_spinlock->users -= 1; - _CORE_spinlock_Release( the_spinlock, lock_context ); - return STATUS_TIMEOUT; - } - #endif - - /* - * The thread is willing to spin so let's set things up so - * another thread has a chance of running. This spinlock has - * to be released by either another thread or an ISR. Since - * POSIX does not say anything about ISRs, that implies that - * another thread must be able to run while spinning. We are - * not blocking so that implies we are at least preemptible - * and possibly time-sliced. - * - * So first, we will enable interrpts to allow for them to happen. - * Then we will "flash" the thread dispatching critical section - * so other threads have a chance to run. - * - * A spinlock cannot be deleted while it is being used so we are - * safe from deletion. - */ - - _CORE_spinlock_Release( the_spinlock, lock_context ); - - /* - * An ISR could occur here. Another thread could get dispatched here. - * Reenter the critical sections so we can attempt the lock again. - */ - - _ISR_lock_ISR_disable( lock_context ); - _CORE_spinlock_Acquire_critical( the_spinlock, lock_context ); - } - -} |