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.

1 files changed, 0 insertions, 6 deletions

diff --git a/cpukit/posix/include/rtems/posix/config.h b/cpukit/posix/include/rtems/posix/config.h
index 636f1e7d79..11c73c2b2f 100644
--- a/cpukit/posix/include/rtems/posix/config.h
+++ b/cpukit/posix/include/rtems/posix/config.h
@@ -111,12 +111,6 @@ typedef struct {
   uint32_t                            maximum_rwlocks;
 
   /**
-   * This field contains the maximum number of POSIX API
-   * spinlocks which are configured for this application.
-   */
-  uint32_t                            maximum_spinlocks;
-
-  /**
    * This field contains the number of POSIX API Initialization
    * threads listed in @a User_initialization_thread_table.
    */