Add POSIX shared memory manager (Shm). Includes a hook-based
approach for the backing memory storage that defaults to the
Workspace, and a test is provided using the heap. A test is
also provided for the basic use of mmap'ing a shared memory
object. This test currently fails at the mmap stage due to
no support for mmap.
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.
Rename _Scheduler_Assignments into _Scheduler_Initial_assignments to
make it clear that they may not reflect the run-time scheduler
assignment.
Update #2797.
The priority values are only valid within a scheduler instance. Thus,
the maximum priority value must be defined per scheduler instance. The
first scheduler instance defines PRIORITY_MAXIMUM. This implies that
RTEMS_MAXIMUM_PRIORITY and POSIX_SCHEDULER_MAXIMUM_PRIORITY are only
valid for threads of the first scheduler instance. Further
API/implementation changes are necessary to fix this.
Update #2556.
Account for the terminating null character. Use _POSIX_PATH_MAX instead
of NAME_MAX according to _POSIX_Semaphore_Manager_initialization() and
_POSIX_Message_queue_Manager_initialization().
The mq_open() function returns a descriptor to a POSIX message queue
object identified by a name. This is similar to sem_open(). In
contrast to the POSIX semaphore the POSIX message queues use a separate
object for the descriptor. This extra object is superfluous, since the
object identifier can be used directly for this purpose, just like for
the semaphores.
Update #2702.
Update #2555.
We must provide thread queue heads for the thread wait information for
each thread proxy (thread queue heads were introduced by
d7665823b2). The thread proxy must be
allocated before the enqueue operation.
Notepads where a feature of RTEMS' tasks that simply functioned in
the same way as POSIX keys or threaded local storage (TLS). They were
introduced well before per task variables, which are also deprecated,
and were barely used in favor of their POSIX alternatives.
In addition to their scarce usage, Notepads took up unnecessary memory.
For each task:
- 16 32-bit integers were allocated.
- A total of 64 bytes per task per thread.
This is especially critical in low memory and safety-critical applications.
They are also defined as uint32_t, and therefore are not guaranteed to
hold a pointer.
Lastly, they are not portable solutions for SMP and uniprocessor systems,
like POSIX keys and TLS.
updates #2493.
Move the storage for the thread queue heads to the threads. Each thread
provides a set of thread queue heads allocated from a dedicated memory
pool. In case a thread blocks on a queue, then it lends its heads to
the queue. In case the thread unblocks, then it takes a free set of
threads from the queue. Since a thread can block on at most one queue
this works. This mechanism is used in FreeBSD. The motivation for this
change is to reduce the memory demands of the synchronization objects.
On a 32-bit uni-processor configuration the Thread_queue_Control size is
now 8 bytes, compared to 64 bytes in RTEMS 4.10 (other changes reduced
the size as well).
Deprecate Classic API Notepads. Mark task_set/get_note() with
the deprecated attribute, and also mark the notepads field.
Replace disable with enable option for notepads in confdefs.h,
and make notepads disabled by default. The previous option
CONFIGURE_DISABLE_CLASSIC_API_NOTEPADS is now unused and
will emit a compile-time warning. A new option
CONFIGURE_ENABLE_CLASSIC_API_NOTEPADS is available to turn
on notepads, but it also will emit a compile-time warning
to indicate that notepads are deprecated.
Closes#2265
Remove miniIMFS. Statically initialize the root IMFS.
Add configuration options to disable individual
features of the root IMFS, e.g.
o CONFIGURE_IMFS_DISABLE_CHOWN,
o CONFIGURE_IMFS_DISABLE_FCHMOD,
o CONFIGURE_IMFS_DISABLE_LINK,
o CONFIGURE_IMFS_DISABLE_MKNOD,
o CONFIGURE_IMFS_DISABLE_MOUNT,
o CONFIGURE_IMFS_DISABLE_READLINK,
o CONFIGURE_IMFS_DISABLE_RENAME,
o CONFIGURE_IMFS_DISABLE_RMNOD,
o CONFIGURE_IMFS_DISABLE_SYMLINK,
o CONFIGURE_IMFS_DISABLE_UNMOUNT, and
o CONFIGURE_IMFS_DISABLE_UTIME.
