Add a new low-level device API to Termios that passes the TTY structure
to the low-level device functions. This greatly simplifies the
low-level device drivers since they are no longer forced to derive their
private data from the minor number.
It makes it possible to use the TTY low-level lock in the device driver
low-level functions which is necessary for proper SMP support. For
example to set the attributes it is often necessary to perform a
read-modify-write operation on a control register used also by interrupt
routines.
A compatibility layer is provided to support device drivers using the
old callback functions so it is not necessary to modify existing device
drivers.
The thread control block contains fields that point to application
configuration dependent memory areas, like the scheduler information,
the API control blocks, the user extension context table, the RTEMS
notepads and the Newlib re-entrancy support. Account for these areas in
the configuration and avoid extra workspace allocations for these areas.
This helps also to avoid heap fragementation and reduces the per thread
memory due to a reduced heap allocation overhead.
The thread deletion is now supported on SMP.
This change fixes the following PRs:
PR1814: SMP race condition between stack free and dispatch
PR2035: psxcancel reveals NULL pointer access in _Thread_queue_Extract()
The POSIX cleanup handler are now called in the right context (should be
called in the context of the terminating thread).
http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_09.html
Add a user extension the reflects a thread termination event. This is
used to reclaim the Newlib reentrancy structure (may use file
operations), the POSIX cleanup handlers and the POSIX key destructors.
Add a local context structure to the SMP lock API for acquire and
release pairs. This context can be used to store the ISR level and
profiling information. It may be later used to enable more
sophisticated lock algorithms, e.g. MCS locks.
There is only one lock that cannot be used with a local context. This
is the per-CPU lock since here we would have to transfer the local
context through a context switch which is very complicated.
Rename rtems_internal_error_description() to
rtems_internal_error_text(). Rename rtems_fatal_source_description() to
rtems_fatal_source_text(). Rename rtems_status_code_description() to
rtems_status_text(). Remove previous implementation of
rtems_status_text().
Renames rtems_deviceio_errno to rtems_status_code_to_errno and
integrates it into the Classic API Status Handler. This function
can now be called by including status.h
The readv() and writev() support was implemented in terms of multiple
calls to the read and write handlers. This imposes a problem on device
files which use an IO vector as single request entity. For example a
low-level network device (e.g. BPF(4)) may use an IO vector to create
one frame from multiple protocol layers each with its own IO vector
entry.
