Add ISR lock to chain control for proper SMP protection. Replace
rtems_chain_extract() with rtems_chain_explicit_extract() and
rtems_chain_insert() with rtems_chain_explicit_insert() on SMP
configurations. Use rtems_chain_explicit_extract() and
rtems_chain_explicit_insert() to provide SMP support.
Use a per-CPU thread dispatch disable level. So instead of one global
thread dispatch disable level we have now one instance per processor.
This is a major performance improvement for SMP. On non-SMP
configurations this may simplifiy the interrupt entry/exit code.
The giant lock is still present, but it is now decoupled from the thread
dispatching in _Thread_Dispatch(), _Thread_Handler(),
_Thread_Restart_self() and the interrupt entry/exit. Access to the
giant lock is now available via _Giant_Acquire() and _Giant_Release().
The giant lock is still implicitly acquired via
_Thread_Dispatch_decrement_disable_level().
The giant lock is only acquired for high-level operations in interrupt
handlers (e.g. release of a semaphore, sending of an event).
As a side-effect this change fixes the lost thread dispatch necessary
indication bug in _Thread_Dispatch().
A per-CPU thread dispatch disable level greatly simplifies the SMP
support for the interrupt entry/exit code since no spin locks have to be
acquired in this area. It is only necessary to get the current
processor index and use this to calculate the address of the own per-CPU
control. This reduces the interrupt latency considerably.
All elements for the interrupt entry/exit code are now part of the
Per_CPU_Control structure: thread dispatch disable level, ISR nest level
and thread dispatch necessary. Nothing else is required (except CPU
port specific stuff like on SPARC).
The original version is missing void and result is that (*x >> 16) is
optimized to ldh rX,[rY]. But it is not allowed/supported to access
bus/address range used by AITC by other than 32 bit wide accesses
and 16-bit access results in the data abort exception.
The corrected version works on real hardware and is even
more readable.
Signed-off-by: Pavel Pisa <ppisa@pikron.com>
This field is unused except for special case simulator clock drivers.
In these places use an alternative. Add and use
_Thread_Set_global_exit_status() and _Thread_Get_global_exit_status().
This commit deletes all RTEMS ChangeLog files. These files have been abandoned
since converting to git version control. The historical data may be recovered
by checking out any commit before this one. Most of the contents of these
ChangeLog files can also be found in the git log.
Two external ChangeLog files, ChangeLog.slac and ChangeLog.zlib, remain.
