This enables per-object SMP locks on SMP configurations and is the first
step to support fine-grained locking. On uni-processor configuration
there will be no overhead. The _Objects_Acquire() is intended to
replace _Objects_Get_isr_disable().
Update #2273.
The _Thread_Dispatch() function is quite complex and the time to set up
and tear down the stack frame is significant. Split this function into
two parts. The complex part is now in _Thread_Do_dispatch(). Call
_Thread_Do_dispatch() in _Thread_Enable_dispatch() only if necessary.
This increases the average case performance.
Simplify _Thread_Handler() for SMP configurations.
Update #2273.
Previously, the _Thread_Heir was updated unconditionally in case a new
heir was determined. The _Thread_Dispatch_necessary was only updated in
case the executing thread was preemptible or an internal thread was
unblocked. Change this to update the _Thread_Heir and
_Thread_Dispatch_necessary only in case the currently selected heir
thread is preemptible or a dispatch is forced. Move the schedule
decision into the change priority operation and use the schedule
operation only in rtems_task_mode() in case preemption is enabled or an
ASR dispatch is necessary. This is a behaviour change. Previously, the
RTEMS_NO_PREEMPT also prevented signal delivery in certain cases (not
always). Now, signal delivery is no longer influenced by
RTEMS_NO_PREEMPT. Since the currently selected heir thread is used to
determine if a new heir is chosen, non-preemptible heir threads
currently not executing now prevent a new heir. This may have an
application impact, see change test tm04. Document this change in sp04.
Update #2273.
Empty structures are implementation-defined in C. GCC gives them a size
of zero. In C++ empty structures have a non-zero size.
Add ISR_LOCK_DEFINE() to define ISR locks for structures used by C and
C++.
Update #2273.
This patch adds the macro BSP_START_NEEDS_REGISTER_INITIALIZATION and
three hooks for BSP-specific register init code to arm/shared/start.S.
Said hooks are bsp_start_init_registers_core (intended for initializing
the ARM core registers), bsp_start_init_registers_banked_fiq (for the
FIQ mode banked registers) and bsp_start_init_registers_vfp (for the FPU
registers). BSP_START_NEEDS_REGISTER_INITIALIZATION would be defined in
a BSP's configure.ac (so that it appears in its bspopts.h).
This patch also adds the register init code required by the TMS570.
We've tested it with the tms570ls3137_hdk.cfg config and it works fine.
In _ARMV4_Exception_fiq_default, set the F bit of the SPSR so that when
it gets loaded back to the CPSR in save_more_context it won't re-enable
the FIQs.
Tested on a TMS570LS3137.
pthread_mutex_trylock() should return EBUSY if the mutex is already
locked. The translations of CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED is
EDEADLK which is correct for pthread_mutex_lock(). This fixes the
translation for trylock.
Closes#2170.
