Remove rtems_current_shell_env as this is dangerous because
the env can be NULL if used outside of a valid shell with the
POSIX key to an env set up.
Clean up the usage of rtems_current_shell_env.
Rename _Scheduler_Update() to _Scheduler_Update_priority(). Add
parameter for the new thread priority to avoid direct usage of
Thread_Control::current_priority in the scheduler operation.
Replace _Scheduler_Allocate() with _Scheduler_Node_initialize(). Remove
the return status and thus the node initialization must be always
successful.
Rename _Scheduler_Free() to _Scheduler_Node_destroy().
Guest systems in paravirtualization environments run usually in user
mode. Thus it is not possible to directly access the PSR and TBR
registers. Use functions instead of inline assembler to access these
registers if RTEMS_PARAVIRT is defined.
A resource is something that has at most one owner at a time and may
have multiple rivals in case an owner is present. The owner and rivals
are impersonated via resource nodes. A resource is represented via the
resource control structure. The resource controls and nodes are
organized as trees. It is possible to detect deadlocks via such a
resource tree. The _Resource_Iterate() function can be used to iterate
through such a resource tree starting at a top node.
Use the PTHREAD mutexes and condition variables if available. This
helps on SMP configurations to avoid the home grown condition variables
via disabled preemption.
Enabling and disabling preemption as done for single core will not work
for SMP. In the bdbuf initialization preemption handling can be avoided
in general by using pthread_once().
- rtems/score/assert.h: Scheduler Simulator uses glibc assert.h on GNU/Linux.
This will likely need to be adjusted more for other host compilers and
C libraries. Also disable _Assert_Not_reached() because some of these
paths do actually return to the called on the Scheduler Simulator.
- basedefs.h: Do not use noreturn attribute when on Scheduler Simulator.
Paths which context switch can return to the command interpreter on
the Scheduler Simulator.
The last optimization missed was incorrect in regards to
PSR write instruction delay must be 3 instructions.
New optimizations:
* align to 32-byte cache line.
* rearrange code into three "blocks" of 4 instructions that
is executed by syscall 2 and 3. This is to optimize for
16/32 byte cache lines.
* use delay-slot instruction in trap table to reduce by one
instruction.
* use the fact that "wr %PSR" implements XOR to reduce by
one instruction.
The following BSPs do not have tick support so the tests fail:
arm1136jfs
arm1136js
arm7tdmi
arm920
armcortexa9 (does not run any more)
avrtest
h8sim
h8sxsim
m32csim
m32rsim
moxiesim
simsh1
simsh2
simsh4
v850e1sim
v850e2sim
v850e2v3sim
v850esim
v850essim
v850sim
This list was provided by Joel in the following post:
http://www.rtems.org/pipermail/rtems-devel/2014-April/006526.html
BSPs for simulators which do not include a clock tick interrupt source
are incapable of running some tests successfully. This is a common
characteristic of some BSPs and a fixed set of tests. There is no point
in duplicating this list of tests in those BSPs test configuration.
Read testsuites/testdata/require-tick-isr.tcfg for details.
Add basic support for the Multiprocessor Resource Sharing Protocol
(MrsP).
The Multiprocessor Resource Sharing Protocol (MrsP) is defined in A.
Burns and A.J. Wellings, A Schedulability Compatible Multiprocessor
Resource Sharing Protocol - MrsP, Proceedings of the 25th Euromicro
Conference on Real-Time Systems (ECRTS 2013), July 2013. It is a
generalization of the Priority Ceiling Protocol to SMP systems. Each
MrsP semaphore uses a ceiling priority per scheduler instance. These
ceiling priorities can be specified with rtems_semaphore_set_priority().
A task obtaining or owning a MrsP semaphore will execute with the
ceiling priority for its scheduler instance as specified by the MrsP
semaphore object. Tasks waiting to get ownership of a MrsP semaphore
will not relinquish the processor voluntarily. In case the owner of a
MrsP semaphore gets preempted it can ask all tasks waiting for this
semaphore to help out and temporarily borrow the right to execute on one
of their assigned processors.
The help out feature is not implemented with this patch.
Switch to the standard ARM startup code. This requires adding the
standard interrupt code. The interrupt code does nothing at this
point in time. I do not know if the ARM simulator in GDB supports
interrupts.
Do not use the Per_CPU_Control::started in
_SMP_Start_multitasking_on_secondary_processor() since this field may be
not up to date when a secondary processor reads it. Use the read-only
scheduler assignment instead.
Add a new fatal error SMP_FATAL_MULTITASKING_START_ON_INVALID_PROCESSOR.
This prevents out-of-bounds access.
It is currently not possible to test these fatal errors. One option
would be to fake values of the _CPU_SMP_Get_current_processor(), but
unfortunately this function is inline on some architectures.
The syscall functions overlapped with RTEMS, for example _write, _read, etc.
Change these to be internal to the BSP and avoid any clash with names in
RTEMS. Add support for SWI_Write0.
Change the console driver to use SWI_Write0. This outputs the character
to the host's stdout. Writing to file name 0 is not captured and managed
by GDB's simulation code while the SWI_Write0 is. The managed stdout
data is encapulated in the MI protocol while writes to file handle 0 are
dropped by GDB when in MI mode.
This is a shell script that lists the BSPs in the source tree by
architecture. The BSP name is given plus the relative path to
BSP source files.
The script uses the same hack, ie looking for *.cfg files, as the
build system so it sees what the build system sees.
