All CPU ports used the same _CPU_Counter_difference() implementation. Remove
this CPU port interface and mandate a monotonically increasing CPU counter.
Close#3456.
At some point during system initialization, the idle threads are created.
Afterwards, the boot processor basically executes within the context of an idle
thread with thread dispatching disabled. On some architectures, the
thread-local storage area of the associated thread must be set in dedicated
processor registers. Add the new CPU port function to do this:
void _CPU_Use_thread_local_storage( const Context_Control *context )
Close#4672.
Add MicroBlaze support for libdebugger. This uses only software break
type instructions to provide self-hosted GDB debugging support for
applications since internal control of debug hardware is not possible.
Also of note, this implementation for MicroBlaze would typically use the
brki instruction for software break, but instead uses an illegal opcode
to manage software breaks as exceptions. This is due to poor interaction
with the debug hardware where the debug hardware will intercept software
breaks instead of allowing the software break vector to execute.
Exception handling should be enabled at all times during execution to
ensure that exceptions are not ignored which would cause further
problems. This separates use of the exception enable bit from use of the
interrupt enable bit in the machine status register so that they can be
manipulated independently.
This patch adds a vector for debug events along with a hook similar to
the exception framework. The debug vector generates an exception frame
for use by libdebugger.
This patch updates the CPU_Exception_frame to include all necessary
registers, combines hardware snd software exception handlers into a
shared vector, provides an architecture-specific hook for taking
control of exception handling, and moves exception handling over to
actually using the CPU_Exception_frame instead of a minimal interrupt
stack frame. As the significant contents of _exception_handler.S have
been entirely rewritten, the copyright information on this file has been
updated to reflect that.
