Hi Denis,
On 25.08.2016 15:45, Denis Huber wrote:
Is it possible to aquire the thread's registers through simply reading them in the UTCB which is pointed by Thread_state::utcb? If yes, what is the layout of the UTCB in the memory? Or do I also have to pause the thread to find relevant registers?
the thread's registers can be read from the UTCB in userland if the kernel saved them there. On Fiasco.OC, this currently only happens when an exception occurs ('Thread::exception()' in thread-ipc.cpp links '_utcb_handler' to the trap state, which is then copied into the UTCB in 'Thread::copy_ts_to_utcb()' in thread-arm.cpp). When pausing the thread, an artificial exception is triggered, which causes the kernel to copy the thread state into the UTCB. Therefore, it is necessary to pause the thread before the register values are available in the UTCB.
Regards, Christian