Hi Josef, El 25/01/18 a las 18:28, Stark, Josef escribió: >> As you should be the parent of the traced component, you can intercept >> the CPU session and remember all thread capabilities created by the >> component. On a fault you iterate through all threads to select those >> that are currently in a page fault. A good example for this is the GDB >> monitor [1]. > Ok, so far, so good, I could successfully get the threads within my > target process and indeed access the correct instruction pointer. > But the next problem is that Thread_state::unresolved_page_fault > for me always 0 is, for all threads (I provoked a pagefault by detaching > the dataspace), so I can't filter out the faulter(s). Do you have a clue? > As long as I don't attach a dataspace at the corresponding address, > it should indeed be an unresolved page fault, or am I wrong here?
At least in the current Genode release, the 'unresolved_page_fault' flag is set in [1] hence in [2] when giving up resolving the fault in core and consigning to the userland handler. I assume you're using a patched fork of an older Genode version so maybe things are different in your case. However, have you had a look ad the GDB monitor? >> Now you want to select from the remaining threads those >> that are in a fault on your specific address. This can't be done with >> the current Genode API, but an easy way to achieve it would be to expand >> the Cpu_state [2] to deliver also the value of the ARM Data Fault >> Address Register or DFAR when calling Cpu_thread_client::state (make >> sure to update the dfar member in [4] as is done in [3]). > Good. I'm using Fiasco.OC though, so I'll have to figure out how to > do this there. Writing a custom kernel function making the assembler call > copied from Genode just froze the VM, but I already asked the Fiasco.OC > people for help. >> Then, you would have to continue execution of >> the thread. Unfortunately, this is normally done automatically by >> Genodes Core when it sees a new mapping that matches the fault address. >> You don't want to do such a mapping, but there is no explicit "resume >> this faulter". So, you have might add such an RPC call [5] and its back >> end [6] to the RM interface. This shouldn't be much invasive. > At least this seems to work. Could you please explain in more detail what you mean with that? How do you get the faulter to continue execution without attaching a dataspace? Cheers, Martin [1] base-foc/src/core/pager_object.cc [2] base/src/core/region_map_component.cc:207 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main