To test user space arbitrary instructions, in loader/main.cpp init_t_ctx(); execState->SynRegsFromNative(&machRegs);
// int index= x86_64::rdx;
// std::string name = "rdx";
// execState->declareSymbolicRegister(index, 8, &name[0]);
execState->processAt(machRegs.regs.rip);
in centralhub.cpp, processFunction() comment the lines which declare symbols.
To test a syscall, install int3 probe at the respective syscall handler, in loader/main.cpp execState->MoniStartOfSE(0xffffffff810b9440);//addr of indirect call in do_syscall_64 to_native(); then, in centralhub.cpp, processFunction() declare memory symbols on kernel stack