pausing nios2 processor using software ???

I am new to the nios2 processor and altera tools in general.

I have a two processor system wherein I have a requirement to pause a processor using software (could be running on any of the processors). I have uC/OS - II as the RTOS and InterNiche TCP/IP stack for network I/O, if that helps.

Given this setup, is there any way in which my software can instruct the processor to freeze its activity? A lot like the way in which nios2-download pauses the processor if there is some error in downloading or verification fails.