sys-apps/watchdog has no keyword for sparc at all, but it compiles and installs without error on my Blade 100 and my Sun Fire V240. With minimal configuration changes, it can be made to work with the Ali M7101 PMU which is present in many Sun systems. The module alim7101_wdt needs to be loaded with the option use_gpio=1, and in /etc/watchdog.conf the line reading /dev/watchdog needs to be uncommented. Reproducible: Always
~sparc done, closing, reopen in 30 days if you want it stable