a kernel history, settable via the SCDEBUG_KERNHIST flag.
this requires a fairly significantly different set of messages than the
normal debug as histories are restricted:
- each message can take one literal format string and upto 4
arguments
- the arguments can not be strings if you want vmstat -u to
work (this could be fixed, and i might, as it would be nice
if we could print syscall names as well as numbers.)
introduce SCDEBUG_DEFAULT that is settable in the kernel config.
fix a problem in kernhist_dump_histories() where it would crash when a
history with no allocated entries was found.
extend kernhist_dumpmask() to handle the usbhist and scdebughist.
679d7c25a6