[Linux/Mips emulation]
   
   Linux/Mips seems to have the strange habit of flushing all caches when
   it starts a new program. This is done by the libc through the flushcache
   system call. 
   
   This system call is nicely implemented: it just flushes all the caches.
   How do I do this on mips? Will the MIPS_CACHEFLUSH case in
   sys/arch/mips/mips/sys_machdep.c:sys_arch() do the job?
   
   There is also a cachectl system call in linux, and I see a MIPS_CACHECTL
   case in the same function. Maybe it fits nicely, what is its purpose
   exactly? 


netbsd/mips has `flushcache' instructions in libc.  look at how those
are implemented.