The earlier posting wrt. add_wired_entry reminded my of this long standing
The kernel does not reserve any address space for use by add_wired_entry().
In other words there is the possibility that vmalloc, ioremap or other
kernel APIs will use the same address space resulting in a crash or worse.
Currently there are three users of add_wired_entry:
The interface itself also is hostile as it directly exposes the MIPS TLB
registers to the C programmer so should die. And often wiring a TLB entry
is a bad idea. TLB entries are a scarce resource and wasting them unwisely
may impact performance. Especially on the lowest-end CPUs with just
16 TLB entries this can be significant but even on the high-end TLBs with
64 entries it's not always clear if wiring entries is a good idea. And
there are a few core types that don't even have the capability of wiring