where curcpu() is defined as curlwp->l_cpu:
- mi_switch(): undo the ~2007ish optimisation to unlock curlwp before
calling cpu_switchto(). It's not safe to let other actors mess with the
LWP (in particular l->l_cpu) while it's still context switching. This
removes l->l_ctxswtch.
- Move the LP_RUNNING flag into l->l_flag and rename to LW_RUNNING since
it's now covered by the LWP's lock.
- Ditch lwp_exit_switchaway() and just call mi_switch() instead. Everything
is in cache anyway so it wasn't buying much by trying to avoid saving old
state. This means cpu_switchto() will never be called with prevlwp ==
NULL.
- Remove some KERNEL_LOCK handling which hasn't been needed for years.
2ddceed1d9