CVS commit: src/sys/arch/alpha/alpha

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Sun Aug 16 20:04:36 UTC 2020

Modified Files:
        src/sys/arch/alpha/alpha: pmap.c

Log Message:
- Undo part of rev 1.264; go back to not acquiring the pmap lock in
  pmap_activate().  As of rev 1.211, the pmap::pm_lev1map field is
  stable across the life of the pmap, and so the conditino that
  the change in 1.264 was intended to avoid would not have happened
  anyway.
- Explicitly use __cacheline_aligned / COHERENCY_UNIT rather than 64
  in a couple of places.
- Update comments around the lev1map lifecycle, and add some assertions
  to enforce the assumptions being described.
- Remove some dubious DEBUG tests that are not MP-safe.
- Chage some long-form #ifdef DIAGNOSTIC checks / panics to KASSERTs.
- Remove the PMAP_ACTIVATE() macro because it's no longer used anywhere
  except for pmap_activate().  Just open-code the equivalent there.
- In pmap_activate(), only perform the SWPCTX if either the PTBR or the
  ASN are different than what the PCB already has.  Also assert that
  preemption is disabled and that the specified lwp is curlwp.
- In pmap_deactivate(), add similar assertions, and add a comment explaining
  why a SWPCTX to get off of the deactivated lev1map is not necessaray.
- Refactor some duplicated code in pmap_growkernel() into a new
  pmap_kptpage_alloc() function.
- In pmap_growkernel(), assert that any user pmap published on the all-pmaps
  list does not reference the kernel_lev1map.
- In pmap_asn_alloc(), get out early if we're called with the kernel pmap,
  since all kernel mappings are ASM.  Remove bogus assertions around the
  value of pmap::pm_lev1map and the current ASN, and simply assert that
  pmap::pm_lev1map is never kernel_lev1map.  Also assert that preemption
  is disabled, since we're manipulating per-cpu data structures.
- Convert the "too much uptime" panic to a simple KASSERT, and update the
  comment to reflect that we're only subject to the longer 75 billion year
  ASN generation overflow (because CPUs that don't implement ASNs never go
  through this code path).


To generate a diff of this commit:
cvs rdiff -u -r1.266 -r1.267 src/sys/arch/alpha/alpha/pmap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.