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

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

Module Name:    src
Committed By:   thorpej
Date:           Sat Sep 19 01:32:16 UTC 2020

Modified Files:
        src/sys/arch/alpha/alpha: locore.s

Log Message:
- The Alpha fast-soft-intrs implementation supports 2 soft interrupt levels,
  so in exception_return() ensure we clear ineligible-at-new-IPL softint
  bits from the SSIR, otherwise we could loop forever in the following
  scenario:

        processing softnet -> clock interrupt -> schedule softclock

- If the softint thread blocks, it's possible to bounce back through
  the softint return trampoline at something other than IPL_HIGH.  This
  is not a problem other than it's contrary to what alpha_softint_dispatch()
  expect, so make alpha_softint_return() go to IPL_HIGH before it does
  anything else.

These two fixes make fast-soft-interrupts work on Alpha.


To generate a diff of this commit:
cvs rdiff -u -r1.135 -r1.136 src/sys/arch/alpha/alpha/locore.s

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