svn commit: r283120 - in head: lib/libpmc sys/dev/hwpmc sys/sys

[John Baldwin]

On Tuesday, May 19, 2015 06:58:19 PM John Baldwin wrote:
> Author: jhb
> Date: Tue May 19 18:58:18 2015
> New Revision: 283120
> URL: https://svnweb.freebsd.org/changeset/base/283120
> 
> Log:
>   Use fixed enum values for PMC_CLASSES().
>   
>   This removes one of the frequent causes of ABI breakage when new CPU
>   types are added to hwpmc(4).
>   
>   Differential Revision:	https://reviews.freebsd.org/D2586
>   Reviewed by:	davide, emaste, gnn (earlier version)
>   MFC after:	2 weeks

The ABI was already broken today with the ARMv8 counters.   Merging this to
stable will break the ABI there as well.  Since PMC_SOFT always gets
renumbered it always breaks pmcccontrol -L when this enum is updated.  I
believe it has already been broken in once stable/10.  My preference would
be that we only MFC this the next time we want to add a new class to 10 to
avoid being too disruptive.  At the time the new class is added, then this
change could be merged as well.

-- 
John Baldwin