I fixed this in 1997, but the fix was over-engineered and fragile and
was broken in 2003 if not before. i386 parameters were copied to 8
other arches verbatim, mostly after they stopped working on i386, and
mostly without the large comment saying how the values were chosen on
i386. powerpc has a non-verbatim copy which just changes the uncritical
parameter and seems to add a sign extension bug to it.
Just treat negative offsets as offsets if they are no more negative than
-db_offset_max (default -64K), and remove all the broken parameters.
-64K is not very negative, but it is enough for frame and stack pointer
offsets since kernel stacks are small.
The over-engineering was mainly to go more negative than -64K for the
negative offset format, without affecting printing for more than a
single address.
Addresses in the top 64K of a (full 32-bit or 64-bit) address space
are now printed less well, but there aren't many interesting ones.
For arches that have many interesting ones very near the top (e.g.,
68k has interrupt vectors there), there would be no good limit for
the negative offset format and -64K is a good as anything.
This is only the minimum set of files needed to boot in qemu. As such it is
missing a few things.
The bus_dma code is currently only stub functions with a full implementation
from the development tree to follow.
The gic driver has been copied as the interrupt framework is different. It
is expected the two drivers will be merged by the arm intrng project,
however this will need to be imported into the tree and support for arm64
would need to be added.
This includes code developed by myself, SemiHalf, Ed Maste, and Robin
Randhawa from ARM. This has been funded by the FreeBSD Foundation, with
early development by myself in my spare time with assistance from Robin.
Differential Revision: https://reviews.freebsd.org/D2199
Reviewed by: emaste, imp
Relnotes: yes
Sponsored by: The FreeBSD Foundation
