Landon J. Fuller [Mon, 27 Nov 2017 22:13:30 +0000 (22:13 +0000)]
bhnd(4): Fix bcma/siba core reset behavior
Add missing support for specifying I/O control flags during core reset,
and resolve a number of siba(4)-specific reset issues:
- Add missing check for target reject flags in siba_is_hw_suspended().
- Remove incorrect wait on SIBA_TMH_BUSY when modifying any target state
register; this should only be done when waiting for initiated
transactions to clear.
- Add missing wait on SIBA_IM_BY when asserting SIBA_IM_RJ.
- Overwrite any previously set SIBA_TML_REJ flag when bringing the core
out of reset. This fixes a lockup that occured when we brought up a core
(after reboot) that had previously been placed into RESET by siba_bwn(4).
Approved by: adrian (mentor, implicit)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D13039
Landon J. Fuller [Mon, 27 Nov 2017 21:30:49 +0000 (21:30 +0000)]
bhnd(4) update inline documentation comments and man pages.
This includes a number of copyedits for the inline code documentation
comments, updates to the existing bhnd(4), bhndb(4), bcma(4), and siba(4)
man pages, and new man pages for bhnd_chipc(4), bhnd_pmu(4), bhndb_pci(4),
bhnd(9), and bhnd_erom(9).
Approved by: adrian (mentor)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D13021
Alan Somers [Mon, 27 Nov 2017 20:01:58 +0000 (20:01 +0000)]
Add basic tests for ctfconvert(1), fold(1) and rs(1)
Add basic command line parsing test coverage for these utilities. The tests
were automatically generated based on their man pages. These tests can be
expanded by hand for more thorough coverage. The aim is to generate very
basic amount of test coverage for all the utilities in the base system.
Mark Johnston [Mon, 27 Nov 2017 17:54:17 +0000 (17:54 +0000)]
Revert r326181 for now.
We can't link an executable using -m32 until the lib32 phase of a
buildworld, though the build works fine when executing make from
cddl/usr.sbin/dtrace/tests. Some other solution will need to be found.
Fedor Uporov [Mon, 27 Nov 2017 17:03:11 +0000 (17:03 +0000)]
Remap ENOATTR to ENODATA in the linuxulator.
In the linux ENOADATA is frequently #defined as ENOATTR.
The change is required for an xattrs support implementation.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:49:00 +0000 (15:49 +0000)]
sys/kgssapi: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:37:16 +0000 (15:37 +0000)]
various: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:28:26 +0000 (15:28 +0000)]
share and pc-sysinstall: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Commit these apart because compile testing doesn't guarantee I didn't made
some nasty mistake. No functional change intended.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:25:02 +0000 (15:25 +0000)]
libexec: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:23:17 +0000 (15:23 +0000)]
sys: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:20:12 +0000 (15:20 +0000)]
sys/kern: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:17:37 +0000 (15:17 +0000)]
sys/geom: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:16:59 +0000 (15:16 +0000)]
sys/gdb: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:15:37 +0000 (15:15 +0000)]
sys/fs: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:14:46 +0000 (15:14 +0000)]
sys/ddb: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:13:23 +0000 (15:13 +0000)]
sys/compat: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:12:43 +0000 (15:12 +0000)]
sys/cam: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:11:47 +0000 (15:11 +0000)]
sys/x86: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:10:39 +0000 (15:10 +0000)]
sys/sparc64: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:09:59 +0000 (15:09 +0000)]
sys/powerpc: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:08:52 +0000 (15:08 +0000)]
sys/i386: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:07:26 +0000 (15:07 +0000)]
sys/mips: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:04:10 +0000 (15:04 +0000)]
sys/arm: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:03:07 +0000 (15:03 +0000)]
sys/amd64: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 15:01:59 +0000 (15:01 +0000)]
sys/sys: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Mon, 27 Nov 2017 14:52:40 +0000 (14:52 +0000)]
sys/dev: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Mateusz Guzik [Sun, 26 Nov 2017 21:10:47 +0000 (21:10 +0000)]
rw: fix runlock_hard when new readers show up
When waiters/writer spinner flags are set no new readers can show up unless
they already have a different rw rock read locked. The change in r326195 failed
to take that into account - in presence of new readers it would spin until
they all drain, which would be lead to trouble if e.g. they go off cpu and
can get scheduled because of this thread.
Justin Hibbits [Sun, 26 Nov 2017 20:30:02 +0000 (20:30 +0000)]
Synchronize TLB1 mappings when created
This allows modules creating mappings to be loaded post-boot, after SMP has
started. Without this, the TLB1 mappings can become unsynchronized and lead
to kernel page faults when accessed on the alternate CPUs.
Michael Tuexen [Sun, 26 Nov 2017 18:19:01 +0000 (18:19 +0000)]
Add to ipfw support for sending an SCTP packet containing an ABORT chunk.
This is similar to the TCP case. where a TCP RST segment can be sent.
There is one limitation: When sending an ABORT in response to an incoming
packet, it should be tested if there is no ABORT chunk in the received
packet. Currently, it is only checked if the first chunk is an ABORT
chunk to avoid parsing the whole packet, which could result in a DOS attack.
Thanks to Timo Voelker for helping me to test this patch.
Reviewed by: bcr@ (man page part), ae@ (generic, non-SCTP part)
Differential Revision: https://reviews.freebsd.org/D13239
Ed Schouten [Sun, 26 Nov 2017 14:56:23 +0000 (14:56 +0000)]
Add a Saved Process Status Register bit for AArch32 execution mode.
The documentation on the Saved Process Status Register (SPSR) is a bit
weird; the M[4] bit is documented separately from M[3:0]. The M[4] bit
can be toggled to switch to 32-bit execution mode. This functionality is
orthogonal to M[3:0].
Change the definition of PSR_M_MASK to no longer include M[4]. Add a new
definition, PSR_AARCH32 that can be used to toggle 32-bit independently.
This bit will be used by the cloudabi32 code to force execution of
userspace code in 32-bit mode.
Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D13148
Ed Schouten [Sun, 26 Nov 2017 14:45:56 +0000 (14:45 +0000)]
Use TO_PTR() to convert integers to pointers.
For FreeBSD/arm64's cloudabi32 support, I'm going to need a TO_PTR() in
this place. Also use it for all of the other source files, so that the
difference remains as minimal as possible.
Ed Schouten [Sun, 26 Nov 2017 14:28:27 +0000 (14:28 +0000)]
Make 32-bit system calls end up in svc_handler().
The nice thing about ARM64 is that it's pretty elegant to install
separate trap/exception handlers for 32-bit and 64-bit processes. That
said, for all other architectures (e.g., i386 on amd64) we always let
32-bit counterparts go through the regular system call codepath. Let's
do the same on ARM64.
Reviewed by: andrew
Differential Revision: https://reviews.freebsd.org/D13146
Nathan Whitehorn [Sun, 26 Nov 2017 03:53:20 +0000 (03:53 +0000)]
Use the cookie now set by loader to determine whether the value passed to
PowerPC kernels in r6 is actually metadata from loader(8) or gibberish
left in r6, which is not required to be anything under the
PAPR/ePAPR/CHRP/OF standards, by another boot loader.
Note that, as a result, systems need a new boot loader to boot PPC kernels
after this revision without ending up at a mountroot prompt. New boot
loaders are backwards compatible and can boot older kernels.
Pedro F. Giffuni [Sun, 26 Nov 2017 02:00:33 +0000 (02:00 +0000)]
lib: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Nathan Whitehorn [Sat, 25 Nov 2017 22:43:52 +0000 (22:43 +0000)]
On AIM systems, it is not actually possible to stop the CPU timer, so we
just set it to a large default value (and inherit any previously existing
value), hoping it never turns over. Instead, silently allow spurious
one-shots from rollovers.
Nathan Whitehorn [Sat, 25 Nov 2017 22:14:30 +0000 (22:14 +0000)]
When booting from an FDT, make sure the FDT itself isn't included the range
of available memory. Boot loaders are supposed to add a reserved entry for
it, but not all do.
Nathan Whitehorn [Sat, 25 Nov 2017 22:13:19 +0000 (22:13 +0000)]
Allow platform modules to set the size of large pizes, as potentially
discovered from firmware, and better handle highly-discontiguous memory
and CPU maps.
Nathan Whitehorn [Sat, 25 Nov 2017 22:05:05 +0000 (22:05 +0000)]
Make n_slbs public in a more straightforward way. Some platforms (like
PowerNV) use firmware-assisted mechanisms to discover it and need access
to the variable.
Nathan Whitehorn [Sat, 25 Nov 2017 22:03:25 +0000 (22:03 +0000)]
Preserve the LPCR on new-ish (POWER7 and POWER8) CPUs, preventing exceptions
and such from ending on the wrong CPU on SMP systems. It would be good to
have this be more generic somehow as POWER9s appear, but PPC does not
have features bits, unfortunately.
Nathan Whitehorn [Sat, 25 Nov 2017 22:01:55 +0000 (22:01 +0000)]
Yield while spinning on APs and avoid announcing all CPUs unless bootverbose
is set. These improve startup performance on massively multithreaded systems
with 8-way SMT and dozens to hundreds of CPUs.
Nathan Whitehorn [Sat, 25 Nov 2017 21:59:59 +0000 (21:59 +0000)]
Whether you can use mttb() or not is more complicated than whether PSL_HV
is set and the right thing to do may be platform-dependent (it requires
firmware on PowerNV, for instance). Make it a new platform method called
platform_smp_timebase_sync().
Nathan Whitehorn [Sat, 25 Nov 2017 21:45:51 +0000 (21:45 +0000)]
Avoid emitting a PT_INTERP section for powerpc64 kernels and arrange for
the first instruction to be at the start of the text segment. This allows
the kernel to be booted correctly by stock kexec-lite.
Nathan Whitehorn [Sat, 25 Nov 2017 21:44:23 +0000 (21:44 +0000)]
Automatically use the ELFv2 ABI on powerpc64 if supported by the compiler.
This has the same effects on DDB working as -mcall=aixdesc, but also is
supported by clang and marginally improves kernel performance.
Mateusz Guzik [Sat, 25 Nov 2017 20:13:50 +0000 (20:13 +0000)]
sx: change sunlock to wake waiters up if it locked sleepq
sleepq is only locked if the curhtread is the last reader. By the time
the lock gets acquired new ones could have arrived. The previous code
would unlock and loop back. This results spurious relocking of sleepq.
Mateusz Guzik [Sat, 25 Nov 2017 20:10:33 +0000 (20:10 +0000)]
locks: retry turnstile/sleepq loops on failed cmpset
In order to go to sleep threads set waiter flags, but that can spuriously
fail e.g. when a new reader arrives. Instead of unlocking everything and
looping back, re-evaluate the new state while still holding the lock necessary
to go to sleep.
Pedro F. Giffuni [Sat, 25 Nov 2017 17:12:48 +0000 (17:12 +0000)]
libc: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Pedro F. Giffuni [Sat, 25 Nov 2017 17:09:43 +0000 (17:09 +0000)]
include: General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Kyle Evans [Sat, 25 Nov 2017 15:14:40 +0000 (15:14 +0000)]
Add r-ccu support for the Allwinner a83t
The r-ccu on the a83t differs from the others only by what it names the
ar100 parents. Export the _CCU macros (now converted to an enu) so that
ccu_sun8i_r can differentiate between a83t r-ccu and the others, then add
the compat string for the a83t r-ccu.
Alexander Motin [Sat, 25 Nov 2017 09:42:14 +0000 (09:42 +0000)]
Slightly fix bidirectional stream number allocation.
This logic is still imperfect, since it allows at most 15 bidirectional
streams out of 30 allowed by specification, but at least now those should
work better. On the other side I don't remember I ever saw controller
supporting the bidirectional streams, so this is likely a nop change.
John Baldwin [Sat, 25 Nov 2017 04:49:12 +0000 (04:49 +0000)]
Decode kevent structures logged via ktrace(2) in kdump.
- Add a new KTR_STRUCT_ARRAY ktrace record type which dumps an array of
structures.
The structure name in the record payload is preceded by a size_t
containing the size of the individual structures. Use this to
replace the previous code that dumped the kevent arrays dumped for
kevent(). kdump is now able to decode the kevent structures rather
than dumping their contents via a hexdump.
One change from before is that the 'changes' and 'events' arrays are
not marked with separate 'read' and 'write' annotations in kdump
output. Instead, the first array is the 'changes' array, and the
second array (only present if kevent doesn't fail with an error) is
the 'events' array. For kevent(), empty arrays are denoted by an
entry with an array containing zero entries rather than no record.
- Move kevent decoding tables from truss to libsysdecode.
This adds three new functions to decode members of struct kevent:
sysdecode_kevent_filter, sysdecode_kevent_flags, and
sysdecode_kevent_fflags.
kdump uses these helper functions to pretty-print kevent fields.
- Move structure definitions for freebsd11 and freebsd32 kevent
structures to <sys/event.h> so that they can be shared with userland.
The 32-bit structures are only exposed if _WANT_KEVENT32 is defined.
The freebsd11 structures are only exposed if _WANT_FREEBSD11_KEVENT is
defined. The 32-bit freebsd11 structure requires both.
- Decode freebsd11 kevent structures in truss for the compat11.kevent()
system call.
- Log 32-bit kevent structures via ktrace for 32-bit compat kevent()
system calls.
- While here, constify the 'void *data' argument to ktrstruct().
Nathan Whitehorn [Fri, 24 Nov 2017 23:41:04 +0000 (23:41 +0000)]
Modify all FreeBSD bootloaders on PowerPC AIM (Book-S) systems to pass a
magic number to the kernel in r7 rather than the (currently unused and
irrelevant) width of the metadata pointer, which I believe was intended
for a never-used approach to the 64-bit port. This enables the kernel,
in a future commit, to switch on the cookie to distinguish a real
metadata pointer from loader(8) from garbage left in r6 by some other
boot loader.