- add a reference to the config(5) manpage;
- hopefully clarify the format of the 'env FILENAME' directive.
I am putting these notes in sys/${arch}/conf/GENERIC and not
in sys/conf/NOTES because:
1. i386/GENERIC already had reference to a similar option (hints..)
and to documentation (handbook)
2. GENERIC is what most users look at when they have to modify or
create a new kernel config, so having the suggestion there is
more effective.
I am only touching i386 and amd64 because the other GENERIC files
are already out of sync, and I am not sure what is the overall plan.
MFC after: 3 days
to GENERIC configuration files. This brings what's in 8.x in sync
with what is in 7.x, but does not change any current defaults.
Possibly they should now be enabled in head by default?
In the existing code we didn't really enforce that callers hold Giant
before calling userland_sysctl(), even though there is no guarantee it
is safe. Fix this by just placing Giant locks around the call to the oid
handler. This also means we only pick up Giant for a very short period
of time. Maybe we should add MPSAFE flags to sysctl or phase it out all
together.
I've also added SYSCTL_LOCK_ASSERT(). We have to make sure sysctl_root()
and name2oid() are called with the sysctl lock held.
Reviewed by: Jille Timmermans <jille quis cx>
Log:
- merge in latest xenbus from dfr's xenhvm
- fix race condition in xs_read_reply by converting tsleep to mtx_sleep
Log:
unmask evtchn in bind_{virq, ipi}_to_irq
Log:
- remove code for handling case of not being able to sleep
- eliminate tsleep - make sleeps atomic
time it is marked for user space callchain capture in the NMI
handler and the time the callchain capture callback runs.
- Improve code and control flow clarity by invoking hwpmc(4)'s user
space callchain capture callback directly from low-level code.
Reviewed by: jhb (kern/subr_trap.c)
Testing (various patch revisions): gnn,
Fabien Thomas <fabien dot thomas at netasq dot com>,
Artem Belevich <artemb at gmail dot com>
memory barriers on i386. It works as a serialization instruction on
all IA32 CPUs.
Alternative solution of using {s,l,}fence requires run-time checking
of the presense of the corresponding SSE or SSE2 extensions, and
possible boot-time patching of the kernel text.
Suggested by: many
Sgtty is a programming interface that has been replaced by termios over
the years. In June we already removed <sgtty.h>, which exposes the
ioctl()'s that are implemented by this interface. The importance of this
flag is overrated right now.
module; the ath module now brings in the hal support. Kernel
config files are almost backwards compatible; supplying
device ath_hal
gives you the same chip support that the binary hal did but you
must also include
options AH_SUPPORT_AR5416
to enable the extended format descriptors used by 11n parts.
It is now possible to control the chip support included in a
build by specifying exactly which chips are to be supported
in the config file; consult ath_hal(4) for information.
Volume 3B: System Programming Guide, Part 2", CPUs with family 0x6 and model
above or 0xE and CPUs with family 0xF and model above or 0x3 have invariant
TSC.
Change types used in the linux' struct msghdr and struct cmsghdr
definitions to the properly-sized architecture-specific types.
Move ancillary data handler from linux_sendit() to linux_sendmsg().
Submitted by: dchagin
and Core Duo), models 0xF (Core2), model 0x17 (Core2Extreme) and
model 0x1C (Atom).
In these CPUs, the actual numbers, kinds and widths of PMCs present
need to queried at run time. Support for specific "architectural"
events also needs to be queried at run time.
Model 0xE CPUs support programmable PMCs, subsequent CPUs
additionally support "fixed-function" counters.
- Use event names that are close to vendor documentation, taking in
account that:
- events with identical semantics on two or more CPUs in this family
can have differing names in vendor documentation,
- identical vendor event names may map to differing events across
CPUs,
- each type of CPU supports a different subset of measurable
events.
Fixed-function and programmable counters both use the same vendor
names for events. The use of a class name prefix ("iaf-" or
"iap-" respectively) permits these to be distinguished.
- In libpmc, refactor pmc_name_of_event() into a public interface
and an internal helper function, for use by log handling code.
- Minor code tweaks: staticize a global, freshen a few comments.
Tested by: gnn
throttle. My SMP kernel hangs when one of those is selected by
powerd. Errata AA21 here:
ftp://download.intel.com/design/PentiumXE/specupdt/31030717.pdf
MFC after: 2 weeks
of the ABI of the currently executing image. Change some places to test
the flags instead of explicit comparing with address of known sysentvec
structures to determine ABI features.
Discussed with: dchagin, imp, jhb, peter
and ifnet functions
- add memory barriers to <machine/atomic.h>
- update drivers to only conditionally define their own
- add lockless producer / consumer ring buffer
- remove ring buffer implementation from cxgb and update its callers
- add if_transmit(struct ifnet *ifp, struct mbuf *m) to ifnet to
allow drivers to efficiently manage multiple hardware queues
(i.e. not serialize all packets through one ifq)
- expose if_qflush to allow drivers to flush any driver managed queues
This work was supported by Bitgravity Inc. and Chelsio Inc.
controller. The controller is also known as L1E(AR8121) and
L2E(AR8113/AR8114). Unlike its predecessor Attansic L1,
AR8121/AR8113/AR8114 uses completely different Rx logic such that
it requires separate driver. Datasheet for AR81xx is not available
to open source driver writers but it shares large part of Tx and
PHY logic of L1. I still don't understand some part of register
meaning and some MAC statistics counters but the driver seems to
have no critical issues for performance and stability.
The AR81xx requires copy operation to pass received frames to upper
stack such that ale(4) consumes a lot of CPU cycles than that of
other controller. A couple of silicon bugs also adds more CPU
cycles to address the known hardware bug. However, if you have fast
CPU you can still saturate the link.
Currently ale(4) supports the following hardware features.
- MSI.
- TCP Segmentation offload.
- Hardware VLAN tag insertion/stripping with checksum offload.
- Tx TCP/UDP checksum offload and Rx IP/TCP/UDP checksum offload.
- Tx/Rx interrupt moderation.
- Hardware statistics counters.
- Jumbo frame.
- WOL.
AR81xx PCIe ethernet controllers are mainly found on ASUS EeePC or
P5Q series of ASUS motherboards. Special thanks to Jeremy Chadwick
who sent the hardware to me. Without his donation writing a driver
for AR81xx would never have been possible. Big thanks to all people
who reported feedback or tested patches.
HW donated by: koitsu
Tested by: bsam, Joao Barros <joao.barros <> gmail DOT com >
Jan Henrik Sylvester <me <> janh DOT de >
Ivan Brawley < ivan <> brawley DOT id DOT au >,
CURRENT ML
- Use `fildes[2]' instead of `*fildes' to make more clear that pipe(2)
fills an array with two descriptors.
- Remove EFAULT from the manual page. Because of the current calling
convention, pipe(2) raises a segmentation fault when an invalid
address is passed.
- Introduce kern_pipe() to make it easier for binary emulations to
implement pipe(2).
- Make Linux binary emulation use kern_pipe(), which means we don't have
to recover td_retval after calling the FreeBSD system call.
Approved by: rdivacky
Discussed on: arch
dependencies. A 'struct pmc_classdep' structure describes operations
on PMCs; 'struct pmc_mdep' contains one or more 'struct pmc_classdep'
structures depending on the CPU in question.
Inside PMC class dependent code, row indices are relative to the
PMCs supported by the PMC class; MI code in "hwpmc_mod.c" translates
global row indices before invoking class dependent operations.
- Augment the OP_GETCPUINFO request with the number of PMCs present
in a PMC class.
- Move code common to Intel CPUs to file "hwpmc_intel.c".
- Move TSC handling to file "hwpmc_tsc.c".
Looking at our source code history, it seems the uname(),
getdomainname() and setdomainname() system calls got deprecated
somewhere after FreeBSD 1.1, but they have never been phased out
properly. Because we don't have a COMPAT_FREEBSD1, just use
COMPAT_FREEBSD4.
Also fix the Linuxolator to build without the setdomainname() routine by
just making it call userland_sysctl on kern.domainname. Also replace the
setdomainname()'s implementation to use this approach, because we're
duplicating code with sysctl_domainname().
I wasn't able to keep these three routines working in our
COMPAT_FREEBSD32, because that would require yet another keyword for
syscalls.master (COMPAT4+NOPROTO). Because this routine is probably
unused already, this won't be a problem in practice. If it turns out to
be a problem, we'll just restore this functionality.
Reviewed by: rdivacky, kib
compiled into the main AMR driver. It's code that is nice to have but not
required for normal operation, and it is reported to cause problems for some
people.
Make the ISA bus keep track of more PNP details. Plus a minor style
fix while I'm here. More could be done here, but except for some SBCs
that don't have ACPI, there's limited value to anybody in doing so.
It is required for async cancellation to work.
Fix PROC_LOCK leak in linux_tgkill when signal delivery attempt is made
to not linux process.
Do not call em_find(p, ...) with p unlocked.
Move common code for linux_tkill() and linux_tgkill() into
linux_do_tkill().
Change linux siginfo_t definition to match actual linux one. Extend
uid fields to 4 bytes from 2. The extension does not change structure
layout and is binary compatible with previous definition, because i386
is little endian, and each uid field has 2 byte padding after it.
Reported by: Nicolas Joly <njoly pasteur fr>
Submitted by: dchangin
MFC after: 1 month
- fix bugs where we would:
- try to map the hypervisors address space
- accidentally kick out an existing kernel mapping for some domain creation memory allocation sizes
- accidentally skip a 2MB kernel mapping for some domain creation memory allocation sizes
- don't rely on trapping in to xen to read rcr2, reference through vcpu
- whitespace cleanups
user-mode pointers. Change types used in the structures definitions to
properly-sized architecture-specific types.
Submitted by: dchagin
MFC after: 1 week
This was located in the ubsa driver, but should be moved into a separate
driver:
- 3G modems provide multiple serial ports to allow AT commands while the PPP
connection is up.
- 3G modems do not provide baud rate or other serial port settings.
- Huawei cards need specific initialisation.
- ubsa is for Belkin adapters, an Linuxy choice for another device like 3G.
Speeds achieved here with a weak signal at best is ~40kb/s (UMTS). No spooky
STALLED messages as well.
Next: Move over all entries for Sierra and Novatel cards once I have found
testers, and implemented serial port enumeration for Sierra (or rather have
Andrea Guzzo do it). They list all endpoints in 1 iface instead of 4 ifaces.
Submitted by: aguzzo@anywi.com
MFC after: 3 weeks
single stepped the process to the system call), we need to clear
the trap flag from the new frame. Otherwise, the new thread will
receive a (likely unexpected) SIGTRAP when it executes the first
instruction after returning to userland.
all to date and the latter also is only used in ia64 and powerpc
code which no longer serves a real purpose after bring-up and just
can be removed as well. Note that architectures like sun4u also
provide no means of implementing IPI'ing a CPU itself natively
in the first place.
Suggested by: jhb
Reviewed by: arch, grehan, jhb
and Xlazypmap differ from the frame for Xtimerint. The Xtimerint puts
pointer to the frame between return address and frame body, while rest
of the functions listed above do not. Correct offset calculation to
allow the ddb backtrace to step over such frames.
Noted and reviewed by: tegge
Tested by: pho
MFC after: 1 week
After I removed all the unit2minor()/minor2unit() calls from the kernel
yesterday, I realised calling minor() everywhere is quite confusing.
Character devices now only have the ability to store a unit number, not
a minor number. Remove the confusion by using dev2unit() everywhere.
This commit could also be considered as a bug fix. A lot of drivers call
minor(), while they should actually be calling dev2unit(). In -CURRENT
this isn't a problem, but it turns out we never had any problem reports
related to that issue in the past. I suspect not many people connect
more than 256 pieces of the same hardware.
Reviewed by: kib
When I changed kern_conf.c three months ago I made device unit numbers
equal to (unneeded) device minor numbers. We used to require
bitshifting, because there were eight bits in the middle that were
reserved for a device major number. Not very long after I turned
dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
The unit2minor() and minor2unit() macro's were no-ops.
We'd better not remove these four macro's from the kernel, because there
is a lot of (external) code that may still depend on them. For now it's
harmless to remove all invocations of unit2minor() and minor2unit().
Reviewed by: kib
to the C99 style. At least, it is easier to read sysent definitions
that way, and search for the actual instances of sigcode etc.
Explicitely initialize sysentvec.sv_maxssiz that was missed in most
sysvecs.
No objection from: jhb
MFC after: 1 month
and bcmp are not the same thing. 'man bcmp' states that the return is
"non-zero" if the two byte strings are not identical. Where as,
'man memcmp' states that the return is the "difference between the
first two differing bytes (treated as unsigned char values" if the
two byte strings are not identical.
So provide a proper memcmp(9), but it is a C implementation not a tuned
assembly implementation. Therefore bcmp(9) should be preferred over memcmp(9).
Reverse the direction of pmap_promote_pde()'s traversal over the specified
page table page. The direction of the traversal can matter if
pmap_promote_pde() has to remove write access (PG_RW) from a PTE that
hasn't been modified (PG_M). In general, if there are two or more such
PTEs to choose among, it is better to write protect the one nearer the
high end of the page table page rather than the low end. This is because
most programs access memory in an ascending direction. The net result of
this change is a sometimes significant reduction in the number of failed
promotion attempts and the number of pages that are write protected by
pmap_promote_pde().
MFamd64 SVN rev 179777 CVS rev 1.621
Tweak the promotion test in pmap_promote_pde(). Specifically, test PG_A
before PG_M. This sometimes prevents unnecessary removal of write access
from a PTE. Overall, the net result is fewer demotions and promotion
failures.
core of this change generalizes the initial page directory setup so that
the kernel can be given arbitrarily large or small.
- small formatting fixes
- update copyright
MFC after: 1 month
so the benefit of having acpi.ko as a standalone module is outweighed by
the complications of drivers compiled into the kernel not including ACPI
attachments by default.
Discussed on: current
On the i386 architecture, the processor only saves the current value
of `%esp' on stack if a privilege switch is necessary when entering
the interrupt handler. Thus, `frame->tf_esp' is only valid for
an entry from user mode. For interrupts taken in kernel mode, we
need to determine the top-of-stack for the interrupted kernel
procedure by adding the appropriate offset to the current frame
pointer.
Reported by: kris, Fabien Thomas
Tested by: Fabien Thomas <fabien.thomas at netasq dot com>
the same vmspace, decrement the reference count of the shared LDT instead
of a newly-made copy. Code factually removed LDT from the process that
did rfork(0).
Introduce user_ldt_deref() function that does decrement of refcount for
the struct proc_ldt, and call it in the rfork(0) case on the shared LDT.
Reviewed by: jhb
MFC after: 1 week
The user_ldt_free() function shall return with dt_lock unlocked.
Error handling code in both functions do not handle this, fix it by
doing necessary lock/unlock.
While there, fix minor style nits.
MFC after: 1 week
code. We only attempt a single reset using this method (a "hard" reset),
and we use two writes to ensure there is a 0 -> 1 transition in bit 2 to
force a reset.
MFC after: 1 week
memory-mapped config access. Add a workaround for these systems by
checking the first function of each slot on bus 0 using both the
memory-mapped config access and the older type 1 I/O port config access.
If we find a slot that is only visible via the type 1 I/O port config
access, we flag that slot. Future PCI config transactions to flagged
slots on bus 0 use type 1 I/O port config access rather than memory mapped
config access.
l_ucontext. To restore the registers content, trampoline needs to
dereference uc_mcontext instead of taking some undefined values from
l_ucontext.
Submitted by: Dmitry Chagin <dchagin@>
MFC after: 1 week
at least pass muster with the loader on 3.0.3
Note that this doesn't actually make it work as Xen 3.0.3
appears to disallow recursive mappings on the page directory
tables, then attempt to build a simple list containing just the high and
low frequencies based on the current CPU frequency calculated during boot
and the contents of the MSR.
MFC after: 1 month
timer. Previously, the various divisors were fixed which meant that while
it gave somewhat reasonable stathz, etc. at hz=1000, it went off the rails
with any other hz value. With these changes, we now pick a lapic timer hz
based on the value of hz. If hz is >= 1500, then the lapic timer runs at
hz. If 1500 hz >= 750, we run the lapic timer at hz * 2. If hz < 750, we
run at hz * 4. We compute a divider at runtime to make stathz run as close
to 128 as we can since stathz really wants to be run at something close to
that frequency. Profiling just runs on every clock tick. So some examples:
With hz = 100, the lapic timer now runs at 400 instead of 2000. stathz
will be 133, and profhz = 400. With hz = 1000 (default), the lapic timer
is still at 2000 (as it is now), stathz is at 133 (as it is now), and
profhz will be 2000 (previously 666).
MFC after: 2 weeks
- Rename pciereg_cfgopen() to pcie_cfgregopen() and expose it to the
rest of the kernel. It now also accepts parameters via function
arguments rather than global variables.
- Add a notion of minimum and maximum bus numbers and reject requests for
an out of range bus.
- Add more range checks on slot/func/reg/bytes parameters to the cfg reg
read/write routines. Don't panic on any invalid parameters, just fail
the request (writes do nothing, reads return -1). This matches the
behavior of the other cfg mechanisms.
- Port the memory mapped configuration space access to amd64. On amd64
we simply use the direct map (via pmap_mapdev()) for the memory mapped
window.
- During acpi_attach() just after loading the ACPI tables, check for a
MCFG table. If it exists, call pciereg_cfgopen() on each subtable
(memory mapped window). For now we only support windows for domain 0
that start with bus 0. This removes the need for more chipset-specific
quirks in the MD code.
- Remove the chipset-specific quirks for the Intel 5000P/V/Z chipsets
since these machines should all have MCFG tables via ACPI.
- Updated pci_cfgregopen() to DTRT if ACPI had invoked pcie_cfgregopen()
earlier.
MFC after: 2 weeks
and 5000P/V/Z chipsets.
- If the base address of the config space BAR is above 4GB for some reason
and this isn't a PAE kernel, then warn about this (under bootverbose)
and don't use the BAR.
PR: kern/126525
Submitted by: Arthur Hartwig @ Nokia
MFC after: 2 weeks
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
virtualization work done by Marko Zec (zec@).
This is the first in a series of commits over the course
of the next few weeks.
Mark all uses of global variables to be virtualized
with a V_ prefix.
Use macros to map them back to their global names for
now, so this is a NOP change only.
We hope to have caught at least 85-90% of what is needed
so we do not invalidate a lot of outstanding patches again.
Obtained from: //depot/projects/vimage-commit2/...
Reviewed by: brooks, des, ed, mav, julian,
jamie, kris, rwatson, zec, ...
(various people I forgot, different versions)
md5 (with a bit of help)
Sponsored by: NLnet Foundation, The FreeBSD Foundation
X-MFC after: never
V_Commit_Message_Reviewed_By: more people than the patch
priority of some of the drivers that manage the same state (e.g. ichss0
vs est0). Specifically, powernow, est, and p4tcc are added at order 10,
ichss at order 20, and smist at order 30. Previously, some laptops were
seeing both ichss0 and est0 attaching and stomping on each other.
XXX: This isn't quite ideal, but works with the existing hacks, I think
what we really want instead is a single "speedstep0" device for CPUs
that the ichss, est, and smist drivers probe (but with differing
priorities).
MFC after: 1 week
found in Soekris hardware, for instance). The hardware supports acceleration
of AES-128-CBC accessible through crypto(4) and supplies entropy to random(4).
TODO:
o Implement rndtest(4) support
o Performance enhancements
Submitted by: Patrick Lamaizière <patfbsd -at- davenulle.org>
Reviewed by: jhb, sam
MFC after: 1 week
features of CPUs like reading/writing machine-specific registers,
retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
the features of cpuctl(4).
- Add subsequent manpages.
The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.
The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.
The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.
Currently only Intel and AMD cpus are supported and were tested.
Approved by: kib
Reviewed by: rpaulo, cokane, Peter Jeremy
MFC after: 1 month
As clearly mentioned on the mailing lists, there is a list of drivers
that have not been ported to the MPSAFE TTY layer yet. Remove them from
the kernel configuration files. This means people can now still use
these drivers if they explicitly put them in their kernel configuration
file, which is good.
People should keep in mind that after August 10, these drivers will not
work anymore. Even though owners of the hardware are capable of getting
these drivers working again, I will see if I can at least get them to a
compilable state (if time permits).
when stack realignment is turned on (it is ALWAYS on for main), however
in a profiling build %ecx would be clobbered by mcount(), this would lead
to a segmentation fault when the code tries to reference any argument.
This fix changes mcount() to preserve %ecx.
PR: bin/119709
Reviewed by: bde
MFC after: 1 week
The uart(4) driver has the advantage of supporting a wider variety of
hardware on a greater amount of platforms. This driver has already been
the standard on platforms such as ia64, powerpc and sparc64.
I've decided not to change anything on pc98. I'd rather let people from
the pc98 team look at this.
Approved by: philip (mentor), marcel
to vm_page_alloc() instead of VM_ALLOC_SYSTEM. VM_ALLOC_SYSTEM was the
logical choice before FreeBSD 7.0 because VM_ALLOC_INTERRUPT could not
reclaim a cached page. Simply put, there was no ordering between
VM_ALLOC_INTERRUPT and VM_ALLOC_SYSTEM as to which "dug deeper" into the
cache and free queues. Now, there is; VM_ALLOC_INTERRUPT dominates
VM_ALLOC_SYSTEM.
While I'm here, teach pmap_growkernel() to request a prezeroed page.
MFC after: 1 week
to global hostname and domainname variables. Where necessary, copy
to or from a stack-local buffer before performing copyin() or
copyout(). A few uses, such as in cd9660 and daemon_saver, remain
under-synchronized and will require further updates.
Correct a bug in which a failed copyin() of domainname would leave
domainname potentially corrupted.
MFC after: 3 weeks
current@ and stable@ for the locking patches. The driver can always be
revived if someone tests it.
This driver also sleeps in its if_init routine, so it likely doesn't really
work at all anyway in modern releases.
Now that st_rdev is being automatically generated by the kernel, there
is no need to define static major/minor numbers for the iodev and
memdev. We still need the minor numbers for the memdev, however, to
distinguish between /dev/mem and /dev/kmem.
Approved by: philip (mentor)
Except for the case where we use the cloner library (clone_create() and
friends), there is no reason to enforce a unique device minor number
policy. There are various drivers in the source tree that allocate unr
pools and such to provide minor numbers, without using them themselves.
Because we still need to support unique device minor numbers for the
cloner library, introduce a new flag called D_NEEDMINOR. All cdevsw's
that are used in combination with the cloner library should be marked
with this flag to make the cloning work.
This means drivers can now freely use si_drv0 to store their own flags
and state, making it effectively the same as si_drv1 and si_drv2. We
still keep the minor() and dev2unit() routines around to make drivers
happy.
The NTFS code also used the minor number in its hash table. We should
not do this anymore. If the si_drv0 field would be changed, it would no
longer end up in the same list.
Approved by: philip (mentor)
