attempting to duplicate Windows spinlocks. Windows spinlocks differ
from FreeBSD spinlocks in the way they block preemption. FreeBSD
spinlocks use critical_enter(), which masks off _all_ interrupts.
This prevents any other threads from being scheduled, but it also
prevents ISRs from running. In Windows, preemption is achieved by
raising the processor IRQL to DISPATCH_LEVEL, which prevents other
threads from preempting you, but does _not_ prevent device ISRs
from running. (This is essentially what Solaris calls dispatcher
locks.) The Windows spinlock itself (kspin_lock) is just an integer
value which is atomically set when you acquire the lock and atomically
cleared when you release it.
FreeBSD doesn't have IRQ levels, so we have to cheat a little by
using thread priorities: normal thread priority is PASSIVE_LEVEL,
lowest interrupt thread priority is DISPATCH_LEVEL, highest thread
priority is DEVICE_LEVEL (PI_REALTIME) and critical_enter() is
HIGH_LEVEL. In practice, only PASSIVE_LEVEL and DISPATCH_LEVEL
matter to us. The immediate benefit of all this is that I no
longer have to rely on a mutex pool.
Now, I'm sure many people will be seized by the urge to criticize
me for doing an end run around our own spinlock implementation, but
it makes more sense to do it this way. Well, it does to me anyway.
Overview of the changes:
- Properly implement hal_lock(), hal_unlock(), hal_irql(),
hal_raise_irql() and hal_lower_irql() so that they more closely
resemble their Windows counterparts. The IRQL is determined by
thread priority.
- Make ntoskrnl_lock_dpc() and ntoskrnl_unlock_dpc() do what they do
in Windows, which is to atomically set/clear the lock value. These
routines are designed to be called from DISPATCH_LEVEL, and are
actually half of the work involved in acquiring/releasing spinlocks.
- Add FASTCALL1(), FASTCALL2() and FASTCALL3() macros/wrappers
that allow us to call a _fastcall function in spite of the fact
that our version of gcc doesn't support __attribute__((__fastcall__))
yet. The macros take 1, 2 or 3 arguments, respectively. We need
to call hal_lock(), hal_unlock() etc... ourselves, but can't really
invoke the function directly. I could have just made the underlying
functions native routines and put _fastcall wrappers around them for
the benefit of Windows binaries, but that would create needless bloat.
- Remove ndis_mtxpool and all references to it. We don't need it
anymore.
- Re-implement the NdisSpinLock routines so that they use hal_lock()
and friends like they do in Windows.
- Use the new spinlock methods for handling lookaside lists and
linked list updates in place of the mutex locks that were there
before.
- Remove mutex locking from ndis_isr() and ndis_intrhand() since they're
already called with ndis_intrmtx held in if_ndis.c.
- Put ndis_destroy_lock() code under explicit #ifdef notdef/#endif.
It turns out there are some drivers which stupidly free the memory
in which their spinlocks reside before calling ndis_destroy_lock()
on them (touch-after-free bug). The ADMtek wireless driver
is guilty of this faux pas. (Why this doesn't clobber Windows I
have no idea.)
- Make NdisDprAcquireSpinLock() and NdisDprReleaseSpinLock() into
real functions instead of aliasing them to NdisAcaquireSpinLock()
and NdisReleaseSpinLock(). The Dpr routines use
KeAcquireSpinLockAtDpcLevel() level and KeReleaseSpinLockFromDpcLevel(),
which acquires the lock without twiddling the IRQL.
- In ndis_linksts_done(), do _not_ call ndis_80211_getstate(). Some
drivers may call the status/status done callbacks as the result of
setting an OID: ndis_80211_getstate() gets OIDs, which means we
might cause the driver to recursively access some of its internal
structures unexpectedly. The ndis_ticktask() routine will call
ndis_80211_getstate() for us eventually anyway.
- Fix the channel setting code a little in ndis_80211_setstate(),
and initialize the channel to IEEE80211_CHAN_ANYC. (The Microsoft
spec says you're not supposed to twiddle the channel in BSS mode;
I may need to enforce this later.) This fixes the problems I was
having with the ADMtek adm8211 driver: we were setting the channel
to a non-standard default, which would cause it to fail to associate
in BSS mode.
- Use hal_raise_irql() to raise our IRQL to DISPATCH_LEVEL when
calling certain miniport routines, per the Microsoft documentation.
I think that's everything. Hopefully, other than fixing the ADMtek
driver, there should be no apparent change in behavior.
the definitions for NDIS_BUS_SPACE_IO and NDIS_BUS_SPACE_MEM logically
belong in hal_var.h. At least, that's my story, and I'm sticking to it.
Also, remove definition of __stdcall from if_ndis.c now that it's pulled
in from pe_var.h.
flag so that it can see if the message string is unicode or not and
do the conversion itself rather than doing it in subr_pe.c. This
prevents subr_pe.c from being dependent on subr_ndis.c.
the RT_MESSAGETABLE resources that some driver binaries have.
This allows us to print error messages in ndis_syslog().
- Correct the implementation of InterlockedIncrement() and
InterlockedDecrement() -- they return uint32_t, not void.
- Correct the declarations of the 64-bit arithmetic shift
routines in subr_ntoskrnl.c (_allshr, allshl, etc...). These
do not follow the _stdcall convention: instead, they appear
to be __attribute__((regparm(3)).
- Change the implementation of KeInitializeSpinLock(). There is
no complementary KeFreeSpinLock() function, so creating a new
mutex on each call to KeInitializeSpinLock() leaks resources
when a driver is unloaded. For now, KeInitializeSpinLock()
returns a handle to the ntoskrnl interlock mutex.
- Use a driver's MiniportDisableInterrupt() and MiniportEnableInterrupt()
routines if they exist. I'm not sure if I'm doing this right
yet, but at the very least this shouldn't break any currently
working drivers, and it makes the Intel PRO/1000 driver work.
- In ndis_register_intr(), save some state that might be needed
later, and save a pointer to the driver's interrupt structure
in the ndis_miniport_block.
- Save a pointer to the driver image for use by ndis_syslog()
when it calls pe_get_message().
Yes, it's what you think it is. Yes, you should run away now.
This is a special compatibility module for allowing Windows NDIS
miniport network drivers to be used with FreeBSD/x86. This provides
_binary_ NDIS compatibility (not source): you can run NDIS driver
code, but you can't build it. There are three main parts:
sys/compat/ndis: the NDIS compat API, which provides binary
compatibility functions for many routines in NDIS.SYS, HAL.dll
and ntoskrnl.exe in Windows (these are the three modules that
most NDIS miniport drivers use). The compat module also contains
a small PE relocator/dynalinker which relocates the Windows .SYS
image and then patches in our native routines.
sys/dev/if_ndis: the if_ndis driver wrapper. This module makes
use of the ndis compat API and can be compiled with a specially
prepared binary image file (ndis_driver_data.h) containing the
Windows .SYS image and registry key information parsed out of the
accompanying .INF file. Once if_ndis.ko is built, it can be loaded
and unloaded just like a native FreeBSD kenrel module.
usr.sbin/ndiscvt: a special utility that converts foo.sys and foo.inf
into an ndis_driver_data.h file that can be compiled into if_ndis.o.
Contains an .inf file parser graciously provided by Matt Dodd (and
mercilessly hacked upon by me) that strips out device ID info and
registry key info from a .INF file and packages it up with a binary
image array. The ndiscvt(8) utility also does some manipulation of
the segments within the .sys file to make life easier for the kernel
loader. (Doing the manipulation here saves the kernel code from having
to move things around later, which would waste memory.)
ndiscvt is only built for the i386 arch. Only files.i386 has been
updated, and none of this is turned on in GENERIC. It should probably
work on pc98. I have no idea about amd64 or ia64 at this point.
This is still a work in progress. I estimate it's about %85 done, but
I want it under CVS control so I can track subsequent changes. It has
been tested with exactly three drivers: the LinkSys LNE100TX v4 driver
(Lne100v4.sys), the sample Intel 82559 driver from the Windows DDK
(e100bex.sys) and the Broadcom BCM43xx wireless driver (bcmwl5.sys). It
still needs to have a net80211 stuff added to it. To use it, you would
do something like this:
# cd /sys/modules/ndis
# make; make load
# cd /sys/modules/if_ndis
# ndiscvt -i /path/to/foo.inf -s /path/to/foo.sys -o ndis_driver_data.h
# make; make load
# sysctl -a | grep ndis
All registry keys are mapped to sysctl nodes. Sometimes drivers refer
to registry keys that aren't mentioned in foo.inf. If this happens,
the NDIS API module creates sysctl nodes for these keys on the fly so
you can tweak them.
An example usage of the Broadcom wireless driver would be:
# sysctl hw.ndis0.EnableAutoConnect=1
# sysctl hw.ndis0.SSID="MY_SSID"
# sysctl hw.ndis0.NetworkType=0 (0 for bss, 1 for adhoc)
# ifconfig ndis0 <my ipaddr> netmask 0xffffff00 up
Things to be done:
- get rid of debug messages
- add in ndis80211 support
- defer transmissions until after a status update with
NDIS_STATUS_CONNECTED occurs
- Create smarter lookaside list support
- Split off if_ndis_pci.c and if_ndis_pccard.c attachments
- Make sure PCMCIA support works
- Fix ndiscvt to properly parse PCMCIA device IDs from INF files
- write ndisapi.9 man page
