Continue my efforts to imitate Windows as closely as possible by

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.

2 files changed, 47 insertions, 50 deletions

diff --git a/sys/dev/if_ndis/if_ndis.c b/sys/dev/if_ndis/if_ndis.c
index 901b313..f7467d9 100644
--- a/sys/dev/if_ndis/if_ndis.c
+++ b/sys/dev/if_ndis/if_ndis.c
@@ -70,6 +70,7 @@ __FBSDID("$FreeBSD$");
 
 #include <compat/ndis/pe_var.h>
 #include <compat/ndis/resource_var.h>
+#include <compat/ndis/hal_var.h>
 #include <compat/ndis/ntoskrnl_var.h>
 #include <compat/ndis/ndis_var.h>
 #include <compat/ndis/cfg_var.h>
@@ -371,8 +372,10 @@ ndis_attach(dev)
 
 	sc = device_get_softc(dev);
 
-	sc->ndis_mtx = mtx_pool_alloc(ndis_mtxpool);
-	sc->ndis_intrmtx = mtx_pool_alloc(ndis_mtxpool);
+	mtx_init(&sc->ndis_mtx, "ndis softc lock",
+	    MTX_NETWORK_LOCK, MTX_DEF);
+	mtx_init(&sc->ndis_intrmtx,
+	    "ndis irq lock", MTX_NETWORK_LOCK, MTX_DEF);
 
         /*
 	 * Hook interrupt early, since calling the driver's
@@ -492,7 +495,6 @@ ndis_attach(dev)
 	/* Do media setup */
 	if (sc->ndis_80211) {
 		struct ieee80211com	*ic = (void *)ifp;
-		ndis_80211_config	config;
 		ndis_80211_rates_ex	rates;
 		struct ndis_80211_nettype_list *ntl;
 		uint32_t		arg;
@@ -650,27 +652,11 @@ nonettypes:
 		r = ndis_get_info(sc, OID_802_11_POWER_MODE, &arg, &i);
 		if (r == 0)
 			ic->ic_caps |= IEEE80211_C_PMGT;
-		i = sizeof(config);
-		bzero((char *)&config, sizeof(config));
-		config.nc_length = i;
-		config.nc_fhconfig.ncf_length = sizeof(ndis_80211_config_fh);
-		r = ndis_get_info(sc, OID_802_11_CONFIGURATION, &config, &i);
-		if (r == 0) {
-			int chan;
-			chan = ieee80211_mhz2ieee(config.nc_dsconfig / 1000, 0);
-			if (chan < 0 || chan >= IEEE80211_CHAN_MAX) {
-				ic->ic_ibss_chan = &ic->ic_channels[1];
-			} else
-				ic->ic_ibss_chan = &ic->ic_channels[chan];
-		} else {
-			device_printf(sc->ndis_dev, "couldn't retrieve "
-			    "channel info: %d\n", r);
-			ic->ic_ibss_chan = &ic->ic_channels[1];
-		}
 		bcopy(eaddr, &ic->ic_myaddr, sizeof(eaddr));
 		ieee80211_ifattach(ifp);
 		ieee80211_media_init(ifp, ieee80211_media_change,
 		    ndis_media_status);
+		ic->ic_ibss_chan = IEEE80211_CHAN_ANYC;
 		ic->ic_bss->ni_chan = ic->ic_ibss_chan;
 	} else {
 		ifmedia_init(&sc->ifmedia, IFM_IMASK, ndis_ifmedia_upd,
@@ -757,6 +743,9 @@ ndis_detach(dev)
 
 	sysctl_ctx_free(&sc->ndis_ctx);
 
+	mtx_destroy(&sc->ndis_mtx);
+	mtx_destroy(&sc->ndis_intrmtx);
+
 	return(0);
 }
 
@@ -1073,8 +1062,6 @@ ndis_linksts_done(adapter)
 		ndis_sched(ndis_starttask, ifp, NDIS_TASKQUEUE);
 		break;
 	case NDIS_STATUS_MEDIA_DISCONNECT:
-		if (sc->ndis_80211)
-			ndis_getstate_80211(sc);
 		if (sc->ndis_link)
 			ndis_sched(ndis_ticktask, sc, NDIS_TASKQUEUE);
 		break;
@@ -1091,14 +1078,17 @@ ndis_intrtask(arg)
 {
 	struct ndis_softc	*sc;
 	struct ifnet		*ifp;
+	uint8_t			irql;
 
 	sc = arg;
 	ifp = &sc->arpcom.ac_if;
 
+	irql = FASTCALL1(hal_raise_irql, DISPATCH_LEVEL);
 	ndis_intrhand(sc);
-	mtx_pool_lock(ndis_mtxpool, sc->ndis_intrmtx);
+	FASTCALL1(hal_lower_irql, irql);
+	mtx_lock(&sc->ndis_intrmtx);
 	ndis_enable_intr(sc);
-	mtx_pool_unlock(ndis_mtxpool, sc->ndis_intrmtx);
+	mtx_unlock(&sc->ndis_intrmtx);
 
 	return;
 }
@@ -1118,14 +1108,14 @@ ndis_intr(arg)
 	if (sc->ndis_block.nmb_miniportadapterctx == NULL)
 		return;
 
-	mtx_pool_lock(ndis_mtxpool, sc->ndis_intrmtx);
+	mtx_lock(&sc->ndis_intrmtx);
 	if (sc->ndis_block.nmb_interrupt->ni_isrreq == TRUE)
 		ndis_isr(sc, &is_our_intr, &call_isr);
 	else {
 		ndis_disable_intr(sc);
 		call_isr = 1;
 	}
-	mtx_pool_unlock(ndis_mtxpool, sc->ndis_intrmtx);
+	mtx_unlock(&sc->ndis_intrmtx);
 
 	if ((is_our_intr || call_isr))
 		ndis_sched(ndis_intrtask, ifp, NDIS_SWI);
@@ -1617,32 +1607,22 @@ ndis_setstate_80211(sc)
 		device_printf (sc->ndis_dev, "set auth failed: %d\n", rval);
 #endif
 
-	/* Set SSID. */
-
-	len = sizeof(ssid);
-	bzero((char *)&ssid, len);
-	ssid.ns_ssidlen = ic->ic_des_esslen;
-	if (ssid.ns_ssidlen == 0) {
-		ssid.ns_ssidlen = 1;
-	} else
-		bcopy(ic->ic_des_essid, ssid.ns_ssid, ssid.ns_ssidlen);
-	rval = ndis_set_info(sc, OID_802_11_SSID, &ssid, &len);
-
-	if (rval)
-		device_printf (sc->ndis_dev, "set ssid failed: %d\n", rval);
-
 	len = sizeof(config);
 	bzero((char *)&config, len);
 	config.nc_length = len;
 	config.nc_fhconfig.ncf_length = sizeof(ndis_80211_config_fh);
-	rval = ndis_get_info(sc, OID_802_11_CONFIGURATION, &config, &len);   
-	if (rval == 0) { 
-		int chan;
+	rval = ndis_get_info(sc, OID_802_11_CONFIGURATION, &config, &len); 
 
-		chan = ieee80211_chan2ieee(ic, ic->ic_bss->ni_chan);
+	if (rval == 0 && ic->ic_ibss_chan != IEEE80211_CHAN_ANYC) { 
+		int chan, chanflag;
+
+		chan = ieee80211_chan2ieee(ic, ic->ic_ibss_chan);
+		chanflag = config.nc_dsconfig > 2500000 ? IEEE80211_CHAN_2GHZ :
+		    IEEE80211_CHAN_5GHZ;
 		if (chan != ieee80211_mhz2ieee(config.nc_dsconfig / 1000, 0)) {
 			config.nc_dsconfig =
-			    ic->ic_bss->ni_chan->ic_freq * 1000;
+			    ic->ic_ibss_chan->ic_freq * 1000;
+			ic->ic_bss->ni_chan = ic->ic_ibss_chan;
 			len = sizeof(config);
 			config.nc_length = len;
 			config.nc_fhconfig.ncf_length =
@@ -1654,10 +1634,24 @@ ndis_setstate_80211(sc)
 				    "DS config to %ukHz: %d\n",
 				    config.nc_dsconfig, rval);
 		}
-	} else
+	} else if (rval)
 		device_printf(sc->ndis_dev, "couldn't retrieve "
 		    "channel info: %d\n", rval);
 
+	/* Set SSID -- always do this last. */
+
+	len = sizeof(ssid);
+	bzero((char *)&ssid, len);
+	ssid.ns_ssidlen = ic->ic_des_esslen;
+	if (ssid.ns_ssidlen == 0) {
+		ssid.ns_ssidlen = 1;
+	} else
+		bcopy(ic->ic_des_essid, ssid.ns_ssid, ssid.ns_ssidlen);
+	rval = ndis_set_info(sc, OID_802_11_SSID, &ssid, &len);
+
+	if (rval)
+		device_printf (sc->ndis_dev, "set ssid failed: %d\n", rval);
+
 	return;
 }
 
diff --git a/sys/dev/if_ndis/if_ndisvar.h b/sys/dev/if_ndis/if_ndisvar.h
index c2bc6b6..2b2f47f 100644
--- a/sys/dev/if_ndis/if_ndisvar.h
+++ b/sys/dev/if_ndis/if_ndisvar.h
@@ -32,6 +32,9 @@
  * $FreeBSD$
  */
 
+#define NDIS_DEFAULT_NODENAME	"FreeBSD NDIS node"
+#define NDIS_NODENAME_LEN	32
+
 struct ndis_pci_type {
 	uint16_t		ndis_vid;
 	uint16_t		ndis_did;
@@ -87,8 +90,8 @@ struct ndis_softc {
 	struct resource		*ndis_res_am;	/* attribute mem (pccard) */
 	struct resource		*ndis_res_cm;	/* common mem (pccard) */
 	int			ndis_rescnt;
-	struct mtx		*ndis_mtx;
-	struct mtx		*ndis_intrmtx;
+	struct mtx		ndis_mtx;
+	struct mtx		ndis_intrmtx;
 	device_t		ndis_dev;
 	int			ndis_unit;
 	ndis_miniport_block	ndis_block;
@@ -124,6 +127,6 @@ struct ndis_softc {
 	int			ndis_mmapcnt;
 };
 
-#define NDIS_LOCK(_sc)		mtx_pool_lock(ndis_mtxpool, (_sc)->ndis_mtx)
-#define NDIS_UNLOCK(_sc)	mtx_pool_unlock(ndis_mtxpool, (_sc)->ndis_mtx)
+#define NDIS_LOCK(_sc)		mtx_lock(&(_sc)->ndis_mtx)
+#define NDIS_UNLOCK(_sc)	mtx_unlock(&(_sc)->ndis_mtx)