2b94c69d1d
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.
57 lines
2.4 KiB
C
57 lines
2.4 KiB
C
/*
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* Copyright (c) 2003
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* Bill Paul <wpaul@windriver.com>. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Bill Paul.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR THE VOICES IN HIS HEAD
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _HAL_VAR_H_
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#define _HAL_VAR_H_
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#ifdef __amd64__
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#define NDIS_BUS_SPACE_IO AMD64_BUS_SPACE_IO
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#define NDIS_BUS_SPACE_MEM AMD64_BUS_SPACE_MEM
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#else
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#define NDIS_BUS_SPACE_IO I386_BUS_SPACE_IO
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#define NDIS_BUS_SPACE_MEM I386_BUS_SPACE_MEM
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#endif
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extern image_patch_table hal_functbl[];
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__BEGIN_DECLS
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__stdcall extern uint8_t hal_lock(/*kspin_lock * */void);
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__stdcall extern void hal_unlock(/*kspin_lock *, uint8_t*/void);
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__stdcall extern uint8_t hal_raise_irql(/*uint8_t*/ void);
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__stdcall extern void hal_lower_irql(/*uint8_t*/ void);
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__stdcall extern uint8_t hal_irql(void);
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__END_DECLS
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#endif /* _HAL_VAR_H_ */
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