beee67e182
4 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Bill Paul
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a91395a9d0 |
Tests with my dual Opteron system have shown that it's possible
for code to start out on one CPU when thunking into Windows mode in ctxsw_utow(), and then be pre-empted and migrated to another CPU before thunking back to UNIX mode in ctxsw_wtou(). This is bad, because then we can end up looking at the wrong 'thread environment block' when trying to come back to UNIX mode. To avoid this, we now pin ourselves to the current CPU when thunking into Windows code. Few other cleanups, since I'm here: - Get rid of the ndis_isr(), ndis_enable_interrupt() and ndis_disable_interrupt() wrappers from kern_ndis.c and just invoke the miniport's methods directly in the interrupt handling routines in subr_ndis.c. We may as well lose the function call overhead, since we don't need to export these things outside of ndis.ko now anyway. - Remove call to ndis_enable_interrupt() from ndis_init() in if_ndis.c. We don't need to do it there anyway (the miniport init routine handles it, if needed). - Fix the logic in NdisWriteErrorLogEntry() a little. - Change some NDIS_STATUS_xxx codes in subr_ntoskrnl.c into STATUS_xxx codes. - Handle kthread_create() failure correctly in PsCreateSystemThread(). |
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Bill Paul
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21628ddbd6 |
This commit makes a big round of updates and fixes many, many things.
First and most importantly, I threw out the thread priority-twiddling implementation of KeRaiseIrql()/KeLowerIrq()/KeGetCurrentIrql() in favor of a new scheme that uses sleep mutexes. The old scheme was really very naughty and sought to provide the same behavior as Windows spinlocks (i.e. blocking pre-emption) but in a way that wouldn't raise the ire of WITNESS. The new scheme represents 'DISPATCH_LEVEL' as the acquisition of a per-cpu sleep mutex. If a thread on cpu0 acquires the 'dispatcher mutex,' it will block any other thread on the same processor that tries to acquire it, in effect only allowing one thread on the processor to be at 'DISPATCH_LEVEL' at any given time. It can then do the 'atomic sit and spin' routine on the spinlock variable itself. If a thread on cpu1 wants to acquire the same spinlock, it acquires the 'dispatcher mutex' for cpu1 and then it too does an atomic sit and spin to try acquiring the spinlock. Unlike real spinlocks, this does not disable pre-emption of all threads on the CPU, but it does put any threads involved with the NDISulator to sleep, which is just as good for our purposes. This means I can now play nice with WITNESS, and I can safely do things like call malloc() when I'm at 'DISPATCH_LEVEL,' which you're allowed to do in Windows. Next, I completely re-wrote most of the event/timer/mutex handling and wait code. KeWaitForSingleObject() and KeWaitForMultipleObjects() have been re-written to use condition variables instead of msleep(). This allows us to use the Windows convention whereby thread A can tell thread B "wake up with a boosted priority." (With msleep(), you instead have thread B saying "when I get woken up, I'll use this priority here," and thread A can't tell it to do otherwise.) The new KeWaitForMultipleObjects() has been better tested and better duplicates the semantics of its Windows counterpart. I also overhauled the IoQueueWorkItem() API and underlying code. Like KeInsertQueueDpc(), IoQueueWorkItem() must insure that the same work item isn't put on the queue twice. ExQueueWorkItem(), which in my implementation is built on top of IoQueueWorkItem(), was also modified to perform a similar test. I renamed the doubly-linked list macros to give them the same names as their Windows counterparts and fixed RemoveListTail() and RemoveListHead() so they properly return the removed item. I also corrected the list handling code in ntoskrnl_dpc_thread() and ntoskrnl_workitem_thread(). I realized that the original logic did not correctly handle the case where a DPC callout tries to queue up another DPC. It works correctly now. I implemented IoConnectInterrupt() and IoDisconnectInterrupt() and modified NdisMRegisterInterrupt() and NdisMDisconnectInterrupt() to use them. I also tried to duplicate the interrupt handling scheme used in Windows. The interrupt handling is now internal to ndis.ko, and the ndis_intr() function has been removed from if_ndis.c. (In the USB case, interrupt handling isn't needed in if_ndis.c anyway.) NdisMSleep() has been rewritten to use a KeWaitForSingleObject() and a KeTimer, which is how it works in Windows. (This is mainly to insure that the NDISulator uses the KeTimer API so I can spot any problems with it that may arise.) KeCancelTimer() has been changed so that it only cancels timers, and does not attempt to cancel a DPC if the timer managed to fire and queue one up before KeCancelTimer() was called. The Windows DDK documentation seems to imply that KeCantelTimer() will also call KeRemoveQueueDpc() if necessary, but it really doesn't. The KeTimer implementation has been rewritten to use the callout API directly instead of timeout()/untimeout(). I still cheat a little in that I have to manage my own small callout timer wheel, but the timer code works more smoothly now. I discovered a race condition using timeout()/untimeout() with periodic timers where untimeout() fails to actually cancel a timer. I don't quite understand where the race is, using callout_init()/callout_reset()/callout_stop() directly seems to fix it. I also discovered and fixed a bug in winx32_wrap.S related to translating _stdcall calls. There are a couple of routines (i.e. the 64-bit arithmetic intrinsics in subr_ntoskrnl) that return 64-bit quantities. On the x86 arch, 64-bit values are returned in the %eax and %edx registers. However, it happens that the ctxsw_utow() routine uses %edx as a scratch register, and x86_stdcall_wrap() and x86_stdcall_call() were only preserving %eax before branching to ctxsw_utow(). This means %edx was getting clobbered in some cases. Curiously, the most noticeable effect of this bug is that the driver for the TI AXC110 chipset would constantly drop and reacquire its link for no apparent reason. Both %eax and %edx are preserved on the stack now. The _fastcall and _regparm wrappers already handled everything correctly. I changed if_ndis to use IoAllocateWorkItem() and IoQueueWorkItem() instead of the NdisScheduleWorkItem() API. This is to avoid possible deadlocks with any drivers that use NdisScheduleWorkItem() themselves. The unicode/ansi conversion handling code has been cleaned up. The internal routines have been moved to subr_ntoskrnl and the RtlXXX routines have been exported so that subr_ndis can call them. This removes the incestuous relationship between the two modules regarding this code and fixes the implementation so that it honors the 'maxlen' fields correctly. (Previously it was possible for NdisUnicodeStringToAnsiString() to possibly clobber memory it didn't own, which was causing many mysterious crashes in the Marvell 8335 driver.) The registry handling code (NdisOpen/Close/ReadConfiguration()) has been fixed to allocate memory for all the parameters it hands out to callers and delete whem when NdisCloseConfiguration() is called. (Previously, it would secretly use a single static buffer.) I also substantially updated if_ndis so that the source can now be built on FreeBSD 7, 6 and 5 without any changes. On FreeBSD 5, only WEP support is enabled. On FreeBSD 6 and 7, WPA-PSK support is enabled. The original WPA code has been updated to fit in more cleanly with the net80211 API, and to eleminate the use of magic numbers. The ndis_80211_setstate() routine now sets a default authmode of OPEN and initializes the RTS threshold and fragmentation threshold. The WPA routines were changed so that the authentication mode is always set first, followed by the cipher. Some drivers depend on the operations being performed in this order. I also added passthrough ioctls that allow application code to directly call the MiniportSetInformation()/MiniportQueryInformation() methods via ndis_set_info() and ndis_get_info(). The ndis_linksts() routine also caches the last 4 events signalled by the driver via NdisMIndicateStatus(), and they can be queried by an application via a separate ioctl. This is done to allow wpa_supplicant to directly program the various crypto and key management options in the driver, allowing things like WPA2 support to work. Whew. |
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Bill Paul
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0a5c534cd2 |
In winx32_wrap.S, preserve return values in the fastcall and regparm
wrappers by pushing them onto the stack rather than keeping them in %esi and %edi. |
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Bill Paul
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d02239a3af |
Create new i386 windows/bsd thunking layer, similar to the amd64 thunking
layer, but with a twist. The twist has to do with the fact that Microsoft supports structured exception handling in kernel mode. On the i386 arch, exception handling is implemented by hanging an exception registration list off the Thread Environment Block (TEB), and the TEB is accessed via the %fs register. The problem is, we use %fs as a pointer to the pcpu stucture, which means any driver that tries to write through %fs:0 will overwrite the curthread pointer and make a serious mess of things. To get around this, Project Evil now creates a special entry in the GDT on each processor. When we call into Windows code, a context switch routine will fix up %fs so it points to our new descriptor, which in turn points to a fake TEB. When the Windows code returns, or calls out to an external routine, we swap %fs back again. Currently, Project Evil makes use of GDT slot 7, which is all 0s by default. I fully expect someone to jump up and say I can't do that, but I couldn't find any code that makes use of this entry anywhere. Sadly, this was the only method I could come up with that worked on both UP and SMP. (Modifying the LDT works on UP, but becomes incredibly complicated on SMP.) If necessary, the context switching stuff can be yanked out while preserving the convention calling wrappers. (Fortunately, it looks like Microsoft uses some special epilog/prolog code on amd64 to implement exception handling, so the same nastiness won't be necessary on that arch.) The advantages are: - Any driver that uses %fs as though it were a TEB pointer won't clobber pcpu. - All the __stdcall/__fastcall/__regparm stuff that's specific to gcc goes away. Also, while I'm here, switch NdisGetSystemUpTime() back to using nanouptime() again. It turns out nanouptime() is way more accurate than just using ticks(). On slower machines, the Atheros drivers I tested seem to take a long time to associate due to the loss in accuracy. |