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571 lines
20 KiB
Plaintext
*** This file contains messages I've culled off the net as well
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as previous discussions all of which have useful info on fixes
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that need to be added to ReactOS. messages are between five
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dashes on a line by themselves. If you implement the fix
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reffered to in a message, feel free to delete it from the file.
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Rex ***
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-----
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Subject: [ros-kernel] Inside the Boot Process
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Date: Mon, 22 Mar 1999 22:05:47 +0100
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From: Emanuele Aliberti <ea@iol.it>
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For those working on the boot loader: in WinNt Magazine november 1998
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issue (http://www.winntmag.com/) there is a detailed description, by
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Mark Russinovich, of the rôle the MBR, NTLDR, boot.ini, ntdetect.com...
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play in the boot process ("Inside the Boot Process, Part 1").
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-----
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Yes with DPCs, KeDrainDpcQueue should go to HIGH_LEVEL because
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it needs to synchronize with KeInsertDpcQueue. Also the idle thread
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should run at DISPATCH_LEVEL and regularly drain the dpc queue, that
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way if an irq happens and the dpc can't be executed immediately it
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will be executed as soon as the processor is idle rather than
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waiting for the next timer tick
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-----
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About the console driver, I think it might be quite useful to have a simple
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way for apps to print to the screen for debugging. But when the kernel is more
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stable, console handling should be moved to user level because console printing
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needs to know about windows and so on which can only be done at user level.
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-----
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Subject: Re: IMSAMP-how to avoid rebooting?
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Date: 9 Nov 1998 00:40:32 -0000
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From: Charles Bryant <n51190709.ch@chch.demon.co.uk>
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Newsgroups: comp.os.ms-windows.programmer.nt.kernel-mode
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References: 1, 2 , 3 , 4
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In article <un264wzle.fsf@xxx.yyy.zzz>, David C. <qqqq@xxx.yyy.zzz> wrote:
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>The reason it won't unload when something is bound to it is the same
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>reason you can't unload any other driver that has an open client. If
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>you install any driver, and have a user program (or another driver) open
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>a handle to it, and then give the "net stop" command to unload it,
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>you'll find that the unload will be delayed until the user program
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>closes its handle.
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When developing a driver I found this to be a considerable nuisance.
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Frequently a bug would leave an IRP stuck in the driver and I
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couldn't unload and reload a fixed version. While reading NTDDK.H I
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found a suspicious constant and discovered that the Flags field in
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the device (the one which you OR in DO_BUFFERED_IO or DO_DIRECT_IO)
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has a bit called DO_UNLOAD_PENDING. By experiment I confirmed that
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this bit is set when you do 'net stop', so a driver can check it
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periodically (e.g. from a timer DPC every ten seconds) and cancel all
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queued IRPs if it is found to be set.
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Since this is not documented anywhere that I can find, it might be
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unwise to rely on it for production code, but it is very useful for
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debugging. Maybe someone with internals knowledge can comment on the
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reliability of it.
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-----
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Subject: Re: Kernel bugs
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Date: Fri, 23 Oct 1998 12:08:36 -0700
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From: rex <rex@lvcablemodem.com>
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To: Jason Filby <jasonfilby@yahoo.com>
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References: 1
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Jason Filby wrote:
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> Hi,
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>
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> Ok -- here's most of what I get when I press a key:
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>
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> Page fault detected at address 1fd4 with eip c042f794
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> Recursive page fault detected
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> Exception 14(2)
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> CS:EIP 20:c042f794
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>
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> Rex -- do you know of anyway to find out which function in what file
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> is causing the exception? I know that for problems in the kernel, you
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> just look in the ntoskrnl\kernel.sym file and find the EIP value which
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> matches the one given in the exception debug text. But what about
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> modules? How can we track exceptions that occur in functions in modules?
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>
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I know this is a little belated, but I thought I'd take astab at answering
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this anyway. add an option to the
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makefile for the module to generate a listing file with
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symbol information. Then, on a boot test, note the
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address that the module is loaded at, and subtract
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this from the EIP value. add any offset used in the
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module link specification (I dont think there currently
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is one), and look for the last symbol with a lower
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address offset.
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Brian, I have an idea on how to make this exception
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dump information a little more useful. We should
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have the load information for the load modules
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in memory somewhere. Perhaps the exception
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dump could check offending addresses to see if
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they lie in the kernel or in a module, and if they
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lie in a module the proper offset could be subtracted
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and this number could be displayed seperately. If
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I get a chance today, I'll make this change and send
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it to ya.
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Rex.
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-----
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Subject: Re: Question on "Sending buffers on the stack to asynchronous DeviceIoControl with buffered I/O"
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Date: Mon, 16 Nov 1998 11:24:57 -0800
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From: "-Paul" <paulsan@microsoftSPAM.com>
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Organization: Microsoft Corp.
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Newsgroups: microsoft.public.win32.programmer.kernel, comp.os.ms-windows.programmer.nt.kernel-mode
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References: 1
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Radu, I post the following information occassionally for questions such as
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yours. I hope it helps.
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-Paul
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Here is an explanation of buffers and DeviceIoControl.
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First, here are the parameters,
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BOOL DeviceIoControl(
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HANDLE hDevice, // handle to device of interest
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DWORD dwIoControlCode, // control code of operation to perform
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LPVOID lpInBuffer, // pointer to buffer to supply input data
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DWORD nInBufferSize, // size of input buffer
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LPVOID lpOutBuffer, // pointer to buffer to receive output data
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DWORD nOutBufferSize, // size of output buffer
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LPDWORD lpBytesReturned, // pointer to variable to receive output byte
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count
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LPOVERLAPPED lpOverlapped // pointer to overlapped structure for
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asynchronous operation
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);
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METHOD_BUFFERED
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user-mode perspective
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lpInBuffer - optional, contains data that is written to the driver
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lpOutBuffer - optional, contains data that is read from the driver after
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the call has completed
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lpInBuffer and lpOutBuffer can be two buffers or a single shared buffer.
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If a shared buffer, lpInBuffer is overwritten by lpOutBuffer.
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I/O Manager perspective
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examines nInBufferSize and nOutBufferSize. Allocates memory from non-paged
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pool and puts the address of this pool in Irp->AssociatedIrp.SystemBuffer.
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The size of this buffer is equal to the size of the larger of the two
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bufferes. This buffer is accessible at any IRQL.
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copies nInBufferSize to irpSp->Parameters.DeviceIoControl.InputBufferLength
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copies nOutBufferSize to
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irpSp->Parameters.DeviceIoControl.OutputBufferLength
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copies contents of lpInBuffer to SystemBuffer allocated above
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calls your driver
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Device Driver perspective
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you have one buffer, Irp->AssociatedIrp.SystemBuffer. You read input data
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from this buffer and you write output data to the same buffer, overwriting
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the input data.
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Before calling IoCompleteRequest, you must
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- set IoStatus.Status to an approriate NtStatus
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- if IoStatus.Status == STATUS_SUCCESS
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set IoStatus.Information to the
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number of bytes you want copied
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from the SystemBuffer back into
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lpOutBuffer.
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I/O Manager Completion Routine perspective
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looks at IoStatus block, if IoStatus.Status = STATUS_SUCCESS, copies the
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number of bytes specified by IoStatus.Information from
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Irp->AssociatedIrp.SystemBuffer into lpOutBuffer
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completes the request
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METHOD_IN_DIRECT
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user-mode perspective
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lpInBuffer - optional, contains data that is written to the driver. This
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buffer is used in the exact same fashion as METHOD_BUFFERED. To avoid
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confusion, mentally rename this buffer to lpControlBuffer. This is
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typically a small, optional buffer that might contain a control structure
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with useful information for the device driver. This buffer is smal and is
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double buffered.
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lpOutBuffer - NOT OPTIONAL, This LARGE buffer contains data that is read by
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the driver. To avoid confusion, mentally rename this buffer to
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lpDataTransferBuffer. This is physically the same buffer that the device
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driver will read from. There is no double buffering. Technically, this
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buffer is still optional, but since you are using this buffering method,
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what would be the point???
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I/O Manager perspective
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If lpInBuffer exists, allocates memory from non-paged pool and puts the
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address of this pool in Irp->AssociatedIrp.SystemBuffer. This buffer is
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accessible at any IRQL.
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copies nInBufferSize to irpSp->Parameters.DeviceIoControl.InputBufferLength
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copies nOutBufferSize to
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irpSp->Parameters.DeviceIoControl.OutputBufferLength
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copies contents of lpInBuffer to SystemBuffer allocated above
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So far this is completely identical to METHOD_BUFFERED. Most likely
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lpInBuffer (mentally renamed to lpControlBuffer) is very small in size.
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For lpOutBuffer (mentally renamed to lpDataTransferBuffer), an MDL is
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allocated. lpOutBuffer is probed and locked into memory. Then, the user
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buffer virtual addresses are checked to be sure they are readable in the
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caller's access mode.
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The MDL is address is stored in Irp->MdlAddress.
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Your driver is called.
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Device Driver perspective
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The device driver can read the copy of lpOutBuffer via
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Irp->AssociatedIrp.SystemBuffer. Anything written by the device driver to
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this buffer is lost. The I/O Manager does not copy any data back to the
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user-mode buffers as it did in the completion routine for METHOD_BUFFERED.
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Art Baker's book is wrong in this respect (page 168, "data going from the
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driver back to the caller is passed through an intermediate system-space
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buffer" and page 177, "When the IOCTL IRP is completed, the contents of the
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system buffer will be copied back into the callers original output buffer".
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The device driver accesses the Win32 buffer directly via Irp->MdlAddress.
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The driver uses whatever Mdl API's to read the buffer. Usually, this
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buffer is to be written to some mass storage media or some similar
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operation. Since this is a large data transfer, assume a completion
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routine is required.
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mark the Irp pending
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queue it
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return status pending
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Device Driver Completion Routine perspective
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standard completion routine operations
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set IoStatus.Status to an approriate NtStatus
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IoStatus.Information is not needed
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completete the request
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I/O Manager Completion Routine perspective
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standard I/O Manager completion routine operations
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unmap the pages
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deallocate the Mdl
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complete the request
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METHOD_OUT_DIRECT
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user-mode perspective
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lpInBuffer - optional, contains data that is written to the driver. This
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buffer is used in the exact same fashion as METHOD_BUFFERED. To avoid
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confusion, mentally rename this buffer to lpControlBuffer. This is
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typically a small, optional buffer that might contain a control structure
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with useful information for the device driver. This buffer is smal and is
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double buffered.
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lpOutBuffer - NOT OPTIONAL, This LARGE buffer contains data that is written
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by the driver and read by the wer-mode application when the request is
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completed. To avoid confusion, mentally rename this buffer to
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lpDataTransferBuffer. This is physically the same buffer that the device
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driver will write to. There is no double buffering. Technically, this
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buffer is still optional, but since you are using this buffering method,
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what would be the point???
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I/O Manager perspective
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If lpInBuffer exists, allocates memory from non-paged pool and puts the
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address of this pool in Irp->AssociatedIrp.SystemBuffer. This buffer is
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accessible at any IRQL.
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copies nInBufferSize to irpSp->Parameters.DeviceIoControl.InputBufferLength
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copies nOutBufferSize to
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irpSp->Parameters.DeviceIoControl.OutputBufferLength
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copies contents of lpInBuffer to SystemBuffer allocated above
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So far this is completely identical to METHOD_BUFFERED. Most likely
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lpInBuffer (mentally renamed to lpControlBuffer) is very small in size.
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For lpOutBuffer (mentally renamed to lpDataTransferBuffer), an MDL is
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allocated. lpOutBuffer is probed and locked into memory. Then the user
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buffer's addresses are checked to make sure the caller could write to them
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in the caller's access mode.
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The MDL is address is stored in Irp->MdlAddress.
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Your driver is called.
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Device Driver perspective
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The device driver can read the copy of lpOutBuffer via
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Irp->AssociatedIrp.SystemBuffer. Anything written by the device driver to
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this buffer is lost.
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The device driver accesses the Win32 buffer directly via Irp->MdlAddress.
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The driver uses whatever Mdl API's to write data to the buffer. Usually,
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this buffer is to be read from some mass storage media or some similar
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operation. Since this is a large data transfer, assume a completion
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routine is required.
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mark the Irp pending
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queue it
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return status pending
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Device Driver Completion Routine perspective
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standard completion routine operations
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set IoStatus.Status to an approriate NtStatus
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IoStatus.Information is not needed
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completete the request
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I/O Manager Completion Routine perspective
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standard I/O Manager completion routine operations
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unmap the pages
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deallocate the Mdl
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complete the request
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METHOD_NEITHER
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I/O Manager perspective
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Irp->UserBuffer = lpOutputBuffer;
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IrpSp->Parameters.DeviceIoControl.Type3InputBuffer = lpInputBuffer;
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No comments here. Don't use METHOD_DIRECT unless you know what you are
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doing. Simple rule.
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If your IOCtl involves no data transfer buffers, then METHOD_NEITHER is the
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fastest path through the I/O Manager that involves an Irp.
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Final Comment
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Don't touch Irp->UserBuffer. This is a bookmark for the I/O Manager. Two
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major problems can occur. 1 - page fault at high IRQL, or 2 - you write
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something to Irp->UserBuffer and the I/O Manager overwrites you in its
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completion routine. File systems access Irp->UserBuffer, but FSD writers
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know all of the above and know when it is safe to touch Irp->UserBuffer.
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Radu Woinaroski wrote in message <364F8F6E.2434B010@scitec.com.au>...
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>Hello,
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>
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>I have a kernel-mode device driver that accepts a number of IoControl
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>commands that use buffered data transfer (METHOD_BUFFERED).
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>
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>A user mode API provides a higher level access then the DeviceIoControl
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>function.
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>
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>The function is implemented like that
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>
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>BOOL
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Something(
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> HANDLE hDevice ,
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> int param1,
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> int param2,
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> DWORD * pReturn,
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> LPOVERLAPPED pOverlapped)
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>{
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> // here a data buffer on the stack sent to asynchronous DeviceIoControl
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>call
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> int aDataIn[2];
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> aDataIn[0] = param1;
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> aDataIn[1] = param2;
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>
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> return DeviceIoControl(
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> hDevice,
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> DO_SOMETHING_IO,
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> aDataIn,
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> sizeof(int)*2,
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> pReturn,
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> sizeof(DWORD),
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> pOverlapped);
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>}
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>
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>The aDataIn buffer will not exist after DeviceIoControl returns (and
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>when the I/O operation terminates). I know that for buffered IO the
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>input data buffer is copyed by de IOManager to a nonpaged-pool area
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>before passing the request to driver dispatch routine (DeviceControl).
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>At the point of calling the dispatch routine (DeviceControl) the driver
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>runs in the context of the calling thread so DeviceIoControl hasn't
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>returned yet (?? or so I think) so aDataI
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n will still be valid at the
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>time IOManager copyes it to its buffer. So, this apears to work ok (at
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>least in my opinion).
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>
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>Does I/O Manager use the Input buffer from the call to the Win32
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>DeviceIoControl any where else after the first copy ?
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>
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>Is there any reason why this approach (passing a buffer on the stack to
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>a asynchronous DeviceIoControl that uses buffered I/O) wouldn't work ?
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>
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>Allocating buffers from heap and deleting them on IO completion while
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>managing asynchronous IO seems too much work ;-) .
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>
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>Thanks in advance for your opinions
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>Radu W.
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>
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>--
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>Radu Woinaroski
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>Scitec
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>Sydney, Australia
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>Radu.Woinaroski@scitec.com.au
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-----
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Subject: Re: PCI ISR problem
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Date: Fri, 20 Nov 1998 18:04:48 GMT
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From: jeh@cmkrnl.com (Jamie Hanrahan)
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Organization: Kernel Mode Systems, San Diego, CA
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Newsgroups: comp.os.ms-windows.programmer.nt.kernel-mode
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References: 1
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On Thu, 19 Nov 1998 15:46:13 -0600, Eric Gardiner
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<eric.gardiner@natinst.com> wrote:
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>I'm having problems with NT4 not hooking the interrupt line indicated by
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>a PCI device. Here's what I'm doing:
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>
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>1) Enumerating the PCI buses on the system (using HalGetBusData) until
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>I find my device.
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>2) Once my device is found, I read the "Interrupt Line Register" in the
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>device's PCI config space to determine what interrupt level to pass to
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>HalGetInterruptVector.
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Whups! No. Call HalAssignSlotResources and look at the returned
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CM_RESOURCE_LIST to find the vector, level, port addresses, etc., for
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your device. (Then pass the returned CM_RESOURCE_LIST to ExFreePool.)
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See Knowledge Base article Q152044.
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--- Jamie Hanrahan, Kernel Mode Systems, San Diego CA (jeh@cmkrnl.com)
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Drivers, internals, networks, applications, and training for VMS and Windows NT
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NT kernel driver FAQ, links, and other information: http://www.cmkrnl.com/
|
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|
Please post replies, followups, questions, etc., in news, not via e-mail.
|
|
-----
|
|
Subject: Re: IRP canceling
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|
Date: Mon, 23 Nov 1998 09:05:47 -0500
|
|
From: Walter Oney <waltoney@oneysoft.com>
|
|
Organization: Walter Oney Software
|
|
Newsgroups: comp.os.ms-windows.programmer.nt.kernel-mode
|
|
References: 1
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|
|
|
Seol,Keun Seok wrote:
|
|
> But, if the IRP was the CurrentIrp of the Device Object,
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> the Driver's Start I/O routine will try to process the IRP.
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> In the DDK help, the Start I/O routine MUST check the current IRP's
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> Cancel bit.
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> If set, Start I/O routine must just return.
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>
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> But I think that the IRP already completed should not be accessed.
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You're absolutely right. I recommend the following code in a standard
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StartIo routine to avoid the problem you point out:
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|
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VOID StartIo(PDEVICE_OBJECT DeviceObject, PIRP Irp)
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{
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KIRQL oldirql;
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IoAcquireCancelSpinLock(&oldirql);
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if (Irp != DeviceObject->CurrentIrp || Irp->Cancel)
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{
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IoReleaseCancelSpinLock(oldirql);
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return;
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}
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else
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{
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IoSetCancelRoutine(Irp, NULL);
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|
IoReleaseCancelSpinLock(oldirql);
|
|
}
|
|
. . .
|
|
}
|
|
|
|
This dovetails with a standard cancel routine:
|
|
|
|
VOID CancelRoutine(PDEVICE_OBJECT DeviceObject, PIRP Irp)
|
|
{
|
|
if (DeviceObject->CurrentIrp == Irp)
|
|
{
|
|
IoReleaseCancelSpinLock(Irp->CancelIrql);
|
|
IoStartNextPacket(DeviceObject, TRUE);
|
|
}
|
|
else
|
|
{
|
|
KeRemoveEntryDeviceQueue(&DeviceObject->DeviceQueue,
|
|
&Irp->Tail.Overlay.DeviceQueueEntry);
|
|
IoReleaseCancelSpinLock(Irp->CancelIrql);
|
|
}
|
|
Irp->IoStatus.Status = STATUS_CANCELLED;
|
|
Irp->IoStatus.Information = 0;
|
|
IoCompleteRequest(Irp, IO_NO_INCREMENT);
|
|
}
|
|
|
|
You need to remember that the C language specification requires that
|
|
evaluation of boolean operators short circuit when the result is known.
|
|
So, if StartIo discovers that the Irp it got as an argument is not the
|
|
same as CurrentIrp, it will not attempt to evaulate Irp->Cancel.
|
|
|
|
Now, as to why this works: StartIo gets called either by IoStartPacket
|
|
or IoStartNextPacket. Each of them will grab the cancel spin lock and
|
|
set CurrentIrp, then release the spin lock and call StartIo. If someone
|
|
should sneak in on another CPU and cancel this very same IRP, your
|
|
cancel routine will immediately release the spin lock and call
|
|
IoStartNextPacket. One of two things will then happen. IoStartNextPacket
|
|
may succeed in getting the cancel spin lock, whereupon it will nullify
|
|
the CurrentIrp pointer. If another IRP is on the queue, it will remove
|
|
it from the queue, set CurrentIrp to point to this *new* IRP, release
|
|
the spin lock, and call StartIo. [You now have two instances of StartIo
|
|
running on two different CPUs for two different IRPs, but it's not a
|
|
problem because they won't be able to interfere with each other.]
|
|
Meanwhile, your original instance of StartIo gets the cancel spin lock
|
|
and sees that CurrentIrp is not equal to the IRP pointer it got as an
|
|
argument, so it gives up.
|
|
|
|
The second way this could play out is that StartIo gets the cancel lock
|
|
before IoStartNextPacket does. In this case, CurrentIrp is still
|
|
pointing to the IRP that's in the process of being cancelled and that
|
|
StartIo got as an argument. But this IRP hasn't been completed yet (the
|
|
CPU that's running your cancel routine is spinning inside
|
|
IoStartNextPacket and therefore hasn't gotten to calling
|
|
IoCompleteRequest yet), so no-one will have been able to call IoFreeIrp
|
|
to make your pointer invalid.
|
|
|
|
People may tell you that you should be using your own queues for IRPs so
|
|
you can avoid bottlenecking the system on the global cancel spin lock.
|
|
That's true enough, but doing it correctly with Plug and Play and Power
|
|
management things in the way is gigantically complicated. There's a
|
|
sample in the NT 5 beta-2 DDK called CANCEL that shows how to manage
|
|
your own queue if you don't worry about PNP and POWER. I hear tell of an
|
|
upcoming MSJ article by a Microsoft developer that may solve the
|
|
complete problem.
|
|
-----
|
|
The END.
|