1. Future Directions For The Windows CE Device Driver Architecture
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Future Directions For The Windows CE Device Driver Architecture
Juggs Ravalia Program Manager Windows Devices Core OS Microsoft Corporation
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Agenda The Windows CE 6.0 Beta Driver Architecture
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Agenda
The Windows CE 6.0 Beta Driver Architecture
Windows CE User Mode Driver Framework
Desktop versus Windows CE Drivers Comparison
Porting Drivers from ← Windows CE 5.0
New Kernel Memory Model
Porting Aspects
PQD/Secure Coping
Quick Reference Guide
Porting Code Snippet
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

3. 4/19/ :45 PM
Drivers Architecture
Drivers will be split into kernel mode and user mode
Kernel Mode
Performance critical
Fully trusted with full access to kernel memory
User Mode
Less critical and lower privilege
Still need to be trusted
OEM can choose where to load its driver (in kernel or in user mode)
Drivers that access k-mode address directly need to be in kernel
Except for some block drivers used by FS and NDIS based Networking drivers
The overall structure of the drivers remain the same
Main changes are in how the drivers access client memory
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

4. 4/19/ :45 PM
Kernel Mode Drivers
Will be loaded in the kernel space by device.dll/gwes.dll
Will have full access to the kernel’s data structures and memory
APIs do not change, will use the same APIs as user mode drivers
Link to a kernel version of coredll.dll called kcoredll.dll
Thin layer for API compatibility
Directly links the services together without thunk layer
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

5. Device Driver Architecture Stream Interface Device Driver Model
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Device Driver Architecture Stream Interface Device Driver Model
Device Manager
Stream Interface
Stream Interface
Stream Interface (DDI)
Monolithic Stream Interface Driver
MDD
NDIS
NDIS Wrapper
NDIS Miniport
Layered Driver
NDIS Wrapper
Card&Socket Services
Card and Socket Services
Device Driver Service Provider Interface (DDSI)
PDD
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

6. Device Driver Architecture Native Device Driver Model
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Device Driver Architecture Native Device Driver Model
Graphics, Windowing, and Events Subsystem (GWES)
Device Driver Interface (DDI)
Device Driver Interface (DDI)
Monolithic Native Driver
MDD
Layered Native Driver
Device Driver Service Provider Interface (DDSI)
The DDI Interface
of Native Drivers is
defined by Microsoft
for each device class
PDD
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

7. User Mode Drivers Also managed by Device Manager Hosted in udevice.exe
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User Mode Drivers
Also managed by Device Manager
Hosted in udevice.exe
Mostly the same APIs as Kernel Mode
UM Drivers lose Kernel privileges
No access to kernel structures or memory
Cannot call certain kernel only APIs like VirtualCopyEx
Kernel will marshal first level parameters during system calls
Must be trusted – signed
Examples
Expansion buses like USB and SDIO
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

8. Why Use UMDF? Recoverability Increased Security Improved Stability
Correct Privileges
Increased
Security
Recoverability
No “Blue-Screens”
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Driver Isolation
Improved
Stability
Why Use UMDF?
Improved stability
User-Mode Drivers are isolated from other drivers
Kernel is isolated from user-mode drivers
Increased security
Compromised driver does not crash the system
Lower privileges restrain a compromised driver
Recoverability
System can recover after a driver crash – no “blue-screens” (Device-Hangs in CE)
The driver can be restarted without rebooting
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

9. User Mode Driver Loading
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User Mode Driver Loading
User Mode Driver Host Process
udevice.exe
User Application
XXX_Init(…) 8
User Mode Driver
ActivateDevice(Ex)
HANDLE Returned 1 10
User Mode
CreateProcess(,,Volume Name)
XXX_Init forwarded to UM Driver Host
Kernel Mode 4 9
Device Context 3 7
Device Manager 6 2
Reflector Service 5 9 10
HANDLE Returned 1
Provided by:
Microsoft
Parent Bus Driver
IHV
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. Registry For User Mode Driver
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Registry For User Mode Driver
User Mode Driver Host process is launched and managed by certain registry settings
Example of the registry keys for Group ID 2
[HKEY_LOCAL_MACHINE\Drivers\ProcGroup_0002]
"ProcName” = "udevice.exe“; Dummy for Service.exe now
"ProcVolPrefix” = "$services“
"Privilege” = dword:xxxxxx ; Processor Privilege Bit Setting
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\Serial]
"SysIntr” = dword:13
"IoBase” = dword:02F8
"IoLen” = dword:8
"Flags” = dword:10 (DEVFLAGS_LOAD_AS_USERPROC - 0x10)
"ProcGroup” = dword:2
"IsrDll” = “isr16550.dll"
"IsrHandler“ = "ISRHandler"
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. Reflector Service Nucleus of UMDF
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Reflector Service
Nucleus of UMDF
One Reflector Object for each UM Driver
Launches and manages UMD Host process
Forwards device request to UM Driver housed in the UM Driver Host
Maps first level pointers from caller to UM Driver process space
Serves UMDs on kernel-privilege actions
Hero that makes UMDs act as KMDs from the User Application’s perspective
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

12. User Mode Driver Host Framework
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User Mode Driver Host Framework
Supports Multiple UMD Host Processes
One UMD Host can supports Multiple UMDs
UMD Host can be extended for special need like Services.exe
The Privileges of a UMD are determined by the UMD Host Process
UMD Host mounts a Volume Service API, used by the Kernel Reflector for communication
Parses the Reflectors’ requests and performs the required action
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

13. User Mode Driver I/O Data Flow
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User Mode Driver I/O Data Flow
Entry DEVFS_IoControl(…) hit
User Mode Driver Host Process
Entry UD_DevDeviceIoControl(…) hit
User Application
DeviceIOControl( HANDLE,
dwIOCTL, plnPtr, dwlnLen,
NULL, 0, NULL, NULL) 5
Unpacks FNIOCTL_PARAM
Calls Driver’s
XXX_IOControl
User Mode Driver 4 1
User Mode 6 3
Kernel Mode 8
Reflector Service
DM_DevDeviceIOControl(…)
Entry Hit
Device Manager 2
VirtualAllocCopyEx(GetCallerProcess(),
hUMHost,pInPtr,dwInLen,PAGE_READWRITE)
Packages FNIOCTL_PARAM Struct
CeFsIoControl(userProcVolume,
IOCTL_USERDRIVER_IOCTL,ptrFnIoCtlParam
sizeof(FNIOCTL_PARAM), …);
DeviceIOControl( CeDuplicateHandle,
IOCTL_USERDRIVER_IOCTL,ptrFnIoCtlParam
sizeof(FNIOCTL_PARAM), …);
Reflector_Control( dwContext,
dwIOCTR, pInPtr, dwInLen, …) 7
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

14. User Mode Driver Data Flow Summary
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User Mode Driver Data Flow Summary
User Mode Driver Host Process
udevice.exe
User Application 4
User Mode Driver 1 6
User Mode
Kernel Mode 5 3
Device Manager
Reflector Service 2 1
Provided by:
Microsoft
Parent Bus Driver
IHV
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

15. Windows XP/CE Driver Architectures
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Windows XP/CE Driver Architectures
Similarities
Support Kernel Drivers
Offer UMDF to host User Mode Drivers
File Handle based APIs to User Apps
Differences
Device Manager
Power Manager
Asynchronous versus Synchronous Support
Interrupt Model – DPCs versus ISTs
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

16. Porting Drivers To CE 6.0 Drivers will mostly run in the kernel
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Porting Drivers To CE 6.0
Drivers will mostly run in the kernel
Driver writers must focus on security and stability more then ever before
Maximum backwards-compatibility is maintained, but some driver modifications are required
Deprecated APIs
Asynchronous buffer access will require driver modifications
User Interface Handling
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

17. Windows CE 5.0 Memory Model
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Windows CE 5.0 Memory Model
Kernel
2 GB Kernel Space
Shared Memory
Single 2 GB VM for all Processes
Slot 34
Slot 33
Slot 32
32 Slots for Processes
Slot 31
: :
Slot 6
Slot 5 – Services.exe
Slot 4 – GWES.exe
Slot 3 – Device.exe
Execution Slot and Shared DLL Slot
Slot 2 – Filesys.exe
Slot 1 – ROM DLLs
Slot 0 – Execution
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

18. Kernel Filesystem GWES Drivers
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New CE Memory Model
Kernel Filesystem GWES Drivers
2 GB Kernel Space
Process Code
User VM
User VM Memory Mapped files
User DLLs
2 GB per Process
32 K Process
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

19. Driver Migration Summary
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Driver Migration Summary
Key porting topics:
Access checking
Marshalling
Thread permissions
Secure copy
User interface
User mode drivers
Quick reference guide
Porting sample code snippet
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

20. 4/19/ :45 PM
Access Checking
In <=CE 5.0, MapCallerPtr was used to validate memory pointed to by either
Pointer parameters or
Embedded pointers
With CE 6.0 Beta, the kernel performs full access check on pointer parameters
Thus, drivers only need to access check embedded pointers
Use kernel access-check APIs - CeOpenCallerBuffer/CeCloseCallerBuffer to verify embedded pointers
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

21. Access Check Diagram 2 GB Kernel Space 2 GB per Process Kernel NK.EXE
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Access Check Diagram
Kernel
NK.EXE
2 GB Kernel Space
Driver.dll
Kernel Checks
this Buffer
Hello.exe
Embedded Ptr
2 GB per Process
Driver Calls
CeOpenCallerBuffer
to check
this Buffer
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

22. Access Checks struct MyStruct { UCHAR *pEmbedded; DWORD dwSize; };
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Access Checks
struct MyStruct { UCHAR *pEmbedded; DWORD dwSize; };
Windows CE 5.0 and prior versions
// In XXX_IOControl...
g_pMappedEmbedded = MapCallerPtr(p->pEmbedded);
// Fail if g_pMappedEmbedded == NULL ...
// Now in the New OS Version
// In XXX_IOControl...
hr = CeOpenCallerPtr( (PVOID*) &g_pMappedEmbedded, pInput->pEmbedded, pInput->dwSize, ARG_I_PTR, FALSE);
// Fail if FAILED(hr) == true
// When done with pointer...
hr = CeCloseCallerPtr((PVOID) g_pMappedEmbedded, pInput->pEmbedded, pInput->dwSize, ARG_I_PTR );
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

23. 4/19/ :45 PM
Marshalling
<= Windows CE 5.0, the MapCallerPtr API also handled pointer marshalling for both
Pointer parameters as well as
Embedded pointers
With the next Windows CE version, Marshalling depends on whether the pointers are used
Synchronously or
Asynchronously
Important!
Synchronous here means accessing the caller’s buffer on the caller’s thread context
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

24. Marshalling When pointers are used synchronously
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Marshalling
When pointers are used synchronously
The caller’s address space is accessible for the lifetime of the call
Eliminates any marshalling needs for both embedded and pointer parameters
Employs Direct Access Marshalling
If used asynchronously
It’s critical that the caller buffer is accessible when the caller’s address space is unavailable
Use the new OS marshalling helper APIs CeAllocAsynchronousBuffer/ CeFreeAsynchronousBuffer
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

25. Synchronous Access Diagram
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Synchronous Access Diagram
Test.exe
Kernel
NK.EXE
App.exe
Hello.exe
Driver.dll
App.exe
App.exe
Test.exe
Test.exe
Hello.exe
Hello.exe
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

26. Asynchronous Access Diagram
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Asynchronous Access Diagram
Hello.exe
NK.EXE
App.exe
Driver Thread
in NK.EXE
Drv.dll
CeAllocAsynchronousBuffer
CeFreeAsynchronousBuffer
App.exe
App.exe
Hello.exe
Hello.exe
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

27. Marshalling // Windows CE 5.0 and prior versions
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Marshalling
// Windows CE 5.0 and prior versions
// In XXX_IOControl...
g_pMappedEmbedded = MapCallerPtr( p->pEmbedded );
// Fail if g_pMappedEmbedded == NULL ...
// Now in the New OS Version
// In XXX_IOControl after CeOpenCallerPtr generates
// g_pMappedEmbedded...
hr = CeAllocAsynchronousBuffer( (PVOID*) &g_pMarshalled, g_pMappedEmbedded, pInput->dwSize, ARG_I_PTR);
// Fail if FAILED(hr) == true
// When done with pointer...
hr = CeFreeAsynchronousBuffer( (PVOID) g_pMarshalled, g_pMappedEmbedded, pInput->dwSize, ARG_I_PTR);
// Now call CeCloseCallerBuffer as usual...
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

28. Thread Permissions <= Windows CE 5.0, With Windows CE 6.0 Beta,
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Thread Permissions
<= Windows CE 5.0,
PSLs had access to caller buffers as execution took place in the caller’s thread context
Other threads like ISTs did not have access to the caller’s buffer
Such threads thus called SetProcPermissions API
With Windows CE 6.0 Beta,
SetProcPermissions API is now deprecated
The CeAllocAsynchronousBuffer API marshals the caller’s buffer into the kernel’s VM
Thereby eliminating the need to change the thread’s permission in any manner
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

29. Secure Copy/PQD To Secure Copy Points to note
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Secure Copy/PQD
To Secure Copy
Use CeAllocDuplicateBuffer / CeFreeDuplicateBuffer APIs
Copies caller’s buffer to prevent from asynchronous modifications
Points to note
Scenario
Helper APIs
Effect
Driver accesses caller’s buffer asynchronously
Driver inherently uses CeAllocAsynchronousBuffer / CeFreeAsynchronousBuffer
for marshalling
Could simply map the user’s VM buffer using VirtualCopy.
User buffer is not copied
Handling Embedded Pointers
Driver inherently employs CeOpenCallerBuffer for access checking
To Secure-Copy call the API with the ForceDuplicate parameter set to TRUE
By default – does not copy caller’s buffer
Set ForceDuplicate =TRUE
This local buffer copy is freed upon calling CeCloseCallerBuffer
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

30. User Interface <= Windows CE 5.0 drivers ran in user mode
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User Interface
<= Windows CE 5.0 drivers ran in user mode
Hence, could display UI without any restrictions
With Windows CE 6.0 Beta, most drivers run in kernel
CommCtrl.dll is not loaded in the kernel
Kernel drivers need to forward the UI request to a User Mode DLL
Code up User Mode DLL and export a function that implements the required UI displaying
Pass the DLL and function name to CeCallUserProc Helper API, with in/out buffers to display desired driver UI
Restriction on embedded pointers
Need to flatten the structure
Handle the embedded pointers as offsets in your User Mode DLL
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

31. Porting To User Mode User mode drivers do have a Perf impact
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Porting To User Mode
User mode drivers do have a Perf impact
The Host/Bus Driver might require changes if the client driver is ported to UM
Our goal:
Kernel drivers should run in user mode without any modifications
Though, some security restrictions apply
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

32. Ported User Mode Driver
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Ported User Mode Driver
NK.EXE
Hello.exe
Driver’s Thread
in udevice.exe
Reflector in
Device
Manager
Hello.exe
Hello.exe
udevice.exe
udevice.exe
Drv.dll
Embedded Ptr
Embedded Ptr
CeOpenCallerBuffer
On Embedded Ptr
CeCloseCallerBuffer
Embedded Ptr
Embedded Ptr
Copies Buffer Data
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

33. User Mode Restrictions
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User Mode Restrictions
Embedded Pointers
Issue when UM driver is called from kernel
Reflector has notion of pointer parameters but not of embedded pointers
Flatten the Structure containing the embedded pointer
User Mode Driver now has to treat embedded pointers as struct offsets
Will investigate to provide Flattening/Unflattening Helper APIs
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

34. Embedded Pointer Restriction
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Embedded Pointer Restriction
NK.EXE
NK.EXE
Hello.exe
Embedded Ptr
Offset
Reflector
Hello.exe
Hello.exe
udevice.exe
udevice.exe
Drv.dll
Offset
Embedded Ptr
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

35. User Mode Driver Restrictions
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User Mode Driver Restrictions
APIs Callable Only in Kernel Mode
Heap APIs – RemoteLocalAlloc, RemoteLocalFree
VM APIs – VirtualCopyEx, VirtualAllocCopyEx
FileSys APIs – GetFSHeapInfo, GetRomFileBytes
Application Call-backs
Call-forwarding and Call-backs from a User Mode server to any process are prohibited
Cannot Install IISR directly – Can Install GIISR via Reflector
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

36. Driver Migration Summary
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Driver Migration Summary
Drivers move to kernel
Isolate to User Mode if suitable
Access check embedded pointers
Asynchronous access demands marshalling
Some drivers are backward compatible
Move driver UI to user space
Enjoy your porting 
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

37. Porting Quick Reference Guide
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Porting Quick Reference Guide
Use Case
Work Required
What the Driver Porting Engineer must do
Parameter – used synchronously
Access checking and
Marshalling
Secure-copy
Nothing; Kernel checks during trap and uses direct access
Use CeAllocDuplicateBuffer to make a local copy
Parameter – used asynchronously
Employ CeAllocAsynchronousBuffer/ CeFreeAsynchronousBuffer – Prepares for async access by creating/mapping caller buffer
Embedded pointer – used synchronously
Use CeOpenCallerBuffer/CeCloseCallerBuffer
Call CeOpenCallerBuffer with ForceDuplicate parameter set to TRUE or Use CeAllocDuplicateBuffer to make a local copy.
Embedded pointer – used asynchronously
Call CeAllocAsynchronousBuffer after you call CeOpenCallerBuffer. 
You must call CeFreeAsynchronousBuffer before you call CeCloseCallerBuffer.
Call CeOpenCallerBuffer with ForceDuplicate set to TRUE or Call CeAllocDuplicateBuffer for a local copy.
For All Cases
Deprecated APIs
Remove Deprecated APIs
Go through Deprecated APIs list to remove the
Example: CeGetCallerTrust, SetKMode and so on
UI/Dialog boxes
UI calls in kernel will always return failure
Use CeCallUserProc
Code up user mode dll exporting the function that implements the required UI displaying.
Then call CeCallUserProc API with dll and function name as input parameters.
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

38. Call To Action Help grow the Mobile and Embedded world
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Call To Action
Help grow the Mobile and Embedded world
Write drivers for Windows CE and sell Chips
Join the Windows CE Driver Development Program
Port your existing drivers to Windows CE 6.0
Post your driver on Windows CE’s Supported Drivers web site
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

39. CeDrvTrg @ microsoft.com
4/19/ :45 PM
Additional Resources
Web Resources
Related WinHEC 2006 Sessions
Future Directions for the Windows CE Operating System Architecture
Future Directions for the Windows CE Test Kit
User-Mode Driver Framework: Introduction and Overview
microsoft.com
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

40. Community Resources Community Sites List of Newsgroups
4/19/ :45 PM
Community Resources
Community Sites
List of Newsgroups
en-us/default.aspx
Attend a free chat or webcast
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

41. Questions? Q & A Thank you all 4/19/2017 11:45 PM
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

42. 4/19/ :45 PM
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

43. 4/19/ :45 PM
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.