[ros-dev] SYSCALL instruction

[Alex Ionescu]

Filip Navara wrote:

> Waldo Alvarez Cañizares wrote:
>
>> Another thing that could be done is to detect the CPU at some time 
>> during initialization and use one of two ntdll (on with SYSCALL an 
>> another without it).
>>
> It's implemented in WinXP much easier than that. On startup it's 
> detected if the processor supports SYSCALL and the appropriate code is 
> sticked into the user shared page. The user mode code then just does 
> jmp at the place in user shared page and it uses the correct code. 
> Easy ;-)
>
> - Filip
> _______________________________________________
> Ros-dev mailing list
> Ros-dev at reactos.com
> http://reactos.com:8080/mailman/listinfo/ros-dev
>
Please check my blog on the current status of SYSCALL on ReactOS. I 
posed a quite extensive overview of what has to be done. I will probably 
finish the implementation once my current work is done.

Btw, Filip, they've changed it again. Instead of being code in 
KUSER_SHARED_DATA, it's now a pointer (so it's call [edx] instead of 
call edx). This makes user-mode hooking of syscalls possible btw, and is 
really cool.

Best regards,
Alex Ionescu