some questions in the l4 config

Bjoern Doebel doebel at
Wed Aug 29 12:54:49 CEST 2007

Hash: SHA1


> 	In the drops home directory we could use `make -C l4 config O=./build` to 
> enter the l4 configuration interface. There are some options I don't 
> understand as following:
> 	Target Architecture  ---
> 			(x86) Target Architecture // This is ok and there are 3 options to be 
> chosen.
> 			CPU type: "586" 	//This option is confused because it depends on our input. 
> For example If my cpu is pentim4 can I input p4 in the CPU type?  In this 
> place is there avaiable small cpu type set? 
> 		(L4.V2)  ABI 
> 			(X) L4.V2
> 			( ) L4.X2
> 			( ) L4.Sec.(V2.emu)
> 			( ) Linux
> 		There are four options to be chosen. L4.v2, L4.X2 and L4.sec are explained 
> in other documents. But I choose Linux in this place what can we do?
> 	Advances:
> 			[*] Use system-call entry code in the KIP (absolute)
This tells L4 to find the entry point for invoking a syscall in the kernel
info page (KIP), instead of invoking syscalls using int30-int39. I read the
code for some minutes and I think to understand, but I propse someone else
steps in here. ;)

> 			[ ] Use hierarchical task system (EXPERIMENTAL)
This enables our shiny new hierarchical task system. Instead of using a
central task server (e.g., simple_ts), tasks form a hierarchy. Every task
is created by  a parent and contacts this parent in order to allocate new
tasks. Task creation is performed locally using the l4_task_new system call.

The hierarchy formed by the tasks enables easier distribution and
accounting of resources (tasks in this case) in an L4 system. The task lib
provides callback hooks through which a parent can be informed upon a
client request - it may then for instance chose to take actions according
to some policy it implements.

The whole concept is somewhat similar to the Bastei OS architecture which
is described in [1].

> 			[ ] Enable RELEASE flag
This flag changes the behavior of some functions and servers. Normally,
e.g., a Panic() makes the system enter the kernel debugger in order to aid
debugging. In RELEASE mode, this macro just terminates the application.

> 			[ ] Do not build anything outside l4 directory    
This makes BID not build the kernel and Dice directories. (This one was
even documented. ;) )


[1] N. Feske, C. Helmuth: "Design of the Bastei OS architecture"

> 	Please also explain these 4 options.
> 	Thans very much.
> 													Cheng Guanghui
> _______________________________________________
> l4-hackers mailing list
> l4-hackers at

- --
Dipl.-Inf. Björn Döbel                 doebel at
Technische Universität Dresden         Tel: +49 351 463 38799
Dept. of Computer Science, OS Chair    Fax: +49 351 463 38284
D-01062 Dresden, Germany
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