Linux 2.6.24 L4FB and VGA_CONSOLE

Marc CHALAND l4 at
Fri Feb 22 14:21:37 CET 2008

>From Ronald Aigner:

> The address of the UTCB is taken in the stub from the environment
> variable. This environment variable (_dice_corba_env->utcb) is set per
> default with l4sys_utcb_get which in turn does 'asm( "%gs:0" )'. The
> problem with Linux applications (running on L4Linux) is that they are
> linked to a glibc that uses %gs for its own purposes. Therefore, the
> UTCB pointer is probably bogus and thus UTCB IPC fails.

Wunderbar :). That explains why I encounter problems with L4Linux.

But this task is abolutely not an L4Linux one. It just uses L4env. The
values for domain, type and protocol are 2 1 6 on client side and
0x221401 0x0 0x7069776c on server side. Return value is absolutely

> The quick fix is to go back to a version of Dice that does not use UTCB
> IPC.

Could you tell me which version is the last without UTCB feature ? SVN
is not very explicit about it :).


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