Fusion - outb/iopl crash, thread local storage

[Philippe Gerum]

Pramode C.E wrote:
> Hello,
> 
> I am using fusion-0.8.2 with kernel 2.6.12 on a Fedora Core 3 system.
> I have a simple RT task which toggles the parallel port pins:
> 
> ..................
> while(1) {
>   outb(c, 0x378);
>   c = ~c;
>   rt_task_wait_period();
> }
> ..................
> 
> The code is crashing with a segmentation fault even though I am calling
> iopl(3) successfully (this is exactly the problem which Vincent
> Levesque had and was
> posted on this list some time back). It seems to work OK if the iopl call is
> repeated before every outb.
> 
> I tried one experiment - I renamed my /lib/tls to /lib/tlsold. Now, the code
> seems to be working OK. Is there some link between this problem and
> thread local storage?
> 

I have no clue yet; the native API indeed uses TLS for some limited 
purpose, but I can't find an obvious reason why this should have an 
impact on i/o permissions. I'll have a look at this asap, I first need 
to reproduce this issue.

-- 

Philippe.