RE: Fast IPC path on IA32

Thanks Alexei,

I've reproduced the bug and just corrected it in our mercurial development
repository. Find the latest version under
http://l4ka.org/projects/pistachio/download.php

--
Jan Stoess
System Architecture Group
University of Karlsruhe


> -----Original Message-----
> From: [email protected] [mailto:[email protected]
> karlsruhe.de] On Behalf Of Alexei Mandrykine
> Sent: Monday, July 23, 2007 03:25
> To: [email protected]
> Subject: Fast IPC path on IA32
> 
> Hello l4ka.
> 
> The code of Fast IPC path on IA32 is broken.
> At least on CVS state on 2006 August 10.
> 
> I spent about two weeks to find why a signal handler does not work
> correctly. The signal handler emaultes signal delivery via
> L4_ExchangeRegisters syscal.
> 
> In case of receiving phase of IPC has to be aborted, application
> generating strange exception - "kernel access raised user pagefault".
> 
> The reason of this exception is tcb_t::return_from_ipc(void) {glue/v4-
> ia32/tcb.h},
> that returns to 'fp_ipc_done' {glue/v4-ia32/trap.S}. At this point ESI
> conveys MR0
> value, but 'fp_ipc_done' uses ESI as pointer to current TCB.
> 
> This bug does not appear if kernel compiled without "Fast IPC path"
> feature.
> 
> 
> --
> Regards,
>  Aleksey Mandrykin                         mailto:[email protected]
>