Back to UTCB IPC

Marc CHALAND l4 at
Thu Mar 6 10:28:10 CET 2008


I am back with my problem with UTCB IPC. To sum up the context :
I use pure l4env applications. Here is the scenario between my server
and my client :
1. client makes an UTCB IPC to manager. Manager does an
l4rm_area_reserve, creates a rcv_fpage, creates worker and sends back
worker thread id to client.
2. client allocates memory and associated flexpage and sends it to server.
3. UTCB IPC is sent to worker with 3 parameters :
  - on client side : utcb->values=0xbff00200: arg1=0x2 arg2=0x1 arg3=0x6
  - on server side : utcb->values=0xbff00200: arg1=0x241401 arg2=0x0
It seems that 0xbff00200 is not mapped on the same memory on client
and server side. As there is no problem for first IPC (utcb->values is
also 0xbff00200), is there any potential problem with flexpage ?

As utcb->values is still the same, what happens if several threads try
to make UTCB IPC ?

Another question : when I link my application with liblogserver.a, I
have strange logs :
.rm.sem.mainMain function returned.
It seems that .rm .sem and .main are added by l4env, but I didn't find where.


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