Problem with 'test-pci'

[Norman Feske]

Hello Frank,

I think, you hit an issue with the handling of boot modules on
OKL4. In contrast to running on Qemu, on real hardware, the padding
space between boot modules is not cleared on startup so that there is
the chance that the actual data is followed by bit garbage. This is
particularly annoying for the config file. We directly pass the locally
mapped config file to our XML parser, which expects a null termination.
However, without initial clearing of memory, there may be no such
termination. So the XML parser continues parsing until it hits the
following (not mapped) page. The next release will fix the problem by
allowing a length limit to be specified to the XML parser. For now, you
can use the short-term fix to manually append a zero character to your
config file.

I would be grateful to know if I'm guessing right and if this quick fix
works for you.

Regards
Norman

Frank Kaiser wrote:
> Hello
> 
>  
> 
> As a preparation of a certain task I want to check the PCI resources of
> my platform (IVI platform with Intel ATOM). For this purpose I built
> Genode-on-OKL4, only consisting of a minimum driver set and the
> /test-pci/ application. Running this image in /qemu/ looks good, but on
> the IVI platform the /init/ process fails with a page fault before or
> when starting the PCI driver which is the first entry in the /config/
> file. The error message is:
> 
> no RM attachment (READ pf_addr=6000 pf_ip=2001286 from 01)
> 
> I have no clue what this message is trying to tell me. The given IP
> points to the function /Genode::strncpy()/. I also wonder why the system
> wants to read from virtual address 0x6000, because all modules are
> allocated beginning at virtual address 0x02000000. Checking /init’s/
> pagetable with OKL4’s KDB on /qemu/ shows a number of allocations below:
> 
> 00000000 [00140027]: tree=f0140000
> 
> 00001000 [001f5067]:   phys=001f5000 pg=f0140004   4KB rwx (RWX) user  WB
> 
> 00003000 [001f7067]:   phys=001f7000 pg=f014000c   4KB rwx (RWX) user  WB
> 
> 00004000 [001f8067]:   phys=001f8000 pg=f0140010   4KB rwx (RWX) user  WB
> 
> 00005000 [001df025]:   phys=001df000 pg=f0140014   4KB r~x (R~X) user  WB
> 
> 00006000 [00275067]:   phys=00275000 pg=f0140018   4KB rwx (RWX) user  WB
> 
> 00007000 [00276067]:   phys=00276000 pg=f014001c   4KB rwx (RWX) user  WB
> 
> 00008000 [00277067]:   phys=00277000 pg=f0140020   4KB rwx (RWX) user  WB
> 
> 00009000 [00278067]:   phys=00278000 pg=f0140024   4KB rwx (RWX) user  WB
> 
> 0000a000 [00368067]:   phys=00368000 pg=f0140028   4KB rwx (RWX) user  WB
> 
> 0000b000 [00369067]:   phys=00369000 pg=f014002c   4KB rwx (RWX) user  WB
> 
> 0000c000 [0036a067]:   phys=0036a000 pg=f0140030   4KB rwx (RWX) user  WB
> 
> 0000d000 [0036b067]:   phys=0036b000 pg=f0140034   4KB rwx (RWX) user  WB
> 
> 0000e000 [0037b067]:   phys=0037b000 pg=f0140038   4KB rwx (RWX) user  WB
> 
> 00012000 [003fa067]:   phys=003fa000 pg=f0140048   4KB rwx (RWX) user  WB
> 
> 00016000 [00852067]:   phys=00852000 pg=f0140058   4KB rwx (RWX) user  WB
> 
> 0004a000 [00336067]:   phys=00336000 pg=f0140128   4KB rwx (RWX) user  WB
> 
> 00066000 [00370067]:   phys=00370000 pg=f0140198   4KB rwx (RWX) user  WB
> 
> On the IVI platform this area at the time of the page fault looks:
> 
> 00000000 [00141027]: tree=f0141000
> 
> 00001000 [001f5067]:   phys=001f5000 pg=f0141004   4KB rwx (RWX) user  WB
> 
> 00005000 [001df025]:   phys=001df000 pg=f0141014   4KB r~x (R~X) user  WB
> 
> I’d like to get some hints where to look into the code for finding the
> cause of the problem. Since I cannot debug the platform, I probably have
> to add more trace messages to get additonal information about what is
> going on.
> 
>  
> 
> Regards
> 
> Frank
> 
> 
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-- 
Norman Feske
Genode Labs

http://www.genode-labs.com · http://genode.org