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[Didier Barvaux <didier@xxxxxxxxxxx>]

Hello,

> It very well may be an issue with the toolchain.  I am building RoHC
> into a Linux Kernel Module and calling it from another LKM.
> Toolchain does not appear to Support 64-bit division in the kernel so
> I get the above "undefined" errors.  
> 
> For version 1.7.0 I applied a patch to replace all uint64_t with long
> and time_t data types.  The TCP profile actually worked fairly well.
> I was able to get SCP, FTP, and serial-over-TCP running, albeit in
> light traffic.  This worked in the short term for some preliminary
> testing.

I'll look at your patch. I remember now that I worked on this topic
too. With a different way to alter the code. See
https://github.com/didier-barvaux/rohc/commit/55a1da25e970637edd746a2cb7fec530157cd4f7

 
> I have since switched to using the master branch for the long term.
> When I build it, only __aeabi_uldivmod appears to be undefined.  

I tested on ARM. I confirm the problem for the kernel module.

 
> I have attached the patch I applied to the master branch.  Just like
> the 1.7.0 patch, it replaces all uint64_t variables with type long,
> to prevent undefined routines. This builds (with several warnings),
> but unfortunately crashes during rohc_decompress3() when a TCP
> session is opened.  ICMP traffic passes without issue.  

It might be due to the TCP profile not being fully robust yet in
master. I hold a lot of patches on a private branch. I'll release them
soon after some more testing.

The problems with the TCP profile also affect the 1.7.x releases. You
were probably testing the library/module with the TCP profile
disabled. This is the default setting because the TCP profile is not
ready.
 

> Are the timer structures in the library required to be uint64_t?

I used uint64_t to be ready for the 2038 bug :)

  
> Is it possible my patch is causing the crash?  I've turned tracing on
> but kernel panics usually prevent me from figuring out the exact
> point of the crash.

Probably not if it happens with TCP traffic.


> I also get the following warnings when building from master:
> src/decomp/d_tcp.c:880:1: warning: the frame size of 16376 bytes is
> larger than 1024 bytes [-Wframe-larger-than=]
> src/decomp/rohc_decomp_rfc3095.c:1671:1: warning: the frame size of
> 1096 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Yes, I know those 2 warnings. I defined large structs as local
variables, so the stack became quite big. I have yet to figure out how
to achieve the same job without them.

I don't know if large stacks may cause problems in the kernel or not.

Regards,
Didier

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