Semaphores in eldk4.1

Semaphores in eldk4.1

[Stuart Hodgson]

Hi,

I have been suing the eldk4.1 tool chain for a few months now and have 
not not encountered any problems with building until now. I build for 
two slightly different archs, ppc_85xx and ppx_82xx.

The problem I have come up against is related to some of the semaphore 
functions in semaphore.h, namely sem_wait, sem_post. This was originally 
noticed in a third party driver I am porting from one board to another 
but a small test program has shown the same results.

Calls to these functions on the ppc_82xx platform return -1 with an 
error code of 38, in this case meaning  ENOSYS (not implemented). On the 
ppc_85xx the same program executes fine, thus I conclude that it is 
specific to the libc-2.3.5 for ppc_82xx. Has anyone else come across 
this problem, I did find one thread but there was no conclusion listed.

I also can not find anything stating that these functions are not 
implemented for the 82xx arch compared with others for the eldk4.1

Thanks

Stuart

Re: Semaphores in eldk4.1

[Ben Warren]

HI Stuart,

Stuart Hodgson wrote:
> Hi,
>
> I have been suing the eldk4.1 tool chain for a few months now and have 
> not not encountered any problems with building until now. I build for 
> two slightly different archs, ppc_85xx and ppx_82xx.
>
> The problem I have come up against is related to some of the semaphore 
> functions in semaphore.h, namely sem_wait, sem_post. This was originally 
> noticed in a third party driver I am porting from one board to another 
> but a small test program has shown the same results.
>
> Calls to these functions on the ppc_82xx platform return -1 with an 
> error code of 38, in this case meaning  ENOSYS (not implemented). On the 
> ppc_85xx the same program executes fine, thus I conclude that it is 
> specific to the libc-2.3.5 for ppc_82xx. Has anyone else come across 
> this problem, I did find one thread but there was no conclusion listed.
>
>   
These work fine for me with ppc_6xx architecture and ELDK 4.1, although 
they didn't with ELDK 4.0. In that case, I was getting ENOSYS on 
sem_open() and sem_init(). Do these functions return 0 for you? I assume 
you're using a kernel that supports POSIX semaphores (I think that 
started at 2.6.12) and that you're using the glibc version of ELDK and 
not ulibc.
> I also can not find anything stating that these functions are not 
> implemented for the 82xx arch compared with others for the eldk4.1
>
> Thanks
>
> Stuart
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
>   
regards,
Ben

Re: Semaphores in eldk4.1

[Wolfgang Denk]

In message <47503B5A.6090604@quadrics.com> you wrote:
> 
> I have been suing the eldk4.1 tool chain for a few months now and have 

Please post ELDK related questions on the ELDK mailing list instead,
see http://lists.denx.de/mailman/listinfo/eldk

> The problem I have come up against is related to some of the semaphore 
> functions in semaphore.h, namely sem_wait, sem_post. This was originally 
> noticed in a third party driver I am porting from one board to another 
--------------------------^^^^^^^^
> but a small test program has shown the same results.

What exactly are you talking about? Device driver (i. e. kernel)
code, or application (i. e. user space) code ?

> Calls to these functions on the ppc_82xx platform return -1 with an 
> error code of 38, in this case meaning  ENOSYS (not implemented). On the 

Did you enable the CONFIG_SYSVIPC option in your Linux kernel
configuration?

> ppc_85xx the same program executes fine, thus I conclude that it is 
> specific to the libc-2.3.5 for ppc_82xx. Has anyone else come across 
> this problem, I did find one thread but there was no conclusion listed.

There is absolutley no difference between ppc_85xx and ppc_82xx as
far as library sources or configuration are concerned. The problem is
most probably in your Linux kernel, I guess.

> I also can not find anything stating that these functions are not 
> implemented for the 82xx arch compared with others for the eldk4.1

Provide a test program that fails for yuou, and we can provide much
better comments.

But please post followups on the ELDK mailing list.

Best regards,

Wolfgang Denk

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