[Xenomai] Any idea how to fix ipipe failing to compile with ARM LPAE enabled?

Gilles Chanteperdrix gilles.chanteperdrix at xenomai.org
Fri Aug 22 23:55:07 CEST 2014


On 08/22/2014 11:36 PM, Gilles Chanteperdrix wrote:
> On 08/22/2014 11:31 PM, Lennart Sorensen wrote:
>> Any idea how to fix ipipe to not cause a linking error when LPAE is enabled on arm?
>>
>> I see the function __ipipe_pin_range_globally is inside an ifdef block that says essentially:
>>
>> #if !IPIPE
>> define __ipipe_pin_range_globally as do nothing
>> #else
>> #if !LPAE
>> define __ipipe_pin_range_globally function
>> #endif
>> #endif
>>
>> So if IPIPE and LPAE are both true, then the function is never defined.
>>
>> This is in arch/arm/mm/fault.c
>>
> I do not believe this is intentional. That being said, the Linux code in
> the #ifdef is not reassuring: exception handlers are not registered when
> the kernel is compiled with LPAE, which could mean that exceptions are
> used for LPAE when compiled with LPAE. If this is the case, then LPAE
> should not be enabled, otherwise your applications will not stay in
> primary mode when these faults happen. How much RAM do you have, can you
> really test LPAE ?

No, I do not think that LPAE uses exceptions. You can try moving the
#endif at the bottom of the file to above the #ifdef CONFIG_IPIPE.

> 


-- 
                                                                Gilles.




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