Re: [Xenomai-core] [PATCH 2/3] x86-64: Work around gcc issues with populating syscall registers

[Jan Kiszka <jan.kiszka@domain.hid>]

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Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> gcc-4.1.3 of kubuntu has problem with proper syscall register
>> initialization in rt_task_shadow if TLS is enabled. But it is likely
>> that more compiler versions below 4.3 and more configuration variants
>> are affected.
>>
>> This patch installs a workaround for these gcc versions which places an
>> optimization barrier before the register variable setup. This forces gcc
>> to actually load the registers.
> 
> I have tried the barrier with arm gcc, it does not work. However,
> marking the registered clobbered instead of the memory fixes arm gcc 4.3
> bug. So, I wonder, would not it make more sense to mark the registers as
> clobbered by the barrier instead of memory on x86 too?
> 

Sounds reasonable. Will give it a try later.

I just noticed that my unification patch includes some unwanted merge
artifact, so it requires another round in any case.

Jan


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