From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Sun, 19 Jul 2009 17:23:03 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-core] [PATCH 2/3] x86-64: Work around gcc issues with
 populating syscall registers
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: Petr Cervenka <grugh@domain.hid>, xenomai-core <xenomai@xenomai.org>

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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 a=
n
>> optimization barrier before the register variable setup. This forces g=
cc
>> to actually load the registers.
>=20
> 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 a=
s
> clobbered by the barrier instead of memory on x86 too?
>=20

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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