From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Sat, 16 Mar 2013 21:27:23 +0100
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] __get_user/__put_user
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Xenomai <xenomai@xenomai.org>

On 03/16/2013 09:25 PM, Jan Kiszka wrote:

> On 2013-03-16 21:19, Gilles Chanteperdrix wrote:
>>
>> Hi,
>>
>> xenomai asm-generic/syscall.h defines __xn_put_user/__xn_get_user as
>> aliases for __put_user/__get_user, which implementation, for the ARM
>> architecture calls might_fault() which triggers an ipipe_root_only() check.
>>
>> So, the question is, what is the best way of avoiding this issue? Remove
>> the call to might_fault() when compiling with CONFIG_IPIPE enabled?
>> Define __ipipe_safe_put_user which avoids the call to might_fault() ?
> 
> Adjust might_fault() in a way that it only considers atomic non-root
> contexts as problematic.


atomic meaning with hardware irqs off? or within an irq handler? This
requires xenomai...

-- 
                                                                Gilles.