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Date:      Sat, 16 Feb 2008 15:10:12 -0800
From:      Marcel Moolenaar <xcllnt@mac.com>
To:        Rafal Jaworowski <raj@semihalf.com>
Cc:        Marcel Moolenaar <marcel@freebsd.org>, Perforce Change Reviews <perforce@freebsd.org>
Subject:   Re: PERFORCE change 135517 for review
Message-ID:  <EDF429F2-E803-4FA7-A387-3A53D15A21F2@mac.com>
In-Reply-To: <47B76A8E.5060607@semihalf.com>
References:  <200802162141.m1GLfgkj048217@repoman.freebsd.org> <47B75EB3.2020001@semihalf.com> <504560A3-EABB-4896-8B3E-C7FC89F31EFB@mac.com> <47B76A8E.5060607@semihalf.com>

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On Feb 16, 2008, at 2:58 PM, Rafal Jaworowski wrote:

> Marcel Moolenaar wrote:
>>>> Change 135517 by marcel@marcel_jnpr on 2008/02/16 21:41:02
>>>>
>>>>    Save U-Boot's registers at startup and restore them when
>>>>    performing a syscall. This way we don't have to compile
>>>>    code specially to avoid using those registers. Otherwise
>>>>    we have to encode knowledge of those registers in at least
>>>>    4 makefiles and introduce a build knob to enable it all.
>>>>    This does not allow us to build everything with a single
>>>>    build world.
>>>>
>>>
>>> Hi Marcel,
>>>
>>> I'm not quite sure this is sufficient... I already had a similar
>>> save/restore
>>> in place, but there is some general problem with U-Boot that leads  
>>> to
>>> hangs
>>> (experienced):
>>
>> Interesting, I didn't see any such problems with 1.3.2-rc1.
>>
>
> Chances are it might not surface, depending on the regs usage pattern,
> compiler etc., for example a -O0 build would usually hide this  
> issue, but in
> principle those regs are not exception/interrupt safe.

Agreed. I didn't see it at -O2, BTW.

We can disable interrupts when not running in U-Boot, right?
The impact should be marginal...

-- 
Marcel Moolenaar
xcllnt@mac.com





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