From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Frysinger <vapier.adi@gmail.com>
Subject: Re: Kernel crashing and log buffers...
Date: Fri, 26 Jun 2009 13:50:22 -0400
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To: David VomLehn <dvomlehn@cisco.com>
Cc: Robin Getz <rgetz@blackfin.uclinux.org>, Greg Ungerer <gerg@snapgear.com>, Russell King <rmk@arm.linux.org.uk>, Paul Mundt <lethal@linux-sh.org>, Tim Bird <tim.bird@am.sony.com>, Wolfgang Denk <wd@denx.de>, Grant Erickson <gerickson@nuovations.com>, linux-embedded <linux-embedded@vger.kernel.org>

On Fri, Jun 26, 2009 at 13:42, David VomLehn wrote:
> On Fri, Jun 26, 2009 at 10:39:50AM -0400, Robin Getz wrote:
>> OK - so after a bit more digging into things (and a poke by Mike) - =
I think
>> most of the stuff already exists.
>>
>> Normal run time issues:
>> --------------------------
>> =C2=A0- MTD_OOPS - on 2007-06-28 this was added to Linus's tree:
>> =C2=A0 =C2=A0 http://lkml.org/lkml/2007/6/18/234
>> =C2=A0 =C2=A0 CONFIG_MTD_OOPS
>> =C2=A0 =C2=A0 =C2=A0 tristate "Log panic/oops to an MTD buffer"
> ...
>> early boot issues:
>> ----------------------
>> =C2=A0- CONFIG_EARLY_PRINTK
>> =C2=A0 =C2=A0- early printk just defined a console - and is supporte=
d by:
>> =C2=A0 =C2=A0 =C2=A0 alpha, blackfin, microblaze, mips, powerpc, sh,=
 x86
>> =C2=A0 =C2=A0- it's pretty trivial to support a memory based buffer =
- some
>> =C2=A0 =C2=A0 =C2=A0archs already support it.
>>
>> I think this only leaves Wolfgang's desire for memory buffers from t=
he
>> bootloader to get (somehow) into the kernel's log buffer for syslog
>> processing...
>>
>> Anyone else agree?
>
> Almost. A couple of us also want memory for "flight data record" FDR =
data
> for doing continuous logging. This would, ideally, be either uncached=
 or cached
> in such a way that data is guaranteed to be written to memory in the =
event of
> a watchdog timer-induced system reset.

can none of the existing mtd devices provide uncached ram ?
otherwise, create a mtd map that simply calls data flush after every
write.  then the existing mtd stack can provide what you want.
-mike