Re: Kernel crashing and log buffers...

[Mike Frysinger <vapier.adi@gmail.com>]

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:
>> --------------------------
>>  - MTD_OOPS - on 2007-06-28 this was added to Linus's tree:
>>     http://lkml.org/lkml/2007/6/18/234
>>     CONFIG_MTD_OOPS
>>       tristate "Log panic/oops to an MTD buffer"
> ...
>> early boot issues:
>> ----------------------
>>  - CONFIG_EARLY_PRINTK
>>    - early printk just defined a console - and is supported by:
>>       alpha, blackfin, microblaze, mips, powerpc, sh, x86
>>    - it's pretty trivial to support a memory based buffer - some
>>      archs already support it.
>>
>> I think this only leaves Wolfgang's desire for memory buffers from the
>> 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