Re: arch/mips/sgi-ip22/Platform:29: *** gcc doesn't support needed option -mr10k-cache-barrier=store. Stop.

[Joshua Kinard <kumba@gentoo.org>]

On 04/10/2014 02:59, Ralf Baechle wrote:
> On Wed, Apr 09, 2014 at 11:02:10PM -0400, Joshua Kinard wrote:
> 
>> Odd, I thought R10K systems were locked to booting 64-bit kernels only.  At
>> least the Octane was when it was bootable.  Not sure about IP27.
>>
>> Maybe that's another one of ARCS' ingenious features...
> 
> No; IP27's address map is huge; a single node can take 2GB RAM.  A full
> blown 512 CPU system could have 0.5TB memory.  Your homework for today:
> try to use all that efficiently with highmem ;-)

I'll need to upgrade my electrical service first.  Then install a fusion
power plant in the backyard, with hamster-wheel backups...


> Octane is essentially a specialized, single-node IP27.  It also can take
> more memory than addressable in a 32 bit kernel which assumes that all memory
> is visible in CKSEG0, all I/O in CKSEG1 - or you need to ioremap to CKSEG2/3.
> So 32 bit kernels just don't cut it on Octane either.

I believe that, in Stan's old patches, there was a cutoff at 2GB detected
memory, because he never resolved a problem with DMA/PCI on machines with
>2GB memory.  So the machine was kinda hamstrung there anyways.  That bit of
code was always confusing to forward-port.

If only I could finally find the motivation to figure out HEART's IRQ
trickery and Linux's IRQ system...


> Similarly 32 bit kernels don't cut it on other systems such as Sibyte,
> SGI O2, Octane.  They may be possible for some configurations but that
> that's either too rarely a useful choice or too inefficient.
> 
> Let's say 32 bit is slowly running out of juice :-)
> 

I wonder if I'll be alive when 128-bit becomes all the rage...


>>>> Are you configuring for IP22 (Indy, Indigo2 R4x00), or IP28 (R10000)?  Note,
>>>> IP26 (R8000) is not supported in Linux.  I think OpenBSD got it working, though.
>>>
>>> Wish I'd have a box ....
>>
>> They do pop up on eBay from time-to-time.  UPS destroyed the case mine came
>> in, though.  I've got it in a closet, with duct tape holding the teal skins
>> on.  It does boot to the PROM, but the RTC is probably dead by now.
> 
> The common problem.  You can cut it open with a dremel or similar tool,
> disconect the internal battery and connect an external battery instead.
> There are howtos for this on the web.  I'm also tired of reprogramming
> the MAC address again when I use my Indy so I should do this myself ...

I'll probably stick to finding old DS1386's on eBay :)  Never had much luck
w/ those cutting discs on a Dremel tool.  They shatter too easily and send
little shards of pain flying across the room.

-- 
Joshua Kinard
Gentoo/MIPS
kumba@gentoo.org
4096R/D25D95E3 2011-03-28

"The past tempts us, the present confuses us, the future frightens us.  And
our lives slip away, moment by moment, lost in that vast, terrible in-between."

--Emperor Turhan, Centauri Republic