From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kazutomo Yoshii <kazutomo@mcs.anl.gov>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
bg-linux@lists.anl-external.org
Subject: Re: [bg-linux] [PATCH 6/7] [RFC] enable early TLBs for BG/P
Date: Fri, 20 May 2011 13:52:21 +1000 [thread overview]
Message-ID: <1305863541.7481.132.camel@pasglop> (raw)
In-Reply-To: <4DD5E218.5030508@mcs.anl.gov>
> Unfortunately, the firmware is also required:
> - to configure Blue Gene Interrupt Controller(BIC)
Can't we just write bare metal code for that ?
> - to configure Torus DMA unit. e.g. fifo
Same
> - to configure global interrupt (even we don't use, we need to disable
> some channel correctly)
Same
> - to access node personality information (node id, DDR size, HZ, etc) or
> maybe we can directly access SRAM?
That should be turned into device-tree at boot, possibly from a
bootloader or from the zImage wrapper.
> etc, etc.
>
> >> As such the IO Node guys, the Compute Node Kernel guys and the
> >> ZeptoOS guys use it quite a bit. The kittyhawk guys on the other hand
> >> barely use it at all, in fact I believe they do all the interaction with
> >> it during uboot and then shut it off.
> >>
> >
> (I'm one of the ZeptoOS guys, btw)
Heh ok.
> As a regular ppc linux usage, our firmware dependency is minimum as well.
> However, with our HPC extension, the firmware functions are called when
> it configures BGP specific network hardware.
>
> We are not planning to submit our HPC extension here anytime soon
> because our work is very special purpose and includes lots of dirty hack
> right now.
Ok.
Cheers,
Ben.
> Thanks,
> Kaz
> > I would prefer that approach.
> >
> >
> >> IIRC, the sticky question is RAS support, there are certain things it
> >> wants to jump to firmware to deal with and expects things to be mapped
> >> an pinned into memory.
> >>
> >> Furthermore, I think it may make assumptions about where in the TLB the
> >> mappings are.
> >>
> > This is gross, especially on a system with only 64 SW loaded TLB
> > entries :-(
> >
> >
> >> Since the kittyhawk guys
> >> obviously ignore this by shutting it down, its not clear just how
> >> important this is. I'm game to
> >> try the dynamic mapping as you suggest if you would prefer it.
> >>
> > I would yes, we can sort things out later for RAS.
> >
> >
> >> Its worth mentioning that I believe with BG/Q, the plan is to rely on
> >> the firmware even more extensively, but I haven't looked at any of the code yet to verify
> >> whether or not this is true.
> >>
> > This is tantamount to linking a binary blob with the kernel ... it's a
> > fine line. At some point we might refuse the patches if they go too far
> > in that direction.
> >
> > Cheers,
> > Ben.
> >
> >
> >> -eric
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
> >> Please read the FAQ at http://www.tux.org/lkml/
> >>
> >
> > _______________________________________________
> > bg-linux mailing list
> > bg-linux@lists.anl-external.org
> > https://lists.anl-external.org/mailman/listinfo/bg-linux
> > http://bg-linux.anl-external.org/wiki
> >
next prev parent reply other threads:[~2011-05-20 3:52 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-18 21:24 [PATCH 1/7] [RFC] Mainline BG/P platform support Eric Van Hensbergen
2011-05-18 21:24 ` [PATCH 2/7] [RFC] add bluegene entry to cputable Eric Van Hensbergen
2011-05-20 0:35 ` Benjamin Herrenschmidt
2011-05-20 1:08 ` Eric Van Hensbergen
2011-05-20 1:50 ` Benjamin Herrenschmidt
2011-05-18 21:24 ` [PATCH 3/7] [RFC] add support for BlueGene/P FPU Eric Van Hensbergen
2011-05-19 5:58 ` Michael Neuling
2011-05-19 13:53 ` Eric Van Hensbergen
2011-05-19 15:22 ` [bg-linux] " Kazutomo Yoshii
2011-05-19 21:36 ` Michael Neuling
2011-05-19 21:55 ` Eric Van Hensbergen
2011-05-19 23:16 ` Michael Neuling
2011-05-20 0:30 ` Eric Van Hensbergen
2011-05-20 0:43 ` Michael Neuling
2011-05-20 0:53 ` Benjamin Herrenschmidt
2011-05-20 0:52 ` Benjamin Herrenschmidt
2011-05-19 21:41 ` [PATCH 3/7] [RFC][V2] add support for BlueGene/P Double FPU Eric Van Hensbergen
2011-05-18 21:24 ` [PATCH 4/7] [RFC] enable L1_WRITETHROUGH mode for BG/P Eric Van Hensbergen
2011-05-19 10:43 ` Josh Boyer
2011-05-19 12:53 ` Eric Van Hensbergen
2011-05-19 21:42 ` [PATCH 4/7] [RFC][V2] enable BGP_L1_WRITETHROUGH " Eric Van Hensbergen
2011-05-20 1:01 ` [PATCH 4/7] [RFC] enable L1_WRITETHROUGH " Benjamin Herrenschmidt
2011-05-18 21:24 ` [PATCH 5/7] [RFC] force 32-byte aligned kmallocs Eric Van Hensbergen
2011-05-20 0:36 ` Benjamin Herrenschmidt
2011-05-20 0:47 ` Eric Van Hensbergen
2011-05-20 1:50 ` Benjamin Herrenschmidt
2011-05-20 1:32 ` [bg-linux] " Kazutomo Yoshii
2011-05-20 2:08 ` Benjamin Herrenschmidt
2011-05-20 2:13 ` Benjamin Herrenschmidt
2011-05-20 3:02 ` Kazutomo Yoshii
2011-05-20 3:13 ` Benjamin Herrenschmidt
2011-05-18 21:24 ` [PATCH 6/7] [RFC] enable early TLBs for BG/P Eric Van Hensbergen
2011-05-20 0:39 ` Benjamin Herrenschmidt
2011-05-20 1:21 ` Eric Van Hensbergen
2011-05-20 1:54 ` Benjamin Herrenschmidt
2011-05-20 3:38 ` [bg-linux] " Kazutomo Yoshii
2011-05-20 3:52 ` Benjamin Herrenschmidt [this message]
2011-05-20 13:01 ` Eric Van Hensbergen
2011-05-20 22:20 ` Benjamin Herrenschmidt
2011-05-18 21:24 ` [PATCH 7/7] [RFC] SMP support code Eric Van Hensbergen
2011-05-20 1:05 ` Benjamin Herrenschmidt
2011-05-19 11:01 ` [PATCH 1/7] [RFC] Mainline BG/P platform support Josh Boyer
2011-05-19 12:35 ` Eric Van Hensbergen
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