[PATCH v2] powerpc/powernv/pci-ioda: fix kdump with non-power-of-2 crashkernel=

Nishanth Aravamudan nacc at linux.vnet.ibm.com
Tue Sep 8 13:10:24 AEST 2015

On 07.09.2015 [19:19:09 +1000], Michael Ellerman wrote:
> On Fri, 2015-09-04 at 11:22 -0700, Nishanth Aravamudan wrote:
> > The 32-bit TCE table initialization relies on the DMA window having a
> > size equal to a power of 2 (and checks for it explicitly). But
> > crashkernel= has no constraint that requires a power-of-2 be specified.
> > This causes the kdump kernel to fail to boot as none of the PCI devices
> > (including the disk controller) are successfully initialized.
> > 
> > After this change, the PCI devices successfully set up the 32-bit TCE
> > table and kdump succeeds.
> > 
> > Fixes: aca6913f5551 ("powerpc/powernv/ioda2: Introduce helpers to allocate TCE pages")
> > Signed-off-by: Nishanth Aravamudan <nacc at linux.vnet.ibm.com>
> > Cc: stable at vger.kernel.org # 4.2
> > 
> > Michael, I kept this as a follow-on patch to my previous one. If you'd
> > rather I made a v3 of that patch with the two fixes combined, I can
> > resend.
> No that's fine. I guess they could have been a single fix, but it's
> not a big deal.

Ok, thanks for understanding.

> > Also, I fixed up the context on my end to be u64, but not sure
> > if that will match your tree (next doesn't have my prior patch applied
> > yet, that I can see).
> next isn't open yet, because we're still in the merge window, ie. rc1
> hasn't come out yet.

Ah got it. I did mean your next branch, not linux-next itself, fwiw.

> This is a fix so it'll go to my fixes branch. Whether I send that to
> Linus before or after rc1 depends on how urgent the fixes people send
> me are. Sounds like you'd like these two to go in asap?

If at all possible, yes please.


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