| Message ID | 20150904182252.GN47557@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Michael Ellerman |
| Headers | show |
----- Original Message ----- > From: "Nishanth Aravamudan" <nacc@linux.vnet.ibm.com> > To: "Michael Ellerman" <mpe@ellerman.id.au> > Cc: "Hari Bathini" <hbathini@in.ibm.com>, "Gavin Shan" <gwshan@linux.vnet.ibm.com>, "Alexey Kardashevskiy" > <aik@ozlabs.ru>, "Ben Herrenschmidt" <benh@kernel.crashing.org>, "Paul Mackerras" <paulus@samba.org>, "David Gibson" > <david@gibson.dropbear.id.au>, "Wei Yang" <weiyang@linux.vnet.ibm.com>, linuxppc-dev@lists.ozlabs.org, "Jan Stancek" > <jstancek@redhat.com> > Sent: Friday, 4 September, 2015 8:22:52 PM > Subject: [PATCH v2] powerpc/powernv/pci-ioda: fix kdump with non-power-of-2 crashkernel= > > 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@linux.vnet.ibm.com> > Cc: stable@vger.kernel.org # 4.2 Tested-by: Jan Stancek <jstancek@redhat.com> I can confirm, that this patch along with http://patchwork.ozlabs.org/patch/513229/ applied on top of 4.2 is fixing kdump for me on Power S812L. (ppc64le bare metal, crashkernel=1024M) Regards, Jan > > --- > > 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. 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). > > diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c > b/arch/powerpc/platforms/powernv/pci-ioda.c > index f1c74c28e564..d5e635f2c3aa 100644 > --- a/arch/powerpc/platforms/powernv/pci-ioda.c > +++ b/arch/powerpc/platforms/powernv/pci-ioda.c > @@ -2078,12 +2078,18 @@ static long pnv_pci_ioda2_setup_default_config(struct > pnv_ioda_pe *pe) > struct iommu_table *tbl = NULL; > long rc; > /* > + * crashkernel= specifies the kdump kernel's maximum memory at > + * some offset and there is no guaranteed the result is a power > + * of 2, which will cause errors later. > + */ > + const u64 max_memory = __rounddown_pow_of_two(memory_hotplug_max()); > + /* > * In memory constrained environments, e.g. kdump kernel, the > * DMA window can be larger than available memory, which will > * cause errors later. > */ > const u64 window_size = > - min((u64)pe->table_group.tce32_size, memory_hotplug_max()); > + min((u64)pe->table_group.tce32_size, max_memory); > > rc = pnv_pci_ioda2_create_table(&pe->table_group, 0, > iommu_page_shift_4k, > >
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@linux.vnet.ibm.com> > Cc: stable@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. > 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. 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? cheers
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@linux.vnet.ibm.com> > > Cc: stable@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. -Nish
On Fri, 2015-04-09 at 18:22:52 UTC, 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@linux.vnet.ibm.com> > Cc: stable@vger.kernel.org # 4.2 > Tested-by: Jan Stancek <jstancek@redhat.com> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/fa14486979b3a47307bcdb10 cheers
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index f1c74c28e564..d5e635f2c3aa 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2078,12 +2078,18 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe) struct iommu_table *tbl = NULL; long rc; /* + * crashkernel= specifies the kdump kernel's maximum memory at + * some offset and there is no guaranteed the result is a power + * of 2, which will cause errors later. + */ + const u64 max_memory = __rounddown_pow_of_two(memory_hotplug_max()); + /* * In memory constrained environments, e.g. kdump kernel, the * DMA window can be larger than available memory, which will * cause errors later. */ const u64 window_size = - min((u64)pe->table_group.tce32_size, memory_hotplug_max()); + min((u64)pe->table_group.tce32_size, max_memory); rc = pnv_pci_ioda2_create_table(&pe->table_group, 0, iommu_page_shift_4k,
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@linux.vnet.ibm.com> Cc: stable@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. 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).