Patch "powerpc/powernv/pci-ioda: fix 32-bit TCE table init in kdump kernel" has been added to the 4.2-stable tree
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This is a note to let you know that I've just added the patch titled
powerpc/powernv/pci-ioda: fix 32-bit TCE table init in kdump kernel
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-powernv-pci-ioda-fix-32-bit-tce-table-init-in-kdump-kernel.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
bb0054552d080dd929907c5925d4bedc8bf6def7Mon Sep 17 00:00:00 2001
From: Nishanth Aravamudan <[email protected]>
Date: Wed, 2 Sep 2015 08:39:28 -0700
Subject: powerpc/powernv/pci-ioda: fix 32-bit TCE table init in kdump kernel
From: Nishanth Aravamudan <[email protected]>
commit bb0054552d080dd929907c5925d4bedc8bf6def7 upstream.
When attempting to kdump with the 4.2 kernel, we see for each PCI device:
pci 0003:01 : [PE# 000] Assign DMA32 space pci 0003:01 : [PE# 000] Setting up 32-bit TCE table at 0..80000000 pci 0003:01 : [PE# 000] Failed to create 32-bit TCE table, err -22 PCI: Domain 0004 has 8 available 32-bit DMA segments PCI: 4 PE# for a total weight of 70 pci 0004:01 : [PE# 002] Assign DMA32 space pci 0004:01 : [PE# 002] Setting up 32-bit TCE table at 0..80000000 pci 0004:01 : [PE# 002] Failed to create 32-bit TCE table, err -22 pci 0004:0d : [PE# 005] Assign DMA32 space pci 0004:0d : [PE# 005] Setting up 32-bit TCE table at 0..80000000 pci 0004:0d : [PE# 005] Failed to create 32-bit TCE table, err -22 pci 0004:0e : [PE# 006] Assign DMA32 space pci 0004:0e : [PE# 006] Setting up 32-bit TCE table at 0..80000000 pci 0004:0e : [PE# 006] Failed to create 32-bit TCE table, err -22 pci 0004:10 : [PE# 008] Assign DMA32 space pci 0004:10 : [PE# 008] Setting up 32-bit TCE table at 0..80000000 pci 0004:10 : [PE# 008] Failed to create 32-bit TCE table, err -22
and eventually the kdump kernel fails to boot as none of the PCI devices (including the disk controller) are successfully initialized.
The EINVAL response is because the DMA window (the 2GB base window) is larger than the kdump kernel's reserved memory (crashkernel=, in this case specified to be 1024M). The check in question,
if ((window_size > memory_hotplug_max()) || !is_power_of_2(window_size))
is a valid sanity check for pnv_pci_ioda2_table_alloc_pages(), so adjust the caller to pass in a smaller window size if our maximum memory value is smaller than the DMA window.
After this change, the PCI devices successfully set up the 32-bit TCE table and kdump succeeds.
The problem was seen on a Firestone machine originally.
--- arch/powerpc/platforms/powernv/pci-ioda.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
arch/powerpc/platforms/powernv/pci-ioda.c +9 -1
@@ -2078,9 +2078,17 @@ static long pnv_pci_ioda2_setup_default_struct iommu_table *tbl =NULL ;long rc; +/* +* 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 ()); + rc =pnv_pci_ioda2_create_table (&pe->table_group,0 ,IOMMU_PAGE_SHIFT_4K , - pe->table_group.tce32_size, + window_size,POWERNV_IOMMU_DEFAULT_LEVELS , &tbl);if (rc) { pe_err(pe, "Failed to create 32-bit TCE table, err %ld",
Patches currently in stable-queue which might be from [email protected] are
queue-4.2/powerpc-powernv-pci-ioda-fix-kdump-with-non-power-of-2-crashkernel.patch queue-4.2/powerpc-powernv-pci-ioda-fix-32-bit-tce-table-init-in-kdump-kernel.patch