From fa14486979b3a47307bcdb10f8b5baa875a5cf68 Mon Sep 17 00:00:00 2001 From: Nishanth Aravamudan Date: Fri, 4 Sep 2015 11:22:52 -0700 Subject: [PATCH] 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 Cc: stable@vger.kernel.org # 4.2 Tested-by: Jan Stancek Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/powernv/pci-ioda.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 77083274a4e3..414fd1a00fda 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2049,13 +2049,19 @@ 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()); + const u64 window_size = min((u64)pe->table_group.tce32_size, max_memory); rc = pnv_pci_ioda2_create_table(&pe->table_group, 0, IOMMU_PAGE_SHIFT_4K, -- 2.39.2