From: Hans de Goede hdegoede@redhat.com
commit 81ee85d0462410de8eeeec1b9761941fd6ed8c7b upstream.
Quoting from the comment describing the WARN functions in include/asm-generic/bug.h:
* WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report * significant kernel issues that need prompt attention if they should ever * appear at runtime. * * Do not use these macros when checking for invalid external inputs
The (buggy) firmware tables which the dmar code was calling WARN_TAINT for really are invalid external inputs. They are not under the kernel's control and the issues in them cannot be fixed by a kernel update. So logging a backtrace, which invites bug reports to be filed about this, is not helpful.
Fixes: 556ab45f9a77 ("ioat2: catch and recover from broken vtd configurations v6") Signed-off-by: Hans de Goede hdegoede@redhat.com Acked-by: Lu Baolu baolu.lu@linux.intel.com Link: https://lore.kernel.org/r/20200309182510.373875-1-hdegoede@redhat.com BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=701847 Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/iommu/intel-iommu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4129,10 +4129,11 @@ static void quirk_ioat_snb_local_iommu(s
/* we know that the this iommu should be at offset 0xa000 from vtbar */ drhd = dmar_find_matched_drhd_unit(pdev); - if (WARN_TAINT_ONCE(!drhd || drhd->reg_base_addr - vtbar != 0xa000, - TAINT_FIRMWARE_WORKAROUND, - "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n")) + if (!drhd || drhd->reg_base_addr - vtbar != 0xa000) { + pr_warn_once(FW_BUG "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n"); + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); pdev->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO; + } } DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB, quirk_ioat_snb_local_iommu);