4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit da77b67195de1c65bef4908fa29967c4d0af2da2 ]
Commit b894157145e4 ("x86/PCI: Mark Broadwell-EP Home Agent & PCU as having non-compliant BARs") marked Home Agent 0 & PCU has having non-compliant BARs. Home Agent 1 also has non-compliant BARs.
Mark Home Agent 1 as having non-compliant BARs so the PCI core doesn't touch them.
The problem with these devices is documented in the Xeon v4 specification update:
BDF2 PCI BARs in the Home Agent Will Return Non-Zero Values During Enumeration
Problem: During system initialization the Operating System may access the standard PCI BARs (Base Address Registers). Due to this erratum, accesses to the Home Agent BAR registers (Bus 1; Device 18; Function 0,4; Offsets (0x14-0x24) will return non-zero values.
Implication: The operating system may issue a warning. Intel has not observed any functional failures due to this erratum.
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e5-v4-spec-updat... Fixes: b894157145e4 ("x86/PCI: Mark Broadwell-EP Home Agent & PCU as having non-compliant BARs") Signed-off-by: Prarit Bhargava prarit@redhat.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com CC: Thomas Gleixner tglx@linutronix.de CC: Ingo Molnar mingo@redhat.com CC: "H. Peter Anvin" hpa@zytor.com CC: Andi Kleen ak@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/pci/fixup.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index 0ae7e9fa348d..89f90549c6a8 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -541,9 +541,16 @@ static void twinhead_reserve_killing_zone(struct pci_dev *dev) } DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x27B9, twinhead_reserve_killing_zone);
+/* + * Broadwell EP Home Agent BARs erroneously return non-zero values when read. + * + * See http://www.intel.com/content/www/us/en/processors/xeon/xeon-e5-v4-spec-updat... + * entry BDF2. + */ static void pci_bdwep_bar(struct pci_dev *dev) { dev->non_compliant_bars = 1; } +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6f60, pci_bdwep_bar); DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fa0, pci_bdwep_bar); DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, pci_bdwep_bar);