[PATCH 4.4 067/137] powerpc/powernv: Fix stale PE primary bus

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>

commit 1bc74f1ccd457832dc515fc1febe6655985fdcd2 upstream.

When PCI bus is unplugged during full hotplug for EEH recovery,
the platform PE instance (struct pnv_ioda_pe) isn't released and
it dereferences the stale PCI bus that has been released. It leads
to kernel crash when referring to the stale PCI bus.

This fixes the issue by correcting the PE's primary bus when it's
oneline at plugging time, in pnv_pci_dma_bus_setup() which is to
be called by pcibios_fixup_bus().

Reported-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Reported-by: Pradipta Ghosh <pradghos@xxxxxxxxxx>
Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
Tested-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/platforms/powernv/pci-ioda.c |    1 +
 arch/powerpc/platforms/powernv/pci.c      |   20 ++++++++++++++++++++
 arch/powerpc/platforms/powernv/pci.h      |    1 +
 3 files changed, 22 insertions(+)

--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3034,6 +3034,7 @@ static void pnv_pci_ioda_shutdown(struct
 
 static const struct pci_controller_ops pnv_pci_ioda_controller_ops = {
        .dma_dev_setup = pnv_pci_dma_dev_setup,
+       .dma_bus_setup = pnv_pci_dma_bus_setup,
 #ifdef CONFIG_PCI_MSI
        .setup_msi_irqs = pnv_setup_msi_irqs,
        .teardown_msi_irqs = pnv_teardown_msi_irqs,
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -762,6 +762,26 @@ void pnv_pci_dma_dev_setup(struct pci_de
 		phb->dma_dev_setup(phb, pdev);
 }
 
+void pnv_pci_dma_bus_setup(struct pci_bus *bus)
+{
+	struct pci_controller *hose = bus->sysdata;
+	struct pnv_phb *phb = hose->private_data;
+	struct pnv_ioda_pe *pe;
+
+	list_for_each_entry(pe, &phb->ioda.pe_list, list) {
+		if (!(pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL)))
+			continue;
+
+		if (!pe->pbus)
+			continue;
+
+		if (bus->number == ((pe->rid >> 8) & 0xFF)) {
+			pe->pbus = bus;
+			break;
+		}
+	}
+}
+
 void pnv_pci_shutdown(void)
 {
 	struct pci_controller *hose;
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -235,6 +235,7 @@ extern void pnv_pci_reset_secondary_bus(
 extern int pnv_eeh_phb_reset(struct pci_controller *hose, int option);
 
 extern void pnv_pci_dma_dev_setup(struct pci_dev *pdev);
+extern void pnv_pci_dma_bus_setup(struct pci_bus *bus);
 extern int pnv_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type);
 extern void pnv_teardown_msi_irqs(struct pci_dev *pdev);