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authorKhalid Aziz <khalid.aziz@hp.com>2012-04-27 13:00:33 -0600
committerBjorn Helgaas <bhelgaas@google.com>2012-05-04 11:07:18 -0600
commitb566a22c23327f18ce941ffad0ca907e50a53d41 (patch)
treece675ff2f56a88778ea051f779868ffb9d746160 /drivers/pci
parentdf558de16c8a90e44ffb405e9224980b15158c93 (diff)
downloadop-kernel-dev-b566a22c23327f18ce941ffad0ca907e50a53d41.zip
op-kernel-dev-b566a22c23327f18ce941ffad0ca907e50a53d41.tar.gz
PCI: disable Bus Master on PCI device shutdown
Disable Bus Master bit on the device in pci_device_shutdown() to ensure PCI devices do not continue to DMA data after shutdown. This can cause memory corruption in case of a kexec where the current kernel shuts down and transfers control to a new kernel while a PCI device continues to DMA to memory that does not belong to it any more in the new kernel. I have tested this code on two laptops, two workstations and a 16-socket server. kexec worked correctly on all of them. Signed-off-by: Khalid Aziz <khalid.aziz@hp.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-driver.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 6b54b23..bf0cee6 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -421,6 +421,12 @@ static void pci_device_shutdown(struct device *dev)
pci_msix_shutdown(pci_dev);
/*
+ * Turn off Bus Master bit on the device to tell it to not
+ * continue to do DMA
+ */
+ pci_disable_device(pci_dev);
+
+ /*
* Devices may be enabled to wake up by runtime PM, but they need not
* be supposed to wake up the system from its "power off" state (e.g.
* ACPI S5). Therefore disable wakeup for all devices that aren't
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