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powerpc/iommu: Remove the dependency on EEH struct in DDW mechanism 

Commit 39baadbf36 ("powerpc/eeh: Remove eeh information from pci_dn")
changed the pci_dn struct by removing its EEH-related members.
As part of this clean-up, DDW mechanism was modified to read the device
configuration address from eeh_dev struct.

As a consequence, now if we disable EEH mechanism on kernel command-line
for example, the DDW mechanism will fail, generating a kernel oops by
dereferencing a NULL pointer (which turns to be the eeh_dev pointer).

This patch just changes the configuration address calculation on DDW
functions to a manual calculation based on pci_dn members instead of
using eeh_dev-based address.

No functional changes were made. This was tested on pSeries, both
in PHyp and qemu guest.

Fixes: 39baadbf36 ("powerpc/eeh: Remove eeh information from pci_dn")
Cc: stable@vger.kernel.org # v3.4+
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Guilherme G. Piccoli 2016-04-11 16:17:23 -03:00 committed by Michael Ellerman
parent c2078d9ef6
commit 8445a87f70
1 changed files with 12 additions and 12 deletions
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24
arch/powerpc/platforms/pseries/iommu.c
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@ -912,7 +912,8 @@ machine_arch_initcall(pseries, find_existing_ddw_windows);
static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
struct ddw_query_response *query)
{
struct eeh_dev *edev;
struct device_node *dn;
struct pci_dn *pdn;
u32 cfg_addr;
u64 buid;
int ret;
@ -923,11 +924,10 @@ static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
* Retrieve them from the pci device, not the node with the
* dma-window property
*/
edev = pci_dev_to_eeh_dev(dev);
cfg_addr = edev->config_addr;
if (edev->pe_config_addr)
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;
dn = pci_device_to_OF_node(dev);
pdn = PCI_DN(dn);
buid = pdn->phb->buid;
cfg_addr = (pdn->busno << 8) | pdn->devfn;
ret = rtas_call(ddw_avail[0], 3, 5, (u32 *)query,
cfg_addr, BUID_HI(buid), BUID_LO(buid));
@ -941,7 +941,8 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddw_avail,
struct ddw_create_response *create, int page_shift,
int window_shift)
{
struct eeh_dev *edev;
struct device_node *dn;
struct pci_dn *pdn;
u32 cfg_addr;
u64 buid;
int ret;
@ -952,11 +953,10 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddw_avail,
* Retrieve them from the pci device, not the node with the
* dma-window property
*/
edev = pci_dev_to_eeh_dev(dev);
cfg_addr = edev->config_addr;
if (edev->pe_config_addr)
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;
dn = pci_device_to_OF_node(dev);
pdn = PCI_DN(dn);
buid = pdn->phb->buid;
cfg_addr = (pdn->busno << 8) | pdn->devfn;
do {
/* extra outputs are LIOBN and dma-addr (hi, lo) */