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authorLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2016-08-15 17:50:43 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-31 05:02:15 -0600
commit9a7f38f1ba555724fd1abc55d133add9b863c92d (patch)
tree187128d6f74f5f1712afc26d55a9fb9d92a127ac
parent57ac6016db6a9cd5810b6d0d69da47b4a6364ca4 (diff)
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PCI: versatile: Fix pci_remap_iospace() failure path
commit 53f4f7ee28076a36e427274d7d5c33b23dfc6221 upstream. On ARM/ARM64 architectures, PCI IO ports are emulated through memory mapped IO, by reserving a chunk of virtual address space starting at PCI_IOBASE and by mapping the PCI host bridges memory address space driving PCI IO cycles to it. PCI host bridge drivers that enable downstream PCI IO cycles map the host bridge memory address responding to PCI IO cycles to the fixed virtual address space through the pci_remap_iospace() API. This means that if the pci_remap_iospace() function fails, the corresponding host bridge PCI IO resource must be considered invalid, in that there is no way for the kernel to actually drive PCI IO transactions if the memory addresses responding to PCI IO cycles cannot be mapped into the CPU virtual address space. The PCI versatile host bridge driver does not remove the PCI IO resource from the host bridge resource windows if the pci_remap_iospace() call fails; this is an actual bug in that the PCI host bridge would consider the PCI IO resource valid (and possibly assign it to downstream devices) even if the kernel was not able to map the PCI host bridge memory address driving IO cycle to the CPU virtual address space (ie pci_remap_iospace() failures). Fix the PCI host bridge driver pci_remap_iospace() failure path, by destroying the PCI host bridge PCI IO resources retrieved through firmware when the pci_remap_iospace() function call fails, therefore preventing the kernel from adding the respective PCI IO resource to the list of PCI host bridge valid resources, fixing the issue. Fixes: b7e78170efd4 ("PCI: versatile: Add DT-based ARM Versatile PB PCIe host driver") Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: Rob Herring <robh@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/pci/host/pci-versatile.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/pci/host/pci-versatile.c b/drivers/pci/host/pci-versatile.c
index f234405770ab..b7dc07002f13 100644
--- a/drivers/pci/host/pci-versatile.c
+++ b/drivers/pci/host/pci-versatile.c
@@ -74,7 +74,7 @@ static int versatile_pci_parse_request_of_pci_ranges(struct device *dev,
int err, mem = 1, res_valid = 0;
struct device_node *np = dev->of_node;
resource_size_t iobase;
- struct resource_entry *win;
+ struct resource_entry *win, *tmp;
err = of_pci_get_host_bridge_resources(np, 0, 0xff, res, &iobase);
if (err)
@@ -84,15 +84,17 @@ static int versatile_pci_parse_request_of_pci_ranges(struct device *dev,
if (err)
goto out_release_res;
- resource_list_for_each_entry(win, res) {
+ resource_list_for_each_entry_safe(win, tmp, res) {
struct resource *res = win->res;
switch (resource_type(res)) {
case IORESOURCE_IO:
err = pci_remap_iospace(res, iobase);
- if (err)
+ if (err) {
dev_warn(dev, "error %d: failed to map resource %pR\n",
err, res);
+ resource_list_destroy_entry(win);
+ }
break;
case IORESOURCE_MEM:
res_valid |= !(res->flags & IORESOURCE_PREFETCH);