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PCI: imx6: Limit DBI register length

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Define the length of the DBI registers and limit config space to its
length. This makes sure that the kernel does not access registers
beyond that point, avoiding the following abort on a i.MX 6Quad:

  # cat /sys/devices/soc0/soc/1ffc000.pcie/pci0000\:00/0000\:00\:00.0/config
  [  100.021433] Unhandled fault: imprecise external abort (0x1406) at 0xb6ea7000
  ...
  [  100.056423] PC is at dw_pcie_read+0x50/0x84
  [  100.060790] LR is at dw_pcie_rd_own_conf+0x44/0x48
  ...

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
This commit is contained in:
Stefan Agner 2019-07-26 16:40:07 +02:00 committed by Lorenzo Pieralisi
parent 5f9e832c13
commit 075af61c19
1 changed files with 33 additions and 0 deletions
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33
drivers/pci/controller/dwc/pci-imx6.c
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@ -57,6 +57,7 @@ enum imx6_pcie_variants {
struct imx6_pcie_drvdata {
enum imx6_pcie_variants variant;
u32 flags;
int dbi_length;
};
struct imx6_pcie {
@ -1212,6 +1213,7 @@ static const struct imx6_pcie_drvdata drvdata[] = {
.variant = IMX6Q,
.flags = IMX6_PCIE_FLAG_IMX6_PHY |
IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE,
.dbi_length = 0x200,
},
[IMX6SX] = {
.variant = IMX6SX,
@ -1254,6 +1256,37 @@ static struct platform_driver imx6_pcie_driver = {
.shutdown = imx6_pcie_shutdown,
};
static void imx6_pcie_quirk(struct pci_dev *dev)
{
struct pci_bus *bus = dev->bus;
struct pcie_port *pp = bus->sysdata;
/* Bus parent is the PCI bridge, its parent is this platform driver */
if (!bus->dev.parent || !bus->dev.parent->parent)
return;
/* Make sure we only quirk devices associated with this driver */
if (bus->dev.parent->parent->driver != &imx6_pcie_driver.driver)
return;
if (bus->number == pp->root_bus_nr) {
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct imx6_pcie *imx6_pcie = to_imx6_pcie(pci);
/*
* Limit config length to avoid the kernel reading beyond
* the register set and causing an abort on i.MX 6Quad
*/
if (imx6_pcie->drvdata->dbi_length) {
dev->cfg_size = imx6_pcie->drvdata->dbi_length;
dev_info(&dev->dev, "Limiting cfg_size to %d\n",
dev->cfg_size);
}
}
}
DECLARE_PCI_FIXUP_CLASS_HEADER(PCI_VENDOR_ID_SYNOPSYS, 0xabcd,
PCI_CLASS_BRIDGE_PCI, 8, imx6_pcie_quirk);
static int __init imx6_pcie_init(void)
{
#ifdef CONFIG_ARM