[PATCH v2 1/3] PCI: dwc: allow to limit registers set length

[Stefan Agner <stefan@xxxxxxxx>]

Add length to the struct dw_pcie and check that the accessors
dw_pcie_(rd|wr)_own_conf() do not read/write beyond that point.

Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
 drivers/pci/controller/dwc/pcie-designware.h      | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 29a05759a294..b422538ee0bb 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -29,6 +29,8 @@ static int dw_pcie_rd_own_conf(struct pcie_port *pp, int where, int size,
 		return pp->ops->rd_own_conf(pp, where, size, val);
 
 	pci = to_dw_pcie_from_pp(pp);
+	if (pci->dbi_length && where + size > pci->dbi_length)
+		return PCIBIOS_BAD_REGISTER_NUMBER;
 	return dw_pcie_read(pci->dbi_base + where, size, val);
 }
 
@@ -41,6 +43,8 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size,
 		return pp->ops->wr_own_conf(pp, where, size, val);
 
 	pci = to_dw_pcie_from_pp(pp);
+	if (pci->dbi_length && where + size > pci->dbi_length)
+		return PCIBIOS_BAD_REGISTER_NUMBER;
 	return dw_pcie_write(pci->dbi_base + where, size, val);
 }
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 9f1a5e399b70..5be5f369abf2 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -215,6 +215,7 @@ struct dw_pcie {
 	struct device		*dev;
 	void __iomem		*dbi_base;
 	void __iomem		*dbi_base2;
+	int			dbi_length;
 	u32			num_viewport;
 	u8			iatu_unroll_enabled;
 	struct pcie_port	pp;
-- 
2.19.1