[PATCH v2 01/53] MIPS: PCI: xtalk-bridge: refuse device numbers past the last slot

[Imre Kaloz <kaloz@kernel.org>]

Config slots 8 and up alias the type 1 window, so a root bus scan finds
phantom copies of whatever device b_pci_cfg selects.  Refuse root bus
accesses past the ASIC's last slot.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Imre Kaloz <kaloz@kernel.org>
---
 arch/mips/pci/pci-xtalk-bridge.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/mips/pci/pci-xtalk-bridge.c b/arch/mips/pci/pci-xtalk-bridge.c
index cf115abb54e0..9451b7546068 100644
--- a/arch/mips/pci/pci-xtalk-bridge.c
+++ b/arch/mips/pci/pci-xtalk-bridge.c
@@ -92,6 +92,11 @@ static int ioc3_cfg_wr(void *addr, int where, int size, u32 value)
 	return PCIBIOS_SUCCESSFUL;
 }
 
+static int bridge_nslots(struct bridge_controller *bc)
+{
+	return BRIDGE_DEV_CNT;
+}
+
 static void bridge_disable_swapping(struct pci_dev *dev)
 {
 	struct bridge_controller *bc = BRIDGE_CONTROLLER(dev->bus);
@@ -127,6 +132,13 @@ static int pci_conf0_read_config(struct pci_bus *bus, unsigned int devfn,
 	u32 cf;
 	int res;
 
+	/*
+	 * Only bridge_nslots() slots exist.  Config slots 8 and up alias the
+	 * type 1 window and would answer for whatever b_pci_cfg selects.
+	 */
+	if (slot >= bridge_nslots(bc))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
 	addr = &bridge->b_type0_cfg_dev[slot].f[fn].c[PCI_VENDOR_ID];
 	if (get_dbe(cf, (u32 *)addr))
 		return PCIBIOS_DEVICE_NOT_FOUND;
@@ -212,6 +224,9 @@ static int pci_conf0_write_config(struct pci_bus *bus, unsigned int devfn,
 	u32 cf;
 	int res;
 
+	if (slot >= bridge_nslots(bc))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
 	addr = &bridge->b_type0_cfg_dev[slot].f[fn].c[PCI_VENDOR_ID];
 	if (get_dbe(cf, (u32 *)addr))
 		return PCIBIOS_DEVICE_NOT_FOUND;
@@ -695,7 +710,7 @@ static int bridge_probe(struct platform_device *pdev)
 	bridge_write(bc, b_dir_map, (bd->masterwid << 20));	/* DMA */
 	bridge_write(bc, b_int_enable, 0);
 
-	for (slot = 0; slot < 8; slot++) {
+	for (slot = 0; slot < bridge_nslots(bc); slot++) {
 		bridge_set(bc, b_device[slot].reg, BRIDGE_DEV_SWAP_DIR);
 		bc->pci_int[slot][0] = -1;
 		bc->pci_int[slot][1] = -1;
-- 
2.47.3