diff options
Diffstat (limited to 'drivers/pci/probe.c')
| -rw-r--r-- | drivers/pci/probe.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 0e8e2c186f50..1910b3394d2c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1094,14 +1094,15 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, * @sec: updated with secondary bus number from EA * @sub: updated with subordinate bus number from EA * - * If @dev is a bridge with EA capability, update @sec and @sub with - * fixed bus numbers from the capability and return true. Otherwise, - * return false. + * If @dev is a bridge with EA capability that specifies valid secondary + * and subordinate bus numbers, return true with the bus numbers in @sec + * and @sub. Otherwise return false. */ static bool pci_ea_fixed_busnrs(struct pci_dev *dev, u8 *sec, u8 *sub) { int ea, offset; u32 dw; + u8 ea_sec, ea_sub; if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) return false; @@ -1113,8 +1114,13 @@ static bool pci_ea_fixed_busnrs(struct pci_dev *dev, u8 *sec, u8 *sub) offset = ea + PCI_EA_FIRST_ENT; pci_read_config_dword(dev, offset, &dw); - *sec = dw & PCI_EA_SEC_BUS_MASK; - *sub = (dw & PCI_EA_SUB_BUS_MASK) >> PCI_EA_SUB_BUS_SHIFT; + ea_sec = dw & PCI_EA_SEC_BUS_MASK; + ea_sub = (dw & PCI_EA_SUB_BUS_MASK) >> PCI_EA_SUB_BUS_SHIFT; + if (ea_sec == 0 || ea_sub < ea_sec) + return false; + + *sec = ea_sec; + *sub = ea_sub; return true; } |