[PATCH 9/14 v3] PCI: pciehp: Check return value of pcie_capability_read_*()

Saheed Olayemi Bolarinwa
2020-07-10T22:20:27Z

On failure pcie_capability_read_dword() sets it's last parameter,
val to 0.
However, with Patch 14/14, it is possible that val is set to ~0 on
failure. This would introduce a bug because (x & x) == (~0 & x).

This bug can be avoided if the return value of pcie_capability_read_word
is checked to confirm success.

Check the return value of pcie_capability_read_dword() to ensure success.
Return a value that indicate the result of pcie_capability_read_word().

Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@gmail.com>
---
drivers/pci/hotplug/pciehp_hpc.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 5af281d97d4f..0b691e37fd04 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -277,10 +277,11 @@ static void pcie_wait_for_presence(struct pci_dev *pdev)
{
int timeout = 1250;
u16 slot_status;
+ int ret;

do {
- pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
- if (slot_status & PCI_EXP_SLTSTA_PDS)
+ ret = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
+ if (!ret && (slot_status & PCI_EXP_SLTSTA_PDS))
return;
msleep(10);
timeout -= 10;
@@ -354,12 +355,13 @@ int pciehp_get_raw_indicator_status(struct hotplug_slot *hotplug_slot,
struct controller *ctrl = to_ctrl(hotplug_slot);
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_ctrl;
+ int ret;

pci_config_pm_runtime_get(pdev);
- pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
+ ret = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
pci_config_pm_runtime_put(pdev);
*status = (slot_ctrl & (PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC)) >> 6;
- return 0;
+ return pcibios_err_to_errno(ret);
}

int pciehp_get_attention_status(struct hotplug_slot *hotplug_slot, u8 *status)
@@ -367,9 +369,10 @@ int pciehp_get_attention_status(struct hotplug_slot *hotplug_slot, u8 *status)
struct controller *ctrl = to_ctrl(hotplug_slot);
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_ctrl;
+ int ret;

pci_config_pm_runtime_get(pdev);
- pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
+ ret = pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
pci_config_pm_runtime_put(pdev);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x, value read %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl);
@@ -389,7 +392,7 @@ int pciehp_get_attention_status(struct hotplug_slot *hotplug_slot, u8 *status)
break;
}

- return 0;
+ return pcibios_err_to_errno(ret);
}

void pciehp_get_power_status(struct controller *ctrl, u8 *status)
--
2.18.2