From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: helgaas@kernel.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>
Cc: "Saheed O. Bolarinwa" <refactormyself@gmail.com>,
bjorn@helgaas.com, skhan@linuxfoundation.org,
linux-pci@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: [PATCH v4 07/12] PCI/ACPI: Check if pcie_capability_read_*() reads ~0
Date: Fri, 31 Jul 2020 13:02:35 +0200 [thread overview]
Message-ID: <20200731110240.98326-8-refactormyself@gmail.com> (raw)
In-Reply-To: <20200731110240.98326-1-refactormyself@gmail.com>
On failure pcie_capability_read_*() sets it's last parameter, val
to 0. However, with Patch 12/12, it is possible that val is set
to ~0 on failure. This would introduces a bug because
(x & x) == (~0 & x).
Since ~0 is an invalid value in here,
Add extra check for ~0 in the if condition to ensure success or
failure.
Suggested-by: Bjorn Helgaas <bjorn@helgaas.com>
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
---
drivers/pci/pci-acpi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 7224b1e5f2a8..873b005947e4 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -253,7 +253,7 @@ static bool pcie_root_rcb_set(struct pci_dev *dev)
return false;
pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl);
- if (lnkctl & PCI_EXP_LNKCTL_RCB)
+ if ((lnkctl != (u16)~0) && (lnkctl & PCI_EXP_LNKCTL_RCB))
return true;
return false;
@@ -797,7 +797,7 @@ bool pciehp_is_native(struct pci_dev *bridge)
return false;
pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap);
- if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
+ if ((slot_cap == (u32)~0) || !(slot_cap & PCI_EXP_SLTCAP_HPC))
return false;
if (pcie_ports_native)
--
2.18.4
prev parent reply other threads:[~2020-07-31 12:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 11:02 [PATCH v4 00/12] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed O. Bolarinwa
2020-07-31 11:02 ` Saheed O. Bolarinwa [this message]
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