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[149.200.78.10]) by smtp.gmail.com with ESMTPSA id g23sm8668514ejb.24.2020.07.31.05.43.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 05:43:08 -0700 (PDT) From: "Saheed O. Bolarinwa" To: helgaas@kernel.org Cc: "Saheed O. Bolarinwa" , bjorn@helgaas.com, skhan@linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 08/12] PCI: Check if pcie_capability_read_*() reads ~0 Date: Fri, 31 Jul 2020 13:43:25 +0200 Message-Id: <20200731114329.100848-1-refactormyself@gmail.com> X-Mailer: git-send-email 2.18.4 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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 introduce 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 Signed-off-by: Saheed O. Bolarinwa --- drivers/pci/probe.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 2f66988cea25..af95f67c19a7 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1124,7 +1124,7 @@ static void pci_enable_crs(struct pci_dev *pdev) /* Enable CRS Software Visibility if supported */ pcie_capability_read_word(pdev, PCI_EXP_RTCAP, &root_cap); - if (root_cap & PCI_EXP_RTCAP_CRSVIS) + if ((root_cap != (u16)~0) && (root_cap & PCI_EXP_RTCAP_CRSVIS)) pcie_capability_set_word(pdev, PCI_EXP_RTCTL, PCI_EXP_RTCTL_CRSSVE); } @@ -1521,7 +1521,7 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev) u32 reg32; pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, ®32); - if (reg32 & PCI_EXP_SLTCAP_HPC) + if ((reg32 != (u32)~0) && (reg32 & PCI_EXP_SLTCAP_HPC)) pdev->is_hotplug_bridge = 1; } @@ -2060,7 +2060,7 @@ bool pcie_relaxed_ordering_enabled(struct pci_dev *dev) pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &v); - return !!(v & PCI_EXP_DEVCTL_RELAX_EN); + return ((v != (u16)~0) && (v & PCI_EXP_DEVCTL_RELAX_EN)); } EXPORT_SYMBOL(pcie_relaxed_ordering_enabled); @@ -2101,11 +2101,11 @@ static void pci_configure_ltr(struct pci_dev *dev) return; pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap); - if (!(cap & PCI_EXP_DEVCAP2_LTR)) + if ((cap == (u32)~0) || !(cap & PCI_EXP_DEVCAP2_LTR)) return; pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl); - if (ctl & PCI_EXP_DEVCTL2_LTR_EN) { + if ((ctl != (u32)~0) && (ctl & PCI_EXP_DEVCTL2_LTR_EN)) { if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) { dev->ltr_path = 1; return; @@ -2147,7 +2147,7 @@ static void pci_configure_eetlp_prefix(struct pci_dev *dev) return; pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap); - if (!(cap & PCI_EXP_DEVCAP2_EE_PREFIX)) + if ((cap == (u32)~0) || !(cap & PCI_EXP_DEVCAP2_EE_PREFIX)) return; pcie_type = pci_pcie_type(dev);