Re: [PATCH v9 1/5] PCI: Add pcie_get_link_speed() helper for safe array access
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2026-03-26 18:09:46
Also in:
linux-arm-msm, linux-mediatek, linux-omap, linux-pci, linux-renesas-soc, linux-tegra, lkml
On Sat, Mar 14, 2026 at 12:55:18AM +0800, Hans Zhang wrote:
The pcie_link_speed[] array is indexed by PCIe generation numbers (1 = 2.5 GT/s, 2 = 5 GT/s, ...). Several drivers use it directly, which can lead to out-of-bounds accesses if an invalid generation number is used. Introduce a helper function pcie_get_link_speed() that returns the corresponding enum pci_bus_speed value for a given generation number, or PCI_SPEED_UNKNOWN if the generation is out of range. This will allow us to safely handle invalid values after the range check is removed from of_pci_get_max_link_speed(). Signed-off-by: Hans Zhang <18255117159@163.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
quoted hunk ↗ jump to hunk
--- drivers/pci/pci.h | 2 ++ drivers/pci/probe.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+)diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 13d998fbacce..409aca7d737a 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h@@ -108,6 +108,8 @@ struct pcie_tlp_log; PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE) extern const unsigned char pcie_link_speed[]; +unsigned char pcie_get_link_speed(unsigned int speed); + extern bool pci_early_dump; extern struct mutex pci_rescan_remove_lock;diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index bccc7a4bdd79..d6592898330c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c@@ -783,6 +783,22 @@ const unsigned char pcie_link_speed[] = { }; EXPORT_SYMBOL_GPL(pcie_link_speed); +/** + * pcie_link_speed_value - Get speed value from PCIe generation number + * @speed: PCIe speed (1-based: 1 = 2.5GT, 2 = 5GT, ...) + * + * Returns the speed value (e.g., PCIE_SPEED_2_5GT) if @speed is valid, + * otherwise returns PCI_SPEED_UNKNOWN. + */ +unsigned char pcie_get_link_speed(unsigned int speed) +{ + if (speed >= ARRAY_SIZE(pcie_link_speed)) + return PCI_SPEED_UNKNOWN; + + return pcie_link_speed[speed]; +} +EXPORT_SYMBOL_GPL(pcie_get_link_speed); + const char *pci_speed_string(enum pci_bus_speed speed) { /* Indexed by the pci_bus_speed enum */-- 2.34.1