Commit 28d20b0d authored by Hans Zhang's avatar Hans Zhang Committed by Manivannan Sadhasivam
Browse files

PCI: Add pcie_get_link_speed() helper for safe array access 



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
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: default avatarHans Zhang <18255117159@163.com>
[mani: Fixed kernel-doc]
Signed-off-by: default avatarManivannan Sadhasivam <mani@kernel.org>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260313165522.123518-2-18255117159@163.com
parent 6de23f81

drivers/pci/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/pci/probe.c

+16 −0
Original line number Diff line number Diff line
@@ -783,6 +783,22 @@ const unsigned char pcie_link_speed[] = { 
};

EXPORT_SYMBOL_GPL(pcie_link_speed);



/**

 * pcie_get_link_speed - 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 */