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PCI: Add pcie_get_link_speed() helper for safe array access

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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: Hans Zhang <18255117159@163.com>
[mani: Fixed kernel-doc]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20260313165522.123518-2-18255117159@163.com
This commit is contained in:
Hans Zhang 2026-03-14 00:55:18 +08:00 committed by Manivannan Sadhasivam
parent 6de23f81a5
commit 28d20b0d89
2 changed files with 18 additions and 0 deletions
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2
drivers/pci/pci.h
View File

@ -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;

16
drivers/pci/probe.c
View File

@ -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 */