[RESEND PATCH v7 0/1] PCI/sysfs: Expose PCIe device serial number

[Matthew Wood <thepacketgeek@gmail.com>]

Add a single sysfs read-only, admin-only interface for reading PCIe device
serial numbers from userspace, using the same hexadecimal 1-byte dashed
formatting as lspci serial number capability output:

    sudo cat /sys/devices/pci0000:c0/0000:c0:01.1/0000:c1:00.0/0000:c2:1f.0/0000:ef:00.0/serial_number
    00-80-ee-00-00-00-41-80

If a device doesn't support the serial number capability, the
serial_number sysfs attribute will not be visible.

Comparing serial number format to lspci output:

    sudo lspci -vvv -s ef:00.0
        ef:00.0 Serial Attached SCSI controller: Broadcom / LSI PCIe Switch management endpoint (rev b0)
            Subsystem: Broadcom / LSI Device 0144
            ...
            Capabilities: [100 v1] Device Serial Number 00-80-ee-00-00-00-41-80
            ...

We have a specific use-case of needing to read the serial number
from an unpriviliged application; this patch exposes the serial number as a
file which means we can change the permissions from an admin context and
allow the unpriviliged userspace app to read the serial number. Otherwise
the serial number cannot be read as it requires both the admin capability
and parsing of the lspci text output which can be fragile and unreliable.


v7:
  Updated docs to change kernel introduction date to December 2025 (6.18)

Matthew Wood (1):
  PCI/sysfs: Expose PCIe device serial number

 Documentation/ABI/testing/sysfs-bus-pci |  9 +++++++++
 drivers/pci/pci-sysfs.c                 | 27 ++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

-- 
2.50.1