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[99.122.55.39]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2697050c4a5sm6669815ad.16.2025.09.17.05.58.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Sep 2025 05:58:18 -0700 (PDT) From: Matthew Wood To: Bjorn Helgaas Cc: Mario Limonciello , Jonathan Cameron , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Keith Busch , =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH v8 1/1] PCI/sysfs: Expose PCI device serial number Date: Wed, 17 Sep 2025 05:58:14 -0700 Message-ID: <20250917125815.722952-2-thepacketgeek@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250917125815.722952-1-thepacketgeek@gmail.com> References: <20250917125815.722952-1-thepacketgeek@gmail.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a single sysfs read-only interface for reading PCI device serial numbers from userspace in a programmatic way. This device attribute uses the same hexadecimal 1-byte dashed formatting as lspci serial number capability output. If a device doesn't support the serial number capability, the serial_number sysfs attribute will not be visible. Signed-off-by: Matthew Wood Reviewed-by: Mario Limonciello Reviewed-by: Jonathan Cameron Reviewed-by: Thomas Weißschuh Reviewed-by: Keith Busch Reviewed-by: Krzysztof Wilczyński --- Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++ drivers/pci/pci-sysfs.c | 21 +++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 69f952fffec7..92debe879ffb 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -612,3 +612,12 @@ Description: # ls doe_features 0001:01 0001:02 doe_discovery + +What: /sys/bus/pci/devices/.../serial_number +Date: December 2025 +Contact: Matthew Wood +Description: + This is visible only for PCI devices that support the serial + number extended capability. The file is read only and due to + the possible sensitivity of accessible serial numbers, admin + only. diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 268c69daa4d5..b7b7412c9f00 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "pci.h" #ifndef ARCH_PCI_DEV_GROUPS @@ -694,6 +695,22 @@ static ssize_t boot_vga_show(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RO(boot_vga); +static ssize_t serial_number_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u64 dsn; + u8 bytes[8]; + + dsn = pci_get_dsn(pci_dev); + if (!dsn) + return -EIO; + put_unaligned_be64(dsn, bytes); + + return sysfs_emit(buf, "%8phD\n", bytes); +} +static DEVICE_ATTR_ADMIN_RO(serial_number); + static ssize_t pci_read_config(struct file *filp, struct kobject *kobj, const struct bin_attribute *bin_attr, char *buf, loff_t off, size_t count) @@ -1698,6 +1715,7 @@ late_initcall(pci_sysfs_init); static struct attribute *pci_dev_dev_attrs[] = { &dev_attr_boot_vga.attr, + &dev_attr_serial_number.attr, NULL, }; @@ -1710,6 +1728,9 @@ static umode_t pci_dev_attrs_are_visible(struct kobject *kobj, if (a == &dev_attr_boot_vga.attr && pci_is_vga(pdev)) return a->mode; + if (a == &dev_attr_serial_number.attr && pci_get_dsn(pdev)) + return a->mode; + return 0; } -- 2.50.1