* [PATCH v6 0/1] PCI/sysfs: Expose PCIe device serial number
@ 2025-07-18 19:32 Matthew Wood
2025-07-18 19:32 ` [PATCH v6 1/1] " Matthew Wood
0 siblings, 1 reply; 4+ messages in thread
From: Matthew Wood @ 2025-07-18 19:32 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Mario Limonciello, Jonathan Cameron, Thomas Weißschuh,
linux-pci, linux-kernel
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
...
This PCIe device sysfs attribute eliminates the need for parsing lspci
output (e.g. regexp) for userspace applications that utilize serial
numbers.
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
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v6 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 19:32 [PATCH v6 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood @ 2025-07-18 19:32 ` Matthew Wood 2025-07-21 9:53 ` Jonathan Cameron 2025-07-21 11:55 ` Thomas Weißschuh 0 siblings, 2 replies; 4+ messages in thread From: Matthew Wood @ 2025-07-18 19:32 UTC (permalink / raw) To: Bjorn Helgaas Cc: Mario Limonciello, Jonathan Cameron, Thomas Weißschuh, linux-kernel, linux-pci Add a single sysfs read-only interface for reading PCIe 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 <thepacketgeek@gmail.com> Reviewed-by: Mario Limonciello <superm1@kernel.org> --- Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++ drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- 2 files changed, 33 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 69f952fffec7..0a2580cdd58c 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: October 2025 +Contact: Matthew Wood <thepacketgeek@gmail.com> +Description: + This is visible only for PCIe 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..1d26e4336f1b 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -30,6 +30,7 @@ #include <linux/msi.h> #include <linux/of.h> #include <linux/aperture.h> +#include <linux/unaligned.h> #include "pci.h" #ifndef ARCH_PCI_DEV_GROUPS @@ -239,6 +240,22 @@ static ssize_t current_link_width_show(struct device *dev, } static DEVICE_ATTR_RO(current_link_width); +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 secondary_bus_number_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -660,6 +677,7 @@ static struct attribute *pcie_dev_attrs[] = { &dev_attr_current_link_width.attr, &dev_attr_max_link_width.attr, &dev_attr_max_link_speed.attr, + &dev_attr_serial_number.attr, NULL, }; @@ -1749,10 +1767,13 @@ static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj, struct device *dev = kobj_to_dev(kobj); struct pci_dev *pdev = to_pci_dev(dev); - if (pci_is_pcie(pdev)) - return a->mode; + if (!pci_is_pcie(pdev)) + return 0; - return 0; + if (a == &dev_attr_serial_number.attr && !pci_get_dsn(pdev)) + return 0; + + return a->mode; } static const struct attribute_group pci_dev_group = { -- 2.50.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v6 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 19:32 ` [PATCH v6 1/1] " Matthew Wood @ 2025-07-21 9:53 ` Jonathan Cameron 2025-07-21 11:55 ` Thomas Weißschuh 1 sibling, 0 replies; 4+ messages in thread From: Jonathan Cameron @ 2025-07-21 9:53 UTC (permalink / raw) To: Matthew Wood Cc: Bjorn Helgaas, Mario Limonciello, Thomas Weißschuh, linux-kernel, linux-pci On Fri, 18 Jul 2025 12:32:29 -0700 Matthew Wood <thepacketgeek@gmail.com> wrote: > Add a single sysfs read-only interface for reading PCIe 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 <thepacketgeek@gmail.com> > Reviewed-by: Mario Limonciello <superm1@kernel.org> Nice. The %8phD that Thomas pointed out was new to me. Very useful! Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> > --- > Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++ > drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- > 2 files changed, 33 insertions(+), 3 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci > index 69f952fffec7..0a2580cdd58c 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: October 2025 > +Contact: Matthew Wood <thepacketgeek@gmail.com> > +Description: > + This is visible only for PCIe 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..1d26e4336f1b 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -30,6 +30,7 @@ > #include <linux/msi.h> > #include <linux/of.h> > #include <linux/aperture.h> > +#include <linux/unaligned.h> > #include "pci.h" > > #ifndef ARCH_PCI_DEV_GROUPS > @@ -239,6 +240,22 @@ static ssize_t current_link_width_show(struct device *dev, > } > static DEVICE_ATTR_RO(current_link_width); > > +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 secondary_bus_number_show(struct device *dev, > struct device_attribute *attr, > char *buf) > @@ -660,6 +677,7 @@ static struct attribute *pcie_dev_attrs[] = { > &dev_attr_current_link_width.attr, > &dev_attr_max_link_width.attr, > &dev_attr_max_link_speed.attr, > + &dev_attr_serial_number.attr, > NULL, > }; > > @@ -1749,10 +1767,13 @@ static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj, > struct device *dev = kobj_to_dev(kobj); > struct pci_dev *pdev = to_pci_dev(dev); > > - if (pci_is_pcie(pdev)) > - return a->mode; > + if (!pci_is_pcie(pdev)) > + return 0; > > - return 0; > + if (a == &dev_attr_serial_number.attr && !pci_get_dsn(pdev)) > + return 0; > + > + return a->mode; > } > > static const struct attribute_group pci_dev_group = { ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v6 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 19:32 ` [PATCH v6 1/1] " Matthew Wood 2025-07-21 9:53 ` Jonathan Cameron @ 2025-07-21 11:55 ` Thomas Weißschuh 1 sibling, 0 replies; 4+ messages in thread From: Thomas Weißschuh @ 2025-07-21 11:55 UTC (permalink / raw) To: Matthew Wood Cc: Bjorn Helgaas, Mario Limonciello, Jonathan Cameron, linux-kernel, linux-pci On Fri, Jul 18, 2025 at 12:32:29PM -0700, Matthew Wood wrote: > Add a single sysfs read-only interface for reading PCIe 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 <thepacketgeek@gmail.com> > Reviewed-by: Mario Limonciello <superm1@kernel.org> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> > --- > Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++ > drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- > 2 files changed, 33 insertions(+), 3 deletions(-) (...) ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-07-21 11:55 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-07-18 19:32 [PATCH v6 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood 2025-07-18 19:32 ` [PATCH v6 1/1] " Matthew Wood 2025-07-21 9:53 ` Jonathan Cameron 2025-07-21 11:55 ` Thomas Weißschuh
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