* [PATCH v3 0/1] PCI/sysfs: Expose PCIe device serial number
@ 2025-07-16 16:32 Matthew Wood
2025-07-16 16:32 ` [PATCH v3 1/1] " Matthew Wood
0 siblings, 1 reply; 4+ messages in thread
From: Matthew Wood @ 2025-07-16 16:32 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Jonathan Cameron, Thomas Weißschuh, linux-pci, linux-kernel
Add a single sysfs read-only interface for reading PCIe device serial
numbers from userspace, using the same hexadecimal 1-byte dashed
formatting as lspci serial number capability output:
more /sys/devices/pci0000:c0/0000:c0:01.1/0000:c1:00.0/0000:c2:1f.0/0000:cc:00.0/device_serial_number
00-80-ee-00-00-00-41-80
If a device doesn't support the serial number capability, the
device_serial_number sysfs attribute will not be visible.
Comparing serial number format to lspci output:
sudo lspci -vvv -s cc:00.0
cc: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 | 7 +++++++
drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++---
2 files changed, 31 insertions(+), 3 deletions(-)
--
2.50.0
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v3 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-16 16:32 [PATCH v3 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood @ 2025-07-16 16:32 ` Matthew Wood 2025-07-16 17:02 ` Mario Limonciello 0 siblings, 1 reply; 4+ messages in thread From: Matthew Wood @ 2025-07-16 16:32 UTC (permalink / raw) To: Bjorn Helgaas Cc: 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 device_serial_number sysfs attribute will not be visible. Signed-off-by: Matthew Wood <thepacketgeek@gmail.com> --- Documentation/ABI/testing/sysfs-bus-pci | 7 +++++++ drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- 2 files changed, 31 insertions(+), 3 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 69f952fffec7..f7e84b3a4204 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -612,3 +612,10 @@ Description: # ls doe_features 0001:01 0001:02 doe_discovery + +What: /sys/bus/pci/devices/.../device_serial_number +Date: July 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. diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 268c69daa4d5..b7b52dea6e31 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -239,6 +239,22 @@ static ssize_t current_link_width_show(struct device *dev, } static DEVICE_ATTR_RO(current_link_width); +static ssize_t device_serial_number_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + u64 dsn; + + dsn = pci_get_dsn(pci_dev); + if (!dsn) + return -EIO; + + return sysfs_emit(buf, "%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx\n", + dsn >> 56, (dsn >> 48) & 0xff, (dsn >> 40) & 0xff, (dsn >> 32) & 0xff, + (dsn >> 24) & 0xff, (dsn >> 16) & 0xff, (dsn >> 8) & 0xff, dsn & 0xff); +} +static DEVICE_ATTR_RO(device_serial_number); + static ssize_t secondary_bus_number_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -660,6 +676,7 @@ 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_device_serial_number.attr, NULL, }; @@ -1749,10 +1766,14 @@ 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; + + if (a == &dev_attr_device_serial_number.attr && !pci_get_dsn(pdev)) + return 0; + + return a->mode; - return 0; } static const struct attribute_group pci_dev_group = { -- 2.50.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-16 16:32 ` [PATCH v3 1/1] " Matthew Wood @ 2025-07-16 17:02 ` Mario Limonciello 2025-07-16 17:43 ` Matthew Wood 0 siblings, 1 reply; 4+ messages in thread From: Mario Limonciello @ 2025-07-16 17:02 UTC (permalink / raw) To: Matthew Wood, Bjorn Helgaas Cc: Jonathan Cameron, Thomas Weißschuh, linux-kernel, linux-pci On 7/16/25 11:32 AM, 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 device_serial_number sysfs attribute will not be visible. > > Signed-off-by: Matthew Wood <thepacketgeek@gmail.com> > --- > Documentation/ABI/testing/sysfs-bus-pci | 7 +++++++ > drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- > 2 files changed, 31 insertions(+), 3 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci > index 69f952fffec7..f7e84b3a4204 100644 > --- a/Documentation/ABI/testing/sysfs-bus-pci > +++ b/Documentation/ABI/testing/sysfs-bus-pci > @@ -612,3 +612,10 @@ Description: > > # ls doe_features > 0001:01 0001:02 doe_discovery > + > +What: /sys/bus/pci/devices/.../device_serial_number > +Date: July 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. > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 268c69daa4d5..b7b52dea6e31 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -239,6 +239,22 @@ static ssize_t current_link_width_show(struct device *dev, > } > static DEVICE_ATTR_RO(current_link_width); > > +static ssize_t device_serial_number_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct pci_dev *pci_dev = to_pci_dev(dev); > + u64 dsn; > + > + dsn = pci_get_dsn(pci_dev); > + if (!dsn) > + return -EIO; > + > + return sysfs_emit(buf, "%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx\n", > + dsn >> 56, (dsn >> 48) & 0xff, (dsn >> 40) & 0xff, (dsn >> 32) & 0xff, > + (dsn >> 24) & 0xff, (dsn >> 16) & 0xff, (dsn >> 8) & 0xff, dsn & 0xff); > +} > +static DEVICE_ATTR_RO(device_serial_number); The serial number /could/ be considered sensitive information. I think it's better to use DEVICE_ATTR_ADMIN_RO. Also, as this is a "device" attribute is it really necessary to encode the extra word and "number"? > + > static ssize_t secondary_bus_number_show(struct device *dev, > struct device_attribute *attr, > char *buf) > @@ -660,6 +676,7 @@ 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_device_serial_number.attr, > NULL, > }; > > @@ -1749,10 +1766,14 @@ 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; > + > + if (a == &dev_attr_device_serial_number.attr && !pci_get_dsn(pdev)) > + return 0; > + > + return a->mode; > > - return 0; > } > > static const struct attribute_group pci_dev_group = { ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-16 17:02 ` Mario Limonciello @ 2025-07-16 17:43 ` Matthew Wood 0 siblings, 0 replies; 4+ messages in thread From: Matthew Wood @ 2025-07-16 17:43 UTC (permalink / raw) To: Mario Limonciello Cc: Bjorn Helgaas, Jonathan Cameron, Thomas Weißschuh, linux-kernel, linux-pci On Wed, Jul 16, 2025 at 10:02 AM Mario Limonciello <superm1@kernel.org> wrote: > > On 7/16/25 11:32 AM, 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 device_serial_number sysfs attribute will not be visible. > > > > Signed-off-by: Matthew Wood <thepacketgeek@gmail.com> > > --- > > Documentation/ABI/testing/sysfs-bus-pci | 7 +++++++ > > drivers/pci/pci-sysfs.c | 27 ++++++++++++++++++++++--- > > 2 files changed, 31 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci > > index 69f952fffec7..f7e84b3a4204 100644 > > --- a/Documentation/ABI/testing/sysfs-bus-pci > > +++ b/Documentation/ABI/testing/sysfs-bus-pci > > @@ -612,3 +612,10 @@ Description: > > > > # ls doe_features > > 0001:01 0001:02 doe_discovery > > + > > +What: /sys/bus/pci/devices/.../device_serial_number > > +Date: July 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. > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > index 268c69daa4d5..b7b52dea6e31 100644 > > --- a/drivers/pci/pci-sysfs.c > > +++ b/drivers/pci/pci-sysfs.c > > @@ -239,6 +239,22 @@ static ssize_t current_link_width_show(struct device *dev, > > } > > static DEVICE_ATTR_RO(current_link_width); > > > > +static ssize_t device_serial_number_show(struct device *dev, > > + struct device_attribute *attr, char *buf) > > +{ > > + struct pci_dev *pci_dev = to_pci_dev(dev); > > + u64 dsn; > > + > > + dsn = pci_get_dsn(pci_dev); > > + if (!dsn) > > + return -EIO; > > + > > + return sysfs_emit(buf, "%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx-%02llx\n", > > + dsn >> 56, (dsn >> 48) & 0xff, (dsn >> 40) & 0xff, (dsn >> 32) & 0xff, > > + (dsn >> 24) & 0xff, (dsn >> 16) & 0xff, (dsn >> 8) & 0xff, dsn & 0xff); > > +} > > +static DEVICE_ATTR_RO(device_serial_number); > > The serial number /could/ be considered sensitive information. I think > it's better to use DEVICE_ATTR_ADMIN_RO. That makes sense, thanks for the suggestion. > > Also, as this is a "device" attribute is it really necessary to encode > the extra word and "number"? Another good point. I will remove the device_ prefix however I think "serial_number" is helpful to keep as "serial" alone is too easy to conflate with any of the other usages of the serial word. > > > + > > static ssize_t secondary_bus_number_show(struct device *dev, > > struct device_attribute *attr, > > char *buf) > > @@ -660,6 +676,7 @@ 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_device_serial_number.attr, > > NULL, > > }; > > > > @@ -1749,10 +1766,14 @@ 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; > > + > > + if (a == &dev_attr_device_serial_number.attr && !pci_get_dsn(pdev)) > > + return 0; > > + > > + return a->mode; > > > > - return 0; > > } > > > > static const struct attribute_group pci_dev_group = { > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-07-16 17:43 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-07-16 16:32 [PATCH v3 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood 2025-07-16 16:32 ` [PATCH v3 1/1] " Matthew Wood 2025-07-16 17:02 ` Mario Limonciello 2025-07-16 17:43 ` Matthew Wood
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