* [PATCH v5 0/1] PCI/sysfs: Expose PCIe device serial number
@ 2025-07-17 16:50 Matthew Wood
2025-07-17 16:50 ` [PATCH v5 1/1] " Matthew Wood
0 siblings, 1 reply; 6+ messages in thread
From: Matthew Wood @ 2025-07-17 16:50 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:
more /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 | 26 ++++++++++++++++++++++---
2 files changed, 32 insertions(+), 3 deletions(-)
--
2.50.0
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH v5 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-17 16:50 [PATCH v5 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood @ 2025-07-17 16:50 ` Matthew Wood 2025-07-18 10:36 ` Jonathan Cameron 0 siblings, 1 reply; 6+ messages in thread From: Matthew Wood @ 2025-07-17 16:50 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 | 26 ++++++++++++++++++++++--- 2 files changed, 32 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..bc0e0add15d1 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 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_ADMIN_RO(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_serial_number.attr, NULL, }; @@ -1749,10 +1766,13 @@ 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 = { -- 2.50.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v5 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-17 16:50 ` [PATCH v5 1/1] " Matthew Wood @ 2025-07-18 10:36 ` Jonathan Cameron 2025-07-18 11:02 ` Thomas Weißschuh 0 siblings, 1 reply; 6+ messages in thread From: Jonathan Cameron @ 2025-07-18 10:36 UTC (permalink / raw) To: Matthew Wood Cc: Bjorn Helgaas, Mario Limonciello, Thomas Weißschuh, linux-kernel, linux-pci On Thu, 17 Jul 2025 09:50:54 -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> Hi Matthew, A suggestion inline. I'm also fine with the current version if that's what people feel more comfortable with. If we stick to what you have here Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com> Jonathan > --- > Documentation/ABI/testing/sysfs-bus-pci | 9 +++++++++ > drivers/pci/pci-sysfs.c | 26 ++++++++++++++++++++++--- > 2 files changed, 32 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..bc0e0add15d1 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 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); I wonder if doing the following i too esoteric. Eyeballing those shifts is painful. u8 bytewise[8]; /* naming hard... */ put_unaligned_u64(dsn, bytewise); return sysfs_emit(buf, "%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x\n", bytewise[0], bytewise[1], bytewise[2], bytewise[3], bytewise[4], bytewise[5], bytewise[6], bytewise[7]); > +} > +static DEVICE_ATTR_ADMIN_RO(serial_number); ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 10:36 ` Jonathan Cameron @ 2025-07-18 11:02 ` Thomas Weißschuh 2025-07-18 16:27 ` Matthew Wood 2025-07-21 9:48 ` Jonathan Cameron 0 siblings, 2 replies; 6+ messages in thread From: Thomas Weißschuh @ 2025-07-18 11:02 UTC (permalink / raw) To: Jonathan Cameron Cc: Matthew Wood, Bjorn Helgaas, Mario Limonciello, linux-kernel, linux-pci On Fri, Jul 18, 2025 at 11:36:11AM +0100, Jonathan Cameron wrote: > On Thu, 17 Jul 2025 09:50:54 -0700 > Matthew Wood <thepacketgeek@gmail.com> wrote: (...) > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > index 268c69daa4d5..bc0e0add15d1 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 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); > > I wonder if doing the following i too esoteric. Eyeballing those shifts is painful. > > u8 bytewise[8]; /* naming hard... */ > > put_unaligned_u64(dsn, bytewise); > > return sysfs_emit(buf, "%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x\n", > bytewise[0], bytewise[1], bytewise[2], bytewise[3], > bytewise[4], bytewise[5], bytewise[6], bytewise[7]); This looks endianess-unsafe. Maybe just do what some drivers are doing: u8 bytes[8]; put_unaligned_be64(dsn, bytes); return sysfs_emit(buf, "%8phD"); > > > > +} > > +static DEVICE_ATTR_ADMIN_RO(serial_number); > > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 11:02 ` Thomas Weißschuh @ 2025-07-18 16:27 ` Matthew Wood 2025-07-21 9:48 ` Jonathan Cameron 1 sibling, 0 replies; 6+ messages in thread From: Matthew Wood @ 2025-07-18 16:27 UTC (permalink / raw) To: Thomas Weißschuh Cc: Jonathan Cameron, Bjorn Helgaas, Mario Limonciello, linux-kernel, linux-pci On Fri, Jul 18, 2025 at 4:02 AM Thomas Weißschuh <thomas.weissschuh@linutronix.de> wrote: > > On Fri, Jul 18, 2025 at 11:36:11AM +0100, Jonathan Cameron wrote: > > On Thu, 17 Jul 2025 09:50:54 -0700 > > Matthew Wood <thepacketgeek@gmail.com> wrote: > > (...) > > > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > > index 268c69daa4d5..bc0e0add15d1 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 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); > > > > I wonder if doing the following i too esoteric. Eyeballing those shifts is painful. > > > > u8 bytewise[8]; /* naming hard... */ > > > > put_unaligned_u64(dsn, bytewise); > > > > return sysfs_emit(buf, "%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x\n", > > bytewise[0], bytewise[1], bytewise[2], bytewise[3], > > bytewise[4], bytewise[5], bytewise[6], bytewise[7]); > > This looks endianess-unsafe. > > Maybe just do what some drivers are doing: > > u8 bytes[8]; > > put_unaligned_be64(dsn, bytes); > > return sysfs_emit(buf, "%8phD"); Thank you both for your continued review! That reads much nicer, I should've known to look at how others were doing this formatting. I'll have a new patch later today. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5 1/1] PCI/sysfs: Expose PCIe device serial number 2025-07-18 11:02 ` Thomas Weißschuh 2025-07-18 16:27 ` Matthew Wood @ 2025-07-21 9:48 ` Jonathan Cameron 1 sibling, 0 replies; 6+ messages in thread From: Jonathan Cameron @ 2025-07-21 9:48 UTC (permalink / raw) To: Thomas Weißschuh Cc: Matthew Wood, Bjorn Helgaas, Mario Limonciello, linux-kernel, linux-pci On Fri, 18 Jul 2025 13:02:00 +0200 Thomas Weißschuh <thomas.weissschuh@linutronix.de> wrote: > On Fri, Jul 18, 2025 at 11:36:11AM +0100, Jonathan Cameron wrote: > > On Thu, 17 Jul 2025 09:50:54 -0700 > > Matthew Wood <thepacketgeek@gmail.com> wrote: > > (...) > > > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > > > index 268c69daa4d5..bc0e0add15d1 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 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); > > > > I wonder if doing the following i too esoteric. Eyeballing those shifts is painful. > > > > u8 bytewise[8]; /* naming hard... */ > > > > put_unaligned_u64(dsn, bytewise); > > > > return sysfs_emit(buf, "%02x-%02x-%02x-%02x-%02x-%02x-%02x-%02x\n", > > bytewise[0], bytewise[1], bytewise[2], bytewise[3], > > bytewise[4], bytewise[5], bytewise[6], bytewise[7]); > > This looks endianess-unsafe. > > Maybe just do what some drivers are doing: > > u8 bytes[8]; > > put_unaligned_be64(dsn, bytes); Absolutely. Typo :( I don't think there is a put_unaligned_u64() > > return sysfs_emit(buf, "%8phD"); > > > > > > > > +} > > > +static DEVICE_ATTR_ADMIN_RO(serial_number); > > > > > ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-07-21 9:48 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-07-17 16:50 [PATCH v5 0/1] PCI/sysfs: Expose PCIe device serial number Matthew Wood 2025-07-17 16:50 ` [PATCH v5 1/1] " Matthew Wood 2025-07-18 10:36 ` Jonathan Cameron 2025-07-18 11:02 ` Thomas Weißschuh 2025-07-18 16:27 ` Matthew Wood 2025-07-21 9:48 ` Jonathan Cameron
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).