[PATCH v3 0/2] ACPI: FPDT: expose FBPT and S3PT subtables via sysfs

Nate DeSimone
2026-03-24T23:17:01Z

The ACPI Firmware Performance Data Table (FPDT) can contain two subtables:

1. Firmware Basic Boot Performance Table (FBPT)
2. S3 Performance Table (S3PT)

The existing /sys/firmware/acpi/tables/FPDT sysfs entry
only exposes the top-level FPDT header, not the subtables themselves.

This series adds sysfs attributes at /sys/firmware/acpi/fpdt/FBPT and
/sys/firmware/acpi/fpdt/S3PT that expose the raw contents of these
subtables. This mirrors the model used by /sys/firmware/dmi/tables/DMI
for DMI/SMBIOS data, and allows userspace tools to parse newer FPDT
record types defined in recent ACPI specifications[1] (e.g. String
Event Records, Microcontroller Boot Performance Data Records, etc.)
without requiring kernel changes for each new record type.

[1]
https://uefi.org/specs/ACPI/6.6/05_ACPI_Software_Programming_Model.html#performance-event-record-types

Signed-off-by: Nate DeSimone <nathaniel.l.desimone@intel.com>
---

Changes in v3:
- changed sysfs_create_bin_file() error handling to a non-fatal warning

Changes in v2:
- removed the intermediate /sys/firmware/acpi/tables/ subdirectory
- tightened file permissions for FBPT and S3PT from 0444 to 0400
- added documentation to Documentation/ABI/testing/sysfs-firmware-acpi

---
Nate DeSimone (2):
ACPI: FPDT: expose FBPT and S3PT subtables via sysfs
Documentation: ABI: add FBPT and S3PT entries to sysfs-firmware-acpi

Documentation/ABI/testing/sysfs-firmware-acpi | 6 ++++
drivers/acpi/acpi_fpdt.c | 28 +++++++++++++++++++
2 files changed, 34 insertions(+)

base-commit: 24f9515de8778410e4b84c85b196c9850d2c1e18
--
2.34.1