Page MenuHomeFreeBSD
Differential D57586

linuxkpi: Alias `sd` field of `struct kobject`
ClosedPublic
Actions

Authored by dumbbell on Jun 14 2026, 9:24 AM.
Tags
Referenced Files
Unknown Object (File)
Mon, Sep 7, 10:01 AM
Unknown Object (File)
Sun, Sep 6, 6:42 PM
Unknown Object (File)
Sat, Sep 5, 8:04 PM
Unknown Object (File)
Fri, Sep 4, 9:10 PM
Unknown Object (File)
Fri, Sep 4, 9:04 PM
Unknown Object (File)
Fri, Sep 4, 4:51 PM
Unknown Object (File)
Fri, Sep 4, 5:01 AM
Unknown Object (File)
Thu, Sep 3, 1:06 AM
View All 47 Files
Subscribers
bz
emaste
imp

Details

Reviewers
bz
Group Reviewers
linuxkpi
Commits
rG33ba6077b0f1: linuxkpi: Alias `sd` field of `struct kobject`
Summary

On Linux, a struct kernfs_node * pointer, representing a directory in sysfs, is kept in the sd struct field.

We don't have that on FreeBSD because we use sysctls instead. Let's alias the sysctl OID pointer to sd using an union.

This pointer is checked by the DRM drivers using:

if (var->kobj.sd) {
    ...
}

The amdgpu DRM driver started to use these checks in Linux 6.13.

This is part of the update of DRM drivers to Linux 6.13.

Sponsored by: The FreeBSD Foundation

Diff Detail

Repository
rG FreeBSD src repository
Lint
Lint Not Applicable
Unit
Tests Not Applicable

Event Timeline

dumbbell created this revision.Jun 14 2026, 9:24 AM
Herald added subscribers: emaste, imp. · View Herald TranscriptJun 14 2026, 9:24 AM
dumbbell requested review of this revision.Jun 14 2026, 9:24 AM
dumbbell added a parent revision: D57585: linuxkpi: Change `strscpy()` and `strscpy_pad()` to make their `len` argument optional.Jun 14 2026, 9:29 AM
dumbbell added a child revision: D57698: linuxkpi: Define and fill `struct cpuinfo_x86->x86_stepping`.Jun 20 2026, 12:07 PM
emaste added a project: linuxkpi.Mon, Aug 17, 5:00 PM
bz accepted this revision.Sat, Sep 5, 9:54 AM
bz added a subscriber: bz.

No objections though I don't use that part of ... and hope the checks will hold up in the future.

sys/compat/linuxkpi/common/include/linux/kobject.h
70

One day we should probably fix this -- would be a nice GSoC project next year?

This revision is now accepted and ready to land.Sat, Sep 5, 9:54 AM
dumbbell marked an inline comment as done.Mon, Sep 7, 5:26 PM
dumbbell added inline comments.
sys/compat/linuxkpi/common/include/linux/kobject.h
70

Yes, I would love to have proper sysfs support. This would improve compatibility with Linux: all the libraries that expect sysfs and all the forum posts from people helping other users would be valid for FreeBSD as well.

Closed by commit rG33ba6077b0f1: linuxkpi: Alias `sd` field of `struct kobject` (authored by dumbbell). · Explain WhyMon, Sep 7, 6:37 PM
This revision was automatically updated to reflect the committed changes.
dumbbell marked an inline comment as done.
dumbbell added a commit: rG33ba6077b0f1: linuxkpi: Alias `sd` field of `struct kobject`.

Revision Contents
Changeset List

PathSize
sys/
compat/
linuxkpi/
common/
include/
linux/
17 lines

Diff 186155

View Options

sys/compat/linuxkpi/common/include/linux/kobject.h

Loading...