src/sys/compat/linuxkpi/common/include/linux, branch main

sys/cdefs.h: Introduce __maybe_unused attribute

2026-05-06T19:51:46Z

The __maybe_unused attribute should be used for variables which may or may not be used, such as when their only use is in an assertion. This attribute is functionally identical to __unused, suppressing compiler warnings for particular variable if it remains unused. Reviewed by: Minsoo Choo , imp Differential Revision: https://reviews.freebsd.org/D56517

linuxkpi: Implement `module_*()` APIs as static functions

2026-05-04T19:13:43Z

This fixes an "unused variable" warning when building DRM drivers. Reviewed by: emaste MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56780

sx: Add `sx_has_waiters()` macro

2026-04-30T11:40:05Z

This macro will return non-zero if there are threads waiting for this lock; otherwise, it will return zero. The function assumes (but does not assert) that the caller already holds the lock and that it is interested in other threads waiting for it to release the lock. The motivation to add this is the implementation of `rwsem_is_contended()` in linuxkpi. This Linux function indicates the same thing to the caller: if other threads are waiting for this semaphore. The amdgpu DRM driver started to use `rwsem_is_contended()` in Linux 6.12. Reviewed by: bz, olce Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56443

linuxkpi: Add `copy_from_user_inatomic_nontemporal()` function

2026-04-30T07:05:02Z

In Linux 7.1, `__copy_from_user_inatomic_nocache()` was renamed to `copy_from_user_inatomic_nontemporal()`. This change was backported to several LTS branches. This includes Linux 6.12.x and the i915 DRM driver started to use it in that version. Reviewed by: bz Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56719

linuxkpi: Define `DEFINE_XARRAY*()` macros

2026-04-30T07:05:02Z

The `DEFINE_XARRAY*()` macros are used to declare a static xarray. As the structure embeds a mutex(9), we also need to declare the static mutex after the `struct xarray`. Thus the slightly awkward definition of `DEFINE_XARRAY_FLAGS()`. The DRM generic code started to use `DEFINE_XARRAY_ALLOC()` in Linux 6.12. Reviewed by: bz Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56446

linuxkpi: Add `struct xa_limit` support to xarray

2026-04-30T07:05:01Z

The `xa_alloc*()` functions family takes a `struct xa_limit` to describe the range of IDs the caller wants to allocate. We were using a single mask to qualify a maximum ID only. This commit changes that to use the same `struct xa_limit`. The logic did not change, except it now supports a minimum ID as well. The definition of `XA_LIMIT()` macro is adapted, as well as the definitions of `xa_limit_*` (only `xa_limit_32b` existed, the other two are added with this commit). The DRM generic code started to use this `struct xa_limit` in Linux 6.12. Reviewed by: bz Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D56445

PHYS_TO_DMAP: Return a void * instead of a vm_offset_t

2026-04-23T17:05:54Z

Add a new PHYS_TO_DMAP_ADDR that still returns an address for use in places that only need an address and not a pointer. Effort: CHERI upstreaming Reviewed by: kib Sponsored by: AFRL, DARPA Pull Request: https://github.com/freebsd/freebsd-src/pull/2068

sf_buf_kva: Return a pointer instead of a vm_offset_t

2026-04-23T17:05:54Z

This removes the need for several casts to pointer in callers. Effort: CHERI upstreaming Reviewed by: kib Sponsored by: AFRL, DARPA Pull Request: https://github.com/freebsd/freebsd-src/pull/2068

pmap_change_attr: Use void * instead of vm_offset_t

2026-04-23T17:05:53Z

Effort: CHERI upstreaming Reviewed by: kib Sponsored by: AFRL, DARPA Pull Request: https://github.com/freebsd/freebsd-src/pull/2068

LinuxKPI: Update seq_file to properly implement the iterator interface

2026-04-23T15:46:54Z

The seq_file.rst documentation in the Linux kernel documents the iterator interface for the seq_file structure. In particular, the ppos passed to seq_read is a logical offset into a seq_file managed by the iterator interface, not an offset into the generated data. For example, if a seq_file outputs state for each node in a linked-list or array, *ppos might be used as the index of the node to output, not a byte offset. Rewrite seq_read to honor this contract which fixes a few bugs: - Treat *ppos as a logical iterator offset that is only updated by the next callback after outputting a single item via the show method. - Use a loop to permit outputting descriptions of multiple items if the user buffer is large enough. - Always invoke the stop method after terminating the loop to cleanup any state setup by start (e.g. if start allocated a buffer or obtained a lock, the stop method is called to cleanup). While here, implement support for SEQ_SKIP as documented in the Linux documentation even though it is not currently used in the tree. Reviewed by: bz Sponsored by: AFRL, DARPA Differential Revision: https://reviews.freebsd.org/D55899