[PATCH v4 0/6] Introduce bitfield and move register macro to rust/kernel/

Joel Fernandes
2025-09-20T18:22:58Z

Hello!

These patches extract and enhance the bitfield support in the register macro in
nova to define Rust structures with bitfields. This is extremely useful as it
allows clean Rust structure definitions without requiring explicit masks and
shifts.

See [1] example code using it.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/patch/?id=76797b31facae8f1a1be139412c78568df1da9f3

v3 of the patches is at:
https://lore.kernel.org/all/20250909212039.227221-1-joelagnelf@nvidia.com/

v2 of the patches is at:
https://lore.kernel.org/all/20250903215428.1296517-1-joelagnelf@nvidia.com/

v1 of the patches is at:
https://lore.kernel.org/all/20250824135954.2243774-1-joelagnelf@nvidia.com/

v3->v4:
* Rebased on -next.
* Added more test cases.
* Added support for fields larger than the struct
(ex, using 'as u32' for a u8 struct.)

v2->v3:
* Renamed bitstruct to bitfield.
* Various suggestions to improve code (Alex, Yury, Miguel).
* Added reviewed-by tags from Elle Rhumsaa.
* Added KUNIT tests including tests for overlap.
* Added F: maintainers file entry for new files under BITOPS.

v1->v2:
* Use build_assert in bitstruct
* Split move and enhance patches for easier review
* Move out of Nova into kernel crate for other drivers like Tyr which will use.
* Miscellaneous cosmetic improvements.

Joel Fernandes (6):
nova-core: bitfield: Move bitfield-specific code from register! into
new macro
nova-core: bitfield: Add support for different storage widths
nova-core: bitfield: Add support for custom visiblity
rust: Move register and bitfield macros out of Nova
rust: Add KUNIT tests for bitfield
rust: bitfield: Use 'as' operator for setter type conversion

MAINTAINERS | 1 +
drivers/gpu/nova-core/falcon.rs | 2 +-
drivers/gpu/nova-core/falcon/gsp.rs | 4 +-
drivers/gpu/nova-core/falcon/sec2.rs | 2 +-
drivers/gpu/nova-core/regs.rs | 6 +-
rust/kernel/bits.rs | 2 +
rust/kernel/bits/bitfield.rs | 736 ++++++++++++++++++
rust/kernel/io.rs | 1 +
.../macros.rs => rust/kernel/io/register.rs | 289 +------
9 files changed, 774 insertions(+), 269 deletions(-)
create mode 100644 rust/kernel/bits/bitfield.rs
rename drivers/gpu/nova-core/regs/macros.rs => rust/kernel/io/register.rs (73%)

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2.34.1