Re: [PATCH v3 0/5] Rust dynamic debug support for pr_debug! and dev_dbg!

[Zhi Wang <zhiw@nvidia.com>]

On Thu, 1 Oct 2026 17:59:35 +0300
Zhi Wang <zhiw@nvidia.com> wrote:

Gentle Ping. :)

> Add runtime dynamic debug control to Rust pr_debug! and dev_dbg!,
> using the existing C control file, boot/module parameters, prefixes
> and jump labels. Callsite flags and static keys always start
> disabled. Users enable messages with dyndbg queries; Rust debug
> assertions do not affect whether a debug message is printed.
> 
> This continues Andrew Ballance's RFC v2:
> https://lore.kernel.org/rust-for-linux/20250620210533.400889-1-andrewjballance@gmail.com/
> 
> This revision retains RFC v2's nested-field static-branch macros and
> static mut descriptors addressed through raw pointers.
> 
> Changes since RFC v2:
> 
> - Make debug logging independent of Rust's debug_assertions setting.
>   Both pr_debug! and dev_dbg! start disabled and are enabled through
>   dyndbg; without dynamic debug support, both remain disabled.
> - Keep caller expressions outside unsafe blocks and avoid implicit
> Rust references when reading descriptor flags without jump labels.
> - Correct big-endian bitfield layout and keep module descriptors
> writable with #[used(compiler)]. This fixes the kernel write fault
> when static_key_enable_cpuslocked() tries to write the static key.
> - Use Kbuild module names and actual format strings for filtering,
> preserve the crate log prefix, and support +d stack output.
> - Complete DYNAMIC_DEBUG_CORE-only support with per-crate opt-in.
> - Port to driver-core-testing and preserve Nova's firmware validation
> when debug logging is disabled.
> 
> Limitations:
> 
> - Function metadata deliberately remains <unknown>;
> 
> Andrew Ballance (3):
>   rust: jump label: add support for nested arguments
>   rust: print: add dynamic debug support to pr_debug!
>   rust: device: add dynamic debug support to dev_dbg!
> 
> Zhi Wang (2):
>   gpu: nova-core: validate firmware versions before debug logging
>   dynamic_debug: expose printing declarations with the core enabled
> 
>  .../admin-guide/dynamic-debug-howto.rst       |  41 ++++
>  MAINTAINERS                                   |   2 +
>  drivers/gpu/nova-core/firmware/booter.rs      |   8 +-
>  drivers/gpu/nova-core/firmware/fsp.rs         |   3 +-
>  .../nova-core/firmware/fwsec/bootloader.rs    |   7 +-
>  drivers/gpu/nova-core/firmware/gsp.rs         |   3 +-
>  drivers/gpu/nova-core/firmware/riscv.rs       |   7 +-
>  include/linux/dynamic_debug.h                 |  16 +-
>  rust/Makefile                                 |   3 +
>  rust/bindings/bindings_helper.h               |   1 +
>  rust/helpers/dynamic_debug.c                  |  33 +++
>  rust/helpers/helpers.c                        |   1 +
>  rust/kernel/device.rs                         |  42 +++-
>  rust/kernel/jump_label.rs                     |  17 +-
>  rust/kernel/print.rs                          |  53 ++++-
>  rust/kernel/print/dynamic_debug.rs            | 192
> ++++++++++++++++++ scripts/Makefile.build                        |
> 1 + scripts/generate_rust_analyzer.py             |   1 +
>  18 files changed, 386 insertions(+), 45 deletions(-)
>  create mode 100644 rust/helpers/dynamic_debug.c
>  create mode 100644 rust/kernel/print/dynamic_debug.rs
> 
> 
> base-commit: f1850e443b0e4f2429ddf42a8d5033ea54ae8a90