[RFC PATCH v2 0/4] rust: add support for dynamic debug

[Andrew Ballance <andrewjballance@gmail.com>]

This patch series adds support for dynamic debug to the rust
pr_debug! and dev_dbg! macros.

I have tested it and it and it does work but, there are a few
differences between this and the c version (hence why this is a rfc).

rust does not have an equivalent to the C __func__ macro. so, for the
time being this hard codes the function name to be the name of the
macro e.g. "pr_debug!" and "dev_dbg!".

This uses the module_path! macro to get the module name, which will not
be exactly the same as the c version if a kernel module defines a rust mod.
e.g. it might be "kernel_module_name::rust_module_name".
this does give a more accurate description of where the print statement
is located but it is not identical to what the c version does.

This patch series also had to make a small change to the jump_label module.
to add a STATIC_KEY_INIT_FALSE and updates the static_branch_unlikely
macro so that it allows keys that are nested multiple structs deep
within a static variable.

Closes: https://github.com/Rust-for-Linux/linux/issues/453
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/291565-Help/topic/Dynamic.20Debug.3F/with/519289668

changes in v2:
 - fix typos
 - define and use STATIC_KEY_INIT_FALSE.
 - use raw pointers to avoid undefined behavior
 - use cleaner version of macro definition for nested arguments (thanks Alice)
link to v1: https://lore.kernel.org/rust-for-linux/20250611202952.1670168-1-andrewjballance@gmail.com/

Andrew Ballance (4):
  rust: jump label: add support for nested arguments
  rust: jump label: add STATIC_KEY_INIT_FALSE
  rust: print: add support for dynamic debug to pr_debug!
  rust: device: add support for dynamic debug to dev_dbg!

 rust/bindings/bindings_helper.h |   1 +
 rust/kernel/device.rs           | 105 +++++++++++++++++++-
 rust/kernel/jump_label.rs       |  15 ++-
 rust/kernel/print.rs            | 171 +++++++++++++++++++++++++++++++-
 4 files changed, 281 insertions(+), 11 deletions(-)

-- 
2.49.0