On Thu, Jun 27, 2024 at 10:34:39AM +0200, Alice Ryhl wrote: > On Tue, Jun 25, 2024 at 6:18 PM Boqun Feng <boqun.feng@xxxxxxxxx> wrote: > > > > Hi Alice, > > > > On Fri, Jun 21, 2024 at 10:35:26AM +0000, Alice Ryhl wrote: > > > Add just enough support for static key so that we can use it from > > > tracepoints. Tracepoints rely on `static_key_false` even though it is > > > deprecated, so we add the same functionality to Rust. > > > > > > It is not possible to use the existing C implementation of > > > arch_static_branch because it passes the argument `key` to inline > > > assembly as an 'i' parameter, so any attempt to add a C helper for this > > > function will fail to compile because the value of `key` must be known > > > at compile-time. > > > > > > Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > > > > [Add linux-arch, and related arch maintainers Cced] > > > > Since inline asms are touched here, please consider copying linux-arch > > and arch maintainers next time ;-) > > Will do. > > > For x86_64 and arm64 bits: > > > > Acked-by: Boqun Feng <boqun.feng@xxxxxxxxx> > > > > One thing though, we should split the arch-specific impls into different > > files, for example: rust/kernel/arch/arm64.rs or rust/arch/arm64.rs. > > That'll be easier for arch maintainers to watch the Rust changes related > > to a particular architecture. > > Is that how you would prefer to name these files? You don't want > static_key somewhere in the filename? > I could have been more explicit. My preference is (for example ARM64) * we have a rust/kernel/arch.rs, where we do: #[cfg(CONFIG_ARM64)] mod arm64::*; #[cfg(CONFIG_ARM64)] pub use arm64::*; * we have a rust/kernel/arch/arm64.rs: pub(crate) mod jump_label; * we have a rust/kernel/arch/arm64/jump_label.rs, where we put ARM64 arch_static_branch() there. (or static_key.rs and arch_static_key_false()). Then linux-arch can watch: rust/kernel/arch.rs rust/kernel/arch/ And ARM64 maintainers can watch: rust/kernel/arch/arm64.rs rust/kernel/arch/arm64 This is similar to how <asm/*.h> are organized today. Does this make sense? Regards, Boqun > > Another thought is that, could you implement an arch_static_branch!() > > (instead of _static_key_false!()) and use it for static_key_false!() > > similar to what we have in C? The benefit is that at least for myself > > it'll be easier to compare the implementation between C and Rust. > > I can try to include that. > > Alice
