On Mon, Mar 17, 2025 at 2:31 PM Tamir Duberstein <tamird@xxxxxxxxx> wrote: > > On Mon, Mar 17, 2025 at 1:50 PM Benno Lossin <benno.lossin@xxxxxxxxx> wrote: > > > > On Mon Mar 17, 2025 at 3:23 PM CET, Tamir Duberstein wrote: > > > Throughout the tree, use the strict provenance APIs stabilized in Rust > > > 1.84.0[1]. Retain backwards-compatibility by introducing forwarding > > > functions at the `kernel` crate root along with polyfills for rustc < > > > 1.84.0. > > > > > > Use `#[allow(clippy::incompatible_msrv)]` to avoid warnings on rustc < > > > 1.84.0 as our MSRV is 1.78.0. > > > > > > In the `kernel` crate, enable the strict provenance lints on rustc >= > > > 1.84.0; do this in `lib.rs` rather than `Makefile` to avoid introducing > > > compiler flags that are dependent on the rustc version in use. > > > > > > Link: https://blog.rust-lang.org/2025/01/09/Rust-1.84.0.html#strict-provenance-apis [1] > > > Suggested-by: Benno Lossin <benno.lossin@xxxxxxxxx> > > > Link: https://lore.kernel.org/all/D8EIXDMRXMJP.36TFCGWZBRS3Y@xxxxxxxxx/ > > > Signed-off-by: Tamir Duberstein <tamird@xxxxxxxxx> > > > > One comment below, with that fixed: > > > > Reviewed-by: Benno Lossin <benno.lossin@xxxxxxxxx> > > > > > --- > > > init/Kconfig | 3 ++ > > > rust/kernel/alloc.rs | 2 +- > > > rust/kernel/devres.rs | 4 +- > > > rust/kernel/io.rs | 14 +++---- > > > rust/kernel/lib.rs | 108 +++++++++++++++++++++++++++++++++++++++++++++++++ > > > rust/kernel/of.rs | 2 +- > > > rust/kernel/pci.rs | 4 +- > > > rust/kernel/str.rs | 16 +++----- > > > rust/kernel/uaccess.rs | 12 ++++-- > > > 9 files changed, 138 insertions(+), 27 deletions(-) > > > > > > > +#[cfg(not(CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE))] > > > +mod strict_provenance { > > > + /// Gets the "address" portion of the pointer. > > > + /// > > > + /// See https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.addr. > > > + #[inline] > > > + pub fn addr<T>(ptr: *const T) -> usize { > > > + // This is core's implementation from > > > + // https://github.com/rust-lang/rust/commit/4291332175d12e79e6061cdc3f5dccac2e28b969 through > > > + // https://github.com/rust-lang/rust/blob/1.84.0/library/core/src/ptr/const_ptr.rs#L172 > > > + // which is the first version that satisfies `CONFIG_RUSTC_HAS_STABLE_STRICT_PROVENANCE`. > > > + #[allow(clippy::undocumented_unsafe_blocks)] > > > + unsafe { > > > + #[allow(clippy::transmutes_expressible_as_ptr_casts)] > > > + core::mem::transmute(ptr.cast::<()>()) > > > + } > > > > I think we should just use `ptr as usize` here instead. It's going away > > at some point and it will only affect optimizations (I don't even know > > if they exist at the moment) of old versions. > > Why get cute? I'd rather defer to the standard library. Ah, this is gone anyway with Boqun's suggestion - this function exists in 1.78.
