linux/samples/rust/rust_print_main.rs

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3.4 KiB

rust: start using the `#[expect(...)]` attribute In Rust, it is possible to `allow` particular warnings (diagnostics, lints) locally, making the compiler ignore instances of a given warning within a given function, module, block, etc. It is similar to `#pragma GCC diagnostic push` + `ignored` + `pop` in C: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-function" static void f(void) {} #pragma GCC diagnostic pop But way less verbose: #[allow(dead_code)] fn f() {} By that virtue, it makes it possible to comfortably enable more diagnostics by default (i.e. outside `W=` levels) that may have some false positives but that are otherwise quite useful to keep enabled to catch potential mistakes. The `#[expect(...)]` attribute [1] takes this further, and makes the compiler warn if the diagnostic was _not_ produced. For instance, the following will ensure that, when `f()` is called somewhere, we will have to remove the attribute: #[expect(dead_code)] fn f() {} If we do not, we get a warning from the compiler: warning: this lint expectation is unfulfilled --> x.rs:3:10 | 3 | #[expect(dead_code)] | ^^^^^^^^^ | = note: `#[warn(unfulfilled_lint_expectations)]` on by default This means that `expect`s do not get forgotten when they are not needed. See the next commit for more details, nuances on its usage and documentation on the feature. The attribute requires the `lint_reasons` [2] unstable feature, but it is becoming stable in 1.81.0 (to be released on 2024-09-05) and it has already been useful to clean things up in this patch series, finding cases where the `allow`s should not have been there. Thus, enable `lint_reasons` and convert some of our `allow`s to `expect`s where possible. This feature was also an example of the ongoing collaboration between Rust and the kernel -- we tested it in the kernel early on and found an issue that was quickly resolved [3]. Cc: Fridtjof Stoldt <xfrednet@gmail.com> Cc: Urgau <urgau@numericable.fr> Link: https://rust-lang.github.io/rfcs/2383-lint-reasons.html#expect-lint-attribute [1] Link: https://github.com/rust-lang/rust/issues/54503 [2] Link: https://github.com/rust-lang/rust/issues/114557 [3] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-18-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-04 22:43:45 +02:00
rust: use derive(CoercePointee) on rustc >= 1.84.0 The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn` unstable features. Alice Ryhl has proposed [1] the introduction of the unstable macro `SmartPointer` to reduce such dependence, along with a RFC patch [2]. Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in Rust 1.84.0 [3], has been fully implemented with the naming discussion resolved. This feature is now on track to stabilization in the language. In order to do so, we shall start using this macro in the `kernel` crate to prove the functionality and utility of the macro as the justification of its stabilization. This patch makes this switch in such a way that the crate remains backward compatible with older Rust compiler versions, via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`. A minimal demonstration example is added to the `samples/rust/rust_print_main.rs` module. Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1] Link: https://lore.kernel.org/all/20240823-derive-smart-pointer-v1-1-53769cd37239@google.com/ [2] Link: https://github.com/rust-lang/rust/pull/131284 [3] Signed-off-by: Xiangfei Ding <dingxiangfei2009@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241203205050.679106-2-dingxiangfei2009@gmail.com [ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE` to match `CC_HAS_*` ones. Moved up new config option, closer to the `CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly reworded example and commit. Added Link to PR. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-12-04 04:47:49 +08:00
rust: use derive(CoercePointee) on rustc >= 1.84.0 The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn` unstable features. Alice Ryhl has proposed [1] the introduction of the unstable macro `SmartPointer` to reduce such dependence, along with a RFC patch [2]. Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in Rust 1.84.0 [3], has been fully implemented with the naming discussion resolved. This feature is now on track to stabilization in the language. In order to do so, we shall start using this macro in the `kernel` crate to prove the functionality and utility of the macro as the justification of its stabilization. This patch makes this switch in such a way that the crate remains backward compatible with older Rust compiler versions, via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`. A minimal demonstration example is added to the `samples/rust/rust_print_main.rs` module. Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1] Link: https://lore.kernel.org/all/20240823-derive-smart-pointer-v1-1-53769cd37239@google.com/ [2] Link: https://github.com/rust-lang/rust/pull/131284 [3] Signed-off-by: Xiangfei Ding <dingxiangfei2009@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241203205050.679106-2-dingxiangfei2009@gmail.com [ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE` to match `CC_HAS_*` ones. Moved up new config option, closer to the `CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly reworded example and commit. Added Link to PR. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-12-04 04:47:49 +08:00
rust: samples: add tracepoint to Rust sample This updates the Rust printing sample to invoke a tracepoint. This ensures that we have a user in-tree from the get-go even though the patch is being merged before its real user. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Cc: Gary Guo <gary@garyguo.net> Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anup Patel <apatel@ventanamicro.com> Cc: Andrew Jones <ajones@ventanamicro.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Conor Dooley <conor.dooley@microchip.com> Cc: Samuel Holland <samuel.holland@sifive.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Bibo Mao <maobibo@loongson.cn> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tianrui Zhao <zhaotianrui@loongson.cn> Link: https://lore.kernel.org/20241030-tracepoint-v12-3-eec7f0f8ad22@google.com Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-30 16:04:26 +00:00
rust: samples: add tracepoint to Rust sample This updates the Rust printing sample to invoke a tracepoint. This ensures that we have a user in-tree from the get-go even though the patch is being merged before its real user. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Cc: Gary Guo <gary@garyguo.net> Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anup Patel <apatel@ventanamicro.com> Cc: Andrew Jones <ajones@ventanamicro.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Conor Dooley <conor.dooley@microchip.com> Cc: Samuel Holland <samuel.holland@sifive.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Bibo Mao <maobibo@loongson.cn> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tianrui Zhao <zhaotianrui@loongson.cn> Link: https://lore.kernel.org/20241030-tracepoint-v12-3-eec7f0f8ad22@google.com Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-30 16:04:26 +00:00
rust: samples: add tracepoint to Rust sample This updates the Rust printing sample to invoke a tracepoint. This ensures that we have a user in-tree from the get-go even though the patch is being merged before its real user. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Cc: Gary Guo <gary@garyguo.net> Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Sean Christopherson <seanjc@google.com> Cc: Uros Bizjak <ubizjak@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <oliver.upton@linux.dev> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Fuad Tabba <tabba@google.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anup Patel <apatel@ventanamicro.com> Cc: Andrew Jones <ajones@ventanamicro.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Conor Dooley <conor.dooley@microchip.com> Cc: Samuel Holland <samuel.holland@sifive.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Bibo Mao <maobibo@loongson.cn> Cc: Tiezhu Yang <yangtiezhu@loongson.cn> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tianrui Zhao <zhaotianrui@loongson.cn> Link: https://lore.kernel.org/20241030-tracepoint-v12-3-eec7f0f8ad22@google.com Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-30 16:04:26 +00:00