diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst index 5c4fa9f5d1cd..c9137710633a 100644 --- a/Documentation/rust/arch-support.rst +++ b/Documentation/rust/arch-support.rst @@ -16,7 +16,7 @@ support corresponds to ``S`` values in the ``MAINTAINERS`` file. Architecture Level of support Constraints ============= ================ ============================================== ``arm64`` Maintained Little Endian only. -``loongarch`` Maintained - +``loongarch`` Maintained \- ``um`` Maintained ``x86_64`` only. ``x86`` Maintained ``x86_64`` only. ============= ================ ============================================== diff --git a/init/Kconfig b/init/Kconfig index aa02aec6aa7d..664bedb9a71f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1899,11 +1899,11 @@ config RUST bool "Rust support" depends on HAVE_RUST depends on RUST_IS_AVAILABLE + depends on !CFI_CLANG depends on !MODVERSIONS depends on !GCC_PLUGINS depends on !RANDSTRUCT depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE - select CONSTRUCTORS help Enables Rust support in the kernel. diff --git a/rust/Makefile b/rust/Makefile index 846e6ab9d5a9..86a125c4243c 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -175,7 +175,6 @@ quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $< mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \ OBJTREE=$(abspath $(objtree)) \ $(RUSTDOC) --test $(rust_flags) \ - @$(objtree)/include/generated/rustc_cfg \ -L$(objtree)/$(obj) --extern alloc --extern kernel \ --extern build_error --extern macros \ --extern bindings --extern uapi \ diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index 424257284d16..09004b56fb65 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -1292,8 +1292,15 @@ impl_zeroable! { i8, i16, i32, i64, i128, isize, f32, f64, - // SAFETY: These are ZSTs, there is nothing to zero. - {} PhantomData, core::marker::PhantomPinned, Infallible, (), + // Note: do not add uninhabited types (such as `!` or `core::convert::Infallible`) to this list; + // creating an instance of an uninhabited type is immediate undefined behavior. For more on + // uninhabited/empty types, consult The Rustonomicon: + // . The Rust Reference + // also has information on undefined behavior: + // . + // + // SAFETY: These are inhabited ZSTs; there is nothing to zero and a valid value exists. + {} PhantomData, core::marker::PhantomPinned, (), // SAFETY: Type is allowed to take any value, including all zeros. {} MaybeUninit, diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index be68d5e567b1..6858e2f8a3ed 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -65,7 +65,7 @@ const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; /// The top level entrypoint to implementing a kernel module. /// /// For any teardown or cleanup operations, your type may implement [`Drop`]. -pub trait Module: Sized + Sync { +pub trait Module: Sized + Sync + Send { /// Called at module initialization time. /// /// Use this method to perform whatever setup or registration your module diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index 96e09c6e8530..265d0e1c1371 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -640,6 +640,10 @@ pub struct Registration { drivers: Pin<&'static mut [DriverVTable]>, } +// SAFETY: The only action allowed in a `Registration` instance is dropping it, which is safe to do +// from any thread because `phy_drivers_unregister` can be called from any thread context. +unsafe impl Send for Registration {} + impl Registration { /// Registers a PHY driver. pub fn register( diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index f489f3157383..520eae5fd792 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -35,18 +35,6 @@ use proc_macro::TokenStream; /// author: "Rust for Linux Contributors", /// description: "My very own kernel module!", /// license: "GPL", -/// params: { -/// my_i32: i32 { -/// default: 42, -/// permissions: 0o000, -/// description: "Example of i32", -/// }, -/// writeable_i32: i32 { -/// default: 42, -/// permissions: 0o644, -/// description: "Example of i32", -/// }, -/// }, /// } /// /// struct MyModule; diff --git a/rust/macros/module.rs b/rust/macros/module.rs index 27979e582e4b..acd0393b5095 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -199,17 +199,6 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { /// Used by the printing macros, e.g. [`info!`]. const __LOG_PREFIX: &[u8] = b\"{name}\\0\"; - /// The \"Rust loadable module\" mark. - // - // This may be best done another way later on, e.g. as a new modinfo - // key or a new section. For the moment, keep it simple. - #[cfg(MODULE)] - #[doc(hidden)] - #[used] - static __IS_RUST_MODULE: () = (); - - static mut __MOD: Option<{type_}> = None; - // SAFETY: `__this_module` is constructed by the kernel at load time and will not be // freed until the module is unloaded. #[cfg(MODULE)] @@ -221,81 +210,132 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { kernel::ThisModule::from_ptr(core::ptr::null_mut()) }}; - // Loadable modules need to export the `{{init,cleanup}}_module` identifiers. - /// # Safety - /// - /// This function must not be called after module initialization, because it may be - /// freed after that completes. - #[cfg(MODULE)] - #[doc(hidden)] - #[no_mangle] - #[link_section = \".init.text\"] - pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{ - __init() - }} + // Double nested modules, since then nobody can access the public items inside. + mod __module_init {{ + mod __module_init {{ + use super::super::{type_}; - #[cfg(MODULE)] - #[doc(hidden)] - #[no_mangle] - pub extern \"C\" fn cleanup_module() {{ - __exit() - }} + /// The \"Rust loadable module\" mark. + // + // This may be best done another way later on, e.g. as a new modinfo + // key or a new section. For the moment, keep it simple. + #[cfg(MODULE)] + #[doc(hidden)] + #[used] + static __IS_RUST_MODULE: () = (); - // Built-in modules are initialized through an initcall pointer - // and the identifiers need to be unique. - #[cfg(not(MODULE))] - #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))] - #[doc(hidden)] - #[link_section = \"{initcall_section}\"] - #[used] - pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init; + static mut __MOD: Option<{type_}> = None; - #[cfg(not(MODULE))] - #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)] - core::arch::global_asm!( - r#\".section \"{initcall_section}\", \"a\" - __{name}_initcall: - .long __{name}_init - . - .previous - \"# - ); + // Loadable modules need to export the `{{init,cleanup}}_module` identifiers. + /// # Safety + /// + /// This function must not be called after module initialization, because it may be + /// freed after that completes. + #[cfg(MODULE)] + #[doc(hidden)] + #[no_mangle] + #[link_section = \".init.text\"] + pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{ + // SAFETY: This function is inaccessible to the outside due to the double + // module wrapping it. It is called exactly once by the C side via its + // unique name. + unsafe {{ __init() }} + }} - #[cfg(not(MODULE))] - #[doc(hidden)] - #[no_mangle] - pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{ - __init() - }} + #[cfg(MODULE)] + #[doc(hidden)] + #[no_mangle] + pub extern \"C\" fn cleanup_module() {{ + // SAFETY: + // - This function is inaccessible to the outside due to the double + // module wrapping it. It is called exactly once by the C side via its + // unique name, + // - furthermore it is only called after `init_module` has returned `0` + // (which delegates to `__init`). + unsafe {{ __exit() }} + }} - #[cfg(not(MODULE))] - #[doc(hidden)] - #[no_mangle] - pub extern \"C\" fn __{name}_exit() {{ - __exit() - }} + // Built-in modules are initialized through an initcall pointer + // and the identifiers need to be unique. + #[cfg(not(MODULE))] + #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))] + #[doc(hidden)] + #[link_section = \"{initcall_section}\"] + #[used] + pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init; - fn __init() -> core::ffi::c_int {{ - match <{type_} as kernel::Module>::init(&THIS_MODULE) {{ - Ok(m) => {{ - unsafe {{ - __MOD = Some(m); + #[cfg(not(MODULE))] + #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)] + core::arch::global_asm!( + r#\".section \"{initcall_section}\", \"a\" + __{name}_initcall: + .long __{name}_init - . + .previous + \"# + ); + + #[cfg(not(MODULE))] + #[doc(hidden)] + #[no_mangle] + pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{ + // SAFETY: This function is inaccessible to the outside due to the double + // module wrapping it. It is called exactly once by the C side via its + // placement above in the initcall section. + unsafe {{ __init() }} + }} + + #[cfg(not(MODULE))] + #[doc(hidden)] + #[no_mangle] + pub extern \"C\" fn __{name}_exit() {{ + // SAFETY: + // - This function is inaccessible to the outside due to the double + // module wrapping it. It is called exactly once by the C side via its + // unique name, + // - furthermore it is only called after `__{name}_init` has returned `0` + // (which delegates to `__init`). + unsafe {{ __exit() }} + }} + + /// # Safety + /// + /// This function must only be called once. + unsafe fn __init() -> core::ffi::c_int {{ + match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{ + Ok(m) => {{ + // SAFETY: No data race, since `__MOD` can only be accessed by this + // module and there only `__init` and `__exit` access it. These + // functions are only called once and `__exit` cannot be called + // before or during `__init`. + unsafe {{ + __MOD = Some(m); + }} + return 0; + }} + Err(e) => {{ + return e.to_errno(); + }} }} - return 0; }} - Err(e) => {{ - return e.to_errno(); + + /// # Safety + /// + /// This function must + /// - only be called once, + /// - be called after `__init` has been called and returned `0`. + unsafe fn __exit() {{ + // SAFETY: No data race, since `__MOD` can only be accessed by this module + // and there only `__init` and `__exit` access it. These functions are only + // called once and `__init` was already called. + unsafe {{ + // Invokes `drop()` on `__MOD`, which should be used for cleanup. + __MOD = None; + }} }} + + {modinfo} }} }} - - fn __exit() {{ - unsafe {{ - // Invokes `drop()` on `__MOD`, which should be used for cleanup. - __MOD = None; - }} - }} - - {modinfo} ", type_ = info.type_, name = info.name, diff --git a/scripts/Makefile.build b/scripts/Makefile.build index baf86c0880b6..533a7799fdfe 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -273,7 +273,7 @@ rust_common_cmd = \ -Zallow-features=$(rust_allowed_features) \ -Zcrate-attr=no_std \ -Zcrate-attr='feature($(rust_allowed_features))' \ - --extern alloc --extern kernel \ + -Zunstable-options --extern force:alloc --extern kernel \ --crate-type rlib -L $(objtree)/rust/ \ --crate-name $(basename $(notdir $@)) \ --sysroot=/dev/null \