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2025-01-28Merge tag 'driver-core-6.14-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core and debugfs updates from Greg KH: "Here is the big set of driver core and debugfs updates for 6.14-rc1. Included in here is a bunch of driver core, PCI, OF, and platform rust bindings (all acked by the different subsystem maintainers), hence the merge conflict with the rust tree, and some driver core api updates to mark things as const, which will also require some fixups due to new stuff coming in through other trees in this merge window. There are also a bunch of debugfs updates from Al, and there is at least one user that does have a regression with these, but Al is working on tracking down the fix for it. In my use (and everyone else's linux-next use), it does not seem like a big issue at the moment. Here's a short list of the things in here: - driver core rust bindings for PCI, platform, OF, and some i/o functions. We are almost at the "write a real driver in rust" stage now, depending on what you want to do. - misc device rust bindings and a sample driver to show how to use them - debugfs cleanups in the fs as well as the users of the fs api for places where drivers got it wrong or were unnecessarily doing things in complex ways. - driver core const work, making more of the api take const * for different parameters to make the rust bindings easier overall. - other small fixes and updates All of these have been in linux-next with all of the aforementioned merge conflicts, and the one debugfs issue, which looks to be resolved "soon"" * tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits) rust: device: Use as_char_ptr() to avoid explicit cast rust: device: Replace CString with CStr in property_present() devcoredump: Constify 'struct bin_attribute' devcoredump: Define 'struct bin_attribute' through macro rust: device: Add property_present() saner replacement for debugfs_rename() orangefs-debugfs: don't mess with ->d_name octeontx2: don't mess with ->d_parent or ->d_parent->d_name arm_scmi: don't mess with ->d_parent->d_name slub: don't mess with ->d_name sof-client-ipc-flood-test: don't mess with ->d_name qat: don't mess with ->d_name xhci: don't mess with ->d_iname mtu3: don't mess wiht ->d_iname greybus/camera - stop messing with ->d_iname mediatek: stop messing with ->d_iname netdevsim: don't embed file_operations into your structs b43legacy: make use of debugfs_get_aux() b43: stop embedding struct file_operations into their objects carl9170: stop embedding file_operations into their objects ...
2025-01-13rust: use derive(CoercePointee) on rustc >= 1.84.0Xiangfei Ding
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>
2025-01-10rust: kernel: move `build_error` hidden function to prevent mistakesMiguel Ojeda
Users were using the hidden exported `kernel::build_error` function instead of the intended `kernel::build_error!` macro, e.g. see the previous commit. To force to use the macro, move it into the `build_assert` module, thus making it a compilation error and avoiding a collision in the same "namespace". Using the function now would require typing the module name (which is hidden), not just a single character. Now attempting to use the function will trigger this error with the right suggestion by the compiler: error[E0423]: expected function, found macro `kernel::build_error` --> samples/rust/rust_minimal.rs:29:9 | 29 | kernel::build_error(); | ^^^^^^^^^^^^^^^^^^^ not a function | help: use `!` to invoke the macro | 29 | kernel::build_error!(); | + An alternative would be using an alias, but it would be more complex and moving it into the module seems right since it belongs there and reduces the amount of code at the crate root. Keep the `#[doc(hidden)]` inside `build_assert` in case the module is not hidden in the future. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241123222849.350287-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-01-07rust: io: move module entry to its correct locationDanilo Krummrich
The module entry of `io` falsely ended up in the "use" block instead of the "mod" block, hence move it to its correct location. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250103164655.96590-3-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-07rust: pci: do not depend on CONFIG_PCI_MSIDanilo Krummrich
The PCI abstractions do not actually depend on CONFIG_PCI_MSI; it also breaks drivers that only depend on CONFIG_PCI, hence drop it. While at it, move the module entry to its correct location. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202501030744.4ucqC1cB-lkp@intel.com/ Fixes: 1bd8b6b2c5d3 ("rust: pci: add basic PCI device / driver abstractions") Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250103164655.96590-2-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: platform: add basic platform device / driver abstractionsDanilo Krummrich
Implement the basic platform bus abstractions required to write a basic platform driver. This includes the following data structures: The `platform::Driver` trait represents the interface to the driver and provides `platform::Driver::probe` for the driver to implement. The `platform::Device` abstraction represents a `struct platform_device`. In order to provide the platform bus specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `platform::Adapter`. Reviewed-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-15-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: of: add `of::DeviceId` abstractionDanilo Krummrich
`of::DeviceId` is an abstraction around `struct of_device_id`. This is used by subsequent patches, in particular the platform bus abstractions, to create OF device ID tables. Reviewed-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Fabien Parent <fabien.parent@linaro.org> Link: https://lore.kernel.org/r/20241219170425.12036-13-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: pci: add basic PCI device / driver abstractionsDanilo Krummrich
Implement the basic PCI abstractions required to write a basic PCI driver. This includes the following data structures: The `pci::Driver` trait represents the interface to the driver and provides `pci::Driver::probe` for the driver to implement. The `pci::Device` abstraction represents a `struct pci_dev` and provides abstractions for common functions, such as `pci::Device::set_master`. In order to provide the PCI specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `pci::Adapter`. `pci::DeviceId` implements PCI device IDs based on the generic `device_id::RawDevceId` abstraction. Co-developed-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-10-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: add devres abstractionDanilo Krummrich
Add a Rust abstraction for the kernel's devres (device resource management) implementation. The Devres type acts as a container to manage the lifetime and accessibility of device bound resources. Therefore it registers a devres callback and revokes access to the resource on invocation. Users of the Devres abstraction can simply free the corresponding resources in their Drop implementation, which is invoked when either the Devres instance goes out of scope or the devres callback leads to the resource being revoked, which implies a call to drop_in_place(). Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-9-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: add `io::{Io, IoRaw}` base typesDanilo Krummrich
I/O memory is typically either mapped through direct calls to ioremap() or subsystem / bus specific ones such as pci_iomap(). Even though subsystem / bus specific functions to map I/O memory are based on ioremap() / iounmap() it is not desirable to re-implement them in Rust. Instead, implement a base type for I/O mapped memory, which generically provides the corresponding accessors, such as `Io::readb` or `Io:try_readb`. `Io` supports an optional const generic, such that a driver can indicate the minimal expected and required size of the mapping at compile time. Correspondingly, calls to the 'non-try' accessors, support compile time checks of the I/O memory offset to read / write, while the 'try' accessors, provide boundary checks on runtime. `IoRaw` is meant to be embedded into a structure (e.g. pci::Bar or io::IoMem) which creates the actual I/O memory mapping and initializes `IoRaw` accordingly. To ensure that I/O mapped memory can't out-live the device it may be bound to, subsystems must embed the corresponding I/O memory type (e.g. pci::Bar) into a `Devres` container, such that it gets revoked once the device is unbound. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Daniel Almeida <daniel.almeida@collabora.com> Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-8-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: add `Revocable` typeWedson Almeida Filho
Revocable allows access to objects to be safely revoked at run time. This is useful, for example, for resources allocated during device probe; when the device is removed, the driver should stop accessing the device resources even if another state is kept in memory due to existing references (i.e., device context data is ref-counted and has a non-zero refcount after removal of the device). Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Link: https://lore.kernel.org/r/20241219170425.12036-7-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: implement `IdArray`, `IdTable` and `RawDeviceId`Danilo Krummrich
Most subsystems use some kind of ID to match devices and drivers. Hence, we have to provide Rust drivers an abstraction to register an ID table for the driver to match. Generally, those IDs are subsystem specific and hence need to be implemented by the corresponding subsystem. However, the `IdArray`, `IdTable` and `RawDeviceId` types provide a generalized implementation that makes the life of subsystems easier to do so. Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Fabien Parent <fabien.parent@linaro.org> Signed-off-by: Fabien Parent <fabien.parent@linaro.org> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Fabien Parent <fabien.parent@linaro.org> Link: https://lore.kernel.org/r/20241219170425.12036-4-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: implement generic driver registrationDanilo Krummrich
Implement the generic `Registration` type and the `RegistrationOps` trait. The `Registration` structure is the common type that represents a driver registration and is typically bound to the lifetime of a module. However, it doesn't implement actual calls to the kernel's driver core to register drivers itself. Instead the `RegistrationOps` trait is provided to subsystems, which have to implement `RegistrationOps::register` and `RegistrationOps::unregister`. Subsystems have to provide an implementation for both of those methods where the subsystem specific variants to register / unregister a driver have to implemented. For instance, the PCI subsystem would call __pci_register_driver() from `RegistrationOps::register` and pci_unregister_driver() from `DrvierOps::unregister`. Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Fabien Parent <fabien.parent@linaro.org> Link: https://lore.kernel.org/r/20241219170425.12036-3-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-20rust: module: add trait `ModuleMetadata`Danilo Krummrich
In order to access static metadata of a Rust kernel module, add the `ModuleMetadata` trait. In particular, this trait provides the name of a Rust kernel module as specified by the `module!` macro. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Fabien Parent <fabien.parent@linaro.org> Link: https://lore.kernel.org/r/20241219170425.12036-2-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-29Merge tag 'char-misc-6.13-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc/IIO/whatever driver subsystem updates from Greg KH: "Here is the 'big and hairy' char/misc/iio and other small driver subsystem updates for 6.13-rc1. Loads of things in here, and even a fun merge conflict! - rust misc driver bindings and other rust changes to make misc drivers actually possible. I think this is the tipping point, expect to see way more rust drivers going forward now that these bindings are present. Next merge window hopefully we will have pci and platform drivers working, which will fully enable almost all driver subsystems to start accepting (or at least getting) rust drivers. This is the end result of a lot of work from a lot of people, congrats to all of them for getting this far, you've proved many of us wrong in the best way possible, working code :) - IIO driver updates, too many to list individually, that subsystem keeps growing and growing... - Interconnect driver updates - nvmem driver updates - pwm driver updates - platform_driver::remove() fixups, loads of them - counter driver updates - misc driver updates (keba?) - binder driver updates and fixes - loads of other small char/misc/etc driver updates and additions, full details in the shortlog. All of these have been in linux-next for a while, with no other reported issues other than that merge conflict" * tag 'char-misc-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (401 commits) mei: vsc: Fix typo "maintstepping" -> "mainstepping" firmware: Switch back to struct platform_driver::remove() misc: isl29020: Fix the wrong format specifier scripts/tags.sh: Don't tag usages of DEFINE_MUTEX fpga: Switch back to struct platform_driver::remove() mei: vsc: Improve error logging in vsc_identify_silicon() mei: vsc: Do not re-enable interrupt from vsc_tp_reset() dt-bindings: spmi: qcom,x1e80100-spmi-pmic-arb: Add SAR2130P compatible dt-bindings: spmi: spmi-mtk-pmif: Add compatible for MT8188 spmi: pmic-arb: fix return path in for_each_available_child_of_node() iio: Move __private marking before struct element priv in struct iio_dev docs: iio: ad7380: add adaq4370-4 and adaq4380-4 iio: adc: ad7380: add support for adaq4370-4 and adaq4380-4 iio: adc: ad7380: use local dev variable to shorten long lines iio: adc: ad7380: fix oversampling formula dt-bindings: iio: adc: ad7380: add adaq4370-4 and adaq4380-4 compatible parts bus: mhi: host: pci_generic: Use pcim_iomap_region() to request and map MHI BAR bus: mhi: host: Switch trace_mhi_gen_tre fields to native endian misc: atmel-ssc: Use of_property_present() for non-boolean properties misc: keba: Add hardware dependency ...
2024-11-26Merge tag 'rust-6.13' of https://github.com/Rust-for-Linux/linuxLinus Torvalds
Pull rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Enable a series of lints, including safety-related ones, e.g. the compiler will now warn about missing safety comments, as well as unnecessary ones. How safety documentation is organized is a frequent source of review comments, thus having the compiler guide new developers on where they are expected (and where not) is very nice. - Start using '#[expect]': an interesting feature in Rust (stabilized in 1.81.0) that makes the compiler warn if an expected warning was _not_ emitted. This is useful to avoid forgetting cleaning up locally ignored diagnostics ('#[allow]'s). - Introduce '.clippy.toml' configuration file for Clippy, the Rust linter, which will allow us to tweak its behaviour. For instance, our first use cases are declaring a disallowed macro and, more importantly, enabling the checking of private items. - Lints-related fixes and cleanups related to the items above. - Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the kernel into stable Rust, one of the major pieces of the puzzle is the support to write custom types that can be used as 'self', i.e. as receivers, since the kernel needs to write types such as 'Arc' that common userspace Rust would not. 'arbitrary_self_types' has been accepted to become stable, and this is one of the steps required to get there. - Remove usage of the 'new_uninit' unstable feature. - Use custom C FFI types. Includes a new 'ffi' crate to contain our custom mapping, instead of using the standard library 'core::ffi' one. The actual remapping will be introduced in a later cycle. - Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize' instead of 32/64-bit integers. - Fix 'size_t' in bindgen generated prototypes of C builtins. - Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue in the projects, which we managed to trigger with the upcoming tracepoint support. It includes a build test since some distributions backported the fix (e.g. Debian -- thanks!). All major distributions we list should be now OK except Ubuntu non-LTS. 'macros' crate: - Adapt the build system to be able run the doctests there too; and clean up and enable the corresponding doctests. 'kernel' crate: - Add 'alloc' module with generic kernel allocator support and remove the dependency on the Rust standard library 'alloc' and the extension traits we used to provide fallible methods with flags. Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'. Add the 'Box' type (a heap allocation for a single value of type 'T' that is also generic over an allocator and considers the kernel's GFP flags) and its shorthand aliases '{K,V,KV}Box'. Add 'ArrayLayout' type. Add 'Vec' (a contiguous growable array type) and its shorthand aliases '{K,V,KV}Vec', including iterator support. For instance, now we may write code such as: let mut v = KVec::new(); v.push(1, GFP_KERNEL)?; assert_eq!(&v, &[1]); Treewide, move as well old users to these new types. - 'sync' module: add global lock support, including the 'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types and the 'global_lock!' macro. Add the 'Lock::try_lock' method. - 'error' module: optimize 'Error' type to use 'NonZeroI32' and make conversion functions public. - 'page' module: add 'page_align' function. - Add 'transmute' module with the existing 'FromBytes' and 'AsBytes' traits. - 'block::mq::request' module: improve rendered documentation. - 'types' module: extend 'Opaque' type documentation and add simple examples for the 'Either' types. drm/panic: - Clean up a series of Clippy warnings. Documentation: - Add coding guidelines for lints and the '#[expect]' feature. - Add Ubuntu to the list of distributions in the Quick Start guide. MAINTAINERS: - Add Danilo Krummrich as maintainer of the new 'alloc' module. And a few other small cleanups and fixes" * tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux: (82 commits) rust: alloc: Fix `ArrayLayout` allocations docs: rust: remove spurious item in `expect` list rust: allow `clippy::needless_lifetimes` rust: warn on bindgen < 0.69.5 and libclang >= 19.1 rust: use custom FFI integer types rust: map `__kernel_size_t` and friends also to usize/isize rust: fix size_t in bindgen prototypes of C builtins rust: sync: add global lock support rust: macros: enable the rest of the tests rust: macros: enable paste! use from macro_rules! rust: enable macros::module! tests rust: kbuild: expand rusttest target for macros rust: types: extend `Opaque` documentation rust: block: fix formatting of `kernel::block::mq::request` module rust: macros: fix documentation of the paste! macro rust: kernel: fix THIS_MODULE header path in ThisModule doc comment rust: page: add Rust version of PAGE_ALIGN rust: helpers: remove unnecessary header includes rust: exports: improve grammar in commentary drm/panic: allow verbose version check ...
2024-11-26Merge tag 'vfs-6.13.rust.pid_namespace' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull pid_namespace rust bindings from Christian Brauner: "This contains my Rust bindings for pid namespaces needed for various rust drivers. Here's a description of the basic C semantics and how they are mapped to Rust. The pid namespace of a task doesn't ever change once the task is alive. A unshare(CLONE_NEWPID) or setns(fd_pidns/pidfd, CLONE_NEWPID) will not have an effect on the calling task's pid namespace. It will only effect the pid namespace of children created by the calling task. This invariant guarantees that after having acquired a reference to a task's pid namespace it will remain unchanged. When a task has exited and been reaped release_task() will be called. This will set the pid namespace of the task to NULL. So retrieving the pid namespace of a task that is dead will return NULL. Note, that neither holding the RCU lock nor holding a reference count to the task will prevent release_task() from being called. In order to retrieve the pid namespace of a task the task_active_pid_ns() function can be used. There are two cases to consider: (1) retrieving the pid namespace of the current task (2) retrieving the pid namespace of a non-current task From system call context retrieving the pid namespace for case (1) is always safe and requires neither RCU locking nor a reference count to be held. Retrieving the pid namespace after release_task() for current will return NULL but no codepath like that is exposed to Rust. Retrieving the pid namespace from system call context for (2) requires RCU protection. Accessing a pid namespace outside of RCU protection requires a reference count that must've been acquired while holding the RCU lock. Note that accessing a non-current task means NULL can be returned as the non-current task could have already passed through release_task(). To retrieve (1) the current_pid_ns!() macro should be used. It ensures that the returned pid namespace cannot outlive the calling scope. The associated current_pid_ns() function should not be called directly as it could be abused to created an unbounded lifetime for the pid namespace. The current_pid_ns!() macro allows Rust to handle the common case of accessing current's pid namespace without RCU protection and without having to acquire a reference count. For (2) the task_get_pid_ns() method must be used. This will always acquire a reference on the pid namespace and will return an Option to force the caller to explicitly handle the case where pid namespace is None. Something that tends to be forgotten when doing the equivalent operation in C. Missing RCU primitives make it difficult to perform operations that are otherwise safe without holding a reference count as long as RCU protection is guaranteed. But it is not important currently. But we do want it in the future. Note that for (2) the required RCU protection around calling task_active_pid_ns() synchronizes against putting the last reference of the associated struct pid of task->thread_pid. The struct pid stored in that field is used to retrieve the pid namespace of the caller. When release_task() is called task->thread_pid will be NULLed and put_pid() on said struct pid will be delayed in free_pid() via call_rcu() allowing everyone with an RCU protected access to the struct pid acquired from task->thread_pid to finish" * tag 'vfs-6.13.rust.pid_namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: rust: add PidNamespace
2024-11-25Merge tag 'trace-rust-v6.13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull rust trace event support from Steven Rostedt: "Allow Rust code to have trace events Trace events is a popular way to debug what is happening inside the kernel or just to find out what is happening. Rust code is being added to the Linux kernel but it currently does not support the tracing infrastructure. Add support of trace events inside Rust code" * tag 'trace-rust-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: rust: jump_label: skip formatting generated file jump_label: rust: pass a mut ptr to `static_key_count` samples: rust: fix `rust_print` build making it a combined module rust: add arch_static_branch jump_label: adjust inline asm to be consistent rust: samples: add tracepoint to Rust sample rust: add tracepoint support rust: add static_branch_unlikely for static_key_false
2024-11-10rust: use custom FFI integer typesGary Guo
Currently FFI integer types are defined in libcore. This commit creates the `ffi` crate and asks bindgen to use that crate for FFI integer types instead of `core::ffi`. This commit is preparatory and no type changes are made in this commit yet. Signed-off-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net [ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate docs slightly and formatted. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-11-05rust: introduce `InPlaceModule`Wedson Almeida Filho
This allows modules to be initialised in-place in pinned memory, which enables the usage of pinned types (e.g., mutexes, spinlocks, driver registrations, etc.) in modules without any extra allocations. Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Miguel Ojeda <ojeda@kernel.org> Link: https://lore.kernel.org/r/20241022213221.2383-3-dakr@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-04rust: add arch_static_branchAlice Ryhl
To allow the Rust implementation of static_key_false to use runtime code patching instead of the generic implementation, pull in the relevant inline assembly from the jump_label.h header by running the C preprocessor on a .rs.S file. Build rules are added for .rs.S files. Since the relevant inline asm has been adjusted to export the inline asm via the ARCH_STATIC_BRANCH_ASM macro in a consistent way, the Rust side does not need architecture specific code to pull in the asm. It is not possible to use the existing C implementation of arch_static_branch via a Rust helper because it passes the argument `key` to inline assembly as an 'i' parameter. 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. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Ard Biesheuvel <ardb@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-v12-5-eec7f0f8ad22@google.com Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Co-developed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Miguel Ojeda <ojeda@kernel.org> 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>
2024-11-04rust: add tracepoint supportAlice Ryhl
Make it possible to have Rust code call into tracepoints defined by C code. It is still required that the tracepoint is declared in a C header, and that this header is included in the input to bindgen. Instead of calling __DO_TRACE directly, the exported rust_do_trace_ function calls an inline helper function. This is because the `cond` argument does not exist at the callsite of DEFINE_RUST_DO_TRACE. __DECLARE_TRACE always emits an inline static and an extern declaration that is only used when CREATE_RUST_TRACE_POINTS is set. These should not end up in the final binary so it is not a problem that they sometimes are emitted without a 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: " =?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-v12-2-eec7f0f8ad22@google.com Reviewed-by: Carlos Llamas <cmllamas@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> 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>
2024-11-04rust: add static_branch_unlikely for static_key_falseAlice Ryhl
Add just enough support for static key so that we can use it from tracepoints. Tracepoints rely on `static_branch_unlikely` with a `struct static_key_false`, so we add the same functionality to Rust. This patch only provides a generic implementation without code patching (matching the one used when CONFIG_JUMP_LABEL is disabled). Later patches add support for inline asm implementations that use runtime patching. When CONFIG_JUMP_LABEL is unset, `static_key_count` is a static inline function, so a Rust helper is defined for `static_key_count` in this case. If Rust is compiled with LTO, this call should get inlined. The helper can be eliminated once we have the necessary inline asm to make atomic operations from Rust. 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: " =?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-v12-1-eec7f0f8ad22@google.com Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-21rust: kernel: fix THIS_MODULE header path in ThisModule doc commentYutaro Ohno
The doc comment for `ThisModule` incorrectly states the C header file for `THIS_MODULE` as `include/linux/export.h`, while the correct path is `include/linux/init.h`. This is because `THIS_MODULE` was moved in commit 5b20755b7780 ("init: move THIS_MODULE from <linux/export.h> to <linux/init.h>"). Update the doc comment for `ThisModule` to reflect the correct header file path for `THIS_MODULE`. Fixes: 5b20755b7780 ("init: move THIS_MODULE from <linux/export.h> to <linux/init.h>") Signed-off-by: Yutaro Ohno <yutaro.ono.418@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/ZxXDZwxWgoEiIYkj@ohnotp Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement kernel `Vec` typeDanilo Krummrich
`Vec` provides a contiguous growable array type with contents allocated with the kernel's allocators (e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`). In contrast to Rust's stdlib `Vec` type, the kernel `Vec` type considers the kernel's GFP flags for all appropriate functions, always reports allocation failures through `Result<_, AllocError>` and remains independent from unstable features. [ This patch starts using a new unstable feature, `inline_const`, but it was stabilized in Rust 1.79.0, i.e. the next version after the minimum one, thus it will not be an issue. - Miguel ] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-17-dakr@kernel.org [ Cleaned `rustdoc` unescaped backtick warning, added a couple more backticks elsewhere, fixed typos, sorted `feature`s, rewrapped documentation lines. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: remove extension of std's `Box`Danilo Krummrich
Now that all existing `Box` users were moved to the kernel `Box` type, remove the `BoxExt` extension and all other related extensions. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-14-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: kernel: move `FromBytes` and `AsBytes` traits to a new `transmute` moduleAliet Exposito Garcia
Refactor the `FromBytes` and `AsBytes` traits from `types.rs` into a new `transmute.rs` module: - Add `rust/kernel/transmute.rs` with the definitions of `FromBytes` and `AsBytes`. - Remove the same trait definitions from `rust/kernel/types.rs`. - Update `rust/kernel/uaccess.rs` to import `AsBytes` and `FromBytes` from `transmute.rs`. The traits and their implementations remain unchanged. Suggested-by: Benno Lossin <benno.lossin@proton.me> Link: https://github.com/Rust-for-Linux/linux/issues/1117 Signed-off-by: Aliet Exposito Garcia <aliet.exposito@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240918225115.2309224-2-aliet.exposito@gmail.com [ Rebased on top of the lints series and slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-09rust: miscdevice: add base miscdevice abstractionAlice Ryhl
Provide a `MiscDevice` trait that lets you specify the file operations that you wish to provide for your misc device. For now, only three file operations are provided: open, close, ioctl. These abstractions only support MISC_DYNAMIC_MINOR. This enforces that new miscdevices should not hard-code a minor number. When implementing ioctl, the Result type is used. This means that you can choose to return either of: * An integer of type isize. * An errno using the kernel::error::Error type. When returning an isize, the integer is returned verbatim. It's mainly intended for returning positive integers to userspace. However, it is technically possible to return errors via the isize return value too. To avoid having a dependency on files, this patch does not provide the file operations callbacks a pointer to the file. This means that they cannot check file properties such as O_NONBLOCK (which Binder needs). Support for that can be added as a follow-up. To avoid having a dependency on vma, this patch does not provide any way to implement mmap (which Binder needs). Support for that can be added as a follow-up. Rust Binder will use these abstractions to create the /dev/binder file when binderfs is disabled. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/rust-for-linux/20240328195457.225001-1-wedsonaf@gmail.com/ Link: https://lore.kernel.org/r/20241001-b4-miscdevice-v2-2-330d760041fa@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-08rust: add PidNamespaceChristian Brauner
The lifetime of `PidNamespace` is bound to `Task` and `struct pid`. The `PidNamespace` of a `Task` doesn't ever change once the `Task` is alive. A `unshare(CLONE_NEWPID)` or `setns(fd_pidns/pidfd, CLONE_NEWPID)` will not have an effect on the calling `Task`'s pid namespace. It will only effect the pid namespace of children created by the calling `Task`. This invariant guarantees that after having acquired a reference to a `Task`'s pid namespace it will remain unchanged. When a task has exited and been reaped `release_task()` will be called. This will set the `PidNamespace` of the task to `NULL`. So retrieving the `PidNamespace` of a task that is dead will return `NULL`. Note, that neither holding the RCU lock nor holding a referencing count to the `Task` will prevent `release_task()` being called. In order to retrieve the `PidNamespace` of a `Task` the `task_active_pid_ns()` function can be used. There are two cases to consider: (1) retrieving the `PidNamespace` of the `current` task (2) retrieving the `PidNamespace` of a non-`current` task From system call context retrieving the `PidNamespace` for case (1) is always safe and requires neither RCU locking nor a reference count to be held. Retrieving the `PidNamespace` after `release_task()` for current will return `NULL` but no codepath like that is exposed to Rust. Retrieving the `PidNamespace` from system call context for (2) requires RCU protection. Accessing `PidNamespace` outside of RCU protection requires a reference count that must've been acquired while holding the RCU lock. Note that accessing a non-`current` task means `NULL` can be returned as the non-`current` task could have already passed through `release_task()`. To retrieve (1) the `current_pid_ns!()` macro should be used which ensure that the returned `PidNamespace` cannot outlive the calling scope. The associated `current_pid_ns()` function should not be called directly as it could be abused to created an unbounded lifetime for `PidNamespace`. The `current_pid_ns!()` macro allows Rust to handle the common case of accessing `current`'s `PidNamespace` without RCU protection and without having to acquire a reference count. For (2) the `task_get_pid_ns()` method must be used. This will always acquire a reference on `PidNamespace` and will return an `Option` to force the caller to explicitly handle the case where `PidNamespace` is `None`, something that tends to be forgotten when doing the equivalent operation in `C`. Missing RCU primitives make it difficult to perform operations that are otherwise safe without holding a reference count as long as RCU protection is guaranteed. But it is not important currently. But we do want it in the future. Note for (2) the required RCU protection around calling `task_active_pid_ns()` synchronizes against putting the last reference of the associated `struct pid` of `task->thread_pid`. The `struct pid` stored in that field is used to retrieve the `PidNamespace` of the caller. When `release_task()` is called `task->thread_pid` will be `NULL`ed and `put_pid()` on said `struct pid` will be delayed in `free_pid()` via `call_rcu()` allowing everyone with an RCU protected access to the `struct pid` acquired from `task->thread_pid` to finish. Link: https://lore.kernel.org/r/20241002-brauner-rust-pid_namespace-v5-1-a90e70d44fde@kernel.org Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-08rust: add seqfile abstractionAlice Ryhl
This adds a simple seq file abstraction that lets you print to a seq file using ordinary Rust printing syntax. An example user from Rust Binder: pub(crate) fn full_debug_print( &self, m: &SeqFile, owner_inner: &mut ProcessInner, ) -> Result<()> { let prio = self.node_prio(); let inner = self.inner.access_mut(owner_inner); seq_print!( m, " node {}: u{:016x} c{:016x} pri {}:{} hs {} hw {} cs {} cw {}", self.debug_id, self.ptr, self.cookie, prio.sched_policy, prio.prio, inner.strong.has_count, inner.weak.has_count, inner.strong.count, inner.weak.count, ); if !inner.refs.is_empty() { seq_print!(m, " proc"); for node_ref in &inner.refs { seq_print!(m, " {}", node_ref.process.task.pid()); } } seq_print!(m, "\n"); for t in &inner.oneway_todo { t.debug_print_inner(m, " pending async transaction "); } Ok(()) } The `SeqFile` type is marked not thread safe so that `call_printf` can be a `&self` method. The alternative is to use `self: Pin<&mut Self>` which is inconvenient, or to have `SeqFile` wrap a pointer instead of wrapping the C struct directly. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241001-seqfile-v1-1-dfcd0fc21e96@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-08Merge patch series "File abstractions needed by Rust Binder"Christian Brauner
Alice Ryhl <aliceryhl@google.com> says: This patchset contains the file abstractions needed by the Rust implementation of the Binder driver. Please see the Rust Binder RFC for usage examples: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com Users of "rust: types: add `NotThreadSafe`": [PATCH 5/9] rust: file: add `FileDescriptorReservation` Users of "rust: task: add `Task::current_raw`": [PATCH 7/9] rust: file: add `Kuid` wrapper [PATCH 8/9] rust: file: add `DeferredFdCloser` Users of "rust: file: add Rust abstraction for `struct file`": [PATCH RFC 02/20] rust_binder: add binderfs support to Rust binder [PATCH RFC 03/20] rust_binder: add threading support Users of "rust: cred: add Rust abstraction for `struct cred`": [PATCH RFC 05/20] rust_binder: add nodes and context managers [PATCH RFC 06/20] rust_binder: add oneway transactions [PATCH RFC 11/20] rust_binder: send nodes in transaction [PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support Users of "rust: security: add abstraction for secctx": [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: file: add `FileDescriptorReservation`": [PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support [PATCH RFC 14/20] rust_binder: add BINDER_TYPE_FDA support Users of "rust: file: add `Kuid` wrapper": [PATCH RFC 05/20] rust_binder: add nodes and context managers [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: file: add abstraction for `poll_table`": [PATCH RFC 07/20] rust_binder: add epoll support This patchset has some uses of read_volatile in place of READ_ONCE. Please see the following rfc for context on this: https://lore.kernel.org/all/20231025195339.1431894-1-boqun.feng@gmail.com/ * patches from https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com: rust: file: add abstraction for `poll_table` rust: file: add `Kuid` wrapper rust: file: add `FileDescriptorReservation` rust: security: add abstraction for secctx rust: cred: add Rust abstraction for `struct cred` rust: file: add Rust abstraction for `struct file` rust: task: add `Task::current_raw` rust: types: add `NotThreadSafe` Link: https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-07rust: enable arbitrary_self_types and remove `Receiver`Gary Guo
The term "receiver" means that a type can be used as the type of `self`, and thus enables method call syntax `foo.bar()` instead of `Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited selection of types (primitives and types in std, e.g. `Box` and `Arc`) to be used as receivers, while custom types cannot. We want the kernel `Arc` type to have the same functionality as the Rust std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait` unstable feature) to gain the functionality. The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and it will allow all types that implement a new `Receiver` trait (different from today's unstable trait) to be used as receivers. This trait will be automatically implemented for all `Deref` types, which include our `Arc` type, so we no longer have to opt-in to be used as receiver. To prepare us for the change, remove the `Receiver` implementation and the associated feature. To still allow `Arc` and others to be used as method receivers, turn on `arbitrary_self_types` feature instead. This feature gate is introduced in 1.23.0. It used to enable both `Deref` types and raw pointer types to be used as receivers, but the latter is now split into a different feature gate in Rust 1.83 nightly. We do not need receivers on raw pointers so this change would not affect us and usage of `arbitrary_self_types` feature would work for all Rust versions that we support (>=1.78). Cc: Adrian Taylor <ade@hohum.me.uk> Link: https://github.com/rust-lang/rfcs/pull/3519 [1] Link: https://github.com/rust-lang/rust/issues/44874 [2] Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915132734.1653004-1-gary@garyguo.net Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: start using the `#[expect(...)]` attributeMiguel Ojeda
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>
2024-09-30rust: security: add abstraction for secctxAlice Ryhl
Add an abstraction for viewing the string representation of a security context. This is needed by Rust Binder because it has a feature where a process can view the string representation of the security context for incoming transactions. The process can use that to authenticate incoming transactions, and since the feature is provided by the kernel, the process can trust that the security context is legitimate. This abstraction makes the following assumptions about the C side: * When a call to `security_secid_to_secctx` is successful, it returns a pointer and length. The pointer references a byte string and is valid for reading for that many bytes. * The string may be referenced until `security_release_secctx` is called. * If CONFIG_SECURITY is set, then the three methods mentioned in rust/helpers are available without a helper. (That is, they are not a #define or `static inline`.) Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-5-88484f7a3dcf@google.com Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Kees Cook <kees@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: cred: add Rust abstraction for `struct cred`Wedson Almeida Filho
Add a wrapper around `struct cred` called `Credential`, and provide functionality to get the `Credential` associated with a `File`. Rust Binder must check the credentials of processes when they attempt to perform various operations, and these checks usually take a `&Credential` as parameter. The security_binder_set_context_mgr function would be one example. This patch is necessary to access these security_* methods from Rust. This Rust abstraction makes the following assumptions about the C side: * `struct cred` is refcounted with `get_cred`/`put_cred`. * It's okay to transfer a `struct cred` across threads, that is, you do not need to call `put_cred` on the same thread as where you called `get_cred`. * The `euid` field of a `struct cred` never changes after initialization. * The `f_cred` field of a `struct file` never changes after initialization. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-4-88484f7a3dcf@google.com Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: file: add Rust abstraction for `struct file`Wedson Almeida Filho
This abstraction makes it possible to manipulate the open files for a process. The new `File` struct wraps the C `struct file`. When accessing it using the smart pointer `ARef<File>`, the pointer will own a reference count to the file. When accessing it as `&File`, then the reference does not own a refcount, but the borrow checker will ensure that the reference count does not hit zero while the `&File` is live. Since this is intended to manipulate the open files of a process, we introduce an `fget` constructor that corresponds to the C `fget` method. In future patches, it will become possible to create a new fd in a process and bind it to a `File`. Rust Binder will use these to send fds from one process to another. We also provide a method for accessing the file's flags. Rust Binder will use this to access the flags of the Binder fd to check whether the non-blocking flag is set, which affects what the Binder ioctl does. This introduces a struct for the EBADF error type, rather than just using the Error type directly. This has two advantages: * `File::fget` returns a `Result<ARef<File>, BadFdError>`, which the compiler will represent as a single pointer, with null being an error. This is possible because the compiler understands that `BadFdError` has only one possible value, and it also understands that the `ARef<File>` smart pointer is guaranteed non-null. * Additionally, we promise to users of the method that the method can only fail with EBADF, which means that they can rely on this promise without having to inspect its implementation. That said, there are also two disadvantages: * Defining additional error types involves boilerplate. * The question mark operator will only utilize the `From` trait once, which prevents you from using the question mark operator on `BadFdError` in methods that return some third error type that the kernel `Error` is convertible into. (However, it works fine in methods that return `Error`.) Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-3-88484f7a3dcf@google.com Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-26rust: kernel: sort Rust modulesMiguel Ojeda
Rust modules are intended to be sorted, thus do so. This makes `rustfmtcheck` to pass again. Fixes: 570172569238 ("Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux") Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240926124751.345471-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-25Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linuxLinus Torvalds
Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up objtool warnings), teach objtool about 'noreturn' Rust symbols and mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we should be objtool-warning-free, so enable it to run for all Rust object files. - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support. - Support 'RUSTC_VERSION', including re-config and re-build on change. - Split helpers file into several files in a folder, to avoid conflicts in it. Eventually those files will be moved to the right places with the new build system. In addition, remove the need to manually export the symbols defined there, reusing existing machinery for that. - Relax restriction on configurations with Rust + GCC plugins to just the RANDSTRUCT plugin. 'kernel' crate: - New 'list' module: doubly-linked linked list for use with reference counted values, which is heavily used by the upcoming Rust Binder. This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed unique for the given ID), 'AtomicTracker' (tracks whether a 'ListArc' exists using an atomic), 'ListLinks' (the prev/next pointers for an item in a linked list), 'List' (the linked list itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor into a 'List' that allows to remove elements), 'ListArcField' (a field exclusively owned by a 'ListArc'), as well as support for heterogeneous lists. - New 'rbtree' module: red-black tree abstractions used by the upcoming Rust Binder. This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a node), 'RBTreeNodeReservation' (a memory reservation for a node), 'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor' (bidirectional cursor that allows to remove elements), as well as an entry API similar to the Rust standard library one. - 'init' module: add 'write_[pin_]init' methods and the 'InPlaceWrite' trait. Add the 'assert_pinned!' macro. - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by introducing an associated type in the trait. - 'alloc' module: add 'drop_contents' method to 'BoxExt'. - 'types' module: implement the 'ForeignOwnable' trait for 'Pin<Box<T>>' and improve the trait's documentation. In addition, add the 'into_raw' method to the 'ARef' type. - 'error' module: in preparation for the upcoming Rust support for 32-bit architectures, like arm, locally allow Clippy lint for those. Documentation: - https://rust.docs.kernel.org has been announced, so link to it. - Enable rustdoc's "jump to definition" feature, making its output a bit closer to the experience in a cross-referencer. - Debian Testing now also provides recent Rust releases (outside of the freeze period), so add it to the list. MAINTAINERS: - Trevor is joining as reviewer of the "RUST" entry. And a few other small bits" * tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits) kasan: rust: Add KASAN smoke test via UAF kbuild: rust: Enable KASAN support rust: kasan: Rust does not support KHWASAN kbuild: rust: Define probing macros for rustc kasan: simplify and clarify Makefile rust: cfi: add support for CFI_CLANG with Rust cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS rust: support for shadow call stack sanitizer docs: rust: include other expressions in conditional compilation section kbuild: rust: replace proc macros dependency on `core.o` with the version text kbuild: rust: rebuild if the version text changes kbuild: rust: re-run Kconfig if the version text changes kbuild: rust: add `CONFIG_RUSTC_VERSION` rust: avoid `box_uninit_write` feature MAINTAINERS: add Trevor Gross as Rust reviewer rust: rbtree: add `RBTree::entry` rust: rbtree: add cursor rust: rbtree: add mutable iterator rust: rbtree: add iterator rust: rbtree: add red-black tree implementation backed by the C version ...
2024-08-31rust: rbtree: add red-black tree implementation backed by the C versionWedson Almeida Filho
The rust rbtree exposes a map-like interface over keys and values, backed by the kernel red-black tree implementation. Values can be inserted, deleted, and retrieved from a `RBTree` by key. This base abstraction is used by binder to store key/value pairs and perform lookups, for example the patch "[PATCH RFC 03/20] rust_binder: add threading support" in the binder RFC [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-3-08ba9197f637@google.com/ [1] Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Matt Gilbride <mattgilbride@google.com> Link: https://lore.kernel.org/r/20240822-b4-rbtree-v12-1-014561758a57@google.com [ Updated link to docs.kernel.org. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-30rust: sizes: add commonly used constantsFUJITA Tomonori
Add rust equivalent to include/linux/sizes.h, makes code more readable. Only SZ_*K that QT2025 PHY driver uses are added. Make generated constants accessible with a proper type. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-23rust: list: add ListArcAlice Ryhl
The `ListArc` type can be thought of as a special reference to a refcounted object that owns the permission to manipulate the `next`/`prev` pointers stored in the refcounted object. By ensuring that each object has only one `ListArc` reference, the owner of that reference is assured exclusive access to the `next`/`prev` pointers. When a `ListArc` is inserted into a `List`, the `List` takes ownership of the `ListArc` reference. There are various strategies for ensuring that a value has only one `ListArc` reference. The simplest is to convert a `UniqueArc` into a `ListArc`. However, the refcounted object could also keep track of whether a `ListArc` exists using a boolean, which could allow for the creation of new `ListArc` references from an `Arc` reference. Whatever strategy is used, the relevant tracking is referred to as "the tracking inside `T`", and the `ListArcSafe` trait (and its subtraits) are used to update the tracking when a `ListArc` is created or destroyed. Note that we allow the case where the tracking inside `T` thinks that a `ListArc` exists, but actually, there isn't a `ListArc`. However, we do not allow the opposite situation where a `ListArc` exists, but the tracking thinks it doesn't. This is because the former can at most result in us failing to create a `ListArc` when the operation could succeed, whereas the latter can result in the creation of two `ListArc` references. Only the latter situation can lead to memory safety issues. This patch introduces the `impl_list_arc_safe!` macro that allows you to implement `ListArcSafe` for types using the strategy where a `ListArc` can only be created from a `UniqueArc`. Other strategies are introduced in later patches. This is part of the linked list that Rust Binder will use for many different things. The strategy where a `ListArc` can only be created from a `UniqueArc` is actually sufficient for most of the objects that Rust Binder needs to insert into linked lists. Usually, these are todo items that are created and then immediately inserted into a queue. The const generic ID allows objects to have several prev/next pointer pairs so that the same object can be inserted into several different lists. You are able to have several `ListArc` references as long as they correspond to different pointer pairs. The ID itself is purely a compile-time concept and will not be present in the final binary. Both the `List` and the `ListArc` will need to agree on the ID for them to work together. Rust Binder uses this in a few places (e.g. death recipients) where the same object can be inserted into both generic todo lists and some other lists for tracking the status of the object. The ID is a const generic rather than a type parameter because the `pair_from_unique` method needs to be able to assert that the two ids are different. There's no easy way to assert that when using types instead of integers. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-2-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-27Merge tag 'rust-6.11' of https://github.com/Rust-for-Linux/linuxLinus Torvalds
Pull Rust updates from Miguel Ojeda: "The highlight is the establishment of a minimum version for the Rust toolchain, including 'rustc' (and bundled tools) and 'bindgen'. The initial minimum will be the pinned version we currently have, i.e. we are just widening the allowed versions. That covers three stable Rust releases: 1.78.0, 1.79.0, 1.80.0 (getting released tomorrow), plus beta, plus nightly. This should already be enough for kernel developers in distributions that provide recent Rust compiler versions routinely, such as Arch Linux, Debian Unstable (outside the freeze period), Fedora Linux, Gentoo Linux (especially the testing channel), Nix (unstable) and openSUSE Slowroll and Tumbleweed. In addition, the kernel is now being built-tested by Rust's pre-merge CI. That is, every change that is attempting to land into the Rust compiler is tested against the kernel, and it is merged only if it passes. Similarly, the bindgen tool has agreed to build the kernel in their CI too. Thus, with the pre-merge CI in place, both projects hope to avoid unintentional changes to Rust that break the kernel. This means that, in general, apart from intentional changes on their side (that we will need to workaround conditionally on our side), the upcoming Rust compiler versions should generally work. In addition, the Rust project has proposed getting the kernel into stable Rust (at least solving the main blockers) as one of its three flagship goals for 2024H2 [1]. I would like to thank Niko, Sid, Emilio et al. for their help promoting the collaboration between Rust and the kernel. Toolchain and infrastructure: - Support several Rust toolchain versions. - Support several bindgen versions. - Remove 'cargo' requirement and simplify 'rusttest', thanks to 'alloc' having been dropped last cycle. - Provide proper error reporting for the 'rust-analyzer' target. 'kernel' crate: - Add 'uaccess' module with a safe userspace pointers abstraction. - Add 'page' module with a 'struct page' abstraction. - Support more complex generics in workqueue's 'impl_has_work!' macro. 'macros' crate: - Add 'firmware' field support to the 'module!' macro. - Improve 'module!' macro documentation. Documentation: - Provide instructions on what packages should be installed to build the kernel in some popular Linux distributions. - Introduce the new kernel.org LLVM+Rust toolchains. - Explain '#[no_std]'. And a few other small bits" Link: https://rust-lang.github.io/rust-project-goals/2024h2/index.html#flagship-goals [1] * tag 'rust-6.11' of https://github.com/Rust-for-Linux/linux: (26 commits) docs: rust: quick-start: add section on Linux distributions rust: warn about `bindgen` versions 0.66.0 and 0.66.1 rust: start supporting several `bindgen` versions rust: work around `bindgen` 0.69.0 issue rust: avoid assuming a particular `bindgen` build rust: start supporting several compiler versions rust: simplify Clippy warning flags set rust: relax most deny-level lints to warnings rust: allow `dead_code` for never constructed bindings rust: init: simplify from `map_err` to `inspect_err` rust: macros: indent list item in `paste!`'s docs rust: add abstraction for `struct page` rust: uaccess: add typed accessors for userspace pointers uaccess: always export _copy_[from|to]_user with CONFIG_RUST rust: uaccess: add userspace pointers kbuild: rust-analyzer: improve comment documentation kbuild: rust-analyzer: better error handling docs: rust: no_std is used rust: alloc: add __GFP_HIGHMEM flag rust: alloc: fix typo in docs for GFP_NOWAIT ...
2024-07-25Merge tag 'driver-core-6.11-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the big set of driver core changes for 6.11-rc1. Lots of stuff in here, with not a huge diffstat, but apis are evolving which required lots of files to be touched. Highlights of the changes in here are: - platform remove callback api final fixups (Uwe took many releases to get here, finally!) - Rust bindings for basic firmware apis and initial driver-core interactions. It's not all that useful for a "write a whole driver in rust" type of thing, but the firmware bindings do help out the phy rust drivers, and the driver core bindings give a solid base on which others can start their work. There is still a long way to go here before we have a multitude of rust drivers being added, but it's a great first step. - driver core const api changes. This reached across all bus types, and there are some fix-ups for some not-common bus types that linux-next and 0-day testing shook out. This work is being done to help make the rust bindings more safe, as well as the C code, moving toward the end-goal of allowing us to put driver structures into read-only memory. We aren't there yet, but are getting closer. - minor devres cleanups and fixes found by code inspection - arch_topology minor changes - other minor driver core cleanups All of these have been in linux-next for a very long time with no reported problems" * tag 'driver-core-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (55 commits) ARM: sa1100: make match function take a const pointer sysfs/cpu: Make crash_hotplug attribute world-readable dio: Have dio_bus_match() callback take a const * zorro: make match function take a const pointer driver core: module: make module_[add|remove]_driver take a const * driver core: make driver_find_device() take a const * driver core: make driver_[create|remove]_file take a const * firmware_loader: fix soundness issue in `request_internal` firmware_loader: annotate doctests as `no_run` devres: Correct code style for functions that return a pointer type devres: Initialize an uninitialized struct member devres: Fix memory leakage caused by driver API devm_free_percpu() devres: Fix devm_krealloc() wasting memory driver core: platform: Switch to use kmemdup_array() driver core: have match() callback in struct bus_type take a const * MAINTAINERS: add Rust device abstractions to DRIVER CORE device: rust: improve safety comments MAINTAINERS: add Danilo as FIRMWARE LOADER maintainer MAINTAINERS: add Rust FW abstractions to FIRMWARE LOADER firmware: rust: improve safety comments ...
2024-07-08rust: add abstraction for `struct page`Alice Ryhl
Adds a new struct called `Page` that wraps a pointer to `struct page`. This struct is assumed to hold ownership over the page, so that Rust code can allocate and manage pages directly. The page type has various methods for reading and writing into the page. These methods will temporarily map the page to allow the operation. All of these methods use a helper that takes an offset and length, performs bounds checks, and returns a pointer to the given offset in the page. This patch only adds support for pages of order zero, as that is all Rust Binder needs. However, it is written to make it easy to add support for higher-order pages in the future. To do that, you would add a const generic parameter to `Page` that specifies the order. Most of the methods do not need to be adjusted, as the logic for dealing with mapping multiple pages at once can be isolated to just the `with_pointer_into_page` method. Rust Binder needs to manage pages directly as that is how transactions are delivered: Each process has an mmap'd region for incoming transactions. When an incoming transaction arrives, the Binder driver will choose a region in the mmap, allocate and map the relevant pages manually, and copy the incoming transaction directly into the page. This architecture allows the driver to copy transactions directly from the address space of one process to another, without an intermediate copy to a kernel buffer. This code is based on Wedson's page abstractions from the old rust branch, but it has been modified by Alice by removing the incomplete support for higher-order pages, by introducing the `with_*` helpers to consolidate the bounds checking logic into a single place, and various other changes. Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240528-alice-mm-v7-4-78222c31b8f4@google.com [ Fixed typos and added a few intra-doc links. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-08rust: uaccess: add userspace pointersWedson Almeida Filho
A pointer to an area in userspace memory, which can be either read-only or read-write. All methods on this struct are safe: attempting to read or write on bad addresses (either out of the bound of the slice or unmapped addresses) will return `EFAULT`. Concurrent access, *including data races to/from userspace memory*, is permitted, because fundamentally another userspace thread/process could always be modifying memory at the same time (in the same way that userspace Rust's `std::io` permits data races with the contents of files on disk). In the presence of a race, the exact byte values read/written are unspecified but the operation is well-defined. Kernelspace code should validate its copy of data after completing a read, and not expect that multiple reads of the same address will return the same value. These APIs are designed to make it difficult to accidentally write TOCTOU bugs. Every time you read from a memory location, the pointer is advanced by the length so that you cannot use that reader to read the same memory location twice. Preventing double-fetches avoids TOCTOU bugs. This is accomplished by taking `self` by value to prevent obtaining multiple readers on a given `UserSlice`, and the readers only permitting forward reads. If double-fetching a memory location is necessary for some reason, then that is done by creating multiple readers to the same memory location. Constructing a `UserSlice` performs no checks on the provided address and length, it can safely be constructed inside a kernel thread with no current userspace process. Reads and writes wrap the kernel APIs `copy_from_user` and `copy_to_user`, which check the memory map of the current process and enforce that the address range is within the user range (no additional calls to `access_ok` are needed). This code is based on something that was originally written by Wedson on the old rust branch. It was modified by Alice by removing the `IoBufferReader` and `IoBufferWriter` traits, and various other changes. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240528-alice-mm-v7-1-78222c31b8f4@google.com [ Wrapped docs to 100 and added a few intra-doc links. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-06-18rust: add firmware abstractionsDanilo Krummrich
Add an abstraction around the kernels firmware API to request firmware images. The abstraction provides functions to access the firmware's size and backing buffer. The firmware is released once the abstraction instance is dropped. Signed-off-by: Danilo Krummrich <dakr@redhat.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20240618154841.6716-3-dakr@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-18rust: add abstraction for struct deviceDanilo Krummrich
Add an (always) reference-counted abstraction for a generic C `struct device`. This abstraction encapsulates existing `struct device` instances and manages its reference count. Subsystems may use this abstraction as a base to abstract subsystem specific device instances based on a generic `struct device`, such as `struct pci_dev`. Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Danilo Krummrich <dakr@redhat.com> Link: https://lore.kernel.org/r/20240618154841.6716-2-dakr@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-14rust: block: introduce `kernel::block::mq` moduleAndreas Hindborg
Add initial abstractions for working with blk-mq. This patch is a maintained, refactored subset of code originally published by Wedson Almeida Filho <wedsonaf@gmail.com> [1]. [1] https://github.com/wedsonaf/linux/tree/f2cfd2fe0e2ca4e90994f96afe268bbd4382a891/rust/kernel/blk/mq.rs Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240611114551.228679-2-nmi@metaspace.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-13Merge tag 'rust-6.10' of https://github.com/Rust-for-Linux/linuxLinus Torvalds
Pull Rust updates from Miguel Ojeda: "The most notable change is the drop of the 'alloc' in-tree fork. This is nicely reflected in the diffstat as a ~10k lines drop. In turn, this makes the version upgrades way simpler and smaller in the future, e.g. the latest one in commit 56f64b370612 ("rust: upgrade to Rust 1.78.0"). More importantly, this increases the chances that a newer compiler version just works, which in turn means supporting several compiler versions is easier now. Thus we will look into finally setting a minimum version in the near future. Toolchain and infrastructure: - Upgrade to Rust 1.78.0 This time around, due to how the kernel and Rust schedules have aligned, there are two upgrades in fact. These allow us to remove one more unstable feature ('offset_of') from the list, among other improvements - Drop 'alloc' in-tree fork of the standard library crate, which means all the unstable features used by 'alloc' (~30 language ones, ~60 library ones) are not a concern anymore - Support DWARFv5 via the '-Zdwarf-version' flag - Support zlib and zstd debuginfo compression via the '-Zdebuginfo-compression' flag 'kernel' crate: - Support allocation flags ('GFP_*'), particularly in 'Box' (via 'BoxExt'), 'Vec' (via 'VecExt'), 'Arc' and 'UniqueArc', as well as in the 'init' module APIs - Remove usage of the 'allocator_api' unstable feature - Remove 'try_' prefix in allocation APIs' names - Add 'VecExt' (an extension trait) to be able to drop the 'alloc' fork - Add the '{make,to}_{upper,lower}case()' methods to 'CStr'/'CString' - Add the 'as_ptr' method to 'ThisModule' - Add the 'from_raw' method to 'ArcBorrow' - Add the 'into_unique_or_drop' method to 'Arc' - Display column number in the 'dbg!' macro output by applying the equivalent change done to the standard library one - Migrate 'Work' to '#[pin_data]' thanks to the changes in the 'macros' crate, which allows to remove an unsafe call in its 'new' associated function - Prevent namespacing issues when using the '[try_][pin_]init!' macros by changing the generated name of guard variables - Make the 'get' method in 'Opaque' const - Implement the 'Default' trait for 'LockClassKey' - Remove unneeded 'kernel::prelude' imports from doctests - Remove redundant imports 'macros' crate: - Add 'decl_generics' to 'parse_generics()' to support default values, and use that to allow them in '#[pin_data]' Helpers: - Trivial English grammar fix Documentation: - Add section on Rust Kselftests to the 'Testing' document - Expand the 'Abstractions vs. bindings' section of the 'General Information' document" * tag 'rust-6.10' of https://github.com/Rust-for-Linux/linux: (31 commits) rust: alloc: fix dangling pointer in VecExt<T>::reserve() rust: upgrade to Rust 1.78.0 rust: kernel: remove redundant imports rust: sync: implement `Default` for `LockClassKey` docs: rust: extend abstraction and binding documentation docs: rust: Add instructions for the Rust kselftest rust: remove unneeded `kernel::prelude` imports from doctests rust: update `dbg!()` to format column number rust: helpers: Fix grammar in comment rust: init: change the generated name of guard variables rust: sync: add `Arc::into_unique_or_drop` rust: sync: add `ArcBorrow::from_raw` rust: types: Make Opaque::get const rust: kernel: remove usage of `allocator_api` unstable feature rust: init: update `init` module to take allocation flags rust: sync: update `Arc` and `UniqueArc` to take allocation flags rust: alloc: update `VecExt` to take allocation flags rust: alloc: introduce the `BoxExt` trait rust: alloc: introduce allocation flags rust: alloc: remove our fork of the `alloc` crate ...
2024-04-23rust: kernel: require `Send` for `Module` implementationsWedson Almeida Filho
The thread that calls the module initialisation code when a module is loaded is not guaranteed [in fact, it is unlikely] to be the same one that calls the module cleanup code on module unload, therefore, `Module` implementations must be `Send` to account for them moving from one thread to another implicitly. Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Cc: stable@vger.kernel.org # 6.8.x: df70d04d5697: rust: phy: implement `Send` for `Registration` Cc: stable@vger.kernel.org Fixes: 247b365dc8dc ("rust: add `kernel` crate") Link: https://lore.kernel.org/r/20240328195457.225001-3-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>