kernel/git/next/linux-next.git/samples/rust/rust_dma.rs, branch master

rust: io: add copying methods

2026-07-11T16:09:04+00:00

One feature that was lost from the old `dma_read!` and `dma_write!` when moving to `io_read!` and `io_write!` was the ability to read/write a large structs. However, the semantics was unclear to begin with, as there was no guarantee about their atomicity even for structs that were small enough to fit in u32. Re-introduce the capability in the form of copying methods. dma_read!(foo, bar) -> io_project!(foo, bar).copy_read() dma_write!(foo, bar, baz) -> io_project!(foo, bar).copy_write(baz) Model these semantics after memcpy so user has clear expectation of lack of atomicity. As an additional benefit of this change, this now works for MMIO as well by mapping them to `memcpy_{from,to}io`. For slices which is DST so the `copy_read` and `copy_write` API above can't work, add `copy_from_slice` and `copy_to_slice` to copy from/to normal memory. Signed-off-by: Gary Guo Reviewed-by: Alexandre Courbot Link: https://patch.msgid.link/20260706-io_projection-v6-19-72cd5d055d54@garyguo.net Signed-off-by: Danilo Krummrich

rust: dma: drop `dma_read!` and `dma_write!` API

2026-07-11T16:09:04+00:00

The primitive read/write use case is covered by the `io_read!` and `io_write!` macro. The non-primitive use case was finicky; they should either be achieved using `CoherentBox` or `as_ref()/as_mut()` to assert the lack of concurrent access, or should be using memcpy-like APIs to express the non-atomic and tearable nature. Reviewed-by: Andreas Hindborg Reviewed-by: Alexandre Courbot Signed-off-by: Gary Guo Reviewed-by: Daniel Almeida Link: https://patch.msgid.link/20260706-io_projection-v6-18-72cd5d055d54@garyguo.net Signed-off-by: Danilo Krummrich

Merge tag 'driver-core-7.2-rc1' of gitolite.kernel.org:pub/scm/linux/kernel/git/driver-core/driver-core

2026-06-15T07:11:17+00:00

Pull driver core updates from Danilo Krummrich: "Deferred probe: - Fix race where deferred probe timeout work could be permanently canceled by using mod_delayed_work() - Fix missing jiffies conversion in deferred_probe_extend_timeout() - Guard timeout extension with delayed_work_pending() to prevent premature firing - Use system_percpu_wq instead of the deprecated system_wq - Update deferred_probe_timeout documentation device: - Replace direct struct device bitfield access (can_match, dma_iommu, dma_skip_sync, dma_ops_bypass, state_synced, dma_coherent, of_node_reused, offline, offline_disabled) with flag-based accessors using bit operations - Reject devices with unregistered buses - Delete unused DEVICE_ATTR_PREALLOC() - Add low-level device attribute macros with const show/store callbacks, allowing device attributes to reside in read-only memory - Move core device attributes to read-only memory - Constify group array pointers in driver_add_groups() / driver_remove_groups(), struct bus_type, and struct device_driver device property: - Fix fwnode reference leak in fwnode_graph_get_endpoint_by_id() - Initialize all fields of fwnode_handle in fwnode_init() - Provide swnode_get()/swnode_put() wrappers around kobject_get/put() - Allow passing struct software_node_ref_args pointers directly to PROPERTY_ENTRY_REF() driver_override: - Migrate amba, cdx, vmbus, and rpmsg to the generic driver_override infrastructure, fixing a UAF from unsynchronized access to driver_override in bus match() callbacks - Remove the now-unused driver_set_override() firmware loader: - Fix recursive lock deadlock in device_cache_fw_images() when async work falls back to synchronous execution - Fix device reference leak in firmware_upload_register() platform: - Pass KBUILD_MODNAME through the platform driver registration macro to create module symlinks in sysfs for built-in drivers; move module_kset initialization to a pure_initcall and tegra cbb registration to core_initcall to ensure correct ordering - Pass THIS_MODULE implicitly through a coresight_init_driver() macro sysfs: - Upgrade OOB write detection in sysfs_kf_seq_show() from printk to WARN - Add return value clamping to sysfs_kf_read() Rust: - ACPI: Fix missing match data for PRP0001 by exporting acpi_of_match_device() - Auxiliary: Replace drvdata() with dedicated registration data on auxiliary_device. drvdata() exposed the driver's bus device private data beyond the driver's own scope, creating ordering constraints and forcing the data to outlive all registrations that access it. Registration data is instead scoped structurally to the Registration object, making lifecycle ordering enforced by construction rather than convention. - Rust-native device driver lifetimes (HRT): Allow Rust device drivers to carry a lifetime parameter on their bus device private data, tied to the device binding scope -- the interval during which a bus device is bound to a driver. Device resources like pci::Bar<'a> and IoMem<'a> can be stored directly in the driver's bus device private data with a lifetime bounded by the binding scope, so the compiler enforces at build time that they do not outlive the binding. This removes Devres indirection from every access site and eliminates try_access() failure paths in destructors. Bus driver traits use a Generic Associated Type (GAT) Data<'bound> to introduce the lifetime on the private data, rather than parameterizing the Driver trait itself. Auxiliary registration data, where the lifetime is not introduced by a trait callback but must be threaded through Registration, uses the ForLt trait (a type-level abstraction for types generic over a lifetime). Misc: - Fix DT overlayed devices not probing by reverting the broken treewide overlay fix and re-running fw_devlink consumer pickup when an overlay is applied to a bound device - Use root_device_register() for faux bus root device; add sanity check for failed bus init - Fix dev_has_sync_state() data race with READ_ONCE() and move it to base.h - Avoid spurious device_links warning when removing a device while its supplier is unbinding - Switch ISA bus to dynamic root device - Fix suspicious RCU usage in kernfs_put() - Remove devcoredump exit callback - Constify devfreq_event_class" * tag 'driver-core-7.2-rc1' of gitolite.kernel.org:pub/scm/linux/kernel/git/driver-core/driver-core: (81 commits) software node: allow passing reference args to PROPERTY_ENTRY_REF() driver core: platform: set mod_name in driver registration coresight: pass THIS_MODULE implicitly through a macro kernel: param: initialize module_kset in a pure_initcall soc/tegra: cbb: Move driver registration from pure_initcall to core_initcall firmware_loader: Fix recursive lock in device_cache_fw_images() driver core: Use system_percpu_wq instead of system_wq driver core: remove driver_set_override() rpmsg: use generic driver_override infrastructure Drivers: hv: vmbus: use generic driver_override infrastructure cdx: use generic driver_override infrastructure amba: use generic driver_override infrastructure rust: devres: add 'static bound to Devres samples: rust: rust_driver_auxiliary: showcase lifetime-bound registration data rust: auxiliary: generalize Registration over ForLt rust: types: add `ForLt` trait for higher-ranked lifetime support gpu: nova-core: separate driver type from driver data samples: rust: rust_driver_pci: use HRT lifetime for Bar rust: io: make IoMem and ExclusiveIoMem lifetime-parameterized rust: pci: make Bar lifetime-parameterized ...

rust: dma: update to keyworded index projection syntax

2026-06-05T08:16:46+00:00

Demonstrate the preferred syntax of index projection in DMA documentation and examples. A few `[i]?` cases are converted to demonstrate the new variant. Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Reviewed-by: Alexandre Courbot Signed-off-by: Gary Guo Acked-by: Danilo Krummrich Link: https://patch.msgid.link/20260602-projection-syntax-rework-v2-4-6989470f5440@garyguo.net Signed-off-by: Miguel Ojeda

rust: pci: make Driver trait lifetime-parameterized

2026-05-27T14:23:10+00:00

Add a 'bound lifetime to the associated Data, changing type Data to type Data<'bound>. This allows the driver's bus device private data to capture the device / driver bound lifetime; device resources can be stored directly by reference rather than requiring Devres. The probe() and unbind() callbacks thus gain a 'bound lifetime parameter on the methods themselves; avoiding a global lifetime on the trait impl. Existing drivers set type Data<'bound> = Self, preserving the current behavior. Reviewed-by: Alexandre Courbot Reviewed-by: Greg Kroah-Hartman Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260525202921.124698-13-dakr@kernel.org Signed-off-by: Danilo Krummrich

rust: device: make Core and CoreInternal lifetime-parameterized

2026-05-27T14:22:42+00:00

Device references in probe callbacks are scoped to the callback, not the full binding duration. Add a lifetime parameter to Core and CoreInternal to accurately represent this in the type system. Suggested-by: Gary Guo Reviewed-by: Greg Kroah-Hartman Reviewed-by: Alexandre Courbot Reviewed-by: Eliot Courtney Reviewed-by: Gary Guo Link: https://patch.msgid.link/20260525202921.124698-12-dakr@kernel.org Signed-off-by: Danilo Krummrich

rust: driver: decouple driver private data from driver type

2026-05-27T14:22:41+00:00

Add a type Data<'bound> associated type to all bus driver traits, decoupling the driver's bus device private data type from the driver struct itself. In the context of adding a 'bound lifetime, making this an associated type has the advantage that it allows us to avoid a driver trait global lifetime and it avoids the need for ForLt for bus device private data; both of which make the subsequent implementation by buses much simpler. All existing drivers and doc examples set type Data = Self to preserve the current behavior. Reviewed-by: Alexandre Courbot Reviewed-by: Gary Guo Reviewed-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20260525202921.124698-5-dakr@kernel.org Signed-off-by: Danilo Krummrich

rust: dma: add zeroed constructor to `Coherent`

2026-03-23T21:33:23+00:00

These constructors create a coherent container of a single object instead of slice. They are named `zeroed` and `zeroed_with_attrs` to emphasis that they are created initialized zeroed. It is intended that there'll be new constructors that take `PinInit` instead of zeroing. Signed-off-by: Gary Guo Reviewed-by: Alice Ryhl Reviewed-by: Alexandre Courbot Link: https://patch.msgid.link/20260320194626.36263-4-dakr@kernel.org [ Use kernel import style. - Danilo ] Signed-off-by: Danilo Krummrich

rust: dma: use pointer projection infra for `dma_{read,write}` macro

2026-03-07T22:06:20+00:00

Current `dma_read!`, `dma_write!` macros also use a custom `addr_of!()`-based implementation for projecting pointers, which has soundness issue as it relies on absence of `Deref` implementation on types. It also has a soundness issue where it does not protect against unaligned fields (when `#[repr(packed)]` is used) so it can generate misaligned accesses. This commit migrates them to use the general pointer projection infrastructure, which handles these cases correctly. As part of migration, the macro is updated to have an improved surface syntax. The current macro have dma_read!(a.b.c[d].e.f) to mean `a.b.c` is a DMA coherent allocation and it should project into it with `[d].e.f` and do a read, which is confusing as it makes the indexing operator integral to the macro (so it will break if you have an array of `CoherentAllocation`, for example). This also is problematic as we would like to generalize `CoherentAllocation` from just slices to arbitrary types. Make the macro expects `dma_read!(path.to.dma, .path.inside.dma)` as the canonical syntax. The index operator is no longer special and is just one type of projection (in additional to field projection). Similarly, make `dma_write!(path.to.dma, .path.inside.dma, value)` become the canonical syntax for writing. Another issue of the current macro is that it is always fallible. This makes sense with existing design of `CoherentAllocation`, but once we support fixed size arrays with `CoherentAllocation`, it is desirable to have the ability to perform infallible indexing as well, e.g. doing a `[0]` index of `[Foo; 2]` is okay and can be checked at build-time, so forcing falliblity is non-ideal. To capture this, the macro is changed to use `[idx]` as infallible projection and `[idx]?` as fallible index projection (those syntax are part of the general projection infra). A benefit of this is that while individual indexing operation may fail, the overall read/write operation is not fallible. Fixes: ad2907b4e308 ("rust: add dma coherent allocator abstraction") Reviewed-by: Benno Lossin Signed-off-by: Gary Guo Link: https://patch.msgid.link/20260302164239.284084-4-gary@kernel.org [ Capitalize safety comments; slightly improve wording in doc-comments. - Danilo ] Signed-off-by: Danilo Krummrich

rust: samples: dma: remove redundant `.as_ref()` for `dev_*` print

2026-01-24T11:30:10+00:00

This is now handled by the macro itself. Signed-off-by: Gary Guo Link: https://patch.msgid.link/20260123175854.176735-4-gary@kernel.org [ Fix up code formatting. - Danilo ] Signed-off-by: Danilo Krummrich