[Tracking/Asahi] Rust DRM abstractions #969
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The rust_fmt_argument function is called from printk() to handle the %pA format specifier. Since it's called from C, we should mark it extern "C" to make sure it's ABI compatible. Cc: [email protected] Fixes: 247b365 ("rust: add `kernel` crate") Signed-off-by: David Gow <[email protected]> Link: Rust-for-Linux#967 Reviewed-by: Björn Roy Baron <[email protected]> Reviewed-by: Gary Guo <[email protected]> [Applied `rustfmt`] Signed-off-by: Miguel Ojeda <[email protected]>
This allows downstream consumers to keep track of private data for shmem mappings. In particular, the Rust abstraction will use this to safely drop data associated with a mapping when it is unmapped. Signed-off-by: Asahi Lina <[email protected]> Reviewed-by: Sven Peter <[email protected]> Reviewed-by: Eric Curtin <[email protected]> Signed-off-by: Hector Martin <[email protected]>
While we normally encourage devm usage by drivers, some consumers (and in particular the upcoming Rust abstractions) might want to manually manage memory. Export the raw functions to make this possible. Signed-off-by: Asahi Lina <[email protected]> Reviewed-by: Sven Peter <[email protected]> Reviewed-by: Eric Curtin <[email protected]> Signed-off-by: Hector Martin <[email protected]>
Other functions touching shmem->sgt take the pages lock, so do that here too. drm_gem_shmem_get_pages() & co take the same lock, so move to the _locked() variants to avoid recursive locking. Signed-off-by: Asahi Lina <[email protected]>
This commit provides the build flags for Rust for AArch64. The core Rust support already in the kernel does the rest. The Rust samples have been tested with this commit. [jcunliffe: Arm specific parts taken from Miguel's upstream tree] Signed-off-by: Miguel Ojeda <[email protected]> Co-developed-by: Jamie Cunliffe <[email protected]> Signed-off-by: Jamie Cunliffe <[email protected]> Reviewed-by: Vincenzo Palazzo <[email protected]> Signed-off-by: Vincenzo Palazzo <[email protected]> Reviewed-by: Gary Guo <[email protected]>
Enable the PAC ret and BTI options in the Rust build flags to match the options that are used when building C. Signed-off-by: Jamie Cunliffe <[email protected]> Reviewed-by: Vincenzo Palazzo <[email protected]>
Disable the neon and fp target features to avoid fp & simd registers. The use of fp-armv8 will cause a warning from rustc about an unknown feature that is specified. The target feature is still passed through to LLVM, this behaviour is documented as part of the warning. This will be fixed in a future version of the rustc toolchain. Signed-off-by: Jamie Cunliffe <[email protected]> Reviewed-by: Vincenzo Palazzo <[email protected]>
This allows printing the inner data of `Arc` and its friends if the inner data implements `Display` or `Debug`. It's useful for logging and debugging purpose. Signed-off-by: Boqun Feng <[email protected]> Reviwed-by: Vincenzo Palazzo <[email protected]> Reviewed-by: Gary Guo <[email protected]> Reviewed-by: Vincenzo Palazzo <[email protected]> Reviewed-by: Andreas Hindborg <[email protected]> Reviewed-by: Björn Roy Baron <[email protected]>
This both demonstrates the usage of different print format in Rust and serves as a selftest for the `Display` and `Debug` implementation of `Arc` and its friends. Signed-off-by: Boqun Feng <[email protected]> Reviewed-by: Björn Roy Baron <[email protected]> Reviewed-by: Finn Behrens <[email protected]> Reviewed-by: Vincenzo Palazzo <[email protected]> Reviewed-by: Gary Guo <[email protected]> Reviewed-by: Andreas Hindborg <[email protected]>
This module is intended to contain functions related to kernel timekeeping and time. Initially, this just wraps ktime_get() and ktime_get_boottime() and returns them as core::time::Duration instances. Signed-off-by: Asahi Lina <[email protected]>
This makes it mirror the way expect_ident() works, and means we can more easily push the result back into the token stream. Signed-off-by: Asahi Lina <[email protected]>
This makes things like concat_idents!(bindings::foo, bar) work. Otherwise, there is no way to concatenate two idents and then use the result as part of a type path. Signed-off-by: Asahi Lina <[email protected]>
Modules can (and usually do) have multiple alias tags, in order to specify multiple possible device matches for autoloading. Allow this by changing the alias ModuleInfo field to an Option<Vec<String>>. Note: For normal device IDs this is autogenerated by modpost (which is not properly integrated with Rust support yet), so it is useful to be able to manually add device match aliases for now, and should still be useful in the future for corner cases that modpost does not handle. This pulls in the expect_group() helper from the rfl/rust branch (with credit to authors). Co-developed-by: Miguel Ojeda <[email protected]> Co-developed-by: Finn Behrens <[email protected]> Co-developed-by: Sumera Priyadarsini <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
Add simple 1:1 wrappers of the C ioctl number manipulation functions. Since these are macros we cannot bindgen them directly, and since they should be usable in const context we cannot use helper wrappers, so we'll have to reimplement them in Rust. Thankfully, the C headers do declare defines for the relevant bitfield positions, so we don't need to duplicate that. Signed-off-by: Asahi Lina <[email protected]>
This mirrors the standard library's alloc::sync::Arc::downcast().
Based on the Rust standard library implementation, ver 1.62.0,
licensed under "Apache-2.0 OR MIT", from:
https://github.com/rust-lang/rust/tree/1.62.0/library/alloc/src
For copyright details, please see:
https://github.com/rust-lang/rust/blob/1.62.0/COPYRIGHT
Signed-off-by: Asahi Lina <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
This is the Rust equivalent to ERR_PTR(), for use in C callbacks. Marked as #[allow(dead_code)] for now, since it does not have any consumers yet. Signed-off-by: Asahi Lina <[email protected]>
Add a function to create `Error` values out of a kernel error return, which safely upholds the invariant that the error code is well-formed (negative and greater than -MAX_ERRNO). If a malformed code is passed in, it will be converted to EINVAL. Imported from rust-for-linux/rust as authored by Miguel and Fox with refactoring from Wedson. Co-developed-by: Miguel Ojeda <[email protected]> Co-developed-by: Fox Chen <[email protected]> Co-developed-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Miguel Ojeda <[email protected]> Signed-off-by: Fox Chen <[email protected]> Signed-off-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
Add a to_result() helper to convert kernel C return values to a Rust Result, mapping >=0 values to Ok(()) and negative values to Err(...), with Error::from_kernel_errno() ensuring that the errno is within range. Imported from rust-for-linux/rust, originally developed by Wedson as part of the AMBA device driver support. Co-developed-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
Some kernel C API functions return a pointer which embeds an optional `errno`. Callers are supposed to check the returned pointer with `IS_ERR()` and if this returns `true`, retrieve the `errno` using `PTR_ERR()`. Create a Rust helper function to implement the Rust equivalent: transform a `*mut T` to `Result<*mut T>`. Lina: Imported from rust-for-linux/linux, with subsequent refactoring and contributions squashed in and attributed below. Replaced usage of from_kernel_errno_unchecked() with an open-coded constructor, since this is the only user anyway. Co-developed-by: Boqun Feng <[email protected]> Signed-off-by: Boqun Feng <[email protected]> Co-developed-by: Miguel Ojeda <[email protected]> Signed-off-by: Miguel Ojeda <[email protected]> Co-developed-by: Fox Chen <[email protected]> Signed-off-by: Fox Chen <[email protected]> Co-developed-by: Gary Guo <[email protected]> Signed-off-by: Gary Guo <[email protected]> Signed-off-by: Sven Van Asbroeck <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
Add a helper macro to easily return C result codes from a Rust function that calls functions which return a Result<T>. Imported from rust-for-linux/rust, originally developed by Wedson as part of file_operations.rs. Co-developed-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Wedson Almeida Filho <[email protected]> Co-developed-by: Fox Chen <[email protected]> Signed-off-by: Fox Chen <[email protected]> Co-developed-by: Miguel Ojeda <[email protected]> Signed-off-by: Miguel Ojeda <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
This is a subset of the Rust standard library `alloc` crate,
version 1.66.0, licensed under "Apache-2.0 OR MIT", from:
https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src
The file is copied as-is, with no modifications whatsoever
(not even adding the SPDX identifiers).
For copyright details, please see:
https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT
Signed-off-by: Asahi Lina <[email protected]>
This is a subset of the Rust standard library `alloc` crate,
version 1.66.0, licensed under "Apache-2.0 OR MIT", from:
https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src
The file is copied as-is, with no modifications whatsoever
(not even adding the SPDX identifiers).
For copyright details, please see:
https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT
Signed-off-by: Asahi Lina <[email protected]>
Add some missing fallible methods that we need.
They are all marked as:
#[stable(feature = "kernel", since = "1.0.0")]
for easy identification.
Lina: Extracted from 487d757 ("rust: alloc: add some `try_*`
methods we need") in rust-for-linux/rust.
Signed-off-by: Miguel Ojeda <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
The XArray is an abstract data type which behaves like a very large array of pointers. Add a Rust abstraction for this data type. The initial implementation uses explicit locking on get operations and returns a guard which blocks mutation, ensuring that the referenced object remains alive. To avoid excessive serialization, users are expected to use an inner type that can be efficiently cloned (such as Arc<T>), and eagerly clone and drop the guard to unblock other users after a lookup. Future variants may support using RCU instead to avoid mutex locking. This abstraction also introduces a reservation mechanism, which can be used by alloc-capable XArrays to reserve a free slot without immediately filling it, and then do so at a later time. If the reservation is dropped without being filled, the slot is freed again for other users, which eliminates the need for explicit cleanup code. Signed-off-by: Asahi Lina <[email protected]>
Some traits exposed by the kernel crate may not be intended to be implemented by downstream modules. Add a Sealed trait to allow avoiding this using the sealed trait pattern. Signed-off-by: Asahi Lina <[email protected]>
Add a RawDevice trait which can be implemented by any type representing a device class (such as a PlatformDevice), and a Device type which represents an owned reference to a generic struct device. Lina: Rewrote commit message, dropped the Amba bits, and squashed in simple changes to the core RawDevice/Device code from latter commits in rust-for-linux/rust. Also include the rust_helper_dev_get_drvdata helper which will be needed by consumers later on. Co-developed-by: Miguel Ojeda <[email protected]> Signed-off-by: Miguel Ojeda <[email protected]> Signed-off-by: Wedson Almeida Filho <[email protected]> Signed-off-by: Asahi Lina <[email protected]>
The io_pgtable subsystem implements page table management for various IOMMU page table formats. This abstraction allows Rust drivers for devices with an embedded MMU to use this shared code. Signed-off-by: Asahi Lina <[email protected]>
RTKit is Apple's proprietary real-time operating system framework, used across many subdevices on Apple Silicon platforms including NVMe, system management, GPU, etc. Add Rust abstractions for this subsystem, so that it can be used by upcoming Rust drivers. Note: Although ARM64 support is not yet merged, this can be built on amd64 with CONFIG_COMPILE_TEST=y. Signed-off-by: Asahi Lina <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
Commit reference: 3dfc5eb
Commit reference: 3dfc5eb
Commit reference: 3dfc5eb
Apple Silicon SoCs (M1, M2, etc.) have a GPU with an ARM64 firmware coprocessor. The firmware and the GPU share page tables in the standard ARM64 format (the firmware literally sets the base as its TTBR0/1 registers). TTBR0 covers the low half of the address space and is intended to be per-GPU-VM (GPU user mappings and kernel-managed buffers), while TTBR1 covers the upper half and is global (firmware code, data, management structures shared with the AP, and a few GPU-accessible data structures). In typical Apple fashion, the permissions are interpreted differently from traditional ARM PTEs. By default, firmware mappings use Apple SPRR permission remapping. The firmware only uses that for its own code/data/MMIO mappings, and those pages are not accessible by the GPU hardware. We never need to touch/manage these mappings, so this patch does not support them. When a specific bit is set in the PTEs, permissions switch to a different scheme which supports various combinations of firmware/GPU access. This is the mode intended to be used by AP GPU drivers, and what we implement here. The prot bits are interpreted as follows: - IOMMU_READ and IOMMU_WRITE have the usual meaning. - IOMMU_PRIV creates firmware-only mappings (no GPU access) - IOMMU_NOEXEC creates GPU-only structures (no FW access) - Otherwise structures are accessible by both GPU and FW - IOMMU_MMIO creates Device mappings for firmware - IOMMU_CACHE creates Normal-NC mappings for firmware (cache-coherent from the point of view of the AP, but slower) - Otherwise creates Normal mappings for firmware (this requires manual cache management on the firmware side, as it is not coherent with the SoC fabric) GPU-only mappings (textures/etc) are expected to use IOMMU_CACHE and are seemingly coherent with the CPU (or otherwise the firmware/GPU already issue the required cache management operations when correctly configured). There is a GPU-RO/FW-RW mode, but it is not currently implemented (it doesn't seem to be very useful for the driver). There seems to be no real noexec control (i.e. for shaders) on the GPU side. All of these mappings are implicitly noexec for the firmware. Drivers are expected to fully manage per-user (TTBR0) page tables, but ownership of shared kernel (TTBR1) page tables is shared between the firmware and the AP OS. We handle this by simply using a smaller IAS to drop down one level of page tables, so the driver can install a PTE in the top-level (firmware-initialized) page table directly and just add an offset to the VAs passed into the io_pgtable code. This avoids having to have any special handling for this here. The firmware-relevant data structures are small, so we do not expect to ever require more VA space than one top-level PTE covers (IAS=36 for the next level, 64 GiB). Only 16K page mode is supported. The coprocessor MMU supports huge pages as usual for ARM64, but the GPU MMU does not, so we do not enable them. Signed-off-by: Asahi Lina <[email protected]>
Signed-off-by: Asahi Lina <[email protected]>
DRM drivers need to be able to declare which driver-specific ioctls they support. This abstraction adds the required types and a helper macro to generate the ioctl definition inside the DRM driver. Note that this macro is not usable until further bits of the abstraction are in place (but it will not fail to compile on its own, if not called). Signed-off-by: Asahi Lina <[email protected]>
Add the initial abstractions for DRM drivers and devices. These go together in one commit since they are fairly tightly coupled types. A few things have been stubbed out, to be implemented as further bits of the DRM subsystem are introduced. Signed-off-by: Asahi Lina <[email protected]>
A DRM File is the DRM counterpart to a kernel file structure, representing an open DRM file descriptor. Add a Rust abstraction to allow drivers to implement their own File types that implement the DriverFile trait. Signed-off-by: Asahi Lina <[email protected]>
The DRM GEM subsystem is the DRM memory management subsystem used by most modern drivers. Add a Rust abstraction to allow Rust DRM driver implementations to use it. Signed-off-by: Asahi Lina <[email protected]>
There doesn't seem to be a way for the Rust bindings to get a compile-time constant reference to drm_gem_shmem_vm_ops, so we need to duplicate that structure in Rust... this isn't nice... Signed-off-by: Asahi Lina <[email protected]>
The DRM shmem helper includes common code useful for drivers which allocate GEM objects as anonymous shmem. Add a Rust abstraction for this. Drivers can choose the raw GEM implementation or the shmem layer, depending on their needs. Signed-off-by: Asahi Lina <[email protected]>
drm_mm provides a simple range allocator, useful for managing virtual address ranges. Add a Rust abstraction to expose this module to Rust drivers. Signed-off-by: Asahi Lina <[email protected]>
DMA fences are the internal synchronization primitive used for DMA operations like GPU rendering, video en/decoding, etc. Add an abstraction to allow Rust drivers to interact with this subsystem. Note: This uses a raw spinlock living next to the fence, since we do not interact with it other than for initialization. TODO: Expose this to the user at some point with a safe abstraction. Signed-off-by: Asahi Lina <[email protected]>
DRM Sync Objects are a container for a DMA fence, and can be waited on signaled, exported, and imported from userspace. Add a Rust abstraction so Rust DRM drivers can support this functionality. Signed-off-by: Asahi Lina <[email protected]>
Some hardware may require more complex resource utilization accounting than the simple job count supported by drm_sched internally. Add a can_run_job callback to allow drivers to implement more logic before deciding whether to run a GPU job. Signed-off-by: Asahi Lina <[email protected]>
The GPU scheduler manages scheduling GPU jobs and dependencies between them. This Rust abstraction allows Rust DRM drivers to use this functionality. Signed-off-by: Asahi Lina <[email protected]>
Drivers may want to support driver-private objects, which cannot be shared. This allows them to share a single lock and enables other optimizations. Add an `exportable` field to drm_gem_object, which blocks PRIME export if set to false. It is initialized to true in drm_gem_private_object_init. Signed-off-by: Asahi Lina <[email protected]>
This allows drivers to control whether a given GEM object is allowed to be exported via PRIME to other drivers.
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I don't mean to sound rude and I'm certainly not an expert, but shouldn't the conflicts be dealt with as well? |
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The development of the Linux kernel happens on the LKML (Linux Kernel Mailing List). There a patch based approach is used that are based on a common ancestor (often an Maintainers will fix conflicts for patches that have been fully reviewed and will put them into their respective So having conflicts in GH does not really mean anything. |
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Also, please see https://rust-for-linux.com/contributing and https://rust-for-linux.com/branches. |
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These are the Rust DRM abstractions (and some related changes to the C side) which I use in the Asahi GPU driver. This branch is based on
AsahiLinux:gpu/rust-for-later, which is #964.The Asahi GPU driver compiles successfully on top of this branch.