Commit graph

19 commits

Author SHA1 Message Date
Dave Airlie
6f17ab9a63 DRM Rust changes for v6.18
Alloc
   - Add BorrowedPage type and AsPageIter trait
   - Implement Vmalloc::to_page() and VmallocPageIter
   - Implement AsPageIter for VBox and VVec
 
 DMA & Scatterlist
   - Add dma::DataDirection and type alias for dma_addr_t
   - Abstraction for struct scatterlist and struct sg_table
 
 DRM
   - In the DRM GEM module, simplify overall use of generics, add
     DriverFile type alias and drop Object::SIZE.
 
 Nova (Core)
   - Various register!() macro improvements (paving the way for lifting
     it to common driver infrastructure)
   - Minor VBios fixes and refactoring
   - Minor firmware request refactoring
   - Advance firmware boot stages; process Booter and patch its
     signature, process GSP and GSP bootloader
   - Switch development fimrware version to r570.144
   - Add basic firmware bindings for r570.144
   - Move GSP boot code to its own module
   - Clean up and take advantage of pin-init features to store most of
     the driver's private data within a single allocation
   - Update ARef import from sync::aref
   - Add website to MAINTAINERS entry
 
 Nova (DRM)
   - Update ARef import from sync::aref
   - Add website to MAINTAINERS entry
 
 Pin-Init
   - Merge pin-init PR from Benno
     - `#[pin_data]` now generates a `*Projection` struct similar to the
       `pin-project` crate.
 
     - Add initializer code blocks to `[try_][pin_]init!` macros: make
       initializer macros accept any number of `_: {/* arbitrary code
       */},` & make them run the code at that point.
 
     - Make the `[try_][pin_]init!` macros expose initialized fields via
       a `let` binding as `&mut T` or `Pin<&mut T>` for later fields.
 
 Rust
   - Various methods for AsBytes and FromBytes traits
 
 Tyr
   - Initial Rust driver skeleton for ARM Mali GPUs.
     - It can power up the GPU, query for GPU metatdata through MMIO and
       provide the metadata to userspace via DRM device IOCTL (struct
       drm_panthor_dev_query).
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Merge tag 'drm-rust-next-2025-09-16' of https://gitlab.freedesktop.org/drm/rust/kernel into drm-next

DRM Rust changes for v6.18

Alloc
  - Add BorrowedPage type and AsPageIter trait
  - Implement Vmalloc::to_page() and VmallocPageIter
  - Implement AsPageIter for VBox and VVec

DMA & Scatterlist
  - Add dma::DataDirection and type alias for dma_addr_t
  - Abstraction for struct scatterlist and struct sg_table

DRM
  - In the DRM GEM module, simplify overall use of generics, add
    DriverFile type alias and drop Object::SIZE.

Nova (Core)
  - Various register!() macro improvements (paving the way for lifting
    it to common driver infrastructure)
  - Minor VBios fixes and refactoring
  - Minor firmware request refactoring
  - Advance firmware boot stages; process Booter and patch its
    signature, process GSP and GSP bootloader
  - Switch development fimrware version to r570.144
  - Add basic firmware bindings for r570.144
  - Move GSP boot code to its own module
  - Clean up and take advantage of pin-init features to store most of
    the driver's private data within a single allocation
  - Update ARef import from sync::aref
  - Add website to MAINTAINERS entry

Nova (DRM)
  - Update ARef import from sync::aref
  - Add website to MAINTAINERS entry

Pin-Init
  - Merge pin-init PR from Benno
    - `#[pin_data]` now generates a `*Projection` struct similar to the
      `pin-project` crate.

    - Add initializer code blocks to `[try_][pin_]init!` macros: make
      initializer macros accept any number of `_: {/* arbitrary code
      */},` & make them run the code at that point.

    - Make the `[try_][pin_]init!` macros expose initialized fields via
      a `let` binding as `&mut T` or `Pin<&mut T>` for later fields.

Rust
  - Various methods for AsBytes and FromBytes traits

Tyr
  - Initial Rust driver skeleton for ARM Mali GPUs.
    - It can power up the GPU, query for GPU metatdata through MMIO and
      provide the metadata to userspace via DRM device IOCTL (struct
      drm_panthor_dev_query).

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: "Danilo Krummrich" <dakr@kernel.org>
Link: https://lore.kernel.org/r/DCUC4SY6SRBD.1ZLHAIQZOC6KG@kernel.org
2025-09-17 16:13:49 +10:00
Danilo Krummrich
7937dca770 rust: alloc: implement VmallocPageIter
Introduce the VmallocPageIter type; an instance of VmallocPageIter may
be exposed by owners of vmalloc allocations to provide borrowed access
to its backing pages.

For instance, this is useful to access and borrow the backing pages of
allocation primitives, such as Box and Vec, backing a scatterlist.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250820145434.94745-4-dakr@kernel.org
[ Drop VmallocPageIter::base_address(), move to allocator/iter.rs and
  stub VmallocPageIter for allocator_test.rs. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-09-04 23:33:27 +02:00
Danilo Krummrich
8e92c9902f rust: alloc: vmalloc: implement Vmalloc::to_page()
Implement an abstraction of vmalloc_to_page() for subsequent use in the
AsPageIter implementation of VBox and VVec.

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://lore.kernel.org/r/20250820145434.94745-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-09-04 18:21:09 +02:00
Danilo Krummrich
fde578c862 rust: alloc: replace aligned_size() with Kmalloc::aligned_layout()
aligned_size() dates back to when Rust did support kmalloc() only, but
is now used in ReallocFunc::call() and hence for all allocators.

However, the additional padding applied by aligned_size() is only
required by the kmalloc() allocator backend.

Hence, replace aligned_size() with Kmalloc::aligned_layout() and use it
for the affected allocators, i.e. kmalloc() and kvmalloc(), only.

While at it, make Kmalloc::aligned_layout() public, such that Rust
abstractions, which have to call subsystem specific kmalloc() based
allocation primitives directly, can make use of it.

Fixes: 8a799831fc ("rust: alloc: implement `ReallocFunc`")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250731154919.4132-2-dakr@kernel.org
[ Remove `const` from Kmalloc::aligned_layout(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-08-11 23:20:53 +02:00
Gary Guo
41b6a8122d rust: alloc: make ReallocFunc::call inline
This function can be called with different function pointers when
different allocator (e.g. Kmalloc, Vmalloc, KVmalloc), however since
this function is not polymorphic, only one instance is generated,
and function pointers are used. Given that this function is called
for any Rust-side allocation/deallocation, performance matters a lot,
so making this function inlineable.

This is discovered when doing helper inlining work, since it's discovered
that even with helpers inlined, rust_helper_ symbols are still present
in final vmlinux binary, and it turns out this function is inhibiting
the inlining, and introducing indirect function calls.

Signed-off-by: Gary Guo <gary@garyguo.net>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250105194054.545201-4-gary@garyguo.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-03-06 20:49:06 +01:00
Gary Guo
d072acda48 rust: use custom FFI integer types
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>
2024-11-10 23:58:00 +01:00
Danilo Krummrich
392e34b6bc kbuild: rust: remove the alloc crate and GlobalAlloc
Now that we have our own `Allocator`, `Box` and `Vec` types we can remove
Rust's `alloc` crate and the `new_uninit` unstable feature.

Also remove `Kmalloc`'s `GlobalAlloc` implementation -- we can't remove
this in a separate patch, since the `alloc` crate requires a
`#[global_allocator]` to set, that implements `GlobalAlloc`.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-29-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15 23:10:32 +02:00
Danilo Krummrich
8362c2608b rust: alloc: implement KVmalloc allocator
Implement `Allocator` for `KVmalloc`, an `Allocator` that tries to
allocate memory with `kmalloc` first and, on failure, falls back to
`vmalloc`.

All memory allocations made with `KVmalloc` end up in
`kvrealloc_noprof()`; all frees in `kvfree()`.

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/20241004154149.93856-10-dakr@kernel.org
[ Reworded typo. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15 22:56:59 +02:00
Danilo Krummrich
61c004781d rust: alloc: implement Vmalloc allocator
Implement `Allocator` for `Vmalloc`, the kernel's virtually contiguous
allocator, typically used for larger objects, (much) larger than page
size.

All memory allocations made with `Vmalloc` end up in `vrealloc()`.

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/20241004154149.93856-9-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15 22:56:59 +02:00
Danilo Krummrich
a34822d1c4 rust: alloc: implement Allocator for Kmalloc
Implement `Allocator` for `Kmalloc`, the kernel's default allocator,
typically used for objects smaller than page size.

All memory allocations made with `Kmalloc` end up in `krealloc()`.

It serves as allocator for the subsequently introduced types `KBox` and
`KVec`.

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/20241004154149.93856-7-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15 22:56:59 +02:00
Danilo Krummrich
8a799831fc rust: alloc: implement ReallocFunc
`ReallocFunc` is an abstraction for the kernel's realloc derivates, such
as `krealloc`, `vrealloc` and `kvrealloc`.

All of the named functions share the same function signature and
implement the same semantics. The `ReallocFunc` abstractions provides a
generalized wrapper around those, to trivialize the implementation of
`Kmalloc`, `Vmalloc` and `KVmalloc` in subsequent patches.

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/20241004154149.93856-5-dakr@kernel.org
[ Added temporary `allow(dead_code)` for `dangling_from_layout` to clean
  warning in `rusttest` target as discussed in the list (but it is
  needed earlier, i.e. in this patch already). Added colon. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15 22:56:27 +02:00
Danilo Krummrich
941e655314 rust: alloc: rename KernelAllocator to Kmalloc
Subsequent patches implement `Vmalloc` and `KVmalloc` allocators, hence
align `KernelAllocator` to this naming scheme.

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/20241004154149.93856-4-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14 17:55:40 +02:00
Danilo Krummrich
a654a6e096 rust: alloc: separate aligned_size from krealloc_aligned
Separate `aligned_size` from `krealloc_aligned`.

Subsequent patches implement `Allocator` derivates, such as `Kmalloc`,
that require `aligned_size` and replace the original `krealloc_aligned`.

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/20241004154149.93856-3-dakr@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14 17:55:40 +02:00
Miguel Ojeda
db4f72c904 rust: enable clippy::undocumented_unsafe_blocks lint
Checking that we are not missing any `// SAFETY` comments in our `unsafe`
blocks is something we have wanted to do for a long time, as well as
cleaning up the remaining cases that were not documented [1].

Back when Rust for Linux started, this was something that could have
been done via a script, like Rust's `tidy`. Soon after, in Rust 1.58.0,
Clippy implemented the `undocumented_unsafe_blocks` lint [2].

Even though the lint has a few false positives, e.g. in some cases where
attributes appear between the comment and the `unsafe` block [3], there
are workarounds and the lint seems quite usable already.

Thus enable the lint now.

We still have a few cases to clean up, so just allow those for the moment
by writing a `TODO` comment -- some of those may be good candidates for
new contributors.

Link: https://github.com/Rust-for-Linux/linux/issues/351 [1]
Link: https://rust-lang.github.io/rust-clippy/master/#/undocumented_unsafe_blocks [2]
Link: https://github.com/rust-lang/rust-clippy/issues/13189 [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/20240904204347.168520-5-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07 21:39:05 +02:00
Vlastimil Babka
ad59baa316 slab, rust: extend kmalloc() alignment guarantees to remove Rust padding
Slab allocators have been guaranteeing natural alignment for
power-of-two sizes since commit 59bb47985c ("mm, sl[aou]b: guarantee
natural alignment for kmalloc(power-of-two)"), while any other sizes are
guaranteed to be aligned only to ARCH_KMALLOC_MINALIGN bytes (although
in practice are aligned more than that in non-debug scenarios).

Rust's allocator API specifies size and alignment per allocation, which
have to satisfy the following rules, per Alice Ryhl [1]:

  1. The alignment is a power of two.
  2. The size is non-zero.
  3. When you round up the size to the next multiple of the alignment,
     then it must not overflow the signed type isize / ssize_t.

In order to map this to kmalloc()'s guarantees, some requested
allocation sizes have to be padded to the next power-of-two size [2].
For example, an allocation of size 96 and alignment of 32 will be padded
to an allocation of size 128, because the existing kmalloc-96 bucket
doesn't guarantee alignent above ARCH_KMALLOC_MINALIGN. Without slab
debugging active, the layout of the kmalloc-96 slabs however naturally
align the objects to 32 bytes, so extending the size to 128 bytes is
wasteful.

To improve the situation we can extend the kmalloc() alignment
guarantees in a way that

1) doesn't change the current slab layout (and thus does not increase
   internal fragmentation) when slab debugging is not active
2) reduces waste in the Rust allocator use case
3) is a superset of the current guarantee for power-of-two sizes.

The extended guarantee is that alignment is at least the largest
power-of-two divisor of the requested size. For power-of-two sizes the
largest divisor is the size itself, but let's keep this case documented
separately for clarity.

For current kmalloc size buckets, it means kmalloc-96 will guarantee
alignment of 32 bytes and kmalloc-196 will guarantee 64 bytes.

This covers the rules 1 and 2 above of Rust's API as long as the size is
a multiple of the alignment. The Rust layer should now only need to
round up the size to the next multiple if it isn't, while enforcing the
rule 3.

Implementation-wise, this changes the alignment calculation in
create_boot_cache(). While at it also do the calulation only for caches
with the SLAB_KMALLOC flag, because the function is also used to create
the initial kmem_cache and kmem_cache_node caches, where no alignment
guarantee is necessary.

In the Rust allocator's krealloc_aligned(), remove the code that padded
sizes to the next power of two (suggested by Alice Ryhl) as it's no
longer necessary with the new guarantees.

Reported-by: Alice Ryhl <aliceryhl@google.com>
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/all/CAH5fLggjrbdUuT-H-5vbQfMazjRDpp2%2Bk3%3DYhPyS17ezEqxwcw@mail.gmail.com/ [1]
Link: https://lore.kernel.org/all/CAH5fLghsZRemYUwVvhk77o6y1foqnCeDzW4WZv6ScEWna2+_jw@mail.gmail.com/ [2]
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2024-07-03 12:23:27 +02:00
Miguel Ojeda
00280272a0 rust: kernel: remove redundant imports
Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:

    error: the item `bindings` is imported redundantly
      --> rust/kernel/print.rs:38:9
       |
    38 |     use crate::bindings;
       |         ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude

Most cases are `use crate::bindings`, plus a few other items like `Box`.
Thus clean them up.

Note that, in the `bindings` case, the message "defined by prelude"
above means the extern prelude, i.e. the `--extern` flags we pass.

Link: https://github.com/rust-lang/rust/pull/117772 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-05-05 19:22:25 +02:00
Wedson Almeida Filho
08d3f54928 rust: alloc: introduce the BoxExt trait
Make fallible versions of `new` and `new_uninit` methods available in
`Box` even though it doesn't implement them because we build `alloc`
with the `no_global_oom_handling` config.

They also have an extra `flags` parameter that allows callers to pass
flags to the allocator.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240328013603.206764-7-wedsonaf@gmail.com
[ Used `Box::write()` to avoid one `unsafe` block as suggested by Boqun. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-16 22:47:20 +02:00
Wedson Almeida Filho
b6a006e21b rust: alloc: introduce allocation flags
We'll use them when allocating `Box`, `Arc`, and `UniqueArc` instances,
as well as when allocating memory for `Vec` elements. These changes will
come in subsequent patches.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-6-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-16 22:05:06 +02:00
Wedson Almeida Filho
31d94d8f58 rust: kernel: move allocator module under alloc
We will add more to the `alloc` module in subsequent patches (e.g.,
allocation flags and extension traits).

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-2-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-16 22:03:14 +02:00
Renamed from rust/kernel/allocator.rs (Browse further)