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>
Make it possible to allocate memory that doesn't need to mapped into the
kernel's address space. This flag is useful together with
Page::alloc_page [1].
Rust Binder needs this for the memory that holds incoming transactions
for each process. Each process will have a few megabytes of memory
allocated with this flag, which is mapped into the process using
vm_insert_page. When the kernel copies data for an incoming transaction
into a process's memory region, it will use kmap_local_page to
temporarily map pages that are being modified. There is no need for them
to take up address space in the kernel when the kernel is not writing an
incoming transaction into the page.
Link: https://lore.kernel.org/all/20240528-alice-mm-v7-4-78222c31b8f4@google.com/ [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240607-highmem-v1-1-d18c5ca4072f@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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>
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>
When compiling for the `rusttest` target, the `core::ptr` import is
unused since its only use happens in the `reserve()` method which is
not compiled in that target:
warning: unused import: `core::ptr`
--> rust/kernel/alloc/vec_ext.rs:7:5
|
7 | use core::ptr;
| ^^^^^^^^^
|
= note: `#[warn(unused_imports)]` on by default
Thus clean it.
Fixes: 97ab3e8eec ("rust: alloc: fix dangling pointer in VecExt<T>::reserve()")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Danilo Krummrich <dakr@redhat.com>
Link: https://lore.kernel.org/r/20240519210735.587323-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull timers and timekeeping updates from Thomas Gleixner:
"Core code:
- Make timekeeping and VDSO time readouts resilent against math
overflow:
In guest context the kernel is prone to math overflow when the host
defers the timer interrupt due to overload, malfunction or malice.
This can be mitigated by checking the clocksource delta for the
maximum deferrement which is readily available. If that value is
exceeded then the code uses a slowpath function which can handle
the multiplication overflow.
This functionality is enabled unconditionally in the kernel, but
made conditional in the VDSO code. The latter is conditional
because it allows architectures to optimize the check so it is not
causing performance regressions.
On X86 this is achieved by reworking the existing check for
negative TSC deltas as a negative delta obviously exceeds the
maximum deferrement when it is evaluated as an unsigned value. That
avoids two conditionals in the hotpath and allows to hide both the
negative delta and the large delta handling in the same slow path.
- Add an initial minimal ktime_t abstraction for Rust
- The usual boring cleanups and enhancements
Drivers:
- Boring updates to device trees and trivial enhancements in various
drivers"
* tag 'timers-core-2024-05-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
clocksource/drivers/arm_arch_timer: Mark hisi_161010101_oem_info const
clocksource/drivers/timer-ti-dm: Remove an unused field in struct dmtimer
clocksource/drivers/renesas-ostm: Avoid reprobe after successful early probe
clocksource/drivers/renesas-ostm: Allow OSTM driver to reprobe for RZ/V2H(P) SoC
dt-bindings: timer: renesas: ostm: Document Renesas RZ/V2H(P) SoC
rust: time: doc: Add missing C header links
clocksource: Make the int help prompt unit readable in ncurses
hrtimer: Rename __hrtimer_hres_active() to hrtimer_hres_active()
timerqueue: Remove never used function timerqueue_node_expires()
rust: time: Add Ktime
vdso: Fix powerpc build U64_MAX undeclared error
clockevents: Convert s[n]printf() to sysfs_emit()
clocksource: Convert s[n]printf() to sysfs_emit()
clocksource: Make watchdog and suspend-timing multiplication overflow safe
timekeeping: Let timekeeping_cycles_to_ns() handle both under and overflow
timekeeping: Make delta calculation overflow safe
timekeeping: Prepare timekeeping_cycles_to_ns() for overflow safety
timekeeping: Fold in timekeeping_delta_to_ns()
timekeeping: Consolidate timekeeping helpers
timekeeping: Refactor timekeeping helpers
...
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 56f64b3706 ("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
...
Currently, a Vec<T>'s ptr value, after calling Vec<T>::new(), is
initialized to Unique::dangling(). Hence, in VecExt<T>::reserve(), we're
passing a dangling pointer (instead of NULL) to krealloc() whenever a new
Vec<T>'s backing storage is allocated through VecExt<T> extension
functions.
This only works as long as align_of::<T>(), used by Unique::dangling() to
derive the dangling pointer, resolves to a value between 0x0 and
ZERO_SIZE_PTR (0x10) and krealloc() hence treats it the same as a NULL
pointer however.
This isn't a case we should rely on, since there may be types whose
alignment may exceed the range still covered by krealloc(), plus other
kernel allocators are not as tolerant either.
Instead, pass a real NULL pointer to krealloc_aligned() if Vec<T>'s
capacity is zero.
Fixes: 5ab560ce12 ("rust: alloc: update `VecExt` to take allocation flags")
Reviewed-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: Danilo Krummrich <dakr@redhat.com>
Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240501134834.22323-1-dakr@redhat.com
[ Solved `use` conflict and applied the `if`-instead-of-`match` change
discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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>
The initializers created by the `[try_][pin_]init!` macros utilize the
guard pattern to drop already initialized fields, when initialization
fails mid-way. These guards are generated to have the same name as the
field that they handle. To prevent namespacing issues [1] when the
field name is the same as e.g. a constant name, add `__` as a prefix
and `_guard` as the suffix.
[ Gary says:
"Here's the simplified example:
```
macro_rules! f {
() => {
let a = 1;
let _: u32 = a;
}
}
const a: u64 = 1;
fn main() {
f!();
}
```
The `a` in `f` have a different hygiene so normally it is scoped to the
macro expansion and wouldn't escape. Interestingly a constant is still
preferred despite the hygiene so constants escaped into the macro,
leading to the error."
- Miguel ]
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/rust-for-linux/1e8a2a1f-abbf-44ba-8344-705a9cbb1627@proton.me/ [1]
Link: https://lore.kernel.org/r/20240403194321.88716-1-benno.lossin@proton.me
[ Added Benno's link and Gary's simplified example. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
To support a potential usage:
static foo: Opaque<Foo> = ..; // Or defined in an extern block.
...
fn bar() {
let ptr = foo.get();
}
`Opaque::get` need to be `const`, otherwise compiler will complain
because calls on statics are limited to const functions.
Also `Opaque::get` should be naturally `const` since it's a composition
of two `const` functions: `UnsafeCell::get` and `ptr::cast`.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240401214543.1242286-1-boqun.feng@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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>
Add support for generic parameters defaults in `#[pin_data]` by using
the newly introduced `decl_generics` instead of the `impl_generics`.
Before this would not compile:
#[pin_data]
struct Foo<const N: usize = 0> {
// ...
}
because it would be expanded to this:
struct Foo<const N: usize = 0> {
// ...
}
const _: () = {
struct __ThePinData<const N: usize = 0> {
__phantom: ::core::marker::PhantomData<fn(Foo<N>) -> Foo<N>>,
}
impl<const N: usize = 0> ::core::clone::Clone for __ThePinData<N> {
fn clone(&self) -> Self {
*self
}
}
// [...] rest of expansion omitted
};
The problem is with the `impl<const N: usize = 0>`, since that is
invalid Rust syntax. It should not mention the default value at all,
since default values only make sense on type definitions.
The new `impl_generics` do not contain the default values, thus
generating correct Rust code.
This is used by the next commit that puts `#[pin_data]` on
`kernel::workqueue::Work`.
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240309155243.482334-2-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust, producing an invalid value of any type is immediate undefined
behavior (UB); this includes via zeroing memory. Therefore, since an
uninhabited type has no valid values, producing any values at all for it is
UB.
The Rust standard library type `core::convert::Infallible` is uninhabited,
by virtue of having been declared as an enum with no cases, which always
produces uninhabited types in Rust.
The current kernel code allows this UB to be triggered, for example by code
like `Box::<core::convert::Infallible>::init(kernel::init::zeroed())`.
Thus, remove the implementation of `Zeroable` for `Infallible`, thereby
avoiding the unsoundness (potential for future UB).
Cc: stable@vger.kernel.org
Fixes: 38cde0bd7b ("rust: init: add `Zeroable` trait and `init::zeroed` function")
Closes: https://github.com/Rust-for-Linux/pinned-init/pull/13
Signed-off-by: Laine Taffin Altman <alexanderaltman@me.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/CA160A4E-561E-4918-837E-3DCEBA74F808@me.com
[ Reformatted the comment slightly. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
This is the next upgrade to the Rust toolchain, from 1.76.0 to 1.77.1
(i.e. the latest) [1].
See the upgrade policy [2] and the comments on the first upgrade in
commit 3ed03f4da0 ("rust: upgrade to Rust 1.68.2").
# Unstable features
The `offset_of` feature (single-field `offset_of!`) that we were using
got stabilized in Rust 1.77.0 [3].
Therefore, now the only unstable features allowed to be used outside the
`kernel` crate is `new_uninit`, though other code to be upstreamed may
increase the list.
Please see [4] for details.
# Required changes
Rust 1.77.0 merged the `unused_tuple_struct_fields` lint into `dead_code`,
thus upgrading it from `allow` to `warn` [5]. In turn, this made `rustc`
complain about the `ThisModule`'s pointer field being never read, but
the previous patch adds the `as_ptr` method to it, needed by Binder [6],
so that we do not need to locally `allow` it.
# Other changes
Rust 1.77.0 introduces the `--check-cfg` feature [7], for which there
is a Call for Testing going on [8]. We were requested to test it and
we found it useful [9] -- we will likely enable it in the future.
# `alloc` upgrade and reviewing
The vast majority of changes are due to our `alloc` fork being upgraded
at once.
There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.
Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.
Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.
To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:
# Get the difference with respect to the old version.
git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
cut -d/ -f3- |
grep -Fv README.md |
xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
git -C linux diff --patch-with-stat --summary -R > old.patch
git -C linux restore rust/alloc
# Apply this patch.
git -C linux am rust-upgrade.patch
# Get the difference with respect to the new version.
git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
cut -d/ -f3- |
grep -Fv README.md |
xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
git -C linux diff --patch-with-stat --summary -R > new.patch
git -C linux restore rust/alloc
Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.
Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1770-2024-03-21 [1]
Link: https://rust-for-linux.com/rust-version-policy [2]
Link: https://github.com/rust-lang/rust/pull/118799 [3]
Link: https://github.com/Rust-for-Linux/linux/issues/2 [4]
Link: https://github.com/rust-lang/rust/pull/118297 [5]
Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-2-08ba9197f637@google.com/#Z31rust:kernel:lib.rs [6]
Link: https://doc.rust-lang.org/nightly/unstable-book/compiler-flags/check-cfg.html [7]
Link: https://github.com/rust-lang/rfcs/pull/3013#issuecomment-1936648479 [8]
Link: https://github.com/rust-lang/rust/issues/82450#issuecomment-1947462977 [9]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240217002717.57507-1-ojeda@kernel.org
[ Upgraded to 1.77.1. Removed `allow(dead_code)` thanks to the previous
patch. Reworded accordingly. No changes to `alloc` during the beta. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Pull networking updates from Jakub Kicinski:
"Core & protocols:
- Large effort by Eric to lower rtnl_lock pressure and remove locks:
- Make commonly used parts of rtnetlink (address, route dumps
etc) lockless, protected by RCU instead of rtnl_lock.
- Add a netns exit callback which already holds rtnl_lock,
allowing netns exit to take rtnl_lock once in the core instead
of once for each driver / callback.
- Remove locks / serialization in the socket diag interface.
- Remove 6 calls to synchronize_rcu() while holding rtnl_lock.
- Remove the dev_base_lock, depend on RCU where necessary.
- Support busy polling on a per-epoll context basis. Poll length and
budget parameters can be set independently of system defaults.
- Introduce struct net_hotdata, to make sure read-mostly global
config variables fit in as few cache lines as possible.
- Add optional per-nexthop statistics to ease monitoring / debug of
ECMP imbalance problems.
- Support TCP_NOTSENT_LOWAT in MPTCP.
- Ensure that IPv6 temporary addresses' preferred lifetimes are long
enough, compared to other configured lifetimes, and at least 2 sec.
- Support forwarding of ICMP Error messages in IPSec, per RFC 4301.
- Add support for the independent control state machine for bonding
per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled
control state machine.
- Add "network ID" to MCTP socket APIs to support hosts with multiple
disjoint MCTP networks.
- Re-use the mono_delivery_time skbuff bit for packets which user
space wants to be sent at a specified time. Maintain the timing
information while traversing veth links, bridge etc.
- Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets.
- Simplify many places iterating over netdevs by using an xarray
instead of a hash table walk (hash table remains in place, for use
on fastpaths).
- Speed up scanning for expired routes by keeping a dedicated list.
- Speed up "generic" XDP by trying harder to avoid large allocations.
- Support attaching arbitrary metadata to netconsole messages.
Things we sprinkled into general kernel code:
- Enforce VM_IOREMAP flag and range in ioremap_page_range and
introduce VM_SPARSE kind and vm_area_[un]map_pages (used by
bpf_arena).
- Rework selftest harness to enable the use of the full range of ksft
exit code (pass, fail, skip, xfail, xpass).
Netfilter:
- Allow userspace to define a table that is exclusively owned by a
daemon (via netlink socket aliveness) without auto-removing this
table when the userspace program exits. Such table gets marked as
orphaned and a restarting management daemon can re-attach/regain
ownership.
- Speed up element insertions to nftables' concatenated-ranges set
type. Compact a few related data structures.
BPF:
- Add BPF token support for delegating a subset of BPF subsystem
functionality from privileged system-wide daemons such as systemd
through special mount options for userns-bound BPF fs to a trusted
& unprivileged application.
- Introduce bpf_arena which is sparse shared memory region between
BPF program and user space where structures inside the arena can
have pointers to other areas of the arena, and pointers work
seamlessly for both user-space programs and BPF programs.
- Introduce may_goto instruction that is a contract between the
verifier and the program. The verifier allows the program to loop
assuming it's behaving well, but reserves the right to terminate
it.
- Extend the BPF verifier to enable static subprog calls in spin lock
critical sections.
- Support registration of struct_ops types from modules which helps
projects like fuse-bpf that seeks to implement a new struct_ops
type.
- Add support for retrieval of cookies for perf/kprobe multi links.
- Support arbitrary TCP SYN cookie generation / validation in the TC
layer with BPF to allow creating SYN flood handling in BPF
firewalls.
- Add code generation to inline the bpf_kptr_xchg() helper which
improves performance when stashing/popping the allocated BPF
objects.
Wireless:
- Add SPP (signaling and payload protected) AMSDU support.
- Support wider bandwidth OFDMA, as required for EHT operation.
Driver API:
- Major overhaul of the Energy Efficient Ethernet internals to
support new link modes (2.5GE, 5GE), share more code between
drivers (especially those using phylib), and encourage more
uniform behavior. Convert and clean up drivers.
- Define an API for querying per netdev queue statistics from
drivers.
- IPSec: account in global stats for fully offloaded sessions.
- Create a concept of Ethernet PHY Packages at the Device Tree level,
to allow parameterizing the existing PHY package code.
- Enable Rx hashing (RSS) on GTP protocol fields.
Misc:
- Improvements and refactoring all over networking selftests.
- Create uniform module aliases for TC classifiers, actions, and
packet schedulers to simplify creating modprobe policies.
- Address all missing MODULE_DESCRIPTION() warnings in networking.
- Extend the Netlink descriptions in YAML to cover message
encapsulation or "Netlink polymorphism", where interpretation of
nested attributes depends on link type, classifier type or some
other "class type".
Drivers:
- Ethernet high-speed NICs:
- Add a new driver for Marvell's Octeon PCI Endpoint NIC VF.
- Intel (100G, ice, idpf):
- support E825-C devices
- nVidia/Mellanox:
- support devices with one port and multiple PCIe links
- Broadcom (bnxt):
- support n-tuple filters
- support configuring the RSS key
- Wangxun (ngbe/txgbe):
- implement irq_domain for TXGBE's sub-interrupts
- Pensando/AMD:
- support XDP
- optimize queue submission and wakeup handling (+17% bps)
- optimize struct layout, saving 28% of memory on queues
- Ethernet NICs embedded and virtual:
- Google cloud vNIC:
- refactor driver to perform memory allocations for new queue
config before stopping and freeing the old queue memory
- Synopsys (stmmac):
- obey queueMaxSDU and implement counters required by 802.1Qbv
- Renesas (ravb):
- support packet checksum offload
- suspend to RAM and runtime PM support
- Ethernet switches:
- nVidia/Mellanox:
- support for nexthop group statistics
- Microchip:
- ksz8: implement PHY loopback
- add support for KSZ8567, a 7-port 10/100Mbps switch
- PTP:
- New driver for RENESAS FemtoClock3 Wireless clock generator.
- Support OCP PTP cards designed and built by Adva.
- CAN:
- Support recvmsg() flags for own, local and remote traffic on CAN
BCM sockets.
- Support for esd GmbH PCIe/402 CAN device family.
- m_can:
- Rx/Tx submission coalescing
- wake on frame Rx
- WiFi:
- Intel (iwlwifi):
- enable signaling and payload protected A-MSDUs
- support wider-bandwidth OFDMA
- support for new devices
- bump FW API to 89 for AX devices; 90 for BZ/SC devices
- MediaTek (mt76):
- mt7915: newer ADIE version support
- mt7925: radio temperature sensor support
- Qualcomm (ath11k):
- support 6 GHz station power modes: Low Power Indoor (LPI),
Standard Power) SP and Very Low Power (VLP)
- QCA6390 & WCN6855: support 2 concurrent station interfaces
- QCA2066 support
- Qualcomm (ath12k):
- refactoring in preparation for Multi-Link Operation (MLO)
support
- 1024 Block Ack window size support
- firmware-2.bin support
- support having multiple identical PCI devices (firmware needs
to have ATH12K_FW_FEATURE_MULTI_QRTR_ID)
- QCN9274: support split-PHY devices
- WCN7850: enable Power Save Mode in station mode
- WCN7850: P2P support
- RealTek:
- rtw88: support for more rtw8811cu and rtw8821cu devices
- rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL
- rtlwifi: speed up USB firmware initialization
- rtwl8xxxu:
- RTL8188F: concurrent interface support
- Channel Switch Announcement (CSA) support in AP mode
- Broadcom (brcmfmac):
- per-vendor feature support
- per-vendor SAE password setup
- DMI nvram filename quirk for ACEPC W5 Pro"
* tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits)
nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y
nexthop: Fix out-of-bounds access during attribute validation
nexthop: Only parse NHA_OP_FLAGS for dump messages that require it
nexthop: Only parse NHA_OP_FLAGS for get messages that require it
bpf: move sleepable flag from bpf_prog_aux to bpf_prog
bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes()
selftests/bpf: Add kprobe multi triggering benchmarks
ptp: Move from simple ida to xarray
vxlan: Remove generic .ndo_get_stats64
vxlan: Do not alloc tstats manually
devlink: Add comments to use netlink gen tool
nfp: flower: handle acti_netdevs allocation failure
net/packet: Add getsockopt support for PACKET_COPY_THRESH
net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID
selftests/bpf: Add bpf_arena_htab test.
selftests/bpf: Add bpf_arena_list test.
selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages
bpf: Add helper macro bpf_addr_space_cast()
libbpf: Recognize __arena global variables.
bpftool: Recognize arena map type
...
Pull workqueue updates from Tejun Heo:
"This cycle, a lot of workqueue changes including some that are
significant and invasive.
- During v6.6 cycle, unbound workqueues were updated so that they are
more topology aware and flexible, which among other things improved
workqueue behavior on modern multi-L3 CPUs. In the process, commit
636b927eba ("workqueue: Make unbound workqueues to use per-cpu
pool_workqueues") switched unbound workqueues to use per-CPU
frontend pool_workqueues as a part of increasing front-back mapping
flexibility.
An unwelcome side effect of this change was that this made max
concurrency enforcement per-CPU blowing up the maximum number of
allowed concurrent executions. I incorrectly assumed that this
wouldn't cause practical problems as most unbound workqueue users
are self-regulate max concurrency; however, there definitely are
which don't (e.g. on IO paths) and the drastic increase in the
allowed max concurrency led to noticeable perf regressions in some
use cases.
This is now addressed by separating out max concurrency enforcement
to a separate struct - wq_node_nr_active - which makes @max_active
consistently mean system-wide max concurrency regardless of the
number of CPUs or (finally) NUMA nodes. This is a rather invasive
and, in places, a bit clunky; however, the clunkiness rises from
the the inherent requirement to handle the disagreement between the
execution locality domain and max concurrency enforcement domain on
some modern machines.
See commit 5797b1c189 ("workqueue: Implement system-wide
nr_active enforcement for unbound workqueues") for more details.
- BH workqueue support is added.
They are similar to per-CPU workqueues but execute work items in
the softirq context. This is expected to replace tasklet. However,
currently, it's missing the ability to disable and enable work
items which is needed to convert many tasklet users. To avoid
crowding this merge window too much, this will be included in the
next merge window. A separate pull request will be sent for the
couple conversion patches that are currently pending.
- Waiman plugged a long-standing hole in workqueue CPU isolation
where ordered workqueues didn't follow wq_unbound_cpumask updates.
Ordered workqueues now follow the same rules as other unbound
workqueues.
- More CPU isolation improvements: Juri fixed another deficit in
workqueue isolation where unbound rescuers don't respect
wq_unbound_cpumask. Leonardo fixed delayed_work timers firing on
isolated CPUs.
- Other misc changes"
* tag 'wq-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (54 commits)
workqueue: Drain BH work items on hot-unplugged CPUs
workqueue: Introduce from_work() helper for cleaner callback declarations
workqueue: Control intensive warning threshold through cmdline
workqueue: Make @flags handling consistent across set_work_data() and friends
workqueue: Remove clear_work_data()
workqueue: Factor out work_grab_pending() from __cancel_work_sync()
workqueue: Clean up enum work_bits and related constants
workqueue: Introduce work_cancel_flags
workqueue: Use variable name irq_flags for saving local irq flags
workqueue: Reorganize flush and cancel[_sync] functions
workqueue: Rename __cancel_work_timer() to __cancel_timer_sync()
workqueue: Use rcu_read_lock_any_held() instead of rcu_read_lock_held()
workqueue: Cosmetic changes
workqueue, irq_work: Build fix for !CONFIG_IRQ_WORK
workqueue: Fix queue_work_on() with BH workqueues
async: Use a dedicated unbound workqueue with raised min_active
workqueue: Implement workqueue_set_min_active()
workqueue: Fix kernel-doc comment of unplug_oldest_pwq()
workqueue: Bind unbound workqueue rescuer to wq_unbound_cpumask
kernel/workqueue: Let rescuers follow unbound wq cpumask changes
...
Currently, `BStr` is just a type alias of `[u8]`, limiting its
representation to a byte list rather than a character list, which is not
ideal for printing and debugging.
Implement `Display` and `Debug` traits for `BStr` to facilitate easier
printing and debugging.
Also, for this purpose, change `BStr` from a type alias of `[u8]` to a
struct wrapper of `[u8]`.
Co-developed-by: Virgile Andreani <armavica@ulminfo.fr>
Signed-off-by: Virgile Andreani <armavica@ulminfo.fr>
Signed-off-by: Yutaro Ohno <yutaro.ono.418@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/ZcSlGMGP-e9HqybA@ohnotp
[ Formatted code comment. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Currently `ForeignOwnable::from_foreign()` only works for non-null
pointers for the existing `impl`s (e.g. `Box`, `Arc`). In turn, this
means callers may write code like:
```rust
// `p` is a pointer that may be null.
if p.is_null() {
None
} else {
unsafe { Some(Self::from_foreign(ptr)) }
}
```
Add a `try_from_foreign()` method to the trait with a default
implementation that returns `None` if `ptr` is null, otherwise
`Some(from_foreign(ptr))`, so that it can be used by callers instead.
Link: https://github.com/Rust-for-Linux/linux/issues/1057
Signed-off-by: Obei Sideg <linux@obei.io>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Link: https://lore.kernel.org/r/0100018d53f737f8-80c1fe97-0019-40d7-ab69-b1b192785cd7-000000@email.amazonses.com
[ Fixed intra-doc links, improved `SAFETY` comment and reworded commit. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Currently, all macros are reexported with #[macro_export] only, which
means that to access `new_work!` from the workqueue, you need to import
it from the path `kernel::new_work` instead of importing it from the
workqueue module like all other items in the workqueue. By adding
reexports of the macros, it becomes possible to import the macros from
the correct modules.
It's still possible to import the macros from the root, but I don't
think we can do anything about that.
There is no functional change. This is merely a code cleanliness
improvement.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240129145837.1419880-1-aliceryhl@google.com
[ Removed new `use kernel::prelude::*`s, reworded title. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
