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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Lockdep:
- Enable PROVE_RAW_LOCK_NESTING with PROVE_LOCKING (Sebastian Andrzej
Siewior)
- Add lockdep_cleanup_dead_cpu() (David Woodhouse)
futexes:
- Use atomic64_inc_return() in get_inode_sequence_number() (Uros
Bizjak)
- Use atomic64_try_cmpxchg_relaxed() in get_inode_sequence_number()
(Uros Bizjak)
RT locking:
- Add sparse annotation PREEMPT_RT's locking (Sebastian Andrzej
Siewior)
spinlocks:
- Use atomic_try_cmpxchg_release() in osq_unlock() (Uros Bizjak)
atomics:
- x86: Use ALT_OUTPUT_SP() for __alternative_atomic64() (Uros Bizjak)
- x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu() (Uros
Bizjak)
KCSAN, seqlocks:
- Support seqcount_latch_t (Marco Elver)
<linux/cleanup.h>:
- Add if_not_guard() conditional guard helper (David Lechner)
- Adjust scoped_guard() macros to avoid potential warning (Przemek
Kitszel)
- Remove address space of returned pointer (Uros Bizjak)
WW mutexes:
- locking/ww_mutex: Adjust to lockdep nest_lock requirements (Thomas
Hellström)
Rust integration:
- Fix raw_spin_lock initialization on PREEMPT_RT (Eder Zulian)
Misc cleanups & fixes:
- lockdep: Fix wait-type check related warnings (Ahmed Ehab)
- lockdep: Use info level for initial info messages (Jiri Slaby)
- spinlocks: Make __raw_* lock ops static (Geert Uytterhoeven)
- pvqspinlock: Convert fields of 'enum vcpu_state' to uppercase
(Qiuxu Zhuo)
- iio: magnetometer: Fix if () scoped_guard() formatting (Stephen
Rothwell)
- rtmutex: Fix misleading comment (Peter Zijlstra)
- percpu-rw-semaphores: Fix grammar in percpu-rw-semaphore.rst (Xiu
Jianfeng)"
* tag 'locking-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
locking/Documentation: Fix grammar in percpu-rw-semaphore.rst
iio: magnetometer: fix if () scoped_guard() formatting
rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RT
kcsan, seqlock: Fix incorrect assumption in read_seqbegin()
seqlock, treewide: Switch to non-raw seqcount_latch interface
kcsan, seqlock: Support seqcount_latch_t
time/sched_clock: Broaden sched_clock()'s instrumentation coverage
time/sched_clock: Swap update_clock_read_data() latch writes
locking/atomic/x86: Use ALT_OUTPUT_SP() for __arch_{,try_}cmpxchg64_emu()
locking/atomic/x86: Use ALT_OUTPUT_SP() for __alternative_atomic64()
cleanup: Add conditional guard helper
cleanup: Adjust scoped_guard() macros to avoid potential warning
locking/osq_lock: Use atomic_try_cmpxchg_release() in osq_unlock()
cleanup: Remove address space of returned pointer
locking/rtmutex: Fix misleading comment
locking/rt: Annotate unlock followed by lock for sparse.
locking/rt: Add sparse annotation for RCU.
locking/rt: Remove one __cond_lock() in RT's spin_trylock_irqsave()
locking/rt: Add sparse annotation PREEMPT_RT's sleeping locks.
locking/pvqspinlock: Convert fields of 'enum vcpu_state' to uppercase
...
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When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using
spinlock_check() + __raw_spin_lock_init() to initialize spin locks is
incorrect, and would cause build errors.
Introduce __spin_lock_init() to initialize a spin lock with lockdep
rquired information for PREEMPT_RT builds, and use it in the Rust
helper.
Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.")
Closes: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241107163223.2092690-2-ezulian@redhat.com
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Alice Ryhl <aliceryhl@google.com> says:
This patchset contains the file abstractions needed by the Rust
implementation of the Binder driver.
Please see the Rust Binder RFC for usage examples:
https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com
Users of "rust: types: add `NotThreadSafe`":
[PATCH 5/9] rust: file: add `FileDescriptorReservation`
Users of "rust: task: add `Task::current_raw`":
[PATCH 7/9] rust: file: add `Kuid` wrapper
[PATCH 8/9] rust: file: add `DeferredFdCloser`
Users of "rust: file: add Rust abstraction for `struct file`":
[PATCH RFC 02/20] rust_binder: add binderfs support to Rust binder
[PATCH RFC 03/20] rust_binder: add threading support
Users of "rust: cred: add Rust abstraction for `struct cred`":
[PATCH RFC 05/20] rust_binder: add nodes and context managers
[PATCH RFC 06/20] rust_binder: add oneway transactions
[PATCH RFC 11/20] rust_binder: send nodes in transaction
[PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support
Users of "rust: security: add abstraction for secctx":
[PATCH RFC 06/20] rust_binder: add oneway transactions
Users of "rust: file: add `FileDescriptorReservation`":
[PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support
[PATCH RFC 14/20] rust_binder: add BINDER_TYPE_FDA support
Users of "rust: file: add `Kuid` wrapper":
[PATCH RFC 05/20] rust_binder: add nodes and context managers
[PATCH RFC 06/20] rust_binder: add oneway transactions
Users of "rust: file: add abstraction for `poll_table`":
[PATCH RFC 07/20] rust_binder: add epoll support
This patchset has some uses of read_volatile in place of READ_ONCE.
Please see the following rfc for context on this:
https://lore.kernel.org/all/20231025195339.1431894-1-boqun.feng@gmail.com/
* patches from https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com:
rust: file: add abstraction for `poll_table`
rust: file: add `Kuid` wrapper
rust: file: add `FileDescriptorReservation`
rust: security: add abstraction for secctx
rust: cred: add Rust abstraction for `struct cred`
rust: file: add Rust abstraction for `struct file`
rust: task: add `Task::current_raw`
rust: types: add `NotThreadSafe`
Link: https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Adds a wrapper around `kuid_t` called `Kuid`. This allows us to define
various operations on kuids such as equality and current_euid. It also
lets us provide conversions from kuid into userspace values.
Rust Binder needs these operations because it needs to compare kuids for
equality, and it needs to tell userspace about the pid and uid of
incoming transactions.
To read kuids from a `struct task_struct`, you must currently use
various #defines that perform the appropriate field access under an RCU
read lock. Currently, we do not have a Rust wrapper for rcu_read_lock,
which means that for this patch, there are two ways forward:
1. Inline the methods into Rust code, and use __rcu_read_lock directly
rather than the rcu_read_lock wrapper. This gives up lockdep for
these usages of RCU.
2. Wrap the various #defines in helpers and call the helpers from Rust.
This patch uses the second option. One possible disadvantage of the
second option is the possible introduction of speculation gadgets, but
as discussed in [1], the risk appears to be acceptable.
Of course, once a wrapper for rcu_read_lock is available, it is
preferable to use that over either of the two above approaches.
Link: https://lore.kernel.org/all/202312080947.674CD2DC7@keescook/ [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915-alice-file-v10-7-88484f7a3dcf@google.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add an abstraction for viewing the string representation of a security
context.
This is needed by Rust Binder because it has a feature where a process
can view the string representation of the security context for incoming
transactions. The process can use that to authenticate incoming
transactions, and since the feature is provided by the kernel, the
process can trust that the security context is legitimate.
This abstraction makes the following assumptions about the C side:
* When a call to `security_secid_to_secctx` is successful, it returns a
pointer and length. The pointer references a byte string and is valid
for reading for that many bytes.
* The string may be referenced until `security_release_secctx` is
called.
* If CONFIG_SECURITY is set, then the three methods mentioned in
rust/helpers are available without a helper. (That is, they are not a
#define or `static inline`.)
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915-alice-file-v10-5-88484f7a3dcf@google.com
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add a wrapper around `struct cred` called `Credential`, and provide
functionality to get the `Credential` associated with a `File`.
Rust Binder must check the credentials of processes when they attempt to
perform various operations, and these checks usually take a
`&Credential` as parameter. The security_binder_set_context_mgr function
would be one example. This patch is necessary to access these security_*
methods from Rust.
This Rust abstraction makes the following assumptions about the C side:
* `struct cred` is refcounted with `get_cred`/`put_cred`.
* It's okay to transfer a `struct cred` across threads, that is, you do
not need to call `put_cred` on the same thread as where you called
`get_cred`.
* The `euid` field of a `struct cred` never changes after
initialization.
* The `f_cred` field of a `struct file` never changes after
initialization.
Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Co-developed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915-alice-file-v10-4-88484f7a3dcf@google.com
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This abstraction makes it possible to manipulate the open files for a
process. The new `File` struct wraps the C `struct file`. When accessing
it using the smart pointer `ARef<File>`, the pointer will own a
reference count to the file. When accessing it as `&File`, then the
reference does not own a refcount, but the borrow checker will ensure
that the reference count does not hit zero while the `&File` is live.
Since this is intended to manipulate the open files of a process, we
introduce an `fget` constructor that corresponds to the C `fget`
method. In future patches, it will become possible to create a new fd in
a process and bind it to a `File`. Rust Binder will use these to send
fds from one process to another.
We also provide a method for accessing the file's flags. Rust Binder
will use this to access the flags of the Binder fd to check whether the
non-blocking flag is set, which affects what the Binder ioctl does.
This introduces a struct for the EBADF error type, rather than just
using the Error type directly. This has two advantages:
* `File::fget` returns a `Result<ARef<File>, BadFdError>`, which the
compiler will represent as a single pointer, with null being an error.
This is possible because the compiler understands that `BadFdError`
has only one possible value, and it also understands that the
`ARef<File>` smart pointer is guaranteed non-null.
* Additionally, we promise to users of the method that the method can
only fail with EBADF, which means that they can rely on this promise
without having to inspect its implementation.
That said, there are also two disadvantages:
* Defining additional error types involves boilerplate.
* The question mark operator will only utilize the `From` trait once,
which prevents you from using the question mark operator on
`BadFdError` in methods that return some third error type that the
kernel `Error` is convertible into. (However, it works fine in methods
that return `Error`.)
Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Co-developed-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Co-developed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915-alice-file-v10-3-88484f7a3dcf@google.com
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In case CONFIG_PREEMPT_RT is enabled __mutex_init() becomes a macro
instead of an extern function (simplified from
include/linux/mutex.h):
#ifndef CONFIG_PREEMPT_RT
extern void __mutex_init(struct mutex *lock, const char *name,
struct lock_class_key *key);
#else
#define __mutex_init(mutex, name, key) \
do { \
rt_mutex_base_init(&(mutex)->rtmutex); \
__mutex_rt_init((mutex), name, key); \
} while (0)
#endif
The macro isn't resolved by bindgen, then. What results in a build
error:
error[E0425]: cannot find function `__mutex_init` in crate `bindings`
--> rust/kernel/sync/lock/mutex.rs:104:28
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104 | unsafe { bindings::__mutex_init(ptr, name, key) }
| ^^^^^^^^^^^^ help: a function with a similar name exists: `__mutex_rt_init`
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::: rust/bindings/bindings_generated.rs:23722:5
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23722 | / pub fn __mutex_rt_init(
23723 | | lock: *mut mutex,
23724 | | name: *const core::ffi::c_char,
23725 | | key: *mut lock_class_key,
23726 | | );
| |_____- similarly named function `__mutex_rt_init` defined here
Fix this by adding a helper.
As explained by Gary Guo in [1] no #ifdef CONFIG_PREEMPT_RT
is needed here as rust/bindings/lib.rs prefers externed function to
helpers if an externed function exists.
Reported-by: Conor Dooley <conor@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/20240913-shack-estate-b376a65921b1@spud/
Link: https://lore.kernel.org/rust-for-linux/20240915123626.1a170103.gary@garyguo.net/ [1]
Fixes: 6d20d629c6d8 ("rust: lock: introduce `Mutex`")
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240916073752.3123484-1-dirk.behme@de.bosch.com
[ Reworded to include the proper example by Dirk. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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The rust rbtree exposes a map-like interface over keys and values,
backed by the kernel red-black tree implementation. Values can be
inserted, deleted, and retrieved from a `RBTree` by key.
This base abstraction is used by binder to store key/value
pairs and perform lookups, for example the patch
"[PATCH RFC 03/20] rust_binder: add threading support"
in the binder RFC [1].
Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-3-08ba9197f637@google.com/ [1]
Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Matt Gilbride <mattgilbride@google.com>
Link: https://lore.kernel.org/r/20240822-b4-rbtree-v12-1-014561758a57@google.com
[ Updated link to docs.kernel.org. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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This removes the need to explicitly export all symbols.
Generate helper exports similarly to what's currently done for Rust
crates. These helpers are exclusively called from within Rust code and
therefore can be treated similar as other Rust symbols.
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240817165302.3852499-1-gary@garyguo.net
[ Fixed dependency path, reworded slightly, edited comment a bit and
rebased on top of the changes made when applying Andreas' patch
(e.g. no `README.md` anymore, so moved the edits). - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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This patch splits up the rust helpers C file. When rebasing patch sets on
upstream linux, merge conflicts in helpers.c is common and time consuming
[1]. Thus, split the file so that each kernel component can live in a
separate file.
This patch lists helper files explicitly and thus conflicts in the file
list is still likely. However, they should be more simple to resolve than
the conflicts usually seen in helpers.c.
[ Removed `README.md` and undeleted the original comment since now,
in v3 of the series, we have a `helpers.c` again; which also allows
us to keep the "Sorted alphabetically" line and makes the diff easier.
In addition, updated the Documentation/ mentions of the file, reworded
title and removed blank lines at the end of `page.c`. - Miguel ]
Link: https://rust-for-linux.zulipchat.com/#narrow/stream/288089-General/topic/Splitting.20up.20helpers.2Ec/near/426694012 [1]
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240815103016.2771842-1-nmi@metaspace.dk
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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