Commit graph

1,426,898 commits

Author SHA1 Message Date
Marco Elver
322366b8f1 rhashtable: Enable context analysis
Enable context analysis for rhashtable, which was used as an initial
test as it contains a combination of RCU, mutex, and bit_spinlock usage.

Users of rhashtable now also benefit from annotations on the API, which
will now warn if the RCU read lock is not held where required.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-33-elver@google.com
2026-01-05 16:43:35 +01:00
Marco Elver
c3d3023f1c stackdepot: Enable context analysis
Enable context analysis for stackdepot.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-32-elver@google.com
2026-01-05 16:43:35 +01:00
Marco Elver
0eaa911f89 kcsan: Enable context analysis
Enable context analysis for the KCSAN subsystem.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-31-elver@google.com
2026-01-05 16:43:35 +01:00
Marco Elver
6556fde265 kcov: Enable context analysis
Enable context analysis for the KCOV subsystem.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-30-elver@google.com
2026-01-05 16:43:34 +01:00
Marco Elver
0f5d764862 kfence: Enable context analysis
Enable context analysis for the KFENCE subsystem.

Notable, kfence_handle_page_fault() required minor restructure, which
also fixed a subtle race; arguably that function is more readable now.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-29-elver@google.com
2026-01-05 16:43:34 +01:00
Marco Elver
48eb4b9a3d MAINTAINERS: Add entry for Context Analysis
Add entry for all new files added for Clang's context analysis.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-28-elver@google.com
2026-01-05 16:43:34 +01:00
Marco Elver
3635ad8782 compiler: Let data_race() imply disabled context analysis
Many patterns that involve data-racy accesses often deliberately ignore
normal synchronization rules to avoid taking a lock.

If we have a lock-guarded variable on which we do a lock-less data-racy
access, rather than having to write context_unsafe(data_race(..)),
simply make the data_race(..) macro imply context-unsafety. The
data_race() macro already denotes the intent that something subtly
unsafe is about to happen, so it should be clear enough as-is.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-27-elver@google.com
2026-01-05 16:43:34 +01:00
Marco Elver
c237f1ceee compiler-context-analysis: Introduce header suppressions
While we can opt in individual subsystems which add the required
annotations, such subsystems inevitably include headers from other
subsystems which may not yet have the right annotations, which then
result in false positive warnings.

Making compatible by adding annotations across all common headers
currently requires an excessive number of __no_context_analysis
annotations, or carefully analyzing non-trivial cases to add the correct
annotations. While this is desirable long-term, providing an incremental
path causes less churn and headaches for maintainers not yet interested
in dealing with such warnings.

Rather than clutter headers unnecessary and mandate all subsystem
maintainers to keep their headers working with context analysis,
suppress all -Wthread-safety warnings in headers. Explicitly opt in
headers with context-enabled primitives.

With this in place, we can start enabling the analysis on more complex
subsystems in subsequent changes.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-26-elver@google.com
2026-01-05 16:43:33 +01:00
Marco Elver
e4588c25c9 compiler-context-analysis: Remove __cond_lock() function-like helper
As discussed in [1], removing __cond_lock() will improve the readability
of trylock code. Now that Sparse context tracking support has been
removed, we can also remove __cond_lock().

Change existing APIs to either drop __cond_lock() completely, or make
use of the __cond_acquires() function attribute instead.

In particular, spinlock and rwlock implementations required switching
over to inline helpers rather than statement-expressions for their
trylock_* variants.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207082832.GU7145@noisy.programming.kicks-ass.net/ [1]
Link: https://patch.msgid.link/20251219154418.3592607-25-elver@google.com
2026-01-05 16:43:33 +01:00
Marco Elver
5b63d0ae94 compiler-context-analysis: Remove Sparse support
Remove Sparse support as discussed at [1].

The kernel codebase is still scattered with numerous places that try to
appease Sparse's context tracking ("annotation for sparse", "fake out
sparse", "work around sparse", etc.). Eventually, as more subsystems
enable Clang's context analysis, these places will show up and need
adjustment or removal of the workarounds altogether.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20250207083335.GW7145@noisy.programming.kicks-ass.net/ [1]
Link: https://lore.kernel.org/all/Z6XTKTo_LMj9KmbY@elver.google.com/ [2]
Link: https://patch.msgid.link/20251219154418.3592607-24-elver@google.com
2026-01-05 16:43:33 +01:00
Marco Elver
4f109baeea um: Fix incorrect __acquires/__releases annotations
With Clang's context analysis, the compiler is a bit more strict about
what goes into the __acquires/__releases annotations and can't refer to
non-existent variables.

On an UM build, mm_id.h is transitively included into mm_types.h, and we
can observe the following error (if context analysis is enabled in e.g.
stackdepot.c):

   In file included from lib/stackdepot.c:17:
   In file included from include/linux/debugfs.h:15:
   In file included from include/linux/fs.h:5:
   In file included from include/linux/fs/super.h:5:
   In file included from include/linux/fs/super_types.h:7:
   In file included from include/linux/list_lru.h:14:
   In file included from include/linux/xarray.h:16:
   In file included from include/linux/gfp.h:7:
   In file included from include/linux/mmzone.h:22:
   In file included from include/linux/mm_types.h:26:
   In file included from arch/um/include/asm/mmu.h:12:
>> arch/um/include/shared/skas/mm_id.h:24:54: error: use of undeclared identifier 'turnstile'
      24 | void enter_turnstile(struct mm_id *mm_id) __acquires(turnstile);
         |                                                      ^~~~~~~~~
   arch/um/include/shared/skas/mm_id.h:25:53: error: use of undeclared identifier 'turnstile'
      25 | void exit_turnstile(struct mm_id *mm_id) __releases(turnstile);
         |                                                     ^~~~~~~~~

One (discarded) option was to use token_context_lock(turnstile) to just
define a token with the already used name, but that would not allow the
compiler to distinguish between different mm_id-dependent instances.

Another constraint is that struct mm_id is only declared and incomplete
in the header, so even if we tried to construct an expression to get to
the mutex instance, this would fail (including more headers transitively
everywhere should also be avoided).

Instead, just declare an mm_id-dependent helper to return the mutex, and
use the mm_id-dependent call expression in the __acquires/__releases
attributes; the compiler will consider the identity of the mutex to be
the call expression. Then using __get_turnstile() in the lock/unlock
wrappers (with context analysis enabled for mmu.c) the compiler will be
able to verify the implementation of the wrappers as-is.

We leave context analysis disabled in arch/um/kernel/skas/ for now. This
change is a preparatory change to allow enabling context analysis in
subsystems that include any of the above headers.

No functional change intended.

Closes: https://lore.kernel.org/oe-kbuild-all/202512171220.vHlvhpCr-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-23-elver@google.com
2026-01-05 16:43:32 +01:00
Marco Elver
6e530e2e31 debugfs: Make debugfs_cancellation a context lock struct
When compiling include/linux/debugfs.h with CONTEXT_ANALYSIS enabled, we
can see this error:

./include/linux/debugfs.h:239:17: error: use of undeclared identifier 'cancellation'
  239 | void __acquires(cancellation)

Move the __acquires(..) attribute after the declaration, so that the
compiler can see the cancellation function argument, as well as making
struct debugfs_cancellation a real context lock to benefit from Clang's
context analysis.

This change is a preparatory change to allow enabling context analysis
in subsystems that include the above header.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-22-elver@google.com
2026-01-05 16:43:32 +01:00
Marco Elver
47907461e4 locking/ww_mutex: Support Clang's context analysis
Add support for Clang's context analysis for ww_mutex.

The programming model for ww_mutex is subtly more complex than other
locking primitives when using ww_acquire_ctx. Encoding the respective
pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state
using Clang's context analysis makes incorrect use of the API harder.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-21-elver@google.com
2026-01-05 16:43:32 +01:00
Marco Elver
d3febf16de locking/local_lock: Support Clang's context analysis
Add support for Clang's context analysis for local_lock_t and
local_trylock_t.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-20-elver@google.com
2026-01-05 16:43:31 +01:00
Marco Elver
8c9c8566e1 locking/local_lock: Include missing headers
Including <linux/local_lock.h> into an empty TU will result in the
compiler complaining:

./include/linux/local_lock.h: In function ‘class_local_lock_irqsave_constructor’:
./include/linux/local_lock_internal.h:95:17: error: implicit declaration of function ‘local_irq_save’; <...>
   95 |                 local_irq_save(flags);                          \
      |                 ^~~~~~~~~~~~~~

As well as (some architectures only, such as 'sh'):

./include/linux/local_lock_internal.h: In function ‘local_lock_acquire’:
./include/linux/local_lock_internal.h:33:20: error: ‘current’ undeclared (first use in this function)
   33 |         l->owner = current;

Include missing headers to allow including local_lock.h where the
required headers are not otherwise included.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-19-elver@google.com
2026-01-05 16:43:31 +01:00
Marco Elver
e4fd3be884 locking/rwsem: Support Clang's context analysis
Add support for Clang's context analysis for rw_semaphore.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-18-elver@google.com
2026-01-05 16:43:31 +01:00
Marco Elver
5e256db932 kref: Add context-analysis annotations
Mark functions that conditionally acquire the passed lock.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-17-elver@google.com
2026-01-05 16:43:31 +01:00
Marco Elver
f0b7ce22d7 srcu: Support Clang's context analysis
Add support for Clang's context analysis for SRCU.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://patch.msgid.link/20251219154418.3592607-16-elver@google.com
2026-01-05 16:43:30 +01:00
Marco Elver
fe00f6e846 rcu: Support Clang's context analysis
Improve the existing annotations to properly support Clang's context
analysis.

The old annotations distinguished between RCU, RCU_BH, and RCU_SCHED;
however, to more easily be able to express that "hold the RCU read lock"
without caring if the normal, _bh(), or _sched() variant was used we'd
have to remove the distinction of the latter variants: change the _bh()
and _sched() variants to also acquire "RCU".

When (and if) we introduce context locks to denote more generally that
"IRQ", "BH", "PREEMPT" contexts are disabled, it would make sense to
acquire these instead of RCU_BH and RCU_SCHED respectively.

The above change also simplified introducing __guarded_by support, where
only the "RCU" context lock needs to be held: introduce __rcu_guarded,
where Clang's context analysis warns if a pointer is dereferenced
without any of the RCU locks held, or updated without the appropriate
helpers.

The primitives rcu_assign_pointer() and friends are wrapped with
context_unsafe(), which enforces using them to update RCU-protected
pointers marked with __rcu_guarded.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://patch.msgid.link/20251219154418.3592607-15-elver@google.com
2026-01-05 16:43:30 +01:00
Marco Elver
eb7d96a13b bit_spinlock: Support Clang's context analysis
The annotations for bit_spinlock.h have simply been using "bitlock" as
the token. For Sparse, that was likely sufficient in most cases. But
Clang's context analysis is more precise, and we need to ensure we
can distinguish different bitlocks.

To do so, add a token context, and a macro __bitlock(bitnum, addr)
that is used to construct unique per-bitlock tokens.

Add the appropriate test.

<linux/list_bl.h> is implicitly included through other includes, and
requires 2 annotations to indicate that acquisition (without release)
and release (without prior acquisition) of its bitlock is intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-14-elver@google.com
2026-01-05 16:43:30 +01:00
Marco Elver
5f7ba05971 bit_spinlock: Include missing <asm/processor.h>
Including <linux/bit_spinlock.h> into an empty TU will result in the
compiler complaining:

./include/linux/bit_spinlock.h:34:4: error: call to undeclared function 'cpu_relax'; <...>
   34 |                         cpu_relax();
      |                         ^
1 error generated.

Include <asm/processor.h> to allow including bit_spinlock.h where
<asm/processor.h> is not otherwise included.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-13-elver@google.com
2026-01-05 16:43:29 +01:00
Marco Elver
8f8a55f49c locking/seqlock: Support Clang's context analysis
Add support for Clang's context analysis for seqlock_t.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-12-elver@google.com
2026-01-05 16:43:29 +01:00
Marco Elver
370f0a345a locking/mutex: Support Clang's context analysis
Add support for Clang's context analysis for mutex.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-11-elver@google.com
2026-01-05 16:43:29 +01:00
Marco Elver
38f1311a22 compiler-context-analysis: Change __cond_acquires to take return value
While Sparse is oblivious to the return value of conditional acquire
functions, Clang's context analysis needs to know the return value
which indicates successful acquisition.

Add the additional argument, and convert existing uses.

Notably, Clang's interpretation of the value merely relates to the use
in a later conditional branch, i.e. 1 ==> context lock acquired in
branch taken if condition non-zero, and 0 ==> context lock acquired in
branch taken if condition is zero. Given the precise value does not
matter, introduce symbolic variants to use instead of either 0 or 1,
which should be more intuitive.

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-10-elver@google.com
2026-01-05 16:43:29 +01:00
Marco Elver
f16a802d40 locking/rwlock, spinlock: Support Clang's context analysis
Add support for Clang's context analysis for raw_spinlock_t,
spinlock_t, and rwlock. This wholesale conversion is required because
all three of them are interdependent.

To avoid warnings in constructors, the initialization functions mark a
lock as acquired when initialized before guarded variables.

The test verifies that common patterns do not generate false positives.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-9-elver@google.com
2026-01-05 16:43:28 +01:00
Marco Elver
7c45154174 lockdep: Annotate lockdep assertions for context analysis
Clang's context analysis can be made aware of functions that assert that
locks are held.

Presence of these annotations causes the analysis to assume the context
lock is held after calls to the annotated function, and avoid false
positives with complex control-flow; for example, where not all
control-flow paths in a function require a held lock, and therefore
marking the function with __must_hold(..) is inappropriate.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-8-elver@google.com
2026-01-05 16:43:28 +01:00
Marco Elver
3931d4b980 cleanup: Basic compatibility with context analysis
Introduce basic compatibility with cleanup.h infrastructure.

We need to allow the compiler to see the acquisition and release of the
context lock at the start and end of a scope. However, the current
"cleanup" helpers wrap the lock in a struct passed through separate
helper functions, which hides the lock alias from the compiler (no
inter-procedural analysis).

While Clang supports scoped guards in C++, it's not possible to apply in
C code: https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#scoped-context

However, together with recent improvements to Clang's alias analysis
abilities, idioms such as this work correctly now:

        void spin_unlock_cleanup(spinlock_t **l) __releases(*l) { .. }
        ...
        {
            spinlock_t *lock_scope __cleanup(spin_unlock_cleanup) = &lock;
            spin_lock(&lock);  // lock through &lock
            ... critical section ...
        }  // unlock through lock_scope -[alias]-> &lock (no warnings)

To generalize this pattern and make it work with existing lock guards,
introduce DECLARE_LOCK_GUARD_1_ATTRS() and WITH_LOCK_GUARD_1_ATTRS().

These allow creating an explicit alias to the context lock instance that
is "cleaned" up with a separate cleanup helper. This helper is a dummy
function that does nothing at runtime, but has the release attributes to
tell the compiler what happens at the end of the scope.

Example usage:

  DECLARE_LOCK_GUARD_1_ATTRS(mutex, __acquires(_T), __releases(*(struct mutex **)_T))
  #define class_mutex_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(mutex, _T)

Note: To support the for-loop based scoped helpers, the auxiliary
variable must be a pointer to the "class" type because it is defined in
the same statement as the guard variable. However, we initialize it with
the lock pointer (despite the type mismatch, the compiler's alias
analysis still works as expected). The "_unlock" attribute receives a
pointer to the auxiliary variable (a double pointer to the class type),
and must be cast and dereferenced appropriately.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-7-elver@google.com
2026-01-05 16:43:28 +01:00
Marco Elver
25d3b21e1d checkpatch: Warn about context_unsafe() without comment
Warn about applications of context_unsafe() without a comment, to
encourage documenting the reasoning behind why it was deemed safe.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-6-elver@google.com
2026-01-05 16:43:27 +01:00
Marco Elver
8f32441d7a Documentation: Add documentation for Compiler-Based Context Analysis
Adds documentation in Documentation/dev-tools/context-analysis.rst, and
adds it to the index.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com
2026-01-05 16:43:27 +01:00
Marco Elver
9b00c1609d compiler-context-analysis: Add test stub
Add a simple test stub where we will add common supported patterns that
should not generate false positives for each new supported context lock.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-4-elver@google.com
2026-01-05 16:43:27 +01:00
Marco Elver
3269701cb2 compiler-context-analysis: Add infrastructure for Context Analysis with Clang
Context Analysis is a language extension, which enables statically
checking that required contexts are active (or inactive), by acquiring
and releasing user-definable "context locks". An obvious application is
lock-safety checking for the kernel's various synchronization primitives
(each of which represents a "context lock"), and checking that locking
rules are not violated.

Clang originally called the feature "Thread Safety Analysis" [1]. This
was later changed and the feature became more flexible, gaining the
ability to define custom "capabilities". Its foundations can be found in
"Capability Systems" [2], used to specify the permissibility of
operations to depend on some "capability" being held (or not held).

Because the feature is not just able to express "capabilities" related
to synchronization primitives, and "capability" is already overloaded in
the kernel, the naming chosen for the kernel departs from Clang's
"Thread Safety" and "capability" nomenclature; we refer to the feature
as "Context Analysis" to avoid confusion. The internal implementation
still makes references to Clang's terminology in a few places, such as
`-Wthread-safety` being the warning option that also still appears in
diagnostic messages.

 [1] https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
 [2] https://www.cs.cornell.edu/talc/papers/capabilities.pdf

See more details in the kernel-doc documentation added in this and
subsequent changes.

Clang version 22+ is required.

[peterz: disable the thing for __CHECKER__ builds]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-3-elver@google.com
2026-01-05 16:43:26 +01:00
Marco Elver
de15fecae4 compiler_types: Move lock checking attributes to compiler-context-analysis.h
The conditional definition of lock checking macros and attributes is
about to become more complex. Factor them out into their own header for
better readability, and to make it obvious which features are supported
by which mode (currently only Sparse). This is the first step towards
generalizing towards "context analysis".

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251219154418.3592607-2-elver@google.com
2026-01-05 16:43:26 +01:00
Raag Jadav
e70711be0d drm/xe/i2c: Force polling mode in survivability
SGUnit interrupts are not initialized in survivability. Force I2C
controller to polling mode while in survivability.

v2: Use helper function instead of manual check (Riana)

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260105080750.16605-1-raag.jadav@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
2026-01-05 07:43:22 -08:00
Tony Luck
e37c9a3dc9 x86,fs/resctrl: Support binary fixed point event counters
resctrl assumes that all monitor events can be displayed as unsigned decimal
integers.

Hardware architecture counters may provide some telemetry events with greater
precision where the event is not a simple count, but is a measurement of some
sort (e.g. Joules for energy consumed).

Add a new argument to resctrl_enable_mon_event() for architecture code to
inform the file system that the value for a counter is a fixed-point value
with a specific number of binary places.

Only allow architecture to use floating point format on events that the file
system has marked with mon_evt::is_floating_point which reflects the contract
with user space on how the event values are displayed.

Display fixed point values with values rounded to ceil(binary_bits * log10(2))
decimal places. Special case for zero binary bits to print "{value}.0".

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
2026-01-05 16:10:41 +01:00
Martin Blumenstingl
26ce0b87a8 drm/meson: venc: add support for HDMI DMT modes up to 3840x2160
Commit 5d0bfe4484 ("drm/meson: Add HDMI 1.4 4k modes") added support
for HDMI 1.4 4k modes, which is what TVs need. For computer monitors
the code is using the DMT code-path, which ends up in
meson_venc_hdmi_supported_mode(), which does not allow the 4k modes yet.

The datasheet for all supported SoCs mentions "4Kx2K@60". It's not
clear whether "4K" here means 3840 or 4096 pixels.

Allow resolutions up to 3840x2160 pixels (including middle steps, such
as WQHD at 2560x1440 pixels) so they can be used with computer monitors
(using the DMT code-path in the driver).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251108134236.1299630-1-martin.blumenstingl@googlemail.com
2026-01-05 16:09:57 +01:00
Krishna Chaitanya Chundru
aa7b4bbcb3 arm64: dts: qcom: qcs6490-rb3gen2: Add TC9563 PCIe switch node
Add a node for the TC9563 PCIe switch, which has three downstream ports.
Two embedded Ethernet devices are present on one of the downstream ports.
As all these ports are present in the node represent the downstream
ports and embedded endpoints.

Power to the TC9563 is supplied through two LDO regulators, controlled by
two GPIOs, which are added as fixed regulators. Configure the TC9563
through I2C.

Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260105-tc9563-v1-1-642fd1fe7893@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
2026-01-05 09:08:38 -06:00
Taniya Das
d6205a1878 clk: qcom: rcg2: compute 2d using duty fraction directly
The duty-cycle calculation in clk_rcg2_set_duty_cycle() currently
derives an intermediate percentage `duty_per = (num * 100) / den` and
then computes:

    d = DIV_ROUND_CLOSEST(n * duty_per * 2, 100);

This introduces integer truncation at the percentage step (division by
`den`) and a redundant scaling by 100, which can reduce precision for
large `den` and skew the final rounding.

Compute `2d` directly from the duty fraction to preserve precision and
avoid the unnecessary scaling:

    d = DIV_ROUND_CLOSEST(n * duty->num * 2, duty->den);

This keeps the intended formula `d ≈ n * 2 * (num/den)` while performing
a single, final rounded division, improving accuracy especially for small
duty cycles or large denominators. It also removes the unused `duty_per`
variable, simplifying the code.

There is no functional changes beyond improved numerical accuracy.

Fixes: 7f891faf59 ("clk: qcom: clk-rcg2: Add support for duty-cycle for RCG")
Signed-off-by: Taniya Das <taniya.das@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260105-duty_cycle_precision-v2-1-d1d466a6330a@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
2026-01-05 09:08:13 -06:00
Thorsten Blum
c957072d44 x86/platform/olpc: Replace strcpy() with strscpy() in xo15_sci_add()
strcpy() has been deprecated¹ because it performs no bounds checking on the
destination buffer, which can lead to buffer overflows. Use the safer
strscpy() instead.

  ¹ https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20251124125455.5495-2-thorsten.blum@linux.dev
2026-01-05 15:58:57 +01:00
Pankaj Patil
5cd2a743ce dt-bindings: cache: qcom,llcc: Remove duplicate llcc7_base for Glymur
Drop redundant llcc7_base entry from Glymur LLCC reg-items

Fixes: bd0b8028ce ("dt-bindings: cache: qcom,llcc: Document Glymur LLCC block")
Signed-off-by: Pankaj Patil <pankaj.patil@oss.qualcomm.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260105130050.1062903-1-pankaj.patil@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
2026-01-05 08:57:12 -06:00
Brandon Brnich
336367fab9 media: chips-media: wave5: Fix Potential Probe Resource Leak
After kthread creation during probe sequence, a handful of other
failures could occur. If this were to happen, the kthread is never
explicitly deleted which results in a resource leak. Add explicit cleanup
of this resource.

Signed-off-by: Brandon Brnich <b-brnich@ti.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:32 +01:00
Marco Crivellari
8e30a27f4a media: platform: mtk-mdp3: add WQ_PERCPU to alloc_workqueue users
Currently if a user enqueues a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistency cannot be addressed without refactoring the API.

alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.

This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

commit 128ea9f6cc ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566 ("workqueue: Add new WQ_PERCPU flag")

This change adds a new WQ_PERCPU flag to explicitly request
alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.

Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:32 +01:00
Benjamin Gaignard
cb3f945c01 media: verisilicon: AV1: Fix tx mode bit setting
AV1 specification describes 3 possibles tx modes: 4x4 only, largest and
select. The hardware allows 5 possibles tx modes: 4x4 only, 8x8, 16x16,
32x32 and select. Since the both aren't exactly matching we need to add
a mapping function to set the correct mode on hardware.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Fixes: 727a400686 ("media: verisilicon: Add Rockchip AV1 decoder")
Cc: stable@vger.kernel.org
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:31 +01:00
Benjamin Gaignard
e0f99b810e media: verisilicon: AV1: Fix enable cdef computation
If all the fields of the CDEF parameters are zero (which is the default),
then av1_enable_cdef register needs to be unset
(despite the V4L2_AV1_SEQUENCE_FLAG_ENABLE_CDEF possibly being set).

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Fixes: 727a400686 ("media: verisilicon: Add Rockchip AV1 decoder")
Cc: stable@vger.kernel.org
Reported-by: Jianfeng Liu <liujianfeng1994@gmail.com>
Closes: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/4786
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[hverkuil: dropped Link tag since it just duplicated the Closes: URL]
2026-01-05 15:56:31 +01:00
Ming Qian
e0203ddf9a media: verisilicon: Avoid G2 bus error while decoding H.264 and HEVC
For the i.MX8MQ platform, there is a hardware limitation: the g1 VPU and
g2 VPU cannot decode simultaneously; otherwise, it will cause below bus
error and produce corrupted pictures, even potentially lead to system hang.

[  110.527986] hantro-vpu 38310000.video-codec: frame decode timed out.
[  110.583517] hantro-vpu 38310000.video-codec: bus error detected.

Therefore, it is necessary to ensure that g1 and g2 operate alternately.
This allows for successful multi-instance decoding of H.264 and HEVC.

To achieve this, g1 and g2 share the same v4l2_m2m_dev, and then the
v4l2_m2m_dev can handle the scheduling.

Fixes: cb5dd5a0fa ("media: hantro: Introduce G2/HEVC decoder")
Cc: stable@vger.kernel.org
Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Co-developed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:31 +01:00
Nicolas Dufresne
db6b97a4f8 media: v4l2-mem2mem: Add a kref to the v4l2_m2m_dev structure
Adding a reference count to the v4l2_m2m_dev structure allow safely
sharing it across multiple hardware nodes. This can be used to prevent
running jobs concurrently on m2m cores that have some internal resource
sharing.

Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[hverkuil: fix typos in v4l2_m2m_put documentation]
2026-01-05 15:56:31 +01:00
Nicolas Dufresne
3e92d7e493 media: mediatek: vcodec: Don't try to decode 422/444 VP9
This is not supported by the hardware and trying to decode
these leads to LAT timeout errors.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:31 +01:00
Sebastian Fricke
1b78aae631 media: mediatek: vcodec: Implement manual request completion
Rework how requests are completed in the MediaTek VCodec driver, by
implementing the new manual request completion feature, which allows to
keep a request open while allowing to add new bitstream data.
This is useful in this case, because the hardware has a LAT and a core
decode work, after the LAT decode the bitstream isn't required anymore
so the source buffer can be set done and the request stays open until
the core decode work finishes.

Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Co-developed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
2026-01-05 15:56:31 +01:00
Hans Verkuil
de9f0c2a1c media: mc: add debugfs node to keep track of requests
Keep track of the number of requests and request objects of a media
device. Helps to verify that all request-related memory is freed.

Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
2026-01-05 15:56:31 +01:00
Hans Verkuil
d14d93f940 media: vicodec: add support for manual completion
Manually complete the requests: this tests the manual completion
code.

Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
2026-01-05 15:56:31 +01:00
Hans Verkuil
c789a7f402 media: mc: add manual request completion
By default when the last request object is completed, the whole
request completes as well.

But sometimes you want to delay this completion to an arbitrary point in
time so add a manual complete mode for this.

In req_queue the driver marks the request for manual completion by
calling media_request_mark_manual_completion, and when the driver
wants to manually complete the request it calls
media_request_manual_complete().

Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
2026-01-05 15:56:31 +01:00