Merge branch 'next' into for-linus

Prepare input updates for 7.1 merge window.

Merge tag 'v7.0-rc3' into next

Sync up with the mainline to brig up the latest changes, specifically
changes to ALPS driver.

Merge branch 'for-7.1-printf-kunit-build' into for-linus

Merge branch 'for-7.1/core-v2' into for-linus

- fixed handling of 0-sized reports (Dmitry Torokhov)
- convert core code to __free() (Dmitry Torokhov)
- support for multiple batteries per HID device

Merge branch 'for-7.1/core-v2' into for-linus

- fixed handling of 0-sized reports (Dmitry Torokhov)
- convert core code to __free() (Dmitry Torokhov)
- support for multiple batteries per HID device (Lucas Zampieri)

show more ...

Merge tag 'trace-ringbuffer-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer updates from Steven Rostedt:

- Add remote buffers for pKVM

pKVM has a hype

Merge tag 'trace-ringbuffer-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ring-buffer updates from Steven Rostedt:

- Add remote buffers for pKVM

pKVM has a hypervisor component that is used to protect the guest
from the host kernel. This hypervisor is a black box to the kernel as
the kernel is to user space. The remote buffers are used to have a
memory mapping between the hypervisor and the kernel where kernel may
send commands to enable tracing within the hypervisor. Then the
kernel will read this memory mapping just like user space can read
the memory mapped ring buffer of the kernel tracing system.

Since the hypervisor only has a single context, it doesn't need to
worry about races between normal context, interrupt context and NMIs
like the kernel does. The ring buffer it uses doesn't need to be as
complex. The remote buffers are a simple version of the ring buffer
that works in a single context. They are still per-CPU and use sub
buffers. The data layout is the same as the kernel's ring buffer to
share the same parsing.

Currently, only ARM64 implements pKVM, but there's work to implement
it also in x86. The remote buffer code is separated out from the ARM
implementation so that it can be used in the future by x86.

The ARM64 updates for pKVM is in the ARM/KVM tree and it merged in
the remote buffers of this tree.

- Make the backup instance non reusable

The backup instance is a copy of the persistent ring buffer so that
the persistent ring buffer could start recording again without using
the data from the previous boot. The backup isn't for normal tracing.
It is made read-only, and after it is consumed, it is automatically
removed.

- Have backup copy persistent instance before it starts recording

To allow the persistent ring buffer to start recording from the
kernel command line commands, move the copy of the backup instance to
before the the command line options start recording.

- Report header_page overwrite field as "char" and not "int'

The rust parser of the header_page file was triggering a warning when
it defined the overwrite variable as "int" but it was only a single
byte in size.

- Fix memory barriers for the trace_buffer CPU mask

When a CPU comes online, the bit is set to allow readers to know that
the CPU buffer is allocated. The bit is set after the allocation is
done, and a smp_wmb() is performed after the allocation and before
the setting of the bit. But instead of adding a smp_rmb() to all
readers, since once a buffer is created for a CPU it is not deleted
if that CPU goes offline, so this allocation is almost always done at
boot up before any readers exist.

If for the unlikely case where a CPU comes online for the first time
after the system boot has finished, send an IPI to all CPUs to force
the smp_rmb() for each CPU.

- Show clock function being used in debugging ring buffer data

When the ring buffer checks are enabled and the ring buffer detects
an inconsistency in the times of the invents, print out the clock
being used when the error occurred. There was a very hard to hit bug
that would happen every so often and it ended up being only triggered
when the jiffies clock was being used. If the bug showed the clock
being used, it would have been much easier to find the problem (which
was an internal function was being traced which caused the clock
accounting to go off).

* tag 'trace-ringbuffer-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
ring-buffer: Prevent off-by-one array access in ring_buffer_desc_page()
ring-buffer: Report header_page overwrite as char
tracing: Allow backup to save persistent ring buffer before it starts
tracing/Documentation: Add a section about backup instance
tracing: Remove the backup instance automatically after read
tracing: Make the backup instance non-reusable
ring-buffer: Enforce read ordering of trace_buffer cpumask and buffers
ring-buffer: Show what clock function is used on timestamp errors
tracing: Check for undefined symbols in simple_ring_buffer
tracing: load/unload page callbacks for simple_ring_buffer
Documentation: tracing: Add tracing remotes
tracing: selftests: Add trace remote tests
tracing: Add a trace remote module for testing
tracing: Introduce simple_ring_buffer
ring-buffer: Export buffer_data_page and macros
tracing: Add helpers to create trace remote events
tracing: Add events/ root files to trace remotes
tracing: Add events to trace remotes
tracing: Add init callback to trace remotes
tracing: Add non-consuming read to trace remotes
...

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Merge tag 'kvmarm-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 7.1

* New features:

- Add support for tracing in the standalone EL2 hypervisor

Merge tag 'kvmarm-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 7.1

* New features:

- Add support for tracing in the standalone EL2 hypervisor code,
which should help both debugging and performance analysis.
This comes with a full infrastructure for 'remote' trace buffers
that can be exposed by non-kernel entities such as firmware.

- Add support for GICv5 Per Processor Interrupts (PPIs), as the
starting point for supporting the new GIC architecture in KVM.

- Finally add support for pKVM protected guests, with anonymous
memory being used as a backing store. About time!

* Improvements and bug fixes:

- Rework the dreaded user_mem_abort() function to make it more
maintainable, reducing the amount of state being exposed to
the various helpers and rendering a substantial amount of
state immutable.

- Expand the Stage-2 page table dumper to support NV shadow
page tables on a per-VM basis.

- Tidy up the pKVM PSCI proxy code to be slightly less hard
to follow.

- Fix both SPE and TRBE in non-VHE configurations so that they
do not generate spurious, out of context table walks that
ultimately lead to very bad HW lockups.

- A small set of patches fixing the Stage-2 MMU freeing in error
cases.

- Tighten-up accepted SMC immediate value to be only #0 for host
SMCCC calls.

- The usual cleanups and other selftest churn.

show more ...

Merge branch kvm-arm64/hyp-tracing into kvmarm-master/next

* kvm-arm64/hyp-tracing: (40 commits)
: .
: EL2 tracing support, adding both 'remote' ring-buffer
: infrastructure and the tracing it

Merge branch kvm-arm64/hyp-tracing into kvmarm-master/next

* kvm-arm64/hyp-tracing: (40 commits)
: .
: EL2 tracing support, adding both 'remote' ring-buffer
: infrastructure and the tracing itself, courtesy of
: Vincent Donnefort. From the cover letter:
:
: "The growing set of features supported by the hypervisor in protected
: mode necessitates debugging and profiling tools. Tracefs is the
: ideal candidate for this task:
:
: * It is simple to use and to script.
:
: * It is supported by various tools, from the trace-cmd CLI to the
: Android web-based perfetto.
:
: * The ring-buffer, where are stored trace events consists of linked
: pages, making it an ideal structure for sharing between kernel and
: hypervisor.
:
: This series first introduces a new generic way of creating remote events and
: remote buffers. Then it adds support to the pKVM hypervisor."
: .
tracing: selftests: Extend hotplug testing for trace remotes
tracing: Non-consuming read for trace remotes with an offline CPU
tracing: Adjust cmd_check_undefined to show unexpected undefined symbols
tracing: Restore accidentally removed SPDX tag
KVM: arm64: avoid unused-variable warning
tracing: Generate undef symbols allowlist for simple_ring_buffer
KVM: arm64: tracing: add ftrace dependency
tracing: add more symbols to whitelist
tracing: Update undefined symbols allow list for simple_ring_buffer
KVM: arm64: Fix out-of-tree build for nVHE/pKVM tracing
tracing: selftests: Add hypervisor trace remote tests
KVM: arm64: Add selftest event support to nVHE/pKVM hyp
KVM: arm64: Add hyp_enter/hyp_exit events to nVHE/pKVM hyp
KVM: arm64: Add event support to the nVHE/pKVM hyp and trace remote
KVM: arm64: Add trace reset to the nVHE/pKVM hyp
KVM: arm64: Sync boot clock with the nVHE/pKVM hyp
KVM: arm64: Add trace remote for the nVHE/pKVM hyp
KVM: arm64: Add tracing capability for the nVHE/pKVM hyp
KVM: arm64: Support unaligned fixmap in the pKVM hyp
KVM: arm64: Initialise hyp_nr_cpus for nVHE hyp
...

Signed-off-by: Marc Zyngier <maz@kernel.org>

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Merge drm/drm-next into drm-xe-next

Backmerging to bring in 7.00-rc3. Important ahead GPU SVM merging THP
support.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>

tracing: Add a trace remote module for testing

Add a module to help testing the tracefs support for trace remotes. This
module:

* Use simple_ring_buffer to write into a ring-buffer.
* Declare a

tracing: Add a trace remote module for testing

Add a module to help testing the tracefs support for trace remotes. This
module:

* Use simple_ring_buffer to write into a ring-buffer.
* Declare a single "selftest" event that can be triggered from
user-space.
* Register a "test" trace remote.

This is intended to be used by trace remote selftests.

Link: https://patch.msgid.link/20260309162516.2623589-15-vdonnefort@google.com
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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tracing: Introduce simple_ring_buffer

Add a simple implementation of the kernel ring-buffer. This intends to
be used later by ring-buffer remotes such as the pKVM hypervisor, hence
the need for a cu

tracing: Introduce simple_ring_buffer

Add a simple implementation of the kernel ring-buffer. This intends to
be used later by ring-buffer remotes such as the pKVM hypervisor, hence
the need for a cut down version (write only) without any dependency.

Link: https://patch.msgid.link/20260309162516.2623589-14-vdonnefort@google.com
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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tracing: Introduce trace remotes

A trace remote relies on ring-buffer remotes to read and control
compatible tracing buffers, written by entity such as firmware or
hypervisor.

Add a Tracefs directo

tracing: Introduce trace remotes

A trace remote relies on ring-buffer remotes to read and control
compatible tracing buffers, written by entity such as firmware or
hypervisor.

Add a Tracefs directory remotes/ that contains all instances of trace
remotes. Each instance follows the same hierarchy as any other to ease
the support by existing user-space tools.

This currently does not provide any event support, which will come
later.

Link: https://patch.msgid.link/20260309162516.2623589-6-vdonnefort@google.com
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Merge drm/drm-next into drm-intel-next

Sync with v7.0-rc1 which contains a few treewide changes affecting i915.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Merge drm/drm-next into drm-misc-next

Let's merge 7.0-rc1 to start the new drm-misc-next window

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf before 7.0-rc1

Cross-merge BPF and other fixes after downstream PR.

No conflicts.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Merge drm/drm-fixes into drm-misc-fixes

7.0-rc1 was just released, let's merge it to kick the new release cycle.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
"User visible changes:

- Add an entry into MAINTAINERS file f

Merge tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:
"User visible changes:

- Add an entry into MAINTAINERS file for RUST versions of code

There's now RUST code for tracing and static branches. To
differentiate that code from the C code, add entries in for the
RUST version (with "[RUST]" around it) so that the right
maintainers get notified on changes.

- New bitmask-list option added to tracefs

When this is set, bitmasks in trace event are not displayed as hex
numbers, but instead as lists: e.g. 0-5,7,9 instead of 0000015f

- New show_event_filters file in tracefs

Instead of having to search all events/*/*/filter for any active
filters enabled in the trace instance, the file show_event_filters
will list them so that there's only one file that needs to be
examined to see if any filters are active.

- New show_event_triggers file in tracefs

Instead of having to search all events/*/*/trigger for any active
triggers enabled in the trace instance, the file
show_event_triggers will list them so that there's only one file
that needs to be examined to see if any triggers are active.

- Have traceoff_on_warning disable trace pintk buffer too

Recently recording of trace_printk() could go to other trace
instances instead of the top level instance. But if
traceoff_on_warning triggers, it doesn't stop the buffer with
trace_printk() and that data can easily be lost by being
overwritten. Have traceoff_on_warning also disable the instance
that has trace_printk() being written to it.

- Update the hist_debug file to show what function the field uses

When CONFIG_HIST_TRIGGERS_DEBUG is enabled, a hist_debug file
exists for every event. This displays the internal data of any
histogram enabled for that event. But it is lacking the function
that is called to process one of its fields. This is very useful
information that was missing when debugging histograms.

- Up the histogram stack size from 16 to 31

Stack traces can be used as keys for event histograms. Currently
the size of the stack that is stored is limited to just 16 entries.
But the storage space in the histogram is 256 bytes, meaning that
it can store up to 31 entries (plus one for the count of entries).
Instead of letting that space go to waste, up the limit from 16 to
31. This makes the keys much more useful.

- Fix permissions of per CPU file buffer_size_kb

The per CPU file of buffer_size_kb was incorrectly set to read only
in a previous cleanup. It should be writable.

- Reset "last_boot_info" if the persistent buffer is cleared

The last_boot_info shows address information of a persistent ring
buffer if it contains data from a previous boot. It is cleared when
recording starts again, but it is not cleared when the buffer is
reset. The data is useless after a reset so clear it on reset too.

Internal changes:

- A change was made to allow tracepoint callbacks to have preemption
enabled, and instead be protected by SRCU. This required some
updates to the callbacks for perf and BPF.

perf needed to disable preemption directly in its callback because
it expects preemption disabled in the later code.

BPF needed to disable migration, as its code expects to run
completely on the same CPU.

- Have irq_work wake up other CPU if current CPU is "isolated"

When there's a waiter waiting on ring buffer data and a new event
happens, an irq work is triggered to wake up that waiter. This is
noisy on isolated CPUs (running NO_HZ_FULL). Trigger an IPI to a
house keeping CPU instead.

- Use proper free of trigger_data instead of open coding it in.

- Remove redundant call of event_trigger_reset_filter()

It was called immediately in a function that was called right after
it.

- Workqueue cleanups

- Report errors if tracing_update_buffers() were to fail.

- Make the enum update workqueue generic for other parts of tracing

On boot up, a work queue is created to convert enum names into
their numbers in the trace event format files. This work queue can
also be used for other aspects of tracing that takes some time and
shouldn't be called by the init call code.

The blk_trace initialization takes a bit of time. Have the
initialization code moved to the new tracing generic work queue
function.

- Skip kprobe boot event creation call if there's no kprobes defined
on cmdline

The kprobe initialization to set up kprobes if they are defined on
the cmdline requires taking the event_mutex lock. This can be held
by other tracing code doing initialization for a long time. Since
kprobes added to the kernel command line need to be setup
immediately, as they may be tracing early initialization code, they
cannot be postponed in a work queue and must be setup in the
initcall code.

If there's no kprobe on the kernel cmdline, there's no reason to
take the mutex and slow down the boot up code waiting to get the
lock only to find out there's nothing to do. Simply exit out early
if there's no kprobes on the kernel cmdline.

If there are kprobes on the cmdline, then someone cares more about
tracing over the speed of boot up.

- Clean up the trigger code a bit

- Move code out of trace.c and into their own files

trace.c is now over 11,000 lines of code and has become more
difficult to maintain. Start splitting it up so that related code
is in their own files.

Move all the trace_printk() related code into trace_printk.c.

Move the __always_inline stack functions into trace.h.

Move the pid filtering code into a new trace_pid.c file.

- Better define the max latency and snapshot code

The latency tracers have a "max latency" buffer that is a copy of
the main buffer and gets swapped with it when a new high latency is
detected. This keeps the trace up to the highest latency around
where this max_latency buffer is never written to. It is only used
to save the last max latency trace.

A while ago a snapshot feature was added to tracefs to allow user
space to perform the same logic. It could also enable events to
trigger a "snapshot" if one of their fields hit a new high. This
was built on top of the latency max_latency buffer logic.

Because snapshots came later, they were dependent on the latency
tracers to be enabled. In reality, the latency tracers depend on
the snapshot code and not the other way around. It was just that
they came first.

Restructure the code and the kconfigs to have the latency tracers
depend on snapshot code instead. This actually simplifies the logic
a bit and allows to disable more when the latency tracers are not
defined and the snapshot code is.

- Fix a "false sharing" in the hwlat tracer code

The loop to search for latency in hardware was using a variable
that could be changed by user space for each sample. If the user
change this variable, it could cause a bus contention, and reading
that variable can show up as a large latency in the trace causing a
false positive. Read this variable at the start of the sample with
a READ_ONCE() into a local variable and keep the code from sharing
cache lines with readers.

- Fix function graph tracer static branch optimization code

When only one tracer is defined for function graph tracing, it uses
a static branch to call that tracer directly. When another tracer
is added, it goes into loop logic to call all the registered
callbacks.

The code was incorrect when going back to one tracer and never
re-enabled the static branch again to do the optimization code.

- And other small fixes and cleanups"

* tag 'trace-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (46 commits)
function_graph: Restore direct mode when callbacks drop to one
tracing: Fix indentation of return statement in print_trace_fmt()
tracing: Reset last_boot_info if ring buffer is reset
tracing: Fix to set write permission to per-cpu buffer_size_kb
tracing: Fix false sharing in hwlat get_sample()
tracing: Move d_max_latency out of CONFIG_FSNOTIFY protection
tracing: Better separate SNAPSHOT and MAX_TRACE options
tracing: Add tracer_uses_snapshot() helper to remove #ifdefs
tracing: Rename trace_array field max_buffer to snapshot_buffer
tracing: Move pid filtering into trace_pid.c
tracing: Move trace_printk functions out of trace.c and into trace_printk.c
tracing: Use system_state in trace_printk_init_buffers()
tracing: Have trace_printk functions use flags instead of using global_trace
tracing: Make tracing_update_buffers() take NULL for global_trace
tracing: Make printk_trace global for tracing system
tracing: Move ftrace_trace_stack() out of trace.c and into trace.h
tracing: Move __trace_buffer_{un}lock_*() functions to trace.h
tracing: Make tracing_selftest_running global to the tracing subsystem
tracing: Make tracing_disabled global for tracing system
tracing: Clean up use of trace_create_maxlat_file()
...

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Merge tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Alexei Starovoitov:

- Support associating BPF program with struct_ops (Amery Hung)

-

Merge tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Alexei Starovoitov:

- Support associating BPF program with struct_ops (Amery Hung)

- Switch BPF local storage to rqspinlock and remove recursion detection
counters which were causing false positives (Amery Hung)

- Fix live registers marking for indirect jumps (Anton Protopopov)

- Introduce execution context detection BPF helpers (Changwoo Min)

- Improve verifier precision for 32bit sign extension pattern
(Cupertino Miranda)

- Optimize BTF type lookup by sorting vmlinux BTF and doing binary
search (Donglin Peng)

- Allow states pruning for misc/invalid slots in iterator loops (Eduard
Zingerman)

- In preparation for ASAN support in BPF arenas teach libbpf to move
global BPF variables to the end of the region and enable arena kfuncs
while holding locks (Emil Tsalapatis)

- Introduce support for implicit arguments in kfuncs and migrate a
number of them to new API. This is a prerequisite for cgroup
sub-schedulers in sched-ext (Ihor Solodrai)

- Fix incorrect copied_seq calculation in sockmap (Jiayuan Chen)

- Fix ORC stack unwind from kprobe_multi (Jiri Olsa)

- Speed up fentry attach by using single ftrace direct ops in BPF
trampolines (Jiri Olsa)

- Require frozen map for calculating map hash (KP Singh)

- Fix lock entry creation in TAS fallback in rqspinlock (Kumar
Kartikeya Dwivedi)

- Allow user space to select cpu in lookup/update operations on per-cpu
array and hash maps (Leon Hwang)

- Make kfuncs return trusted pointers by default (Matt Bobrowski)

- Introduce "fsession" support where single BPF program is executed
upon entry and exit from traced kernel function (Menglong Dong)

- Allow bpf_timer and bpf_wq use in all programs types (Mykyta
Yatsenko, Andrii Nakryiko, Kumar Kartikeya Dwivedi, Alexei
Starovoitov)

- Make KF_TRUSTED_ARGS the default for all kfuncs and clean up their
definition across the tree (Puranjay Mohan)

- Allow BPF arena calls from non-sleepable context (Puranjay Mohan)

- Improve register id comparison logic in the verifier and extend
linked registers with negative offsets (Puranjay Mohan)

- In preparation for BPF-OOM introduce kfuncs to access memcg events
(Roman Gushchin)

- Use CFI compatible destructor kfunc type (Sami Tolvanen)

- Add bitwise tracking for BPF_END in the verifier (Tianci Cao)

- Add range tracking for BPF_DIV and BPF_MOD in the verifier (Yazhou
Tang)

- Make BPF selftests work with 64k page size (Yonghong Song)

* tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (268 commits)
selftests/bpf: Fix outdated test on storage->smap
selftests/bpf: Choose another percpu variable in bpf for btf_dump test
selftests/bpf: Remove test_task_storage_map_stress_lookup
selftests/bpf: Update task_local_storage/task_storage_nodeadlock test
selftests/bpf: Update task_local_storage/recursion test
selftests/bpf: Update sk_storage_omem_uncharge test
bpf: Switch to bpf_selem_unlink_nofail in bpf_local_storage_{map_free, destroy}
bpf: Support lockless unlink when freeing map or local storage
bpf: Prepare for bpf_selem_unlink_nofail()
bpf: Remove unused percpu counter from bpf_local_storage_map_free
bpf: Remove cgroup local storage percpu counter
bpf: Remove task local storage percpu counter
bpf: Change local_storage->lock and b->lock to rqspinlock
bpf: Convert bpf_selem_unlink to failable
bpf: Convert bpf_selem_link_map to failable
bpf: Convert bpf_selem_unlink_map to failable
bpf: Select bpf_local_storage_map_bucket based on bpf_local_storage
selftests/xsk: fix number of Tx frags in invalid packet
selftests/xsk: properly handle batch ending in the middle of a packet
bpf: Prevent reentrance into call_rcu_tasks_trace()
...

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Merge branch 'for-6.20/sony' into for-linus

- Support for Rock band 4 PS4 and PS5 guitars (Rosalie Wanders)

tracing: Better separate SNAPSHOT and MAX_TRACE options

The latency tracers (scheduler, irqsoff, etc) were created when tracing
was first added. These tracers required a "snapshot" buffer that was t

tracing: Better separate SNAPSHOT and MAX_TRACE options

The latency tracers (scheduler, irqsoff, etc) were created when tracing
was first added. These tracers required a "snapshot" buffer that was the
same size as the ring buffer being written to. When a new max latency was
hit, the main ring buffer would swap with the snapshot buffer so that the
trace leading up to the latency would be saved in the snapshot buffer (The
snapshot buffer is never written to directly and the data within it can be
viewed without fear of being overwritten).

Later, a new feature was added to allow snapshots to be taken by user
space or even event triggers. This created a "snapshot" file that allowed
users to trigger a snapshot from user space to save the current trace.

The config for this new feature (CONFIG_TRACER_SNAPSHOT) would select the
latency tracer config (CONFIG_TRACER_MAX_LATENCY) as it would need all the
functionality from it as it already existed. But this was incorrect. As
the snapshot feature is really what the latency tracers need and not the
other way around.

Have CONFIG_TRACER_MAX_TRACE select CONFIG_TRACER_SNAPSHOT where the
tracers that needs the max latency buffer selects the TRACE_MAX_TRACE
which will then select TRACER_SNAPSHOT.

Also, go through trace.c and trace.h and make the code that only needs the
TRACER_MAX_TRACE protected by that and the code that always requires the
snapshot to be protected by TRACER_SNAPSHOT.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20260208183856.767870992@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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Merge branch 'ftrace-bpf-use-single-direct-ops-for-bpf-trampolines'

Jiri Olsa says:

====================
ftrace,bpf: Use single direct ops for bpf trampolines

hi,
while poking the multi-tracing in

Merge branch 'ftrace-bpf-use-single-direct-ops-for-bpf-trampolines'

Jiri Olsa says:

====================
ftrace,bpf: Use single direct ops for bpf trampolines

hi,
while poking the multi-tracing interface I ended up with just one ftrace_ops
object to attach all trampolines.

This change allows to use less direct API calls during the attachment changes
in the future code, so in effect speeding up the attachment.

In current code we get a speed up from using just a single ftrace_ops object.

- with current code:

Performance counter stats for 'bpftrace -e fentry:vmlinux:ksys_* {} -c true':

6,364,157,902 cycles:k
828,728,902 cycles:u
1,064,803,824 instructions:u # 1.28 insn per cycle
23,797,500,067 instructions:k # 3.74 insn per cycle

4.416004987 seconds time elapsed

0.164121000 seconds user
1.289550000 seconds sys

- with the fix:

Performance counter stats for 'bpftrace -e fentry:vmlinux:ksys_* {} -c true':

6,535,857,905 cycles:k
810,809,429 cycles:u
1,064,594,027 instructions:u # 1.31 insn per cycle
23,962,552,894 instructions:k # 3.67 insn per cycle

1.666961239 seconds time elapsed

0.157412000 seconds user
1.283396000 seconds sys

The speedup seems to be related to the fact that with single ftrace_ops object
we don't call ftrace_shutdown anymore (we use ftrace_update_ops instead) and
we skip the synchronize rcu calls (each ~100ms) at the end of that function.

rfc: https://lore.kernel.org/bpf/20250729102813.1531457-1-jolsa@kernel.org/
v1: https://lore.kernel.org/bpf/20250923215147.1571952-1-jolsa@kernel.org/
v2: https://lore.kernel.org/bpf/20251113123750.2507435-1-jolsa@kernel.org/
v3: https://lore.kernel.org/bpf/20251120212402.466524-1-jolsa@kernel.org/
v4: https://lore.kernel.org/bpf/20251203082402.78816-1-jolsa@kernel.org/
v5: https://lore.kernel.org/bpf/20251215211402.353056-10-jolsa@kernel.org/

v6 changes:
- rename add_hash_entry_direct to add_ftrace_hash_entry_direct [Steven]
- factor hash_add/hash_sub [Steven]
- add kerneldoc header for update_ftrace_direct_* functions [Steven]
- few assorted smaller fixes [Steven]
- added missing direct_ops wrappers for !CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
case [Steven]

v5 changes:
- do not export ftrace_hash object [Steven]
- fix update_ftrace_direct_add new_filter_hash leak [ci]

v4 changes:
- rebased on top of bpf-next/master (with jmp attach changes)
added patch 1 to deal with that
- added extra checks for update_ftrace_direct_del/mod to address
the ci bot review

v3 changes:
- rebased on top of bpf-next/master
- fixed update_ftrace_direct_del cleanup path
- added missing inline to update_ftrace_direct_* stubs

v2 changes:
- rebased on top fo bpf-next/master plus Song's livepatch fixes [1]
- renamed the API functions [2] [Steven]
- do not export the new api [Steven]
- kept the original direct interface:

I'm not sure if we want to melt both *_ftrace_direct and the new interface
into single one. It's bit different in semantic (hence the name change as
Steven suggested [2]) and I don't think the changes are not that big so
we could easily keep both APIs.

v1 changes:
- make the change x86 specific, after discussing with Mark options for
arm64 [Mark]

thanks,
jirka

[1] https://lore.kernel.org/bpf/20251027175023.1521602-1-song@kernel.org/
[2] https://lore.kernel.org/bpf/20250924050415.4aefcb91@batman.local.home/
---
====================

Link: https://patch.msgid.link/20251230145010.103439-1-jolsa@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

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bpf,x86: Use single ftrace_ops for direct calls

Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.

With single ftrace_ops object we can use

bpf,x86: Use single ftrace_ops for direct calls

Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.

With single ftrace_ops object we can use update_ftrace_direct_* api
that allows multiple ip sites updates on single ftrace_ops object.

Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on
each arch that supports this.

At the moment we can enable this only on x86 arch, because arm relies
on ftrace_ops object representing just single trampoline image (stored
in ftrace_ops::direct_call). Archs that do not support this will continue
to use *_ftrace_direct api.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-10-jolsa@kernel.org

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Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.q

Merge tag 'v6.19-rc1' into msm-next

Merge Linux 6.19-rc1 in order to catch up with other changes (e.g. UBWC
config database defining UBWC_6).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

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Merge drm/drm-next into drm-xe-next

Backmerging to bring in 6.19-rc1. An important upstream bugfix and
to help unblock PTL CI.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after 6.19-rc1

Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Merge drm/drm-next into drm-intel-next

Sync-up some display code needed for Async flips refactor.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>