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Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This is a simple synchronization mechanism allowing an in-band caller
to pass a point in the code making sure that no out-of-band operations
which might traverse the same crossing are in flight.

Out-of-band callers delimit the danger zone by down-ing and up-ing the
barrier at the crossing, the in-band code should ask for passing the
crossing.

CAUTION: the caller must guarantee that evl_down_crossing() cannot be
invoked _after_ evl_pass_crossing() is entered for a given crossing.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Returns the current kthread descriptor or NULL if another thread
context is running. CAUTION: does not account for IRQ context.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

We need more flexibility in the argument passed to the thread
function. Change for an opaque pointer passed to evl_run_kthread() and
variants instead of the current kthread descriptor.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

By convention, all thread-related calls which implicitly affect
current and therefore do not take any @thread parameter should use a
short-form name, such as evl_delay(), evl_sleep(). For this reason,
the following renames took place:

- evl_set_thread_period -> evl_set_period
- evl_wait_thread_period -> evl_wait_period
- evl_delay_thread -> evl_delay

In addition, complete the set of kthread-specific calls which are
based on the inner thread interface (this one working for user and
kernel threads indifferently):

- evl_kthread_unblock
- evl_kthread_join
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This is an internal interface which should deal with ktime directly,
not timespec64. In addition, rename to set() in order to match the
converse short form read() call.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This is a tiny fix for the repeated evl/sched.h inclusion.
Signed-off-by: lio <liu.hailong6@zte.com.cn>

Trace event *evl_sched_attrs* calls TP_printk("%s") to out print the thread
name get by evl_element_name().

However, evl_element_name() may return NULL sometimes, and TP_printk(%s)
may cause some problems.

This patch will avoid this.
Signed-off-by: lio <carver4lio@163.com>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Prioritization of timers in timer queues dates back to the Dark Ages
of Xenomai 2.x, when multiple time bases would co-exist in the core,
some of which representing date values as a count of periodic ticks.
In such a case, multiple timers might elapse on the very same tick,
hence the need for prioritizing them.

With a single time base indexing timers on absolute date values, which
are expressed as a 64bit monotonic count of nanoseconds, the
likelihood of observing identical trigger dates is very low.

Furthermore, the formerly defined priorities where assigned as
follows:

1) high priority to the per-thread periodic and resource timers
2) medium priority to the user-defined timers
3) low priority to the in-band tick emulation timer

It turns out that forcibly prioritizing 1) over 2) is at least
debatable, if not questionable: resource timers have no high priority
at all, they merely tick on the (unlikely) timeout condition. On the
other hand, user-defined timers may well deal with high priority
events only some EVL driver code may know about.

Finally, handling 3) is a fast operation on top of Dovetail, which is
already deferred internally whenever the timer management core detects
that some oob activity is running/pending.

So we may remove the logic handling the timer priority, only relying
on the trigger date for dispatching. This should save precious cycles
in the hot path without any actual downside.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Align naming of the kthread termination-related calls on the in-band
counterparts. At this chance, further clarify the interface by having
evl_kthread_should_stop() explicitly return a boolean status.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

We cannot safely run the stage switching machinery while running in
NMI context.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

The trap_entry handler may expect hard irqs off on entry. It may
demote the current context to the in-band stage, may return with hard
irqs on.

The trap_exit handler only runs if trap_entry was called for the same
trap occurrence. It may expect hard irqs off on entry, may switch the
current context back to the oob stage. Must return with hard irqs
off. This departs from the previous implementation which allowed the
trap_exit handler to return with hard irqs on.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This change first asserts that the FIFO class is the topmost
scheduling class by design.  From this point, we may check this class
upfront when looking for the next runnable thread to pick, without
going though the indirection of its .sched_pick handler.

This allows the compiler to fold most of the FIFO picking code into
the generic __pick_next_thread() routine, saving an indirect call.
This is nicer to the I-cache in all cases, and spares the cycles which
would otherwise be consumed by some vulnerability mitigation code like
retpolines.

On a highly cache-stressed i.mx6q, the worst case latency figures with
this change in dropped from about 5%.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

There is no user for this one.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This reverts commit 7c81fc4f

.

Reinstate the dovetail/poll.h wrapper files we had to drop from the
mere Dovetail code.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Some drivers may need to poll multiple heads concurrently on a single
oob_poll() invocation. Replace the single wait.next backlink to the
poll head by an array of connectors multiple heads. The oob_poll()
handler of a driver can now attach the wait descriptor it receives
(struct oob_poll_wait) to up to EVL_POLL_NR_CONNECTORS different poll
heads (currently set to 4).
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Core EVL headers should be readable from the asm-generic/ section
(e.g. evl/wait.h), which among other things requires the tracepoint
definitions not to be pulled in. The latter should be read from the
files implementating them instead.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

The syscall_exit tracer appeared in v5.9, so prefix our tracer
definitions with evl_ to avoid naming conflicts.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# On branch wip/evl-5.9-rc3
# Changes to be committed:
#	modified:   include/trace/events/evl.h
#

Suggested-by: lio <liu.hailong6@zte.com.cn>
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

We need to stop the sampling timer as soon as the test sitter unblocks
from waiting on the flag due to SIGINT/SIGALRM which denotes the end
of the measurement, so that we won't push extraneous samples to the
histogram.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

A thread might resume oob from a CPU which is excluded from the set
dedicated to oob scheduling (evl_cpu_affinity), due to a migration
which occurred while in-band (e.g. sched_setaffinity()).

Make sure the thread is allowed to run shortly on the target CPU
nevertheless, so that it can exit cleanly before returning from
evl_switch_oob(). The previous implementation would leave it hanging
in limbo.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

We need a way to peek at a flag state without clearing it if set.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

All pointers passed as 64 bit long integer in the ABI in order to deal
with compat mode refer to user memory. Annotate their description
accordingly.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Enable drivers to create EVL factories in order to extend the core
services with new elements/features, benefiting from the object
lifetime management brought by the factory support.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

We need to wait for the synthetic irq fired by irq_work_queue() to be
delivered on the current CPU, so we'd better not stall the in-band
stage prior to waiting for the handler to complete (flush_work()).
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>

This mode measures the delay between the moment a synthetic interrupt
is posted from the oob stage and when it is eventually received by its
in-band handler. When measured under significant pressure, this gives
the typical interrupt latency experienced by the in-band kernel due to
local interrupt disabling.

As a result of this change, the current ABI revision is bumped to 25.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>

Signed-off-by: Philippe Gerum <rpm@xenomai.org>