Add low level event recording support

Add low level event recording infrastructure for system and user
defined events.  The infrastructure is able to record high frequency
events such as

 * SMP lock acquire/release,
 * interrupt entry/exit,
 * thread switches,
 * UMA zone allocate/free, and
 * Ethernet packet input/output, etc.

It allows post-mortem analysis in fatal error handlers, e.g. the last
events are in the record buffer, the newest event overwrites the oldest
event.  It is possible to detect record buffer overflows for consumers
that expect a continuous stream of events, e.g. to display the system
state in real-time.

The implementation supports high-end SMP machines (more than 1GHz
processor frequency, more than four processors).

Add a new API instead. The implementation uses per-processor data
structures and no atomic read-modify-write operations.  It is uses
per-processor ring buffers to record the events.

The CPU counter is used to get the time of events. It is combined with
periodic uptime events to synchronize it with CLOCK_REALTIME.

The existing capture engine tries to solve this problem also, but its
performance is not good enough for high-end production systems.  The
main issues are the variable-size buffers and the use of SMP locks for
synchronization.  To fix this, the API would change significantly.

Update #3665.

1 files changed, 132 insertions, 0 deletions

diff --git a/cpukit/libtrace/record/record.c b/cpukit/libtrace/record/record.c
new file mode 100644
index 0000000000..33b770badd
--- /dev/null
+++ b/cpukit/libtrace/record/record.c
@@ -0,0 +1,132 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (C) 2018, 2019 embedded brains GmbH
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <rtems/record.h>
+#include <rtems/config.h>
+#include <rtems/score/assert.h>
+
+#include <string.h>
+
+void rtems_record_produce( rtems_record_event event, rtems_record_data data )
+{
+  rtems_record_context context;
+
+  rtems_record_prepare( &context );
+  rtems_record_add( &context, event, data );
+  rtems_record_commit( &context );
+}
+
+void rtems_record_produce_2(
+  rtems_record_event event_0,
+  rtems_record_data  data_0,
+  rtems_record_event event_1,
+  rtems_record_data  data_1
+)
+{
+  rtems_record_context context;
+
+  rtems_record_prepare( &context );
+  rtems_record_add( &context, event_0, data_0 );
+  rtems_record_add( &context, event_1, data_1 );
+  rtems_record_commit( &context );
+}
+
+void rtems_record_produce_n(
+  const rtems_record_item *items,
+  size_t                   n
+)
+{
+  rtems_record_context context;
+
+  _Assert( n > 0 );
+
+  rtems_record_prepare( &context );
+
+  do {
+    rtems_record_add( &context, items->event, items->data );
+    ++items;
+    --n;
+  } while ( n > 0 );
+
+  rtems_record_commit( &context );
+}
+
+void rtems_record_drain( rtems_record_drain_visitor visitor, void *arg )
+{
+  uint32_t cpu_max;
+  uint32_t cpu_index;
+
+  cpu_max = rtems_configuration_get_maximum_processors();
+
+  for ( cpu_index = 0; cpu_index < cpu_max; ++cpu_index ) {
+    Per_CPU_Control   *cpu;
+    Record_Control    *control;
+    unsigned int       tail;
+    unsigned int       head;
+
+    cpu = _Per_CPU_Get_by_index( cpu_index );
+    control = cpu->record;
+
+    tail = _Record_Tail( control );
+    head = _Atomic_Load_uint( &control->head, ATOMIC_ORDER_ACQUIRE );
+
+    if ( tail == head ) {
+      continue;
+    }
+
+    control->tail = head;
+
+    control->Header[ 0 ].event = RTEMS_RECORD_PROCESSOR;
+    control->Header[ 0 ].data = cpu_index;
+    control->Header[ 1 ].event = RTEMS_RECORD_TAIL;
+    control->Header[ 1 ].data = tail;
+    control->Header[ 2 ].event = RTEMS_RECORD_HEAD;
+    control->Header[ 2 ].data = head;
+    ( *visitor )( control->Header, RTEMS_ARRAY_SIZE( control->Header ), arg );
+
+    if ( _Record_Is_overflow( control, tail, head ) ) {
+      tail = head + 1;
+    }
+
+    tail = _Record_Index( control, tail );
+    head = _Record_Index( control, head );
+
+    if ( tail < head ) {
+      ( *visitor )( &control->Items[ tail ], head - tail, arg );
+    } else {
+      ( *visitor )( &control->Items[ tail ], control->mask + 1 - tail, arg );
+
+      if ( head > 0 ) {
+        ( *visitor )( &control->Items[ 0 ], head, arg );
+      }
+    }
+  }
+}