Merge tag 'trace-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Allow kernel trace instance creation to specify what events are
   created

   Inside the kernel, a subsystem may create a tracing instance that it
   can use to send events to user space. This sub-system may not care
   about the thousands of events that exist in eventfs. Allow the
   sub-system to specify what sub-systems of events it cares about, and
   only those events are exposed to this instance.

 - Allow the ring buffer to be broken up into bigger sub-buffers than
   just the architecture page size.

   A new tracefs file called "buffer_subbuf_size_kb" is created. The
   user can now specify a minimum size the sub-buffer may be in
   kilobytes. Note, that the implementation currently make the
   sub-buffer size a power of 2 pages (1, 2, 4, 8, 16, ...) but the user
   only writes in kilobyte size, and the sub-buffer will be updated to
   the next size that it will can accommodate it. If the user writes in
   10, it will change the size to be 4 pages on x86 (16K), as that is
   the next available size that can hold 10K pages.

 - Update the debug output when a corrupt time is detected in the ring
   buffer. If the ring buffer detects inconsistent timestamps, there's a
   debug config options that will dump the contents of the meta data of
   the sub-buffer that is used for debugging. Add some more information
   to this dump that helps with debugging.

 - Add more timestamp debugging checks (only triggers when the config is
   enabled)

 - Increase the trace_seq iterator to 2 page sizes.

 - Allow strings written into tracefs_marker to be larger. Up to just
   under 2 page sizes (based on what trace_seq can hold).

 - Increase the trace_maker_raw write to be as big as a sub-buffer can
   hold.

 - Remove 32 bit time stamp logic, now that the rb_time_cmpxchg() has
   been removed.

 - More selftests were added.

 - Some code clean ups as well.

* tag 'trace-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (29 commits)
  ring-buffer: Remove stale comment from ring_buffer_size()
  tracing histograms: Simplify parse_actions() function
  tracing/selftests: Remove exec permissions from trace_marker.tc test
  ring-buffer: Use subbuf_order for buffer page masking
  tracing: Update subbuffer with kilobytes not page order
  ringbuffer/selftest: Add basic selftest to test changing subbuf order
  ring-buffer: Add documentation on the buffer_subbuf_order file
  ring-buffer: Just update the subbuffers when changing their allocation order
  ring-buffer: Keep the same size when updating the order
  tracing: Stop the tracing while changing the ring buffer subbuf size
  tracing: Update snapshot order along with main buffer order
  ring-buffer: Make sure the spare sub buffer used for reads has same size
  ring-buffer: Do no swap cpu buffers if order is different
  ring-buffer: Clear pages on error in ring_buffer_subbuf_order_set() failure
  ring-buffer: Read and write to ring buffers with custom sub buffer size
  ring-buffer: Set new size of the ring buffer sub page
  ring-buffer: Add interface for configuring trace sub buffer size
  ring-buffer: Page size per ring buffer
  ring-buffer: Have ring_buffer_print_page_header() be able to access ring_buffer_iter
  ring-buffer: Check if absolute timestamp goes backwards
  ...

2 files changed, 177 insertions, 0 deletions

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc
new file mode 100644
index 000000000000..d44d09a33a74
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/ringbuffer_subbuf_size.tc
@@ -0,0 +1,95 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Change the ringbuffer sub-buffer size
+# requires: buffer_subbuf_size_kb
+# flags: instance
+
+get_buffer_data_size() {
+	sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+get_buffer_data_offset() {
+	sed -ne 's/^.*data.*offset:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+get_event_header_size() {
+	type_len=`sed -ne 's/^.*type_len.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	time_len=`sed -ne 's/^.*time_delta.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	array_len=`sed -ne 's/^.*array.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	total_bits=$((type_len+time_len+array_len))
+	total_bits=$((total_bits+7))
+	echo $((total_bits/8))
+}
+
+get_print_event_buf_offset() {
+	sed -ne 's/^.*buf.*offset:\([0-9][0-9]*\).*/\1/p' events/ftrace/print/format
+}
+
+event_header_size=`get_event_header_size`
+print_header_size=`get_print_event_buf_offset`
+
+data_offset=`get_buffer_data_offset`
+
+marker_meta=$((event_header_size+print_header_size))
+
+make_str() {
+        cnt=$1
+	printf -- 'X%.0s' $(seq $cnt)
+}
+
+write_buffer() {
+	size=$1
+
+	str=`make_str $size`
+
+	# clear the buffer
+	echo > trace
+
+	# write the string into the marker
+	echo $str > trace_marker
+
+	echo $str
+}
+
+test_buffer() {
+	size_kb=$1
+	page_size=$((size_kb*1024))
+
+	size=`get_buffer_data_size`
+
+	# the size must be greater than or equal to page_size - data_offset
+	page_size=$((page_size-data_offset))
+	if [ $size -lt $page_size ]; then
+		exit fail
+	fi
+
+	# Now add a little more the meta data overhead will overflow
+
+	str=`write_buffer $size`
+
+	# Make sure the line was broken
+	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; exit}' trace`
+
+	if [ "$new_str" = "$str" ]; then
+		exit fail;
+	fi
+
+	# Make sure the entire line can be found
+	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; }' trace`
+
+	if [ "$new_str" != "$str" ]; then
+		exit fail;
+	fi
+}
+
+ORIG=`cat buffer_subbuf_size_kb`
+
+# Could test bigger sizes than 32K, but then creating the string
+# to write into the ring buffer takes too long
+for a in 4 8 16 32 ; do
+	echo $a > buffer_subbuf_size_kb
+	test_buffer $a
+done
+
+echo $ORIG > buffer_subbuf_size_kb
+
diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
new file mode 100644
index 000000000000..9aa0db2b84fc
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
@@ -0,0 +1,82 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Basic tests on writing to trace_marker
+# requires: trace_marker
+# flags: instance
+
+get_buffer_data_size() {
+	sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+get_buffer_data_offset() {
+	sed -ne 's/^.*data.*offset:\([0-9][0-9]*\).*/\1/p' events/header_page
+}
+
+get_event_header_size() {
+	type_len=`sed -ne 's/^.*type_len.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	time_len=`sed -ne 's/^.*time_delta.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	array_len=`sed -ne 's/^.*array.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
+	total_bits=$((type_len+time_len+array_len))
+	total_bits=$((total_bits+7))
+	echo $((total_bits/8))
+}
+
+get_print_event_buf_offset() {
+	sed -ne 's/^.*buf.*offset:\([0-9][0-9]*\).*/\1/p' events/ftrace/print/format
+}
+
+event_header_size=`get_event_header_size`
+print_header_size=`get_print_event_buf_offset`
+
+data_offset=`get_buffer_data_offset`
+
+marker_meta=$((event_header_size+print_header_size))
+
+make_str() {
+        cnt=$1
+	# subtract two for \n\0 as marker adds these
+	cnt=$((cnt-2))
+	printf -- 'X%.0s' $(seq $cnt)
+}
+
+write_buffer() {
+	size=$1
+
+	str=`make_str $size`
+
+	# clear the buffer
+	echo > trace
+
+	# write the string into the marker
+	echo -n $str > trace_marker
+
+	echo $str
+}
+
+test_buffer() {
+
+	size=`get_buffer_data_size`
+	oneline_size=$((size-marker_meta))
+	echo size = $size
+	echo meta size = $marker_meta
+
+	# Now add a little more the meta data overhead will overflow
+
+	str=`write_buffer $size`
+
+	# Make sure the line was broken
+	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; exit}' trace`
+
+	if [ "$new_str" = "$str" ]; then
+		exit fail;
+	fi
+
+	# Make sure the entire line can be found
+	new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; }' trace`
+
+	if [ "$new_str" != "$str" ]; then
+		exit fail;
+	fi
+}
+
+test_buffer