Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Add function names as a way to filter function addresses

 - Add sample module to test ftrace ops and dynamic trampolines

 - Allow stack traces to be passed from beginning event to end event for
   synthetic events. This will allow seeing the stack trace of when a
   task is scheduled out and recorded when it gets scheduled back in.

 - Add trace event helper __get_buf() to use as a temporary buffer when
   printing out trace event output.

 - Add kernel command line to create trace instances on boot up.

 - Add enabling of events to instances created at boot up.

 - Add trace_array_puts() to write into instances.

 - Allow boot instances to take a snapshot at the end of boot up.

 - Allow live patch modules to include trace events

 - Minor fixes and clean ups

* tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits)
  tracing: Remove unnecessary NULL assignment
  tracepoint: Allow livepatch module add trace event
  tracing: Always use canonical ftrace path
  tracing/histogram: Fix stacktrace histogram Documententation
  tracing/histogram: Fix stacktrace key
  tracing/histogram: Fix a few problems with stacktrace variable printing
  tracing: Add BUILD_BUG() to make sure stacktrace fits in strings
  tracing/histogram: Don't use strlen to find length of stacktrace variables
  tracing: Allow boot instances to have snapshot buffers
  tracing: Add trace_array_puts() to write into instance
  tracing: Add enabling of events to boot instances
  tracing: Add creation of instances at boot command line
  tracing: Fix trace_event_raw_event_synth() if else statement
  samples: ftrace: Make some global variables static
  ftrace: sample: avoid open-coded 64-bit division
  samples: ftrace: Include the nospec-branch.h only for x86
  tracing: Acquire buffer from temparary trace sequence
  tracing/histogram: Wrap remaining shell snippets in code blocks
  tracing/osnoise: No need for schedule_hrtimeout range
  bpf/tracing: Use stage6 of tracing to not duplicate macros
  ...

1 files changed, 29 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 21b7f87b00fe..276a793168a6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1509,6 +1509,15 @@
 			boot up that is likely to be overridden by user space
 			start up functionality.
 
+			Optionally, the snapshot can also be defined for a tracing
+			instance that was created by the trace_instance= command
+			line parameter.
+
+			trace_instance=foo,sched_switch ftrace_boot_snapshot=foo
+
+			The above will cause the "foo" tracing instance to trigger
+			a snapshot at the end of boot up.
+
 	ftrace_dump_on_oops[=orig_cpu]
 			[FTRACE] will dump the trace buffers on oops.
 			If no parameter is passed, ftrace will dump
@@ -6283,6 +6292,26 @@
 			comma-separated list of trace events to enable. See
 			also Documentation/trace/events.rst
 
+	trace_instance=[instance-info]
+			[FTRACE] Create a ring buffer instance early in boot up.
+			This will be listed in:
+
+				/sys/kernel/tracing/instances
+
+			Events can be enabled at the time the instance is created
+			via:
+
+				trace_instance=<name>,<system1>:<event1>,<system2>:<event2>
+
+			Note, the "<system*>:" portion is optional if the event is
+			unique.
+
+				trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall
+
+			will enable the "sched_switch" event (note, the "sched:" is optional, and
+			the same thing would happen if it was left off). The irq_handler_entry
+			event, and all events under the "initcall" system.
+
 	trace_options=[option-list]
 			[FTRACE] Enable or disable tracer options at boot.
 			The option-list is a comma delimited list of options