Tracing updates:

- Added new "bootconfig".
    Looks for a file appended to initrd to add boot config options.
    This has been discussed thoroughly at Linux Plumbers.
    Very useful for adding kprobes at bootup.
    Only enabled if "bootconfig" is on the real kernel command line.
 
  - Created dynamic event creation.
    Merges common code between creating synthetic events and
      kprobe events.
 
  - Rename perf "ring_buffer" structure to "perf_buffer"
 
  - Rename ftrace "ring_buffer" structure to "trace_buffer"
    Had to rename existing "trace_buffer" to "array_buffer"
 
  - Allow trace_printk() to work withing (some) tracing code.
 
  - Sort of tracing configs to be a little better organized
 
  - Fixed bug where ftrace_graph hash was not being protected properly
 
  - Various other small fixes and clean ups
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Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added new "bootconfig".

   This looks for a file appended to initrd to add boot config options,
   and has been discussed thoroughly at Linux Plumbers.

   Very useful for adding kprobes at bootup.

   Only enabled if "bootconfig" is on the real kernel command line.

 - Created dynamic event creation.

   Merges common code between creating synthetic events and kprobe
   events.

 - Rename perf "ring_buffer" structure to "perf_buffer"

 - Rename ftrace "ring_buffer" structure to "trace_buffer"

   Had to rename existing "trace_buffer" to "array_buffer"

 - Allow trace_printk() to work withing (some) tracing code.

 - Sort of tracing configs to be a little better organized

 - Fixed bug where ftrace_graph hash was not being protected properly

 - Various other small fixes and clean ups

* tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits)
  bootconfig: Show the number of nodes on boot message
  tools/bootconfig: Show the number of bootconfig nodes
  bootconfig: Add more parse error messages
  bootconfig: Use bootconfig instead of boot config
  ftrace: Protect ftrace_graph_hash with ftrace_sync
  ftrace: Add comment to why rcu_dereference_sched() is open coded
  tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
  tracing: Annotate ftrace_graph_hash pointer with __rcu
  bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
  tracing: Use seq_buf for building dynevent_cmd string
  tracing: Remove useless code in dynevent_arg_pair_add()
  tracing: Remove check_arg() callbacks from dynevent args
  tracing: Consolidate some synth_event_trace code
  tracing: Fix now invalid var_ref_vals assumption in trace action
  tracing: Change trace_boot to use synth_event interface
  tracing: Move tracing selftests to bottom of menu
  tracing: Move mmio tracer config up with the other tracers
  tracing: Move tracing test module configs together
  tracing: Move all function tracing configs together
  tracing: Documentation for in-kernel synthetic event API
  ...

include/linux/trace_events.h

@@ -11,7 +11,7 @@
 #include <linux/tracepoint.h>
 
 struct trace_array;
-struct trace_buffer;
+struct array_buffer;
 struct tracer;
 struct dentry;
 struct bpf_prog;
@@ -79,7 +79,7 @@ struct trace_entry {
 struct trace_iterator {
 	struct trace_array	*tr;
 	struct tracer		*trace;
-	struct trace_buffer	*trace_buffer;
+	struct array_buffer	*array_buffer;
 	void			*private;
 	int			cpu_file;
 	struct mutex		mutex;
@@ -153,7 +153,7 @@ void tracing_generic_entry_update(struct trace_entry *entry,
 struct trace_event_file;
 
 struct ring_buffer_event *
-trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
+trace_event_buffer_lock_reserve(struct trace_buffer **current_buffer,
 				struct trace_event_file *trace_file,
 				int type, unsigned long len,
 				unsigned long flags, int pc);
@@ -226,12 +226,13 @@ extern int trace_event_reg(struct trace_event_call *event,
 			    enum trace_reg type, void *data);
 
 struct trace_event_buffer {
-	struct ring_buffer		*buffer;
+	struct trace_buffer		*buffer;
 	struct ring_buffer_event	*event;
 	struct trace_event_file		*trace_file;
 	void				*entry;
 	unsigned long			flags;
 	int				pc;
+	struct pt_regs			*regs;
 };
 
 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
@@ -364,6 +365,128 @@ enum {
 	EVENT_FILE_FL_WAS_ENABLED_BIT,
 };
 
+extern struct trace_event_file *trace_get_event_file(const char *instance,
+						     const char *system,
+						     const char *event);
+extern void trace_put_event_file(struct trace_event_file *file);
+
+#define MAX_DYNEVENT_CMD_LEN	(2048)
+
+enum dynevent_type {
+	DYNEVENT_TYPE_SYNTH = 1,
+	DYNEVENT_TYPE_KPROBE,
+	DYNEVENT_TYPE_NONE,
+};
+
+struct dynevent_cmd;
+
+typedef int (*dynevent_create_fn_t)(struct dynevent_cmd *cmd);
+
+struct dynevent_cmd {
+	struct seq_buf		seq;
+	const char		*event_name;
+	unsigned int		n_fields;
+	enum dynevent_type	type;
+	dynevent_create_fn_t	run_command;
+	void			*private_data;
+};
+
+extern int dynevent_create(struct dynevent_cmd *cmd);
+
+extern int synth_event_delete(const char *name);
+
+extern void synth_event_cmd_init(struct dynevent_cmd *cmd,
+				 char *buf, int maxlen);
+
+extern int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd,
+				       const char *name,
+				       struct module *mod, ...);
+
+#define synth_event_gen_cmd_start(cmd, name, mod, ...)	\
+	__synth_event_gen_cmd_start(cmd, name, mod, ## __VA_ARGS__, NULL)
+
+struct synth_field_desc {
+	const char *type;
+	const char *name;
+};
+
+extern int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd,
+					   const char *name,
+					   struct module *mod,
+					   struct synth_field_desc *fields,
+					   unsigned int n_fields);
+extern int synth_event_create(const char *name,
+			      struct synth_field_desc *fields,
+			      unsigned int n_fields, struct module *mod);
+
+extern int synth_event_add_field(struct dynevent_cmd *cmd,
+				 const char *type,
+				 const char *name);
+extern int synth_event_add_field_str(struct dynevent_cmd *cmd,
+				     const char *type_name);
+extern int synth_event_add_fields(struct dynevent_cmd *cmd,
+				  struct synth_field_desc *fields,
+				  unsigned int n_fields);
+
+#define synth_event_gen_cmd_end(cmd)	\
+	dynevent_create(cmd)
+
+struct synth_event;
+
+struct synth_event_trace_state {
+	struct trace_event_buffer fbuffer;
+	struct synth_trace_event *entry;
+	struct trace_buffer *buffer;
+	struct synth_event *event;
+	unsigned int cur_field;
+	unsigned int n_u64;
+	bool enabled;
+	bool add_next;
+	bool add_name;
+};
+
+extern int synth_event_trace(struct trace_event_file *file,
+			     unsigned int n_vals, ...);
+extern int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
+				   unsigned int n_vals);
+extern int synth_event_trace_start(struct trace_event_file *file,
+				   struct synth_event_trace_state *trace_state);
+extern int synth_event_add_next_val(u64 val,
+				    struct synth_event_trace_state *trace_state);
+extern int synth_event_add_val(const char *field_name, u64 val,
+			       struct synth_event_trace_state *trace_state);
+extern int synth_event_trace_end(struct synth_event_trace_state *trace_state);
+
+extern int kprobe_event_delete(const char *name);
+
+extern void kprobe_event_cmd_init(struct dynevent_cmd *cmd,
+				  char *buf, int maxlen);
+
+#define kprobe_event_gen_cmd_start(cmd, name, loc, ...)			\
+	__kprobe_event_gen_cmd_start(cmd, false, name, loc, ## __VA_ARGS__, NULL)
+
+#define kretprobe_event_gen_cmd_start(cmd, name, loc, ...)		\
+	__kprobe_event_gen_cmd_start(cmd, true, name, loc, ## __VA_ARGS__, NULL)
+
+extern int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd,
+					bool kretprobe,
+					const char *name,
+					const char *loc, ...);
+
+#define kprobe_event_add_fields(cmd, ...)	\
+	__kprobe_event_add_fields(cmd, ## __VA_ARGS__, NULL)
+
+#define kprobe_event_add_field(cmd, field)	\
+	__kprobe_event_add_fields(cmd, field, NULL)
+
+extern int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...);
+
+#define kprobe_event_gen_cmd_end(cmd)		\
+	dynevent_create(cmd)
+
+#define kretprobe_event_gen_cmd_end(cmd)	\
+	dynevent_create(cmd)
+
 /*
  * Event file flags:
  *  ENABLED	  - The event is enabled