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
  ...

1 files changed, 212 insertions, 0 deletions

diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index 89779eb84a07..9f2e8520b748 100644
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -223,3 +223,215 @@ static __init int init_dynamic_event(void)
 	return 0;
 }
 fs_initcall(init_dynamic_event);
+
+/**
+ * dynevent_arg_add - Add an arg to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @arg: The argument to append to the current cmd
+ * @check_arg: An (optional) pointer to a function checking arg sanity
+ *
+ * Append an argument to a dynevent_cmd.  The argument string will be
+ * appended to the current cmd string, followed by a separator, if
+ * applicable.  Before the argument is added, the @check_arg function,
+ * if present, will be used to check the sanity of the current arg
+ * string.
+ *
+ * The cmd string and separator should be set using the
+ * dynevent_arg_init() before any arguments are added using this
+ * function.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_arg_add(struct dynevent_cmd *cmd,
+		     struct dynevent_arg *arg,
+		     dynevent_check_arg_fn_t check_arg)
+{
+	int ret = 0;
+
+	if (check_arg) {
+		ret = check_arg(arg);
+		if (ret)
+			return ret;
+	}
+
+	ret = seq_buf_printf(&cmd->seq, " %s%c", arg->str, arg->separator);
+	if (ret) {
+		pr_err("String is too long: %s%c\n", arg->str, arg->separator);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_arg_pair_add - Add an arg pair to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @arg_pair: The argument pair to append to the current cmd
+ * @check_arg: An (optional) pointer to a function checking arg sanity
+ *
+ * Append an argument pair to a dynevent_cmd.  An argument pair
+ * consists of a left-hand-side argument and a right-hand-side
+ * argument separated by an operator, which can be whitespace, all
+ * followed by a separator, if applicable.  This can be used to add
+ * arguments of the form 'type variable_name;' or 'x+y'.
+ *
+ * The lhs argument string will be appended to the current cmd string,
+ * followed by an operator, if applicable, followd by the rhs string,
+ * followed finally by a separator, if applicable.  Before the
+ * argument is added, the @check_arg function, if present, will be
+ * used to check the sanity of the current arg strings.
+ *
+ * The cmd strings, operator, and separator should be set using the
+ * dynevent_arg_pair_init() before any arguments are added using this
+ * function.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
+			  struct dynevent_arg_pair *arg_pair,
+			  dynevent_check_arg_fn_t check_arg)
+{
+	int ret = 0;
+
+	if (check_arg) {
+		ret = check_arg(arg_pair);
+		if (ret)
+			return ret;
+	}
+
+	ret = seq_buf_printf(&cmd->seq, " %s%c%s%c", arg_pair->lhs,
+			     arg_pair->operator, arg_pair->rhs,
+			     arg_pair->separator);
+	if (ret) {
+		pr_err("field string is too long: %s%c%s%c\n", arg_pair->lhs,
+		       arg_pair->operator, arg_pair->rhs,
+		       arg_pair->separator);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_str_add - Add a string to a dynevent_cmd
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
+ * @str: The string to append to the current cmd
+ *
+ * Append a string to a dynevent_cmd.  The string will be appended to
+ * the current cmd string as-is, with nothing prepended or appended.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int dynevent_str_add(struct dynevent_cmd *cmd, const char *str)
+{
+	int ret = 0;
+
+	ret = seq_buf_puts(&cmd->seq, str);
+	if (ret) {
+		pr_err("String is too long: %s\n", str);
+		return -E2BIG;
+	}
+
+	return ret;
+}
+
+/**
+ * dynevent_cmd_init - Initialize a dynevent_cmd object
+ * @cmd: A pointer to the dynevent_cmd struct representing the cmd
+ * @buf: A pointer to the buffer to generate the command into
+ * @maxlen: The length of the buffer the command will be generated into
+ * @type: The type of the cmd, checked against further operations
+ * @run_command: The type-specific function that will actually run the command
+ *
+ * Initialize a dynevent_cmd.  A dynevent_cmd is used to build up and
+ * run dynamic event creation commands, such as commands for creating
+ * synthetic and kprobe events.  Before calling any of the functions
+ * used to build the command, a dynevent_cmd object should be
+ * instantiated and initialized using this function.
+ *
+ * The initialization sets things up by saving a pointer to the
+ * user-supplied buffer and its length via the @buf and @maxlen
+ * params, and by saving the cmd-specific @type and @run_command
+ * params which are used to check subsequent dynevent_cmd operations
+ * and actually run the command when complete.
+ */
+void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
+		       enum dynevent_type type,
+		       dynevent_create_fn_t run_command)
+{
+	memset(cmd, '\0', sizeof(*cmd));
+
+	seq_buf_init(&cmd->seq, buf, maxlen);
+	cmd->type = type;
+	cmd->run_command = run_command;
+}
+
+/**
+ * dynevent_arg_init - Initialize a dynevent_arg object
+ * @arg: A pointer to the dynevent_arg struct representing the arg
+ * @separator: An (optional) separator, appended after adding the arg
+ *
+ * Initialize a dynevent_arg object.  A dynevent_arg represents an
+ * object used to append single arguments to the current command
+ * string.  After the arg string is successfully appended to the
+ * command string, the optional @separator is appended.  If no
+ * separator was specified when initializing the arg, a space will be
+ * appended.
+ */
+void dynevent_arg_init(struct dynevent_arg *arg,
+		       char separator)
+{
+	memset(arg, '\0', sizeof(*arg));
+
+	if (!separator)
+		separator = ' ';
+	arg->separator = separator;
+}
+
+/**
+ * dynevent_arg_pair_init - Initialize a dynevent_arg_pair object
+ * @arg_pair: A pointer to the dynevent_arg_pair struct representing the arg
+ * @operator: An (optional) operator, appended after adding the first arg
+ * @separator: An (optional) separator, appended after adding the second arg
+ *
+ * Initialize a dynevent_arg_pair object.  A dynevent_arg_pair
+ * represents an object used to append argument pairs such as 'type
+ * variable_name;' or 'x+y' to the current command string.  An
+ * argument pair consists of a left-hand-side argument and a
+ * right-hand-side argument separated by an operator, which can be
+ * whitespace, all followed by a separator, if applicable.  After the
+ * first arg string is successfully appended to the command string,
+ * the optional @operator is appended, followed by the second arg and
+ * and optional @separator.  If no separator was specified when
+ * initializing the arg, a space will be appended.
+ */
+void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
+			    char operator, char separator)
+{
+	memset(arg_pair, '\0', sizeof(*arg_pair));
+
+	if (!operator)
+		operator = ' ';
+	arg_pair->operator = operator;
+
+	if (!separator)
+		separator = ' ';
+	arg_pair->separator = separator;
+}
+
+/**
+ * dynevent_create - Create the dynamic event contained in dynevent_cmd
+ * @cmd: The dynevent_cmd object containing the dynamic event creation command
+ *
+ * Once a dynevent_cmd object has been successfully built up via the
+ * dynevent_cmd_init(), dynevent_arg_add() and dynevent_arg_pair_add()
+ * functions, this function runs the final command to actually create
+ * the event.
+ *
+ * Return: 0 if the event was successfully created, error otherwise.
+ */
+int dynevent_create(struct dynevent_cmd *cmd)
+{
+	return cmd->run_command(cmd);
+}
+EXPORT_SYMBOL_GPL(dynevent_create);