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, 204 insertions, 34 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index aa515d578c5b..d8264ebb9581 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -22,7 +22,6 @@
 
 #define KPROBE_EVENT_SYSTEM "kprobes"
 #define KRETPROBE_MAXACTIVE_MAX 4096
-#define MAX_KPROBE_CMDLINE_SIZE 1024
 
 /* Kprobe early definition from command line */
 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
@@ -902,6 +901,167 @@ static int create_or_delete_trace_kprobe(int argc, char **argv)
 	return ret == -ECANCELED ? -EINVAL : ret;
 }
 
+static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
+{
+	return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
+}
+
+/**
+ * kprobe_event_cmd_init - Initialize a kprobe event command object
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @buf: A pointer to the buffer used to build the command
+ * @maxlen: The length of the buffer passed in @buf
+ *
+ * Initialize a synthetic event command object.  Use this before
+ * calling any of the other kprobe_event functions.
+ */
+void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
+{
+	dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
+			  trace_kprobe_run_command);
+}
+EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
+
+/**
+ * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @name: The name of the kprobe event
+ * @loc: The location of the kprobe event
+ * @kretprobe: Is this a return probe?
+ * @args: Variable number of arg (pairs), one pair for each field
+ *
+ * NOTE: Users normally won't want to call this function directly, but
+ * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
+ * adds a NULL to the end of the arg list.  If this function is used
+ * directly, make sure the last arg in the variable arg list is NULL.
+ *
+ * Generate a kprobe event command to be executed by
+ * kprobe_event_gen_cmd_end().  This function can be used to generate the
+ * complete command or only the first part of it; in the latter case,
+ * kprobe_event_add_fields() can be used to add more fields following this.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
+				 const char *name, const char *loc, ...)
+{
+	char buf[MAX_EVENT_NAME_LEN];
+	struct dynevent_arg arg;
+	va_list args;
+	int ret;
+
+	if (cmd->type != DYNEVENT_TYPE_KPROBE)
+		return -EINVAL;
+
+	if (kretprobe)
+		snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
+	else
+		snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
+
+	ret = dynevent_str_add(cmd, buf);
+	if (ret)
+		return ret;
+
+	dynevent_arg_init(&arg, 0);
+	arg.str = loc;
+	ret = dynevent_arg_add(cmd, &arg, NULL);
+	if (ret)
+		return ret;
+
+	va_start(args, loc);
+	for (;;) {
+		const char *field;
+
+		field = va_arg(args, const char *);
+		if (!field)
+			break;
+
+		if (++cmd->n_fields > MAX_TRACE_ARGS) {
+			ret = -EINVAL;
+			break;
+		}
+
+		arg.str = field;
+		ret = dynevent_arg_add(cmd, &arg, NULL);
+		if (ret)
+			break;
+	}
+	va_end(args);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
+
+/**
+ * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
+ * @cmd: A pointer to the dynevent_cmd struct representing the new event
+ * @args: Variable number of arg (pairs), one pair for each field
+ *
+ * NOTE: Users normally won't want to call this function directly, but
+ * rather use the kprobe_event_add_fields() wrapper, which
+ * automatically adds a NULL to the end of the arg list.  If this
+ * function is used directly, make sure the last arg in the variable
+ * arg list is NULL.
+ *
+ * Add probe fields to an existing kprobe command using a variable
+ * list of args.  Fields are added in the same order they're listed.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
+{
+	struct dynevent_arg arg;
+	va_list args;
+	int ret;
+
+	if (cmd->type != DYNEVENT_TYPE_KPROBE)
+		return -EINVAL;
+
+	dynevent_arg_init(&arg, 0);
+
+	va_start(args, cmd);
+	for (;;) {
+		const char *field;
+
+		field = va_arg(args, const char *);
+		if (!field)
+			break;
+
+		if (++cmd->n_fields > MAX_TRACE_ARGS) {
+			ret = -EINVAL;
+			break;
+		}
+
+		arg.str = field;
+		ret = dynevent_arg_add(cmd, &arg, NULL);
+		if (ret)
+			break;
+	}
+	va_end(args);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
+
+/**
+ * kprobe_event_delete - Delete a kprobe event
+ * @name: The name of the kprobe event to delete
+ *
+ * Delete a kprobe event with the give @name from kernel code rather
+ * than directly from the command line.
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int kprobe_event_delete(const char *name)
+{
+	char buf[MAX_EVENT_NAME_LEN];
+
+	snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
+
+	return trace_run_command(buf, create_or_delete_trace_kprobe);
+}
+EXPORT_SYMBOL_GPL(kprobe_event_delete);
+
 static int trace_kprobe_release(struct dyn_event *ev)
 {
 	struct trace_kprobe *tk = to_trace_kprobe(ev);
@@ -1175,35 +1335,35 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 		    struct trace_event_file *trace_file)
 {
 	struct kprobe_trace_entry_head *entry;
-	struct ring_buffer_event *event;
-	struct ring_buffer *buffer;
-	int size, dsize, pc;
-	unsigned long irq_flags;
 	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	struct trace_event_buffer fbuffer;
+	int dsize;
 
 	WARN_ON(call != trace_file->event_call);
 
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	local_save_flags(irq_flags);
-	pc = preempt_count();
+	local_save_flags(fbuffer.flags);
+	fbuffer.pc = preempt_count();
+	fbuffer.trace_file = trace_file;
 
 	dsize = __get_data_size(&tk->tp, regs);
-	size = sizeof(*entry) + tk->tp.size + dsize;
 
-	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-						call->event.type,
-						size, irq_flags, pc);
-	if (!event)
+	fbuffer.event =
+		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+					call->event.type,
+					sizeof(*entry) + tk->tp.size + dsize,
+					fbuffer.flags, fbuffer.pc);
+	if (!fbuffer.event)
 		return;
 
-	entry = ring_buffer_event_data(event);
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
 	entry->ip = (unsigned long)tk->rp.kp.addr;
 	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 
-	event_trigger_unlock_commit_regs(trace_file, buffer, event,
-					 entry, irq_flags, pc, regs);
+	trace_event_buffer_commit(&fbuffer);
 }
 
 static void
@@ -1223,36 +1383,35 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 		       struct trace_event_file *trace_file)
 {
 	struct kretprobe_trace_entry_head *entry;
-	struct ring_buffer_event *event;
-	struct ring_buffer *buffer;
-	int size, pc, dsize;
-	unsigned long irq_flags;
+	struct trace_event_buffer fbuffer;
 	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+	int dsize;
 
 	WARN_ON(call != trace_file->event_call);
 
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	local_save_flags(irq_flags);
-	pc = preempt_count();
+	local_save_flags(fbuffer.flags);
+	fbuffer.pc = preempt_count();
+	fbuffer.trace_file = trace_file;
 
 	dsize = __get_data_size(&tk->tp, regs);
-	size = sizeof(*entry) + tk->tp.size + dsize;
-
-	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-						call->event.type,
-						size, irq_flags, pc);
-	if (!event)
+	fbuffer.event =
+		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+					call->event.type,
+					sizeof(*entry) + tk->tp.size + dsize,
+					fbuffer.flags, fbuffer.pc);
+	if (!fbuffer.event)
 		return;
 
-	entry = ring_buffer_event_data(event);
+	fbuffer.regs = regs;
+	entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
 	entry->func = (unsigned long)tk->rp.kp.addr;
 	entry->ret_ip = (unsigned long)ri->ret_addr;
 	store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 
-	event_trigger_unlock_commit_regs(trace_file, buffer, event,
-					 entry, irq_flags, pc, regs);
+	trace_event_buffer_commit(&fbuffer);
 }
 
 static void
@@ -1698,11 +1857,12 @@ static __init void setup_boot_kprobe_events(void)
 	enable_boot_kprobe_events();
 }
 
-/* Make a tracefs interface for controlling probe points */
-static __init int init_kprobe_trace(void)
+/*
+ * Register dynevent at subsys_initcall. This allows kernel to setup kprobe
+ * events in fs_initcall without tracefs.
+ */
+static __init int init_kprobe_trace_early(void)
 {
-	struct dentry *d_tracer;
-	struct dentry *entry;
 	int ret;
 
 	ret = dyn_event_register(&trace_kprobe_ops);
@@ -1712,6 +1872,16 @@ static __init int init_kprobe_trace(void)
 	if (register_module_notifier(&trace_kprobe_module_nb))
 		return -EINVAL;
 
+	return 0;
+}
+subsys_initcall(init_kprobe_trace_early);
+
+/* Make a tracefs interface for controlling probe points */
+static __init int init_kprobe_trace(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
 	d_tracer = tracing_init_dentry();
 	if (IS_ERR(d_tracer))
 		return 0;