Merge tag 'ftrace-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull ftrace updates from Steven Rostedt:

 - Record function parameters for function and function graph tracers

   An option has been added to function tracer (func-args) and the
   function graph tracer (funcgraph-args) that when set, the tracers
   will record the registers that hold the arguments into each function
   event. On reading of the trace, it will use BTF to print those
   arguments. Most archs support up to 6 arguments (depending on the
   complexity of the arguments) and those are printed.

   If a function has more arguments then what was recorded, the output
   will end with " ... )".

   Example of function graph tracer:

	6)              | dummy_xmit [dummy](skb = 0x8887c100, dev = 0x872ca000) {
	6)              |   consume_skb(skb = 0x8887c100) {
	6)              |     skb_release_head_state(skb = 0x8887c100) {
	6)  0.178 us    |       sock_wfree(skb = 0x8887c100)
	6)  0.627 us    |     }

 - The rest of the changes are minor clean ups and fixes

* tag 'ftrace-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Use hashtable.h for event_hash
  tracing: Fix use-after-free in print_graph_function_flags during tracer switching
  function_graph: Remove the unused variable func
  ftrace: Add arguments to function tracer
  ftrace: Have funcgraph-args take affect during tracing
  ftrace: Add support for function argument to graph tracer
  ftrace: Add print_function_args()
  ftrace: Have ftrace_free_filter() WARN and exit if ops is active
  fgraph: Correct typo in ftrace_return_to_handler comment

1 files changed, 41 insertions, 5 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index df56f9b76010..98ccf3f00c51 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -25,6 +25,9 @@ static void
 function_trace_call(unsigned long ip, unsigned long parent_ip,
 		    struct ftrace_ops *op, struct ftrace_regs *fregs);
 static void
+function_args_trace_call(unsigned long ip, unsigned long parent_ip,
+			 struct ftrace_ops *op, struct ftrace_regs *fregs);
+static void
 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
 			  struct ftrace_ops *op, struct ftrace_regs *fregs);
 static void
@@ -42,9 +45,10 @@ enum {
 	TRACE_FUNC_NO_OPTS		= 0x0, /* No flags set. */
 	TRACE_FUNC_OPT_STACK		= 0x1,
 	TRACE_FUNC_OPT_NO_REPEATS	= 0x2,
+	TRACE_FUNC_OPT_ARGS		= 0x4,
 
 	/* Update this to next highest bit. */
-	TRACE_FUNC_OPT_HIGHEST_BIT	= 0x4
+	TRACE_FUNC_OPT_HIGHEST_BIT	= 0x8
 };
 
 #define TRACE_FUNC_OPT_MASK	(TRACE_FUNC_OPT_HIGHEST_BIT - 1)
@@ -114,6 +118,8 @@ static ftrace_func_t select_trace_function(u32 flags_val)
 	switch (flags_val & TRACE_FUNC_OPT_MASK) {
 	case TRACE_FUNC_NO_OPTS:
 		return function_trace_call;
+	case TRACE_FUNC_OPT_ARGS:
+		return function_args_trace_call;
 	case TRACE_FUNC_OPT_STACK:
 		return function_stack_trace_call;
 	case TRACE_FUNC_OPT_NO_REPEATS:
@@ -220,7 +226,34 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
 
 	data = this_cpu_ptr(tr->array_buffer.data);
 	if (!atomic_read(&data->disabled))
-		trace_function(tr, ip, parent_ip, trace_ctx);
+		trace_function(tr, ip, parent_ip, trace_ctx, NULL);
+
+	ftrace_test_recursion_unlock(bit);
+}
+
+static void
+function_args_trace_call(unsigned long ip, unsigned long parent_ip,
+			 struct ftrace_ops *op, struct ftrace_regs *fregs)
+{
+	struct trace_array *tr = op->private;
+	struct trace_array_cpu *data;
+	unsigned int trace_ctx;
+	int bit;
+	int cpu;
+
+	if (unlikely(!tr->function_enabled))
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0)
+		return;
+
+	trace_ctx = tracing_gen_ctx();
+
+	cpu = smp_processor_id();
+	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	if (!atomic_read(&data->disabled))
+		trace_function(tr, ip, parent_ip, trace_ctx, fregs);
 
 	ftrace_test_recursion_unlock(bit);
 }
@@ -270,7 +303,7 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
 
 	if (likely(disabled == 1)) {
 		trace_ctx = tracing_gen_ctx_flags(flags);
-		trace_function(tr, ip, parent_ip, trace_ctx);
+		trace_function(tr, ip, parent_ip, trace_ctx, NULL);
 #ifdef CONFIG_UNWINDER_FRAME_POINTER
 		if (ftrace_pids_enabled(op))
 			skip++;
@@ -349,7 +382,7 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
 	trace_ctx = tracing_gen_ctx_dec();
 	process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
 
-	trace_function(tr, ip, parent_ip, trace_ctx);
+	trace_function(tr, ip, parent_ip, trace_ctx, NULL);
 
 out:
 	ftrace_test_recursion_unlock(bit);
@@ -389,7 +422,7 @@ function_stack_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
 		trace_ctx = tracing_gen_ctx_flags(flags);
 		process_repeats(tr, ip, parent_ip, last_info, trace_ctx);
 
-		trace_function(tr, ip, parent_ip, trace_ctx);
+		trace_function(tr, ip, parent_ip, trace_ctx, NULL);
 		__trace_stack(tr, trace_ctx, STACK_SKIP);
 	}
 
@@ -403,6 +436,9 @@ static struct tracer_opt func_opts[] = {
 	{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
 #endif
 	{ TRACER_OPT(func-no-repeats, TRACE_FUNC_OPT_NO_REPEATS) },
+#ifdef CONFIG_FUNCTION_TRACE_ARGS
+	{ TRACER_OPT(func-args, TRACE_FUNC_OPT_ARGS) },
+#endif
 	{ } /* Always set a last empty entry */
 };