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, 12 insertions, 2 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fd3cb2b2ab82..4f424364d1c6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2878,13 +2878,16 @@ trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
 
 void
 trace_function(struct trace_array *tr, unsigned long ip, unsigned long
-	       parent_ip, unsigned int trace_ctx)
+	       parent_ip, unsigned int trace_ctx, struct ftrace_regs *fregs)
 {
 	struct trace_buffer *buffer = tr->array_buffer.buffer;
 	struct ring_buffer_event *event;
 	struct ftrace_entry *entry;
+	int size = sizeof(*entry);
 
-	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
+	size += FTRACE_REGS_MAX_ARGS * !!fregs * sizeof(long);
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, size,
 					    trace_ctx);
 	if (!event)
 		return;
@@ -2892,6 +2895,13 @@ trace_function(struct trace_array *tr, unsigned long ip, unsigned long
 	entry->ip			= ip;
 	entry->parent_ip		= parent_ip;
 
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	if (fregs) {
+		for (int i = 0; i < FTRACE_REGS_MAX_ARGS; i++)
+			entry->args[i] = ftrace_regs_get_argument(fregs, i);
+	}
+#endif
+
 	if (static_branch_unlikely(&trace_function_exports_enabled))
 		ftrace_exports(event, TRACE_EXPORT_FUNCTION);
 	__buffer_unlock_commit(buffer, event);