Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "New tracing features:

   - The ring buffer is no longer disabled when reading the trace file.

     The trace_pipe file was made to be used for live tracing and
     reading as it acted like the normal producer/consumer. As the trace
     file would not consume the data, the easy way of handling it was to
     just disable writes to the ring buffer.

     This came to a surprise to the BPF folks who complained about lost
     events due to reading. This is no longer an issue. If someone wants
     to keep the old disabling there's a new option "pause-on-trace"
     that can be set.

   - New set_ftrace_notrace_pid file. PIDs in this file will not be
     traced by the function tracer.

     Similar to set_ftrace_pid, which makes the function tracer only
     trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
     does the reverse.

   - New set_event_notrace_pid file. PIDs in this file will cause events
     not to be traced if triggered by a task with a matching PID.

     Similar to the set_event_pid file but will not be traced. Note,
     sched_waking and sched_switch events may still be traced if one of
     the tasks referenced by those events contains a PID that is allowed
     to be traced.

  Tracing related features:

   - New bootconfig option, that is attached to the initrd file.

     If bootconfig is on the command line, then the initrd file is
     searched looking for a bootconfig appended at the end.

   - New GPU tracepoint infrastructure to help the gfx drivers to get
     off debugfs (acked by Greg Kroah-Hartman)

  And other minor updates and fixes"

* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
  tracing: Do not allocate buffer in trace_find_next_entry() in atomic
  tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
  selftests/ftrace: Add test to test new set_event_notrace_pid file
  selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
  tracing: Create set_event_notrace_pid to not trace tasks
  ftrace: Create set_ftrace_notrace_pid to not trace tasks
  ftrace: Make function trace pid filtering a bit more exact
  ftrace/kprobe: Show the maxactive number on kprobe_events
  tracing: Have the document reflect that the trace file keeps tracing enabled
  ring-buffer/tracing: Have iterator acknowledge dropped events
  tracing: Do not disable tracing when reading the trace file
  ring-buffer: Do not disable recording when there is an iterator
  ring-buffer: Make resize disable per cpu buffer instead of total buffer
  ring-buffer: Optimize rb_iter_head_event()
  ring-buffer: Do not die if rb_iter_peek() fails more than thrice
  ring-buffer: Have rb_iter_head_event() handle concurrent writer
  ring-buffer: Add page_stamp to iterator for synchronization
  ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
  ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
  tracing: Save off entry when peeking at next entry
  ...

1 files changed, 26 insertions, 9 deletions

diff --git a/lib/bootconfig.c b/lib/bootconfig.c
index ec3ce7fd299f..912ef4921398 100644
--- a/lib/bootconfig.c
+++ b/lib/bootconfig.c
@@ -29,12 +29,14 @@ static int xbc_node_num __initdata;
 static char *xbc_data __initdata;
 static size_t xbc_data_size __initdata;
 static struct xbc_node *last_parent __initdata;
+static const char *xbc_err_msg __initdata;
+static int xbc_err_pos __initdata;
 
 static int __init xbc_parse_error(const char *msg, const char *p)
 {
-	int pos = p - xbc_data;
+	xbc_err_msg = msg;
+	xbc_err_pos = (int)(p - xbc_data);
 
-	pr_err("Parse error at pos %d: %s\n", pos, msg);
 	return -EINVAL;
 }
 
@@ -738,33 +740,44 @@ void __init xbc_destroy_all(void)
 /**
  * xbc_init() - Parse given XBC file and build XBC internal tree
  * @buf: boot config text
+ * @emsg: A pointer of const char * to store the error message
+ * @epos: A pointer of int to store the error position
  *
  * This parses the boot config text in @buf. @buf must be a
  * null terminated string and smaller than XBC_DATA_MAX.
  * Return the number of stored nodes (>0) if succeeded, or -errno
  * if there is any error.
+ * In error cases, @emsg will be updated with an error message and
+ * @epos will be updated with the error position which is the byte offset
+ * of @buf. If the error is not a parser error, @epos will be -1.
  */
-int __init xbc_init(char *buf)
+int __init xbc_init(char *buf, const char **emsg, int *epos)
 {
 	char *p, *q;
 	int ret, c;
 
+	if (epos)
+		*epos = -1;
+
 	if (xbc_data) {
-		pr_err("Error: bootconfig is already initialized.\n");
+		if (emsg)
+			*emsg = "Bootconfig is already initialized";
 		return -EBUSY;
 	}
 
 	ret = strlen(buf);
 	if (ret > XBC_DATA_MAX - 1 || ret == 0) {
-		pr_err("Error: Config data is %s.\n",
-			ret ? "too big" : "empty");
+		if (emsg)
+			*emsg = ret ? "Config data is too big" :
+				"Config data is empty";
 		return -ERANGE;
 	}
 
 	xbc_nodes = memblock_alloc(sizeof(struct xbc_node) * XBC_NODE_MAX,
 				   SMP_CACHE_BYTES);
 	if (!xbc_nodes) {
-		pr_err("Failed to allocate memory for bootconfig nodes.\n");
+		if (emsg)
+			*emsg = "Failed to allocate bootconfig nodes";
 		return -ENOMEM;
 	}
 	memset(xbc_nodes, 0, sizeof(struct xbc_node) * XBC_NODE_MAX);
@@ -814,9 +827,13 @@ int __init xbc_init(char *buf)
 	if (!ret)
 		ret = xbc_verify_tree();
 
-	if (ret < 0)
+	if (ret < 0) {
+		if (epos)
+			*epos = xbc_err_pos;
+		if (emsg)
+			*emsg = xbc_err_msg;
 		xbc_destroy_all();
-	else
+	} else
 		ret = xbc_node_num;
 
 	return ret;