[GIT PULL] tracing: Fixes for 4.11

[Steven Rostedt]

Linus,

There was some breakage with the changes for jump labels in the 4.11 merge
window. Namely powerpc broke as jump labels uses the two LSB bits as flags
in initialization. A check was added to make sure that all jump label
entries were 4 bytes aligned, but powerpc didn't work that way for modules.
Adding an alignment in the module linker script appeared to be the best
solution.

Jump labels also added an anonymous union to access those LSB bits as a
normal long. But because this structure had static initialization, it broke
older compilers that could not statically initialize anonymous unions
without brackets.

The command line parameter for setting function graph filter broke the
"EMPTY_HASH" descriptor by modifying it instead of creating a new hash to
hold the entries.

The command line parameter ftrace_graph_max_depth was added to allow its
setting at boot time. It uses existing code and only the command line hook
was added. This is not really a fix, but as it uses existing code without
affecting anything else, I added it to this release. It was ready before the
merge window closed, but I wanted to let it sit in linux-next for a couple
of days first.


Please pull the latest trace-v4.11-rc1 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.11-rc1

Tag SHA1: e7549646ac33d2bab79bd58ee58b7bf1516ef1e5
Head SHA1: 65a50c656276b0846bea09dd011c0a3d35b77f3e


Boris Ostrovsky (1):
      jump_label: Fix anonymous union initialization

Chunyu Hu (1):
      tracing: Fix code comment for ftrace_ops_get_func()

David Daney (1):
      module: set __jump_table alignment to 8

Rik van Riel (1):
      tracing: Add #undef to fix compile error

Steven Rostedt (VMware) (2):
      ftrace/graph: Do not modify the EMPTY_HASH for the function_graph filter
      jump_label: Add comment about initialization order for anonymous unions

Todd Brandt (1):
      ftrace/graph: Add ftrace_graph_max_depth kernel parameter

----
 Documentation/admin-guide/kernel-parameters.txt |  6 ++++++
 include/linux/jump_label.h                      | 11 +++++++++--
 include/trace/events/syscalls.h                 |  1 +
 kernel/trace/ftrace.c                           | 23 ++++++++++++++++++-----
 scripts/module-common.lds                       |  2 ++
 5 files changed, 36 insertions(+), 7 deletions(-)
---------------------------
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 21e2d8863705..1c9016b27ee9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1173,6 +1173,12 @@
 			functions that can be changed at run time by the
 			set_graph_notrace file in the debugfs tracing directory.
 
+	ftrace_graph_max_depth=<uint>
+			[FTRACE] Used with the function graph tracer. This is
+			the max depth it will trace into a function. This value
+			can be changed at run time by the max_graph_depth file
+			in the tracefs tracing directory. default: 0 (no limit)
+
 	gamecon.map[2|3]=
 			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
 			support via parallel port (up to 5 devices per port)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 680c98b2f41c..28e04a33535a 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -90,6 +90,13 @@ extern bool static_key_initialized;
 struct static_key {
 	atomic_t enabled;
 /*
+ * Note:
+ *   To make anonymous unions work with old compilers, the static
+ *   initialization of them requires brackets. This creates a dependency
+ *   on the order of the struct with the initializers. If any fields
+ *   are added, STATIC_KEY_INIT_TRUE and STATIC_KEY_INIT_FALSE may need
+ *   to be modified.
+ *
  * bit 0 => 1 if key is initially true
  *	    0 if initially false
  * bit 1 => 1 if points to struct static_key_mod
@@ -166,10 +173,10 @@ extern void static_key_disable(struct static_key *key);
  */
 #define STATIC_KEY_INIT_TRUE					\
 	{ .enabled = { 1 },					\
-	  .entries = (void *)JUMP_TYPE_TRUE }
+	  { .entries = (void *)JUMP_TYPE_TRUE } }
 #define STATIC_KEY_INIT_FALSE					\
 	{ .enabled = { 0 },					\
-	  .entries = (void *)JUMP_TYPE_FALSE }
+	  { .entries = (void *)JUMP_TYPE_FALSE } }
 
 #else  /* !HAVE_JUMP_LABEL */
 
diff --git a/include/trace/events/syscalls.h b/include/trace/events/syscalls.h
index 14e49c798135..b35533b94277 100644
--- a/include/trace/events/syscalls.h
+++ b/include/trace/events/syscalls.h
@@ -1,5 +1,6 @@
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM raw_syscalls
+#undef TRACE_INCLUDE_FILE
 #define TRACE_INCLUDE_FILE syscalls
 
 #if !defined(_TRACE_EVENTS_SYSCALLS_H) || defined(TRACE_HEADER_MULTI_READ)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0c0609326391..d129ae51329a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4415,16 +4415,24 @@ static int __init set_graph_notrace_function(char *str)
 }
 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
 
+static int __init set_graph_max_depth_function(char *str)
+{
+	if (!str)
+		return 0;
+	fgraph_max_depth = simple_strtoul(str, NULL, 0);
+	return 1;
+}
+__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
+
 static void __init set_ftrace_early_graph(char *buf, int enable)
 {
 	int ret;
 	char *func;
 	struct ftrace_hash *hash;
 
-	if (enable)
-		hash = ftrace_graph_hash;
-	else
-		hash = ftrace_graph_notrace_hash;
+	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+	if (WARN_ON(!hash))
+		return;
 
 	while (buf) {
 		func = strsep(&buf, ",");
@@ -4434,6 +4442,11 @@ static void __init set_ftrace_early_graph(char *buf, int enable)
 			printk(KERN_DEBUG "ftrace: function %s not "
 					  "traceable\n", func);
 	}
+
+	if (enable)
+		ftrace_graph_hash = hash;
+	else
+		ftrace_graph_notrace_hash = hash;
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -5487,7 +5500,7 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
  * Normally the mcount trampoline will call the ops->func, but there
  * are times that it should not. For example, if the ops does not
  * have its own recursion protection, then it should call the
- * ftrace_ops_recurs_func() instead.
+ * ftrace_ops_assist_func() instead.
  *
  * Returns the function that the trampoline should call for @ops.
  */
diff --git a/scripts/module-common.lds b/scripts/module-common.lds
index 73a2c7da0e55..53234e85192a 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -19,4 +19,6 @@ SECTIONS {
 
 	. = ALIGN(8);
 	.init_array		0 : { *(SORT(.init_array.*)) *(.init_array) }
+
+	__jump_table		0 : ALIGN(8) { KEEP(*(__jump_table)) }
 }