ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs

In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.

For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.

This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 11 insertions, 9 deletions

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 8ee3c0bb5d8a..5ed081c6471c 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -107,7 +107,7 @@ static int trace_selftest_test_probe1_cnt;
 static void trace_selftest_test_probe1_func(unsigned long ip,
 					    unsigned long pip,
 					    struct ftrace_ops *op,
-					    struct pt_regs *pt_regs)
+					    struct ftrace_regs *fregs)
 {
 	trace_selftest_test_probe1_cnt++;
 }
@@ -116,7 +116,7 @@ static int trace_selftest_test_probe2_cnt;
 static void trace_selftest_test_probe2_func(unsigned long ip,
 					    unsigned long pip,
 					    struct ftrace_ops *op,
-					    struct pt_regs *pt_regs)
+					    struct ftrace_regs *fregs)
 {
 	trace_selftest_test_probe2_cnt++;
 }
@@ -125,7 +125,7 @@ static int trace_selftest_test_probe3_cnt;
 static void trace_selftest_test_probe3_func(unsigned long ip,
 					    unsigned long pip,
 					    struct ftrace_ops *op,
-					    struct pt_regs *pt_regs)
+					    struct ftrace_regs *fregs)
 {
 	trace_selftest_test_probe3_cnt++;
 }
@@ -134,7 +134,7 @@ static int trace_selftest_test_global_cnt;
 static void trace_selftest_test_global_func(unsigned long ip,
 					    unsigned long pip,
 					    struct ftrace_ops *op,
-					    struct pt_regs *pt_regs)
+					    struct ftrace_regs *fregs)
 {
 	trace_selftest_test_global_cnt++;
 }
@@ -143,7 +143,7 @@ static int trace_selftest_test_dyn_cnt;
 static void trace_selftest_test_dyn_func(unsigned long ip,
 					 unsigned long pip,
 					 struct ftrace_ops *op,
-					 struct pt_regs *pt_regs)
+					 struct ftrace_regs *fregs)
 {
 	trace_selftest_test_dyn_cnt++;
 }
@@ -414,7 +414,7 @@ static int trace_selftest_recursion_cnt;
 static void trace_selftest_test_recursion_func(unsigned long ip,
 					       unsigned long pip,
 					       struct ftrace_ops *op,
-					       struct pt_regs *pt_regs)
+					       struct ftrace_regs *fregs)
 {
 	/*
 	 * This function is registered without the recursion safe flag.
@@ -429,7 +429,7 @@ static void trace_selftest_test_recursion_func(unsigned long ip,
 static void trace_selftest_test_recursion_safe_func(unsigned long ip,
 						    unsigned long pip,
 						    struct ftrace_ops *op,
-						    struct pt_regs *pt_regs)
+						    struct ftrace_regs *fregs)
 {
 	/*
 	 * We said we would provide our own recursion. By calling
@@ -548,9 +548,11 @@ static enum {
 static void trace_selftest_test_regs_func(unsigned long ip,
 					  unsigned long pip,
 					  struct ftrace_ops *op,
-					  struct pt_regs *pt_regs)
+					  struct ftrace_regs *fregs)
 {
-	if (pt_regs)
+	struct pt_regs *regs = ftrace_get_regs(fregs);
+
+	if (regs)
 		trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
 	else
 		trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;