ftrace: Return pt_regs to function trace callback

Return as the 4th paramater to the function tracer callback the pt_regs.

Later patches that implement regs passing for the architectures will require
having the ftrace_ops set the SAVE_REGS flag, which will tell the arch
to take the time to pass a full set of pt_regs to the ftrace_ops callback
function. If the arch does not support it then it should pass NULL.

If an arch can pass full regs, then it should define:
 ARCH_SUPPORTS_FTRACE_SAVE_REGS to 1

Link: http://lkml.kernel.org/r/20120702201821.019966811@goodmis.org

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

9 files changed, 47 insertions, 30 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 3651fdc3bec9..e4202881fb00 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -10,6 +10,7 @@
 #include <linux/kallsyms.h>
 #include <linux/linkage.h>
 #include <linux/bitops.h>
+#include <linux/ptrace.h>
 #include <linux/ktime.h>
 #include <linux/sched.h>
 #include <linux/types.h>
@@ -54,7 +55,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 struct ftrace_ops;
 
 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
-                              struct ftrace_ops *op);
+                              struct ftrace_ops *op, struct pt_regs *regs);
 
 /*
  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
@@ -188,7 +189,8 @@ static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
         return *this_cpu_ptr(ops->disabled);
 }
 
-extern void ftrace_stub(unsigned long a0, unsigned long a1, struct ftrace_ops *op);
+extern void ftrace_stub(unsigned long a0, unsigned long a1,
+                        struct ftrace_ops *op, struct pt_regs *regs);
 
 #else /* !CONFIG_FUNCTION_TRACER */
 /*
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4cbca2e6eb70..6ff07ad0ede3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -103,7 +103,7 @@ static struct ftrace_ops control_ops;
 
 #if ARCH_SUPPORTS_FTRACE_OPS
 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
-                                 struct ftrace_ops *op);
+                                 struct ftrace_ops *op, struct pt_regs *regs);
 #else
 /* See comment below, where ftrace_ops_list_func is defined */
 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
@@ -121,7 +121,7 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
  */
 static void
 ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
-                        struct ftrace_ops *op)
+                        struct ftrace_ops *op, struct pt_regs *regs)
 {
         if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
                 return;
@@ -129,19 +129,19 @@ ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
         trace_recursion_set(TRACE_GLOBAL_BIT);
         op = rcu_dereference_raw(ftrace_global_list); /*see above*/
         while (op != &ftrace_list_end) {
-                op->func(ip, parent_ip, op);
+                op->func(ip, parent_ip, op, regs);
                 op = rcu_dereference_raw(op->next); /*see above*/
         };
         trace_recursion_clear(TRACE_GLOBAL_BIT);
 }
 
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
-                            struct ftrace_ops *op)
+                            struct ftrace_ops *op, struct pt_regs *regs)
 {
         if (!test_tsk_trace_trace(current))
                 return;
 
-        ftrace_pid_function(ip, parent_ip, op);
+        ftrace_pid_function(ip, parent_ip, op, regs);
 }
 
 static void set_ftrace_pid_function(ftrace_func_t func)
@@ -763,7 +763,7 @@ ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 
 static void
 function_profile_call(unsigned long ip, unsigned long parent_ip,
-                      struct ftrace_ops *ops)
+                      struct ftrace_ops *ops, struct pt_regs *regs)
 {
         struct ftrace_profile_stat *stat;
         struct ftrace_profile *rec;
@@ -793,7 +793,7 @@ function_profile_call(unsigned long ip, unsigned long parent_ip,
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 {
-        function_profile_call(trace->func, 0, NULL);
+        function_profile_call(trace->func, 0, NULL, NULL);
         return 1;
 }
 
@@ -2771,7 +2771,7 @@ static int __init ftrace_mod_cmd_init(void)
 device_initcall(ftrace_mod_cmd_init);
 
 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
-                                      struct ftrace_ops *op)
+                                      struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct ftrace_func_probe *entry;
         struct hlist_head *hhd;
@@ -3923,7 +3923,7 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
 
 static void
 ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
-                        struct ftrace_ops *op)
+                        struct ftrace_ops *op, struct pt_regs *regs)
 {
         if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
                 return;
@@ -3938,7 +3938,7 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
         while (op != &ftrace_list_end) {
                 if (!ftrace_function_local_disabled(op) &&
                     ftrace_ops_test(op, ip))
-                        op->func(ip, parent_ip, op);
+                        op->func(ip, parent_ip, op, regs);
 
                 op = rcu_dereference_raw(op->next);
         };
@@ -3952,7 +3952,7 @@ static struct ftrace_ops control_ops = {
 
 static inline void
 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
-                       struct ftrace_ops *ignored)
+                       struct ftrace_ops *ignored, struct pt_regs *regs)
 {
         struct ftrace_ops *op;
 
@@ -3971,7 +3971,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
         op = rcu_dereference_raw(ftrace_ops_list);
         while (op != &ftrace_list_end) {
                 if (ftrace_ops_test(op, ip))
-                        op->func(ip, parent_ip, op);
+                        op->func(ip, parent_ip, op, regs);
                 op = rcu_dereference_raw(op->next);
         };
         preempt_enable_notrace();
@@ -3983,17 +3983,24 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  * the list function ignores the op parameter, we do not want any
  * C side effects, where a function is called without the caller
  * sending a third parameter.
+ * Archs are to support both the regs and ftrace_ops at the same time.
+ * If they support ftrace_ops, it is assumed they support regs.
+ * If call backs want to use regs, they must either check for regs
+ * being NULL, or ARCH_SUPPORTS_FTRACE_SAVE_REGS.
+ * Note, ARCH_SUPPORT_SAVE_REGS expects a full regs to be saved.
+ * An architecture can pass partial regs with ftrace_ops and still
+ * set the ARCH_SUPPORT_FTARCE_OPS.
  */
 #if ARCH_SUPPORTS_FTRACE_OPS
 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
-                                 struct ftrace_ops *op)
+                                 struct ftrace_ops *op, struct pt_regs *regs)
 {
-        __ftrace_ops_list_func(ip, parent_ip, NULL);
+        __ftrace_ops_list_func(ip, parent_ip, NULL, regs);
 }
 #else
 static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
 {
-        __ftrace_ops_list_func(ip, parent_ip, NULL);
+        __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
 }
 #endif
 
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index a872a9a298a0..9824419c8404 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -259,7 +259,7 @@ EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);
 #ifdef CONFIG_FUNCTION_TRACER
 static void
 perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
-                          struct ftrace_ops *ops)
+                          struct ftrace_ops *ops, struct pt_regs *pt_regs)
 {
         struct ftrace_entry *entry;
         struct hlist_head *head;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 88daa5177bf4..8c6696833686 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1682,7 +1682,7 @@ static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
 
 static void
 function_test_events_call(unsigned long ip, unsigned long parent_ip,
-                          struct ftrace_ops *op)
+                          struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct ring_buffer_event *event;
         struct ring_buffer *buffer;
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index fceb7a9aa06d..5675ebd541f0 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -49,7 +49,7 @@ static void function_trace_start(struct trace_array *tr)
 
 static void
 function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip,
-                                 struct ftrace_ops *op)
+                                 struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct trace_array *tr = func_trace;
         struct trace_array_cpu *data;
@@ -77,7 +77,8 @@ function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip,
 
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip,
-                    struct ftrace_ops *op)
+                    struct ftrace_ops *op, struct pt_regs *pt_regs)
+
 {
         struct trace_array *tr = func_trace;
         struct trace_array_cpu *data;
@@ -109,7 +110,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
 
 static void
 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
-                          struct ftrace_ops *op)
+                          struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct trace_array *tr = func_trace;
         struct trace_array_cpu *data;
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 2862c77f95d9..c7a9ba936de6 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -137,7 +137,7 @@ static int func_prolog_dec(struct trace_array *tr,
  */
 static void
 irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
-                    struct ftrace_ops *op)
+                    struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct trace_array *tr = irqsoff_trace;
         struct trace_array_cpu *data;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 0caf4f5da569..7547e36d483e 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -108,7 +108,8 @@ out_enable:
  * wakeup uses its own tracer function to keep the overhead down:
  */
 static void
-wakeup_tracer_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op)
+wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
+                   struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         struct trace_array *tr = wakeup_trace;
         struct trace_array_cpu *data;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 9ae40c823af8..add37e019fd0 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -104,7 +104,8 @@ static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
 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 ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe1_cnt++;
 }
@@ -112,7 +113,8 @@ static void trace_selftest_test_probe1_func(unsigned long ip,
 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 ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe2_cnt++;
 }
@@ -120,7 +122,8 @@ static void trace_selftest_test_probe2_func(unsigned long ip,
 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 ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_probe3_cnt++;
 }
@@ -128,7 +131,8 @@ static void trace_selftest_test_probe3_func(unsigned long ip,
 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 ftrace_ops *op,
+                                            struct pt_regs *pt_regs)
 {
         trace_selftest_test_global_cnt++;
 }
@@ -136,7 +140,8 @@ static void trace_selftest_test_global_func(unsigned long ip,
 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 ftrace_ops *op,
+                                         struct pt_regs *pt_regs)
 {
         trace_selftest_test_dyn_cnt++;
 }
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index e20006d5fb6a..2fa5328e8893 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -111,7 +111,8 @@ static inline void check_stack(void)
 }
 
 static void
-stack_trace_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op)
+stack_trace_call(unsigned long ip, unsigned long parent_ip,
+                 struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
         int cpu;