[PATCH v8 23/35] function_graph: Pass ftrace_regs to retfunc

Masami Hiramatsu (Google)
2024-02-25T15:19:19Z

Pass ftrace_regs to the fgraph_ops::retfunc(). If ftrace_regs is not
available, it passes a NULL instead. User callback function can access
some registers (including return address) via this ftrace_regs.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v8:
- Pass ftrace_regs to retfunc, instead of adding retregfunc.
Changes in v6:
- update to use ftrace_regs_get_return_value() because of reordering
patches.
Changes in v3:
- Update for new multiple fgraph.
- Save the return address to instruction pointer in ftrace_regs.
---
include/linux/ftrace.h | 3 ++-
kernel/trace/fgraph.c | 14 ++++++++++----
kernel/trace/ftrace.c | 3 ++-
kernel/trace/trace.h | 3 ++-
kernel/trace/trace_functions_graph.c | 7 ++++---
kernel/trace/trace_irqsoff.c | 3 ++-
kernel/trace/trace_sched_wakeup.c | 3 ++-
kernel/trace/trace_selftest.c | 3 ++-
8 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index c2456f8ede0f..96b42f994c2f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1067,7 +1067,8 @@ struct fgraph_ops;

/* Type of the callback handlers for tracing function graph*/
typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *,
- struct fgraph_ops *); /* return */
+ struct fgraph_ops *,
+ struct ftrace_regs *); /* return */
typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *,
struct fgraph_ops *,
struct ftrace_regs *); /* entry */
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 7462307c0459..d90d8da20d08 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -255,7 +255,8 @@ static int entry_run(struct ftrace_graph_ent *trace, struct fgraph_ops *ops,
}

/* ftrace_graph_return set to this to tell some archs to run function graph */
-static void return_run(struct ftrace_graph_ret *trace, struct fgraph_ops *ops)
+static void return_run(struct ftrace_graph_ret *trace, struct fgraph_ops *ops,
+ struct ftrace_regs *fregs)
{
}

@@ -447,7 +448,8 @@ int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace,
}

static void ftrace_graph_ret_stub(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
}

@@ -791,6 +793,9 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe
}

trace.rettime = trace_clock_local();
+ if (fregs)
+ ftrace_regs_set_instruction_pointer(fregs, ret);
+
#ifdef CONFIG_FUNCTION_GRAPH_RETVAL
trace.retval = ftrace_regs_get_return_value(fregs);
#endif
@@ -804,7 +809,7 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe
if (gops == &fgraph_stub)
continue;

- gops->retfunc(&trace, gops);
+ gops->retfunc(&trace, gops, fregs);
}

/*
@@ -968,7 +973,8 @@ void ftrace_graph_sleep_time_control(bool enable)
* Simply points to ftrace_stub, but with the proper protocol.
* Defined by the linker script in linux/vmlinux.lds.h
*/
-void ftrace_stub_graph(struct ftrace_graph_ret *trace, struct fgraph_ops *gops);
+void ftrace_stub_graph(struct ftrace_graph_ret *trace, struct fgraph_ops *gops,
+ struct ftrace_regs *fregs);

/* The callbacks that hook a function */
trace_func_graph_ret_t ftrace_graph_return = ftrace_stub_graph;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 162ece7a39b4..08decd56a7b9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -835,7 +835,8 @@ static int profile_graph_entry(struct ftrace_graph_ent *trace,
}

static void profile_graph_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
struct ftrace_ret_stack *ret_stack;
struct ftrace_profile_stat *stat;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 53adc73c460b..3106b54c555f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -681,7 +681,8 @@ void trace_latency_header(struct seq_file *m);
void trace_default_header(struct seq_file *m);
void print_trace_header(struct seq_file *m, struct trace_iterator *iter);

-void trace_graph_return(struct ftrace_graph_ret *trace, struct fgraph_ops *gops);
+void trace_graph_return(struct ftrace_graph_ret *trace, struct fgraph_ops *gops,
+ struct ftrace_regs *fregs);
int trace_graph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops,
struct ftrace_regs *fregs);

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b9785fc919c9..241407000109 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -240,7 +240,7 @@ void __trace_graph_return(struct trace_array *tr,
}

void trace_graph_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops, struct ftrace_regs *fregs)
{
unsigned long *task_var = fgraph_get_task_var(gops);
struct trace_array *tr = gops->private;
@@ -270,7 +270,8 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
}

static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
ftrace_graph_addr_finish(gops, trace);

@@ -283,7 +284,7 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
(trace->rettime - trace->calltime < tracing_thresh))
return;
else
- trace_graph_return(trace, gops);
+ trace_graph_return(trace, gops, fregs);
}

static struct fgraph_ops funcgraph_ops = {
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index ad739d76fc86..504de7a05498 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -208,7 +208,8 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace,
}

static void irqsoff_graph_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
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 23360a2700de..9ffbd9326898 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -144,7 +144,8 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace,
}

static void wakeup_graph_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
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 1c3faaeae979..5959c6d262ba 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -807,7 +807,8 @@ static __init int store_entry(struct ftrace_graph_ent *trace,
}

static __init void store_return(struct ftrace_graph_ret *trace,
- struct fgraph_ops *gops)
+ struct fgraph_ops *gops,
+ struct ftrace_regs *fregs)
{
struct fgraph_fixture *fixture = container_of(gops, struct fgraph_fixture, gops);
const char *type = fixture->store_type_name;