Re: [PATCH v14 05/19] function_graph: Pass ftrace_regs to retfunc

From: Steven Rostedt
Date: Sun Sep 15 2024 - 05:00:42 EST


Can I get an Acked-by from the X86 maintainers for this patch?

Thanks!

-- Steve

[ Note this is modifies the return side ]

On Fri, 13 Sep 2024 00:09:02 +0900
"Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> ---
> 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 | 16 +++++++++++-----
> 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, 27 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 13987cd63553..e7c41d9988e1 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -1069,7 +1069,8 @@ 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 30bebe43607d..6a3e2db16aa4 100644
> --- a/kernel/trace/fgraph.c
> +++ b/kernel/trace/fgraph.c
> @@ -297,7 +297,8 @@ 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)
> {
> }
>
> @@ -491,7 +492,8 @@ 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)
> {
> }
>
> @@ -787,6 +789,9 @@ __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
> @@ -796,7 +801,7 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe
> #ifdef CONFIG_HAVE_STATIC_CALL
> if (static_branch_likely(&fgraph_do_direct)) {
> if (test_bit(fgraph_direct_gops->idx, &bitmap))
> - static_call(fgraph_retfunc)(&trace, fgraph_direct_gops);
> + static_call(fgraph_retfunc)(&trace, fgraph_direct_gops, fregs);
> } else
> #endif
> {
> @@ -806,7 +811,7 @@ __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);
> }
> }
>
> @@ -956,7 +961,8 @@ 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 775040a9f541..fd6c5a50c5e5 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -840,7 +840,8 @@ 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 28d8ad5e31e6..f4a3f75bd916 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -682,7 +682,8 @@ 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 89067f02094a..1ebd0899238f 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;