On Sun, Sep 15, 2024 at 04:49:20AM -0400, Steven Rostedt wrote: > On Fri, 13 Sep 2024 00:09:02 +0900 > "Masami Hiramatsu (Google)" <[email protected]> wrote: > > > From: Masami Hiramatsu (Google) <[email protected]> > > > > 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) <[email protected]> > > --- > > 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);
Where does the instruction pointer get used after this? The arm64 'return_to_handler' function doesn't look at it when we return. Will
