Re: [PATCH v7 28/36] tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs

Masami Hiramatsu
2024-02-16T13:09:09Z

On Thu, 15 Feb 2024 11:11:34 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 7 Feb 2024 00:12:40 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> >
> > Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs.
> > If the architecture defines its own ftrace_regs, this copies partial
> > registers to pt_regs and returns it. If not, ftrace_regs is the same as
> > pt_regs and ftrace_partial_regs() will return ftrace_regs::regs.
>
> This says what this patch is doing and not why it is doing it.

Hmm, OK. The reason is the eBPF needs this to keep the same pt_regs
interface to access registers.
Thus when replacing the pt_regs with ftrace_regs in fprobes (which is
used by kprobe_multi eBPF event), this will be required.
I'll add this to next version.

Thanks,

>
> -- Steve
>
> >
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > Acked-by: Florent Revest <revest@chromium.org>
> > ---
> > Changes from previous series: NOTHING, just forward ported.
> > ---

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>