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

[Google]

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

> On Wed,  7 Feb 2024 00:12:40 +0900
> "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:
> 
> > From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> > 
> > 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@xxxxxxxxxx>
> > Acked-by: Florent Revest <revest@xxxxxxxxxxxx>
> > ---
> >  Changes from previous series: NOTHING, just forward ported.
> > ---


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>