Re: [PATCH v4 4/9] fprobe: rethook: Use ftrace_regs in fprobe exit handler and rethook

[Florent Revest]

On Wed, Aug 23, 2023 at 5:16 PM Masami Hiramatsu (Google)
<mhiramat@xxxxxxxxxx> wrote:
>
> From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> Change the fprobe exit handler and rethook to use ftrace_regs data structure
> instead of pt_regs. This also introduce HAVE_PT_REGS_TO_FTRACE_REGS_CAST
> which means the ftrace_regs's memory layout is equal to the pt_regs so
> that those are able to cast. Only if it is enabled, kretprobe will use
> rethook since kretprobe requires pt_regs for backward compatibility.
>
> This means the archs which currently implement rethook for kretprobes needs to
> set that flag and it must ensure struct ftrace_regs is same as pt_regs.
> If not, it must be either disabling kretprobe or implementing kretprobe
> trampoline separately from rethook trampoline.
>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Acked-by: Florent Revest <revest@xxxxxxxxxxxx>