On Mon, 21 Oct 2024 17:46:19 +0100
Will Deacon <will@xxxxxxxxxx> wrote:
> On Wed, Oct 16, 2024 at 09:59:00AM +0900, Masami Hiramatsu (Google) wrote:
> > From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> >
> > Add ftrace_partial_regs() which converts the ftrace_regs to pt_regs.
> > This is for the eBPF which 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 used.
> >
> > 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.
> >
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> > Acked-by: Florent Revest <revest@xxxxxxxxxxxx>
> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> > Cc: Will Deacon <will@xxxxxxxxxx>
> > Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
> > Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> > Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
> >
> > ---
> > Changes in v14:
> > - Add riscv change.
> > Changes in v8:
> > - Add the reason why this required in changelog.
> > Changes from previous series: NOTHING, just forward ported.
> > ---
> > arch/arm64/include/asm/ftrace.h | 11 +++++++++++
> > arch/riscv/include/asm/ftrace.h | 14 ++++++++++++++
> > include/linux/ftrace.h | 17 +++++++++++++++++
> > 3 files changed, 42 insertions(+)
> >
> > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> > index b5fa57b61378..d344c69eb01e 100644
> > --- a/arch/arm64/include/asm/ftrace.h
> > +++ b/arch/arm64/include/asm/ftrace.h
> > @@ -135,6 +135,17 @@ ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
> > return arch_ftrace_regs(fregs)->fp;
> > }
> >
> > +static __always_inline struct pt_regs *
> > +ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
> > +{
> > + memcpy(regs->regs, arch_ftrace_regs(fregs)->regs, sizeof(u64) * 9);
>
> Since ftrace_regs::regs is an 'unsigned long regs[9]' can we just use
> sizeof() on that instead of hard-coding the length of the array here?
Good catch! I will update it.
Thank you!
>
> Will
--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
