On Tue, 17 Sep 2024 11:14:54 +0100
Will Deacon <w...@kernel.org> wrote:
> On Sun, Sep 15, 2024 at 05:22:04AM -0400, Steven Rostedt wrote:
> > On Fri, 13 Sep 2024 00:09:35 +0900
> > "Masami Hiramatsu (Google)" <mhira...@kernel.org> wrote:
> >
> > > From: Masami Hiramatsu (Google) <mhira...@kernel.org>
> > >
> > > 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) <mhira...@kernel.org>
> > > Acked-by: Florent Revest <rev...@chromium.org>
> > > ---
> > > 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 | 12 ++++++++++++
> > > include/linux/ftrace.h | 17 +++++++++++++++++
> > > 3 files changed, 40 insertions(+)
> > >
> > > diff --git a/arch/arm64/include/asm/ftrace.h
> > > b/arch/arm64/include/asm/ftrace.h
> > > index dffaab3dd1f1..5cd587afab6d 100644
> > > --- a/arch/arm64/include/asm/ftrace.h
> > > +++ b/arch/arm64/include/asm/ftrace.h
> > > @@ -132,6 +132,17 @@ ftrace_regs_get_frame_pointer(const struct
> > > ftrace_regs *fregs)
> > > return fregs->fp;
> > > }
> > >
> > > +static __always_inline struct pt_regs *
> > > +ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs
> > > *regs)
> > > +{
> > > + memcpy(regs->regs, fregs->regs, sizeof(u64) * 9);
> > > + regs->sp = fregs->sp;
> > > + regs->pc = fregs->pc;
> > > + regs->regs[29] = fregs->fp;
> > > + regs->regs[30] = fregs->lr;
> > > + return regs;
> > > +}
>
> Ah, I guess this is where we pick up the lr that was set in patch 5.
Yeah, this one also copies the fregs->pc to regs->pc, mainly for bpf.
>
> Acked-by: Will Deacon <w...@kernel.org>
Thank you!
>
> Will
--
Masami Hiramatsu (Google) <mhira...@kernel.org>
