Re: [PATCH v2 2/2] arm64: insn: drop NOP from steppable hint list

Masami Hiramatsu
2026-02-24T08:23:57Z

On Tue, 17 Feb 2026 16:57:08 +0000
Mark Rutland <mark.rutland@arm.com> wrote:

> On Tue, Feb 17, 2026 at 07:08:55PM +0530, Khaja Hussain Shaik Khaji wrote:
> > NOP is already handled via instruction emulation and does not require
> > single-stepping. Drop it from aarch64_insn_is_steppable_hint().
> >
> > Signed-off-by: Khaja Hussain Shaik Khaji <khaja.khaji@oss.qualcomm.com>
> > ---
> > arch/arm64/include/asm/insn.h | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
> > index e1d30ba99d01..9429f76906e0 100644
> > --- a/arch/arm64/include/asm/insn.h
> > +++ b/arch/arm64/include/asm/insn.h
> > @@ -456,7 +456,6 @@ static __always_inline bool aarch64_insn_is_steppable_hint(u32 insn)
> > case AARCH64_INSN_HINT_BTIC:
> > case AARCH64_INSN_HINT_BTIJ:
> > case AARCH64_INSN_HINT_BTIJC:
> > - case AARCH64_INSN_HINT_NOP:
> > return true;
> > default:
> > return false;
>
> The intent is that aarch64_insn_is_steppable_hint() says whether an
> instruction is safe to step, not whether it *must* be stepped. I think
> we can leave NOP here unless this is causing some functional problem?

Agreed. I think we should keep this as it is.

Thank you,

>
> Mark.
>

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