linux-kernel - Re: [PATCH 3/7] riscv: kprobes: Use patch_text

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Message-ID: <87a5nwfwfo.fsf@all.your.base.are.belong.to.us>
Date: Mon, 19 Feb 2024 13:52:27 +0100
From: Björn Töpel <bjorn@...nel.org>
To: Samuel Holland <samuel.holland@...ive.com>, Palmer Dabbelt
 <palmer@...belt.com>
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, Samuel
 Holland <samuel.holland@...ive.com>
Subject: Re: [PATCH 3/7] riscv: kprobes: Use patch_text_nosync() for insn slots

Samuel Holland <samuel.holland@...ive.com> writes:

> These instructions are not yet visible to the rest of the system,
> so there is no need to do the whole stop_machine() dance.
>
> Signed-off-by: Samuel Holland <samuel.holland@...ive.com>
> ---
>
>  arch/riscv/kernel/probes/kprobes.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
> index 2f08c14a933d..cbf8197072bf 100644
> --- a/arch/riscv/kernel/probes/kprobes.c
> +++ b/arch/riscv/kernel/probes/kprobes.c
> @@ -28,9 +28,9 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
>  
>  	p->ainsn.api.restore = (unsigned long)p->addr + offset;
>  
> -	patch_text(p->ainsn.api.insn, &p->opcode, 1);
> -	patch_text((void *)((unsigned long)(p->ainsn.api.insn) + offset),
> -		   &insn, 1);
> +	patch_text_nosync(p->ainsn.api.insn, &p->opcode, 1);
> +	patch_text_nosync(p->ainsn.api.insn + offset,
> +			  &insn, 1);

Nit: 100 chars lines!

Nice find!

Reviewed-by: Björn Töpel <bjorn@...osinc.com>