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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Guo Ren <guoren@linux.alibaba.com>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: keep interrupts disabled for BREAKPOINT exception
Date: Tue, 30 Mar 2021 18:33:16 +0900	[thread overview]
Message-ID: <20210330183316.942215efe8e6e8455ad14113@kernel.org> (raw)
In-Reply-To: <20210330021624.2b776386@xhacker>

Hi Jisheng,

On Tue, 30 Mar 2021 02:16:24 +0800
Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:

> From: Jisheng Zhang <jszhang@kernel.org>
> 
> Current riscv's kprobe handlers are run with both preemption and
> interrupt enabled, this violates kprobe requirements. Fix this issue
> by keeping interrupts disabled for BREAKPOINT exception.

Not only while the breakpoint exception but also until the end of
the single step (maybe you are using __BUG_INSN_32 ??) need to be
disable interrupts. Can this do that?

Thank you,

> 
> Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  arch/riscv/kernel/entry.S | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index 744f3209c48d..4114b65698ec 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -130,6 +130,8 @@ skip_context_tracking:
>  	 */
>  	andi t0, s1, SR_PIE
>  	beqz t0, 1f
> +	li t0, EXC_BREAKPOINT
> +	beq s4, t0, 1f
>  #ifdef CONFIG_TRACE_IRQFLAGS
>  	call trace_hardirqs_on
>  #endif
> -- 
> 2.31.0
> 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

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  reply	other threads:[~2021-03-30  9:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-29 18:16 [PATCH] riscv: keep interrupts disabled for BREAKPOINT exception Jisheng Zhang
2021-03-30  9:33 ` Masami Hiramatsu [this message]
2021-03-31 14:22   ` Jisheng Zhang
2021-04-01  0:30     ` Masami Hiramatsu
2021-04-03 18:30       ` Maciej W. Rozycki
2021-04-08 11:23         ` Jisheng Zhang
2021-04-08 22:38           ` Masami Hiramatsu
2021-04-08 22:45             ` Maciej W. Rozycki
2021-04-01  8:49     ` liaochang (A)
2021-04-02 13:32       ` Jisheng Zhang
2021-04-06  7:27         ` liaochang (A)
2021-04-12  1:09 ` Palmer Dabbelt

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