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: Thu, 1 Apr 2021 09:30:36 +0900 [thread overview]
Message-ID: <20210401093036.037f2abbce7ed5d1e68466b7@kernel.org> (raw)
In-Reply-To: <20210331222244.45a5807c@xhacker>
Hi,
On Wed, 31 Mar 2021 22:22:44 +0800
Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
> On Tue, 30 Mar 2021 18:33:16 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > Hi Jisheng,
>
> Hi Masami,
>
> >
> > 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?
> >
>
> interrupt is disabled during "single step" by kprobes_save_local_irqflag()
> and kprobes_restore_local_irqflag(). The code flow looks like:
>
> do_trap_break() // for bp
> kprobe_breakpoint_handler()
> setup_singlestep()
> kprobes_restore_local_irqflag()
>
> do_trap_break() // for ss
> kprobe_single_step_handler()
> kprobes_restore_local_irqflag()
OK, thanks for the confirmation!
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Thanks,
--
Masami Hiramatsu <mhiramat@kernel.org>
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next prev parent reply other threads:[~2021-04-01 0:31 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
2021-03-31 14:22 ` Jisheng Zhang
2021-04-01 0:30 ` Masami Hiramatsu [this message]
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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