From: Andrea Parri <parri.andrea@gmail.com>
To: Guo Ren <guoren@kernel.org>
Cc: "Björn Töpel" <bjorn@kernel.org>,
"liaochang (A)" <liaochang1@huawei.com>,
palmer@dabbelt.com, paul.walmsley@sifive.com,
mhiramat@kernel.org, conor.dooley@microchip.com,
penberg@kernel.org, mark.rutland@arm.com,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
"Guo Ren" <guoren@linux.alibaba.com>
Subject: Re: [PATCH] riscv: kprobe: Optimize kprobe with accurate atomicity
Date: Tue, 31 Jan 2023 11:56:59 +0100 [thread overview]
Message-ID: <Y9jz+zUDebQ4VLlF@andrea> (raw)
In-Reply-To: <CAJF2gTTaartwjVdmtmsm1FqmYVuAq5_nGYU5zc6nkdTtCm200A@mail.gmail.com>
> > It's the concurrent modification that I was referring to (removing
> > stop_machine()). You're saying "it'll always work", I'm saying "I'm not
> > so sure". :-) E.g., writing c.ebreak on an 32b insn. Can you say that
> Software must ensure write c.ebreak on the head of an 32b insn.
>
> That means IFU only see:
> - c.ebreak + broken/illegal insn.
> or
> - origin insn
>
> Even in the worst case, such as IFU fetches instructions one by one:
> If the IFU gets the origin insn, it will skip the broken/illegal insn.
> If the IFU gets the c.ebreak + broken/illegal insn, then an ebreak
> exception is raised.
>
> Because c.ebreak would raise an exception, I don't see any problem.
That's the problem, this discussion is:
Reviewer: "I'm not sure, that's not written in our spec"
Submitter: "I said it, it's called -accurate atomicity-"
Andrea
next prev parent reply other threads:[~2023-01-31 10:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 16:15 [PATCH] riscv: kprobe: Optimize kprobe with accurate atomicity guoren
2023-01-28 3:52 ` liaochang (A)
2023-01-28 4:45 ` Guo Ren
2023-01-30 15:28 ` Björn Töpel
2023-01-30 15:49 ` Mark Rutland
2023-01-30 16:56 ` Björn Töpel
2023-01-31 1:48 ` Guo Ren
2023-01-31 7:12 ` Björn Töpel
2023-01-31 8:30 ` Guo Ren
2023-01-31 10:33 ` Mark Rutland
2023-02-16 15:23 ` Masami Hiramatsu
2023-02-20 10:35 ` Mark Rutland
2023-02-21 1:30 ` Guo Ren
2023-01-31 1:01 ` Guo Ren
2023-01-31 1:09 ` Guo Ren
2023-01-31 7:03 ` Björn Töpel
2023-01-31 8:27 ` Guo Ren
2023-01-31 6:40 ` Björn Töpel
2023-01-31 8:15 ` Guo Ren
2023-01-31 10:56 ` Andrea Parri [this message]
2023-01-31 13:23 ` Guo Ren
2023-02-16 7:54 ` Björn Töpel
2023-02-17 2:28 ` Guo Ren
2023-02-17 7:32 ` Björn Töpel
2023-02-21 1:56 ` Guo Ren
2023-02-16 15:42 ` Masami Hiramatsu
2023-02-21 0:57 ` Guo Ren
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