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To:     Xu Lu <luxu.kernel@bytedance.com>,
        Atish Patra <atishp@atishpatra.org>
Cc:     paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, maz@kernel.org, anup@brainfault.org,
        dengliang.1214@bytedance.com, liyu.yukiteru@bytedance.com,
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        =?utf-8?Q?Cl=C3=A9ment_L=C3=A9ger?= <cleger@rivosinc.com>
Subject: Re: [External] Re: [RFC 00/12] riscv: Introduce Pseudo NMI
In-Reply-To: <CAPYmKFuNr18_jJYZ6X4Rrty=bU0cXiuHpAqSt2+YqDWV6rAveg@mail.gmail.com>
References: <20231023082911.23242-1-luxu.kernel@bytedance.com>
 <CAOnJCUKH0muFHWujXEqJtb4Uv6Kfh5DeJeR2qg9vj7Kc5w43dw@mail.gmail.com>
 <CAPYmKFuNr18_jJYZ6X4Rrty=bU0cXiuHpAqSt2+YqDWV6rAveg@mail.gmail.com>
Date:   Fri, 27 Oct 2023 09:55:19 +0200
Message-ID: <874jic4hzs.ffs@tglx>
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On Thu, Oct 26 2023 at 21:56, Xu Lu wrote:
> On Thu, Oct 26, 2023 at 7:02=E2=80=AFAM Atish Patra <atishp@atishpatra.or=
g> wrote:
> First, please allow me to explain that CSR_IE Pseudo NMI actually can sup=
port
> more than PMU profiling. For example, if we choose to make external major
> interrupt as NMI and use ithreshold or eithreshold in AIA to control whic=
h minor
> external interrupts can be sent to CPU, then we actually can support mult=
iple
> minor interrupts as NMI while keeping the other minor interrupts still
> normal irqs.

What is the use case for these NMIs? Anything else than profiling is not
really possible in NMI context at all.

Thanks,

        tglx