linux-kernel - Re: [External] Re: [RFC 00/12] riscv: Introduce Pseudo NMI

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Date:   Fri, 27 Oct 2023 09:55:19 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Xu Lu <luxu.kernel@...edance.com>,
        Atish Patra <atishp@...shpatra.org>
Cc:     paul.walmsley@...ive.com, palmer@...belt.com,
        aou@...s.berkeley.edu, maz@...nel.org, anup@...infault.org,
        dengliang.1214@...edance.com, liyu.yukiteru@...edance.com,
        sunjiadong.lff@...edance.com, xieyongji@...edance.com,
        lihangjing@...edance.com, chaiwen.cc@...edance.com,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        Clément Léger <cleger@...osinc.com>
Subject: Re: [External] Re: [RFC 00/12] riscv: Introduce Pseudo NMI

On Thu, Oct 26 2023 at 21:56, Xu Lu wrote:
> On Thu, Oct 26, 2023 at 7:02 AM Atish Patra <atishp@...shpatra.org> wrote:
> First, please allow me to explain that CSR_IE Pseudo NMI actually can support
> 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 which minor
> external interrupts can be sent to CPU, then we actually can support multiple
> 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