linux-kernel - Re: [PATCH v2 3/5] irqchip: RISC-V Local Interrupt Controller Driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180910221646.GA7368@infradead.org>
Date:   Mon, 10 Sep 2018 15:16:46 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Anup Patel <anup@...infault.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Palmer Dabbelt <palmer@...ive.com>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
        Atish Patra <atish.patra@....com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Palmer Dabbelt <palmer@...belt.com>,
        linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v2 3/5] irqchip: RISC-V Local Interrupt Controller Driver

On Mon, Sep 10, 2018 at 10:41:22PM +0530, Anup Patel wrote:
> RISC-V priv spec 1.10 defines the 9 bits in MIE and MIP registers and
> other bits are reserved.
> 
> The unused bits in MIP are WIRI (reserved write ignored and read ignored)
> and unused bits in MIE are WPRI (reserved write preserve values and
> read ignored).
> 
> The RISC-V priv spec 1.10 does not tell that unused reserved bits in
> MIE/MIP cannot be used for:
> 1. CPU implementation specific local interrupts
> 2. Per-CPU device interrupts.
> 
> The RISC-V priv spec 1.10 tries to only describe MIE/MIP bits which
> are mandatory on any RISC-V 1.10 compliant CPU but it possible to
> used other reserved bits for implementation specific local interrupts.

Reserved means reserved for future versions of the spec, not for vendor
specific bad ideas.