From: hch@infradead.org (Christoph Hellwig)
To: linux-riscv@lists.infradead.org
Subject: [RFC 0/2] RISC-V: A proposal to add vendor-specific code
Date: Mon, 5 Nov 2018 01:08:52 -0800 [thread overview]
Message-ID: <20181105090852.GA14924@infradead.org> (raw)
In-Reply-To: <CAK8P3a2c98VVPArCkdAR=-nnDBq1gYRCLDDgQB71eGiTSRdb4A@mail.gmail.com>
On Mon, Nov 05, 2018 at 09:52:52AM +0100, Arnd Bergmann wrote:
> > I fundamentally disagree with this? and think it should be the contrary.
> >
> > 1. The kernel shall support no vendor specific instructions whatsoever,
> > period.
>
> I think what was meant above is
>
> 1. If a vendor extension requires kernel support, that support
> must be able to be built into a kernel image without breaking support
> for CPUs that do not have that extension, to allow building a single
> kernel image that works on all CPUs.
No. This literally means no vendor extensions involving instructions
or CSRs in the kernel. They are fine for userspace, or for the M-mode
code including impementation of the SBI, but not for the kernel.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Vincent Chen <vincentc@andestech.com>,
aou@eecs.berkeley.edu, alankao@andestech.com,
greentime@andestech.com, zong@andestech.com, palmer@sifive.com,
linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
kito@andestech.com, linux-riscv@lists.infradead.org,
deanbo422@gmail.com
Subject: Re: [RFC 0/2] RISC-V: A proposal to add vendor-specific code
Date: Mon, 5 Nov 2018 01:08:52 -0800 [thread overview]
Message-ID: <20181105090852.GA14924@infradead.org> (raw)
Message-ID: <20181105090852.LoXeXNvbShr2p5gHIYWw-yAx9OkCw50UFRrAFRDhzeA@z> (raw)
In-Reply-To: <CAK8P3a2c98VVPArCkdAR=-nnDBq1gYRCLDDgQB71eGiTSRdb4A@mail.gmail.com>
On Mon, Nov 05, 2018 at 09:52:52AM +0100, Arnd Bergmann wrote:
> > I fundamentally disagree with this… and think it should be the contrary.
> >
> > 1. The kernel shall support no vendor specific instructions whatsoever,
> > period.
>
> I think what was meant above is
>
> 1. If a vendor extension requires kernel support, that support
> must be able to be built into a kernel image without breaking support
> for CPUs that do not have that extension, to allow building a single
> kernel image that works on all CPUs.
No. This literally means no vendor extensions involving instructions
or CSRs in the kernel. They are fine for userspace, or for the M-mode
code including impementation of the SBI, but not for the kernel.
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next prev parent reply other threads:[~2018-11-05 9:08 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 10:35 [RFC 0/2] RISC-V: A proposal to add vendor-specific code Vincent Chen
2018-10-31 10:35 ` Vincent Chen
2018-10-31 10:35 ` [RFC 1/2] RISC-V: An infrastructure " Vincent Chen
2018-10-31 10:35 ` Vincent Chen
2018-10-31 10:35 ` [RFC 2/2] RISC-V: make dma_map_ops work without cache coherent agent Vincent Chen
2018-10-31 10:35 ` Vincent Chen
2018-10-31 11:16 ` [RFC 0/2] RISC-V: A proposal to add vendor-specific code Anup Patel
2018-10-31 11:16 ` Anup Patel
2018-10-31 11:45 ` Arnd Bergmann
2018-10-31 11:45 ` Arnd Bergmann
2018-10-31 14:17 ` Christoph Hellwig
2018-10-31 14:17 ` Christoph Hellwig
2018-11-01 0:55 ` Alan Kao
2018-11-01 0:55 ` Alan Kao
2018-11-01 17:50 ` Palmer Dabbelt
2018-11-01 17:50 ` Palmer Dabbelt
2018-11-02 0:41 ` Alan Kao
2018-11-02 0:41 ` Alan Kao
2018-10-31 17:27 ` Palmer Dabbelt
2018-10-31 17:27 ` Palmer Dabbelt
2018-10-31 19:17 ` Olof Johansson
2018-10-31 19:17 ` Olof Johansson
2018-11-01 17:48 ` Karsten Merker
2018-11-05 6:58 ` Vincent Chen
2018-11-05 6:58 ` Vincent Chen
2018-11-05 7:05 ` Christoph Hellwig
2018-11-05 7:05 ` Christoph Hellwig
2018-11-05 8:52 ` Arnd Bergmann
2018-11-05 8:52 ` Arnd Bergmann
2018-11-05 9:08 ` Christoph Hellwig [this message]
2018-11-05 9:08 ` Christoph Hellwig
2018-11-05 13:51 ` Arnd Bergmann
2018-11-05 13:51 ` Arnd Bergmann
2018-11-06 6:59 ` Christoph Hellwig
2018-11-06 6:59 ` Christoph Hellwig
2018-11-06 23:45 ` Palmer Dabbelt
2018-11-06 23:45 ` Palmer Dabbelt
2018-11-07 9:51 ` Arnd Bergmann
2018-11-07 9:51 ` Arnd Bergmann
2018-11-06 23:45 ` Palmer Dabbelt
2018-11-06 23:45 ` Palmer Dabbelt
2018-11-08 2:43 ` Vincent Chen
2018-11-08 2:43 ` Vincent Chen
2018-11-05 19:39 ` Nick Kossifidis
2018-11-05 19:39 ` Nick Kossifidis
2018-11-06 6:56 ` Christoph Hellwig
2018-11-06 6:56 ` Christoph Hellwig
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