From: Atish Patra <Atish.Patra@wdc.com>
To: "hch@infradead.org" <hch@infradead.org>
Cc: "aou@eecs.berkeley.edu" <aou@eecs.berkeley.edu>,
"alankao@andestech.com" <alankao@andestech.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"anup@brainfault.org" <anup@brainfault.org>,
"palmer@sifive.com" <palmer@sifive.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"rppt@linux.ibm.com" <rppt@linux.ibm.com>,
"gary@garyguo.net" <gary@garyguo.net>,
"paul.walmsley@sifive.com" <paul.walmsley@sifive.com>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"allison@lohutok.net" <allison@lohutok.net>
Subject: Re: [PATCH v2 0/3] Add support for SBI v0.2
Date: Fri, 27 Sep 2019 22:57:45 +0000 [thread overview]
Message-ID: <8683f51f26708a468bcdf16a48db1cffac6c28d8.camel@wdc.com> (raw)
In-Reply-To: <20190927221913.GA4700@infradead.org>
On Fri, 2019-09-27 at 15:19 -0700, Christoph Hellwig wrote:
> On Thu, Sep 26, 2019 at 05:09:12PM -0700, Atish Patra wrote:
> > The Supervisor Binary Interface(SBI) specification[1] now defines a
> > base extension that provides extendability to add future extensions
> > while maintaining backward compatibility with previous versions.
> > The new version is defined as 0.2 and older version is marked as
> > 0.1.
> >
> > This series adds support v0.2 and a unified calling convention
> > implementation between 0.1 and 0.2. It also adds minimal SBI
> > functions
> > from 0.2 as well to keep the series lean.
>
> So before we do this game can be please make sure we have a clean 0.2
> environment that never uses the legacy extensions as discussed
> before?
> Without that all this work is rather futile.
>
As per our discussion offline, here are things need to be done to
achieve that.
1. Replace timer, sfence and ipi with better alternative APIs
- sbi_set_timer will be same but with new calling convention
- send_ipi and sfence_* apis can be modified in such a way that
- we don't have to use unprivileged load anymore
- Make it scalable
2. Drop clear_ipi, console, and shutdown in 0.2.
We will have a new kernel config (LEGACY_SBI) that can be manually
enabled if older firmware need to be used. By default, LEGACY_SBI will
be disabled and kernel with new SBI will be built. We will have to set
a flag day in a year or so when we can remove the LEGACY_SBI
completely.
Let us know if it is not an acceptable approach to anybody.
I will post a RFC patch with new alternate v0.2 APIs sometime next
week.
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Regards,
Atish
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next prev parent reply other threads:[~2019-09-27 22:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 0:09 [PATCH v2 0/3] Add support for SBI v0.2 Atish Patra
2019-09-27 0:09 ` [PATCH v2 1/3] RISC-V: Mark existing SBI as 0.1 SBI Atish Patra
2019-09-27 5:47 ` Anup Patel
2019-09-27 22:19 ` Christoph Hellwig
2019-09-27 0:09 ` [PATCH v2 2/3] RISC-V: Add basic support for SBI v0.2 Atish Patra
2019-09-27 5:47 ` Anup Patel
2019-10-03 5:18 ` Anup Patel
2019-09-27 0:09 ` [PATCH v2 3/3] RISC-V: Move SBI related macros under uapi Atish Patra
2019-09-27 5:48 ` Anup Patel
2019-09-27 22:21 ` Christoph Hellwig
2019-10-03 5:30 ` Anup Patel
2019-10-08 15:39 ` Christoph Hellwig
2019-09-27 22:19 ` [PATCH v2 0/3] Add support for SBI v0.2 Christoph Hellwig
2019-09-27 22:57 ` Atish Patra [this message]
2019-10-01 4:58 ` Alan Kao
2019-10-01 7:31 ` Atish Patra
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