Re: [Qemu-devel] [PATCH for 4.1] RISC-V: Ignore the S and U extensions when formatting ISA strings

From: Peter Maydell <peter.maydell@linaro.org>
To: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	"open list:RISC-V" <qemu-riscv@nongnu.org>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Atish Patra <Atish.Patra@wdc.com>
Subject: Re: [Qemu-devel] [PATCH for 4.1] RISC-V: Ignore the S and U extensions when formatting ISA strings
Date: Wed, 7 Aug 2019 17:08:20 +0100	[thread overview]
Message-ID: <CAFEAcA8q-NSx51TkcbLSgVTyHNYjDe5pK5+u9HXABxANQEhT1w@mail.gmail.com> (raw)
In-Reply-To: <20190807145939.1281-1-palmer@sifive.com>

On Wed, 7 Aug 2019 at 16:02, Palmer Dabbelt <palmer@sifive.com> wrote:
>
> The ISA strings we're providing from QEMU aren't actually legal RISC-V
> ISA strings, as both the S and U extensions cannot exist as
> single-letter extensions and must instead be multi-letter strings.
> We're still using the ISA strings inside QEMU to track the availiable
> extensions, so this patch just strips out the S and U extensions when
> formatting ISA strings.
>
> This boots Linux on top of 4.1-rc3, which no longer has the U extension
> in /proc/cpuinfo.
>
> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
> ---
> This is another late one, but I'd like to target it for 4.1 as we're
> providing illegal ISA strings and I don't want to bake that into a bunch
> of other code.

Sorry, you've missed the 4.1 train by about 24 hours. There
will be no further changes to 4.1 unless they are absolute
showstoppers (security bugs, bad data loss, etc), and this doesn't
count, judging by the description.

thanks
-- PMM