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From: Rich Felker <dalias@libc.org>
To: Paul Burton <paul.burton@mips.com>
Cc: Andy Lutomirski <luto@kernel.org>,
	Linux MIPS Mailing List <linux-mips@linux-mips.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Paul Burton <paul.burton@imgtec.com>,
	David Daney <david.daney@cavium.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	James Hogan <jhogan@kernel.org>
Subject: Re: Fixing MIPS delay slot emulation weakness?
Date: Sun, 16 Dec 2018 13:11:37 -0500	[thread overview]
Message-ID: <20181216181137.GF23599@brightrain.aerifal.cx> (raw)
In-Reply-To: <20181215212643.sfk2zwzatdfysbk3@pburton-laptop>

On Sat, Dec 15, 2018 at 09:26:45PM +0000, Paul Burton wrote:
> > The really nice but less compatible fix would be to let processes or
> > even the whole system opt out by promising not to put anything in FPU
> > branch delay slots, of course.
> 
> The ultimate fix comes with a switch to the nanoMIPS ISA which has no
> delay slots :)

I don't understand the MIPS position that introducing new ISAs
(including silently-new like r6) and not supporting or deprecating
support for the old one is a solution to anything. If one doesn't care
about the ability to run existing binaries for your platform, one
might as well switch to RISC-V or ARM or whatever. The whole advantage
of an ISA as a "platform" is the ability to run existing software and
use existing tooling (not just compilers; think also JITs, FFI
frameworks, etc), not any particular design advantage the ISA has.

Rich

  reply	other threads:[~2018-12-16 18:11 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-15 19:19 Fixing MIPS delay slot emulation weakness? Andy Lutomirski
2018-12-15 21:26 ` Paul Burton
2018-12-16 18:11   ` Rich Felker [this message]
2018-12-16 18:55   ` Andy Lutomirski
2018-12-15 22:50 ` Rich Felker
2018-12-16  2:15   ` Maciej W. Rozycki
2018-12-16  2:32     ` Rich Felker
2018-12-16 13:50       ` Maciej W. Rozycki
2018-12-16 18:13         ` Rich Felker
2018-12-16 18:59           ` Andy Lutomirski
2018-12-16 19:45             ` Maciej W. Rozycki
2018-12-17  0:59             ` Rich Felker
2018-12-17  1:55               ` Maciej W. Rozycki
2018-12-18  1:13                 ` Aaro Koskinen
2018-12-19  4:32 ` Paul Burton
2018-12-19 21:12   ` Hugh Dickins
2018-12-20 17:56     ` Paul Burton
2018-12-20 17:45 ` [PATCH] MIPS: math-emu: Write-protect delay slot emulation pages Paul Burton
     [not found]   ` <20181220192616.42976218FE@mail.kernel.org>
2018-12-21 21:16     ` Paul Burton
2018-12-22 19:16       ` Sasha Levin
2018-12-23 16:16   ` Paul Burton

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