[no subject]

[John Bradford]

richard.brunner@xxxxxxx
In-Reply-To: <20030930073814.GA26649@xxxxxxxxxxxxxxxxxx>
References:  <20030930073814.GA26649@xxxxxxxxxxxxxxxxxx>
Subject: Re: [PATCH] Mutilated form of Andi Kleen's AMD prefetch errata patch

Quote from Jamie Lokier <jamie@xxxxxxxxxxxxx>:

>    2. Nevertheless, when a kernel _not_ optimised for those AMD processors
>       is run on one, the "alternative" mechanism now correctly replaces
>       prefetch instructions with nops.

> It's a reasonable argument that if a kernel version, say 2.6.0, promises
> to hide the errata from _userspace_ programs, then the generic or
> not-AMD-optimised kernels should do that too.  Otherwise userspace may
> as well provide the workaround itself, by catching SIGSEGV - because it
> is perfectly normal and common to run a generic kernel on an AMD.

This problem, and others like it, would be solved for ever with
Adrian's bitmap-of-supported-cpus patch, though.  With that, there is
no 'generic' kernel, either it supports Athlons, or it doesn't.  100%
elimination of Athlon specific code for other CPUs.  Everybody is
happy.

Of course a kernel compiled strictly for 386s may seem to boot on an
Athlon but not work properly.  So what?  Just don't run the 'wrong'
kernel.

John.
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