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From: Alistair Popple <alistair@popple.id.au>
To: Josh Boyer <jwboyer@gmail.com>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] ppc476: Enable a linker work around for IBM errata #46
Date: Tue, 25 Feb 2014 10:52:07 +1100	[thread overview]
Message-ID: <25816197.m2jECl2CbU@mexican> (raw)
In-Reply-To: <CA+5PVA4Hx4iKkL+vLJjOTwMaKOL-dJPJpSHLjR+nU6MTTGvFcA@mail.gmail.com>

On Mon, 24 Feb 2014 08:35:06 Josh Boyer wrote:
> On Mon, Feb 24, 2014 at 2:00 AM, Alistair Popple <alistair@popple.id.au> 
wrote:
> > This patch adds an option to enable a work around for an icache bug on
> > 476 that can cause execution of stale instructions when falling
> > through pages (IBM errata #46). It requires a recent version of
> > binutils which supports the --ppc476-workaround option.
> > 
> > The work around enables the appropriate linker options and ensures
> > that all module output sections are aligned to 4K page boundaries. The
> > work around is only required when building modules.
> 
> What happens if you're using 64K pages?  Is the alignment 4K always,
> or does it need to be aligned to PAGE_SIZE?

The work around inserts an extra instruction on 4K page boundaries. As a 64K 
(or a 16K) page boundary is also a 4K page boundary the work around should 
cover those page sizes as well.

- Alistair

> josh

      reply	other threads:[~2014-02-24 23:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-24  7:00 [PATCH] ppc476: Enable a linker work around for IBM errata #46 Alistair Popple
2014-02-24 13:35 ` Josh Boyer
2014-02-24 23:52   ` Alistair Popple [this message]

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