From: Anthony Liguori <anthony@codemonkey.ws>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Alexander Graf <agraf@suse.de>,
Rob Herring <rob.herring@calxeda.com>,
qemu-devel@nongnu.org, Grant Likely <grant.likely@secretlab.ca>,
Paul Brook <paul@codesourcery.com>,
"Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
Jeremy Kerr <jeremy.kerr@canonical.com>,
John Williams <john.williams@petalogix.com>
Subject: Re: [Qemu-devel] [PATCH v2] arm: add device tree support
Date: Wed, 01 Feb 2012 07:25:20 -0600 [thread overview]
Message-ID: <4F293D40.90804@codemonkey.ws> (raw)
In-Reply-To: <CAFEAcA89A1SBezb2DEbMWL5qD+Me3_uXufmneHyxwz4Kj8dBeA@mail.gmail.com>
On 02/01/2012 07:10 AM, Peter Maydell wrote:
> On 1 February 2012 13:04, Anthony Liguori<anthony@codemonkey.ws> wrote:
>> How does it race? Devices normally never touch memory so a loader device
>> will be the only thing mucking with memory.
>
> The obvious one is "loader reset function wants to set starting PC to
> entry point of kernel/etc" vs "CPU device reset wants to set starting
> PC to hardware-mandated reset vector". We have this at the moment, of
> course, and I think we implicitly rely on reset handlers being called
> in order of registration...
I'm a bit confused, why can't the kernel loader be implemented in terms of a
firmware blob?
This is what we do for x86 and it solves this problem robustly. Isn't it just a
matter of a few instructions to do a jmp to a known location?
Regards,
Anthony Liguori
>
> (The other irritating case is where the CPU device reset wants
> to read the starting PC out of memory, like the Cortex-M3, but
> really that one is because we don't distinguish "going into reset"
> from "coming out of reset".)
>
> -- PMM
>
next prev parent reply other threads:[~2012-02-01 13:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-01 0:11 [Qemu-devel] [PATCH v2] arm: add device tree support Grant Likely
2012-02-01 1:10 ` Alexander Graf
2012-02-01 1:35 ` Paul Brook
2012-02-01 1:44 ` Alexander Graf
2012-02-01 2:37 ` Anthony Liguori
2012-02-01 2:40 ` John Williams
2012-02-01 13:04 ` Anthony Liguori
2012-02-01 13:10 ` Peter Maydell
2012-02-01 13:25 ` Anthony Liguori [this message]
2012-02-01 13:32 ` Alexander Graf
2012-02-01 13:44 ` Anthony Liguori
2012-02-01 13:49 ` Alexander Graf
2012-02-01 13:52 ` Anthony Liguori
2012-02-01 13:55 ` Alexander Graf
2012-02-01 15:13 ` Anthony Liguori
2012-02-01 17:38 ` Grant Likely
2012-02-01 20:59 ` Alexander Graf
2012-02-01 2:35 ` Anthony Liguori
2012-02-22 19:42 ` Peter Maydell
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