From: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>
To: Anton Blanchard <anton@samba.org>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [kexec-lite PATCH] trampoline: Reset primary cpu endian to big-endian
Date: Wed, 8 Jul 2015 13:11:42 +1000 [thread overview]
Message-ID: <559C94EE.8050201@au1.ibm.com> (raw)
In-Reply-To: <20150708115632.725120f1@kryten>
On 08/07/15 11:56, Anton Blanchard wrote:
> Hi Sam,
>
>> Older big-endian ppc64 kernels don't include the FIXUP_ENDIAN check,
>> meaning if we kexec from a little-endian kernel the target kernel will
>> fail to boot.
>> Returning to big-endian before we enter the target kernel ensures that
>> the target kernel can boot whether or not it includes FIXUP_ENDIAN.
>
> Thanks!
>
> I wonder if we can do something simpler, and always enter via rfid.
> Avoids the need for the endian trampoline. Something like:
>
> mtsrr0 r4
>
> mfmsr r5
> clrrdi r5,r5,1 /* Clear MSR_LE */
> mtsrr1 r5
>
> li r5,0
>
> rfid
>
> Anton
>
Ah that's a neat idea, I'll test and send a V2.
Cheers,
Sam
--
-----------
LTC Ozlabs
IBM
prev parent reply other threads:[~2015-07-08 3:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-08 1:25 [kexec-lite PATCH] trampoline: Reset primary cpu endian to big-endian Samuel Mendoza-Jonas
2015-07-08 1:56 ` Anton Blanchard
2015-07-08 3:11 ` Samuel Mendoza-Jonas [this message]
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