From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 605FA1A1D83 for ; Wed, 8 Jul 2015 13:37:28 +1000 (AEST) Received: from na01-bl2-obe.outbound.protection.outlook.com (mail-bl2on0113.outbound.protection.outlook.com [65.55.169.113]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 7AB361402BD for ; Wed, 8 Jul 2015 13:37:27 +1000 (AEST) Message-ID: <1436326636.2658.68.camel@freescale.com> Subject: Re: [kexec-lite PATCH V2] trampoline: Reset primary cpu endian to big-endian From: Scott Wood To: Samuel Mendoza-Jonas CC: , Date: Tue, 7 Jul 2015 22:37:16 -0500 In-Reply-To: <1436326178-17021-1-git-send-email-sam.mj@au1.ibm.com> References: <1436326178-17021-1-git-send-email-sam.mj@au1.ibm.com> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2015-07-08 at 13:29 +1000, Samuel Mendoza-Jonas wrote: > 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. > > Signed-off-by: Samuel Mendoza-Jonas > --- > V2: As suggested by Anton take advantage of the rfid call and switch off > MSR_LE and branch to the target kernel in the same step. > > kexec_trampoline.S | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/kexec_trampoline.S b/kexec_trampoline.S > index a3eb314..3751112 100644 > --- a/kexec_trampoline.S > +++ b/kexec_trampoline.S > @@ -88,8 +88,15 @@ start: > > li r5,0 > > - mtctr r4 > - bctr > + mtsrr0 r4 > + > + mfmsr r5 > + clrrdi r5,r5,1 /* Clear MSR_LE */ > + mtsrr1 r5 > + > + li r5,0 > + > + rfid Is kexec-lite meant to be specific to book3s-64? The README just says "A simple kexec for flattened device tree platforms" and I see a __powerpc64__ ifdef in kexec_trampoline.S (but not in the above patch)... -Scott