Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] powerpc/rtas: fix early boot failure.
To:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <aab41779cac995ebdc03e700a9dc7cfc30a28770.1553503163.git.christophe.leroy@c-s.fr>
From:   Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <04c77eea-bda1-2bad-062f-d86d2ce6f192@lwfinger.net>
Date:   Mon, 25 Mar 2019 11:18:28 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.5.2
MIME-Version: 1.0
In-Reply-To: <aab41779cac995ebdc03e700a9dc7cfc30a28770.1553503163.git.christophe.leroy@c-s.fr>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 3/25/19 3:43 AM, Christophe Leroy wrote:
> Commit 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing
> stack pointer while in RTAS") changes the code to use a field in
> thread struct to store the stack pointer while in RTAS instead of
> using SPRN_SPRG2. It therefore converts all places which were
> manipulating SPRN_SPRG2 to use that field. During early startup,
> the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that
> field in thread struct. But at least in start_here, that's done
> wrongly because it used the physical address of the fields while
> MMU is on at that time.
> 
> So the virtual address of the field should be used instead, but in
> the meantime, thread struct has already been zeroised and initialised
> so we can just drop this initialisation.
> 
> Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
> Fixes: 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing stack pointer while in RTAS")
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

Tested-by: Larry Finger <Larry.Finger@lwfinger.net>

My PPC box now boots OK.

Larry