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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Larry Finger <Larry.Finger@lwfinger.net>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/rtas: fix early boot failure.
Date: Mon, 1 Apr 2019 13:14:13 +0200	[thread overview]
Message-ID: <558fbb7e-a454-055e-ca29-a2e4dfb6cf6a@c-s.fr> (raw)
In-Reply-To: <aab41779cac995ebdc03e700a9dc7cfc30a28770.1553503163.git.christophe.leroy@c-s.fr>

Michael,

Looks like you missed this fix for rc3.

Christophe

Le 25/03/2019 à 09:43, Christophe Leroy a écrit :
> 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 the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that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>
> ---
>   arch/powerpc/kernel/head_32.S | 8 --------
>   1 file changed, 8 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
> index 48051c8977c5..e25b615e9f9e 100644
> --- a/arch/powerpc/kernel/head_32.S
> +++ b/arch/powerpc/kernel/head_32.S
> @@ -851,10 +851,6 @@ __secondary_start:
>   	tophys(r4,r2)
>   	addi	r4,r4,THREAD	/* phys address of our thread_struct */
>   	mtspr	SPRN_SPRG_THREAD,r4
> -#ifdef CONFIG_PPC_RTAS
> -	li	r3,0
> -	stw	r3, RTAS_SP(r4)		/* 0 => not in RTAS */
> -#endif
>   	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
>   	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
>   	mtspr	SPRN_SPRG_PGDIR, r4
> @@ -941,10 +937,6 @@ start_here:
>   	tophys(r4,r2)
>   	addi	r4,r4,THREAD	/* init task's THREAD */
>   	mtspr	SPRN_SPRG_THREAD,r4
> -#ifdef CONFIG_PPC_RTAS
> -	li	r3,0
> -	stw	r3, RTAS_SP(r4)		/* 0 => not in RTAS */
> -#endif
>   	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
>   	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
>   	mtspr	SPRN_SPRG_PGDIR, r4
> 

  parent reply	other threads:[~2019-04-01 11:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-25  8:43 [PATCH] powerpc/rtas: fix early boot failure Christophe Leroy
2019-03-25  8:43 ` Christophe Leroy
2019-03-25 16:18 ` Larry Finger
2019-03-25 16:18   ` Larry Finger
2019-04-01 11:14 ` Christophe Leroy [this message]
2019-04-08 13:03 ` Michael Ellerman

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