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Subject: Re: [RFC] powerpc: add kexec support on Book-E
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
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Date: Fri, 10 Oct 2008 14:53:46 +1100
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Cc: linuxppc-dev@ozlabs.org, Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
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On Wed, 2008-10-01 at 23:20 +0200, Sebastian Andrzej Siewior wrote:

> +#define KEXEC_MODE_NOMMU 1
> +#define KEXEC_MODE_BOOKE 2

No need for runtime detection here, you cannot and likely never will be
able to build a kernel that does bot BookE and real mode...

> +
> +/* 1. Find the index of the entry we're executing in */
> +	bl	invstr			/* Find our address */
> +invstr:
> +	mflr	r6			/* Make it accessible */
> +	mfmsr	r7
> +	rlwinm	r4,r7,27,31,31		/* extract MSR[IS] */
> +	mfspr	r7, SPRN_PID0
> +	slwi	r7,r7,16
> +	or	r7,r7,r4
> +	mtspr	SPRN_MAS6,r7
> +	tlbsx	0,r6			/* search MSR[IS], SPID=PID0 */
> +	mfspr	r7,SPRN_MAS1
> +	andis.	r7,r7,MAS1_VALID@h
> +	bne	match_TLB

This isn't just BookE .. it's specifically FSL BookE (or "merged"
architecture). This isn't going to work on 44x for example. You need to
make it clearer.

Cheers,
Ben.