Simply disabling MMU in cpu_v7_reset doesn't work for kexec

Eric Miao eric.y.miao at gmail.com
Wed Apr 21 09:19:06 EDT 2010


On Wed, Apr 21, 2010 at 9:18 PM, Eric Miao <eric.y.miao at gmail.com> wrote:
> Tried the following simple code to disable MMU in cpu_v7_reset() doesn't
> seem to work for kexec reboot. I was expecting the following instructions
> after MMU is disabled are still reachable in the instruction fetching pipe.
>

	.align	5
 ENTRY(cpu_v7_reset)
+	mrc	p15, 0, r1, c1, c0, 0		@ ctrl register
+	bic	r1, r1, #0x0001			@ ...............m
+	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
+	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I and D TLBs
 	mov	pc, r0
 ENDPROC(cpu_v7_reset)


> Not tried JTAG but posted here early in case anyone knows the correct
> sequence of disabling MMU before reset.
>
> - eric
>



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