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ARM: pxa: fix page table corruption on resume

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Before this patch, the following error would sometimes occur after a
resume on pxa3xx:

    /path/to/mm/memory.c:144: bad pmd 8040542e.

The problem was that a temporary page table mapping was being improperly
restored.

The PXA3xx resume code creates a temporary mapping of resume_turn_on_mmu
to avoid a prefetch abort.  The pxa3xx_resume_after_mmu code requires
that the r1 register holding the address of this mapping not be
modified, however, resume_turn_on_mmu does modify it. It is mostly
correct in that r1 receives the base table address, but it may also
get other bits in 13:0.  This results in pxa3xx_resume_after_mmu
restoring the original mapping to the wrong place, corrupting memory
and leaving the temporary mapping in place.

Signed-off-by: Matt Reimer <mreimer@sdgsystems.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
This commit is contained in:
Aric D. Blumer 2010-12-29 11:18:29 -05:00 committed by Eric Miao
parent 823a2df258
commit 24c7855774
1 changed files with 2 additions and 2 deletions
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4
arch/arm/mach-pxa/sleep.S
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@ -353,8 +353,8 @@ resume_turn_on_mmu:
@ Let us ensure we jump to resume_after_mmu only when the mcr above
@ actually took effect. They call it the "cpwait" operation.
mrc p15, 0, r1, c2, c0, 0 @ queue a dependency on CP15
sub pc, r2, r1, lsr #32 @ jump to virtual addr
mrc p15, 0, r0, c2, c0, 0 @ queue a dependency on CP15
sub pc, r2, r0, lsr #32 @ jump to virtual addr
nop
nop
nop