[Crash-utility] Throw read error on vmcore produced by ARM soc.

[Li Haifeng]

2013/3/29 Russell King - ARM Linux <linux at arm.linux.org.uk>:
> On Thu, Mar 28, 2013 at 11:37:34AM -0400, Dave Anderson wrote:
>> I don't know about the arm_ioremap issue -- that's for the ARM guys to
>> answer.
>
> Not really.  Basically, we don't support ioremapping of areas of RAM
> already mapped elsewhere by the kernel.  In other words, if RAM is
> part of the kernel's memory map, then ioremap() is forbidden.
>
> Why?  Because if we were to allow it, we'd end up with conflicting
> mappings being created, which is a violation of the architecture
> requirements.
>
> The quoted pfn_valid() implementation isn't used if the memory map
> has holes in it - as selected by:
>
> config HAVE_ARCH_PFN_VALID
>         def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM
>
> Maybe that also needs to be enabled with crashkernels if they also
> provide a memory map which has holes in?

Thanks.

At least, it looks like that comment for WARN_ON(pfn_valid()) in
arm_ioremap() will not lead to vmcore corrupt.

:-)

>
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