Re: [PATCH v8 9/9] vmcore: support mmap() on /proc/vmcore

[HATAYAMA Daisuke]

(2013/05/24 18:02), Maxim Uvarov wrote:
> 2013/5/24 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx <mailto:akpm@xxxxxxxxxxxxxxxxxxxx>>
>
>     On Thu, 23 May 2013 14:25:48 +0900 HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx <mailto:d.hatayama@xxxxxxxxxxxxxx>> wrote:
>
>      > This patch introduces mmap_vmcore().
>      >
>      > Don't permit writable nor executable mapping even with mprotect()
>      > because this mmap() is aimed at reading crash dump memory.
>      > Non-writable mapping is also requirement of remap_pfn_range() when
>      > mapping linear pages on non-consecutive physical pages; see
>      > is_cow_mapping().
>      >
>      > Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by
>      > remap_vmalloc_range_pertial at the same time for a single
>      > vma. do_munmap() can correctly clean partially remapped vma with two
>      > functions in abnormal case. See zap_pte_range(), vm_normal_page() and
>      > their comments for details.
>      >
>      > On x86-32 PAE kernels, mmap() supports at most 16TB memory only. This
>      > limitation comes from the fact that the third argument of
>      > remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long.
>
>     More reviewing and testing, please.
>
>
> Do you have git pull for both kernel and userland changes? I would like to do some more testing on my machines.
>
> Maxim.

Thanks! That's very helpful.

--
Thanks.
HATAYAMA, Daisuke

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