(2013/06/07 6:31), Arnd Bergmann wrote:
On Thursday 23 May 2013 14:25:48 HATAYAMA Daisuke 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.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
I get build errors on 'make randconfig' from this, when building
NOMMU kernels on ARM. I suppose the new feature should be hidden
in #ifdef CONFIG_MMU.
Arnd
Thanks for trying the build and your report!
OTOH, I don't have no-MMU architectures; x86 box only. I cannot reproduce this build error. Could you give me your build log? I want to use it to detect what part depends on CONFIG_MMU.
--
Thanks.
HATAYAMA, Daisuke
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