(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 at jp.fujitsu.com> >> Acked-by: Vivek Goyal <vgoyal at redhat.com> > > 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
