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Commit 7f614cd1 authored by HATAYAMA Daisuke's avatar HATAYAMA Daisuke Committed by Linus Torvalds
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vmcore: treat memory chunks referenced by PT_LOAD program header entries in...


vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list

Treat memory chunks referenced by PT_LOAD program header entries in
page-size boundary in vmcore_list.  Formally, for each range [start,
end], we set up the corresponding vmcore object in vmcore_list to
[rounddown(start, PAGE_SIZE), roundup(end, PAGE_SIZE)].

This change affects layout of /proc/vmcore.  The gaps generated by the
rearrangement are newly made visible to applications as holes.
Concretely, they are two ranges [rounddown(start, PAGE_SIZE), start] and
[end, roundup(end, PAGE_SIZE)].

Suppose variable m points at a vmcore object in vmcore_list, and
variable phdr points at the program header of PT_LOAD type the variable
m corresponds to.  Then, pictorially:

  m->offset                    +---------------+
                               | hole          |
phdr->p_offset =               +---------------+
  m->offset + (paddr - start)  |               |\
                               | kernel memory | phdr->p_memsz
                               |               |/
                               +---------------+
                               | hole          |
  m->offset + m->size          +---------------+

where m->offset and m->offset + m->size are always page-size aligned.

Signed-off-by: default avatarHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f2bdacdd
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