[PATCHSET v4 0/5] pagemap: make useable for non-privilege users

Konstantin Khlebnikov
2015-07-14T15:39:38Z

This patchset makes pagemap useable again in the safe way (after row hammer
bug it was made CAP_SYS_ADMIN-only). This patchset restores access for
non-privileged users but hides PFNs from them.

Also it adds bit 'map-exlusive' which is set if page is mapped only here:
it helps in estimation of working set without exposing pfns and allows to
distinguish CoWed and non-CoWed private anonymous pages.

Second patch removes page-shift bits and completes migration to the new
pagemap format: flags soft-dirty and mmap-exlusive are available only
in the new format.

Changes since v3:
* patches reordered: cleanup now in second patch
* update pagemap for hugetlb, add missing 'FILE' bit
* fix PM_PFRAME_BITS: its 55 not 54 as was in previous versions

---

Konstantin Khlebnikov (5):
pagemap: check permissions and capabilities at open time
pagemap: switch to the new format and do some cleanup
pagemap: rework hugetlb and thp report
pagemap: hide physical addresses from non-privileged users
pagemap: add mmap-exclusive bit for marking pages mapped only here

Documentation/vm/pagemap.txt | 3
fs/proc/task_mmu.c | 267 ++++++++++++++++++------------------------
tools/vm/page-types.c | 35 +++---
3 files changed, 137 insertions(+), 168 deletions(-)

--
Konstantin