[PATCH v2 0/6] mm, x86/vdso: Special IO mapping improvements

From: Andy Lutomirski
Date: Mon Dec 14 2015 - 13:31:29 EST


This applies on top of the earlier vdso pvclock series I sent out.
Once that lands in -tip, this will apply to -tip.

This series cleans up the hack that is our vvar mapping. We currently
initialize the vvar mapping as a special mapping vma backed by nothing
whatsoever and then we abuse remap_pfn_range to populate it.

This cheats the mm core, probably breaks under various evil madvise
workloads, and prevents handling faults in more interesting ways.

To clean it up, this series:

- Adds a special mapping .fault operation
- Adds a vm_insert_pfn_prot helper
- Uses the new .fault infrastructure in x86's vdso and vvar mappings
- Hardens the HPET mapping, mitigating an HW attack surface that bothers me

akpm, can you ack patck 1?

Changes from v1:
- Lots of changelog clarification requested by akpm
- Minor tweaks to style and comments in the first two patches

Andy Lutomirski (6):
mm: Add a vm_special_mapping .fault method
mm: Add vm_insert_pfn_prot
x86/vdso: Track each mm's loaded vdso image as well as its base
x86,vdso: Use .fault for the vdso text mapping
x86,vdso: Use .fault instead of remap_pfn_range for the vvar mapping
x86/vdso: Disallow vvar access to vclock IO for never-used vclocks

arch/x86/entry/vdso/vdso2c.h | 7 --
arch/x86/entry/vdso/vma.c | 124 ++++++++++++++++++++------------
arch/x86/entry/vsyscall/vsyscall_gtod.c | 9 ++-
arch/x86/include/asm/clocksource.h | 9 +--
arch/x86/include/asm/mmu.h | 3 +-
arch/x86/include/asm/vdso.h | 3 -
arch/x86/include/asm/vgtod.h | 6 ++
include/linux/mm.h | 2 +
include/linux/mm_types.h | 22 +++++-
mm/memory.c | 25 ++++++-
mm/mmap.c | 13 ++--
11 files changed, 151 insertions(+), 72 deletions(-)

--
2.5.0

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