[PATCH v9 0/10] Support Write-Through mapping on x86

[Toshi Kani]

This patchset adds support of Write-Through (WT) mapping on x86.
The study below shows that using WT mapping may be useful for
non-volatile memory.

http://www.hpl.hp.com/techreports/2012/HPL-2012-236.pdf

The patchset consists of the following changes.
 - Patch 1/10 to 5/10 add ioremap_wt()
 - Patch 6/10 adds pgprot_writethrough()
 - Patch 7/10 to 8/10 add set_memory_wt()
 - Patch 9/10 refactors !pat_enable paths
 - Patch 10/10 changes the pmem driver to call ioremap_wt()

All new/modified interfaces have been tested.

---
v9:
- Changed to export the set_xxx_wt() interfaces with GPL.
  (Ingo Molnar)
- Changed is_new_memtype_allowed() to handle WT cases.
- Changed arch-specific io.h to define ioremap_wt().
- Changed the pmem driver to use ioremap_wt().
- Rebased to 4.1-rc3 and resolved minor conflicts.

v8:
- Rebased to 4.0-rc1 and resolved conflicts with 9d34cfdf4 in
  patch 5/7.

v7:
- Rebased to 3.19-rc3 as Juergen's patchset for the PAT management
  has been accepted.

v6:
- Dropped the patch moving [set|get]_page_memtype() to pat.c
  since the tip branch already has this change.
- Fixed an issue when CONFIG_X86_PAT is not defined.

v5:
- Clarified comment of why using slot 7. (Andy Lutomirski,
  Thomas Gleixner)
- Moved [set|get]_page_memtype() to pat.c. (Thomas Gleixner)
- Removed BUG() from set_page_memtype(). (Thomas Gleixner)

v4:
- Added set_memory_wt() by adding WT support of regular memory.

v3:
- Dropped the set_memory_wt() patch. (Andy Lutomirski)
- Refactored the !pat_enabled handling. (H. Peter Anvin,
  Andy Lutomirski)
- Added the picture of PTE encoding. (Konrad Rzeszutek Wilk)

v2:
- Changed WT to use slot 7 of the PAT MSR. (H. Peter Anvin,
  Andy Lutomirski)
- Changed to have conservative checks to exclude all Pentium 2, 3,
  M, and 4 families. (Ingo Molnar, Henrique de Moraes Holschuh,
  Andy Lutomirski)
- Updated documentation to cover WT interfaces and usages.
  (Andy Lutomirski, Yigal Korman)

---
Toshi Kani (10):
 1/10 x86, mm, pat: Set WT to PA7 slot of PAT MSR
 2/10 x86, mm, pat: Change reserve_memtype() for WT
 3/10 x86, asm: Change is_new_memtype_allowed() for WT
 4/10 x86, mm, asm-gen: Add ioremap_wt() for WT
 5/10 arch/*/asm/io.h: Add ioremap_wt() to all architectures
 6/10 x86, mm, pat: Add pgprot_writethrough() for WT
 7/10 x86, mm, asm: Add WT support to set_page_memtype()
 8/10 x86, mm: Add set_memory_wt() for WT
 9/10 x86, mm, pat: Refactor !pat_enable handling
10/10 drivers/block/pmem: Map NVDIMM with ioremap_wt()

---
 Documentation/x86/pat.txt            |  13 ++-
 arch/arc/include/asm/io.h            |   1 +
 arch/arm/include/asm/io.h            |   1 +
 arch/arm64/include/asm/io.h          |   1 +
 arch/avr32/include/asm/io.h          |   1 +
 arch/frv/include/asm/io.h            |   7 ++
 arch/m32r/include/asm/io.h           |   1 +
 arch/m68k/include/asm/io_mm.h        |   7 ++
 arch/m68k/include/asm/io_no.h        |   6 ++
 arch/metag/include/asm/io.h          |   3 +
 arch/microblaze/include/asm/io.h     |   1 +
 arch/mn10300/include/asm/io.h        |   1 +
 arch/nios2/include/asm/io.h          |   1 +
 arch/s390/include/asm/io.h           |   1 +
 arch/sparc/include/asm/io_32.h       |   1 +
 arch/sparc/include/asm/io_64.h       |   1 +
 arch/tile/include/asm/io.h           |   1 +
 arch/x86/include/asm/cacheflush.h    |   6 +-
 arch/x86/include/asm/io.h            |   2 +
 arch/x86/include/asm/pgtable.h       |   8 +-
 arch/x86/include/asm/pgtable_types.h |   3 +
 arch/x86/mm/init.c                   |   6 +-
 arch/x86/mm/iomap_32.c               |  12 +--
 arch/x86/mm/ioremap.c                |  26 ++++-
 arch/x86/mm/pageattr.c               |  61 +++++++++--
 arch/x86/mm/pat.c                    | 194 ++++++++++++++++++++++++-----------
 arch/xtensa/include/asm/io.h         |   1 +
 drivers/block/pmem.c                 |   4 +-
 include/asm-generic/io.h             |   9 ++
 include/asm-generic/iomap.h          |   4 +
 include/asm-generic/pgtable.h        |   4 +
 31 files changed, 296 insertions(+), 92 deletions(-)

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