[PATCH v7 0/7] Support Write-Through mapping on x86

From: Toshi Kani
Date: Tue Jan 06 2015 - 16:05:59 EST


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

All new/modified interfaces have been tested.

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 (7):
1/7 x86, mm, pat: Set WT to PA7 slot of PAT MSR
2/7 x86, mm, pat: Change reserve_memtype() to handle WT
3/7 x86, mm, asm-gen: Add ioremap_wt() for WT
4/7 x86, mm, pat: Add pgprot_writethrough() for WT
5/7 x86, mm, pat: Refactor !pat_enable handling
6/7 x86, mm, asm: Add WT support to set_page_memtype()
7/7 x86, mm: Add set_memory_wt() for WT

---
Documentation/x86/pat.txt | 13 ++-
arch/x86/include/asm/cacheflush.h | 6 +-
arch/x86/include/asm/io.h | 2 +
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 | 184 ++++++++++++++++++++++++-----------
include/asm-generic/io.h | 9 ++
include/asm-generic/iomap.h | 4 +
include/asm-generic/pgtable.h | 4 +
12 files changed, 244 insertions(+), 86 deletions(-)

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