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 This patchset applies on top of the Juergen's patchset below, which provides the basis of the PAT management. https://lkml.org/lkml/2014/11/3/330 All new/modified interfaces have been tested. 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 (8): 1/8 x86, mm, pat: Set WT to PA7 slot of PAT MSR 2/8 x86, mm, pat, asm: Move [get|set]_page_memtype() to pat.c 3/8 x86, mm, pat: Change reserve_memtype() to handle WT 4/8 x86, mm, asm-gen: Add ioremap_wt() for WT 5/8 x86, mm, pat: Add pgprot_writethrough() for WT 6/8 x86, mm, pat: Refactor !pat_enable handling 7/8 x86, mm, asm: Add WT support to set_page_memtype() 8/8 x86, mm: Add set_memory_wt() for WT --- Documentation/x86/pat.txt | 13 +- arch/x86/include/asm/cacheflush.h | 75 +---------- 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 | 241 ++++++++++++++++++++++++----------- include/asm-generic/io.h | 4 + include/asm-generic/iomap.h | 4 + include/asm-generic/pgtable.h | 4 + -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>