[RFC,v1,0/4] Implement huge VMAP and VMALLOC on powerpc 8xx

Message

Christophe Leroy April 28, 2021, 4:46 p.m. UTC

This series is a first tentative to implement huge VMAP and VMALLOC
on powerpc 8xx. This series applies on Linux next.
For the time being the 8xx specificities are plugged directly into
generic mm functions. I have no real idea on how to make it a nice
beautiful generic implementation for the time being, hence this RFC
in order to get suggestions.

powerpc 8xx has 4 page sizes:
- 4k
- 16k
- 512k
- 8M

At the time being, vmalloc and vmap only support huge pages which are
leaf at PMD level.

Here the PMD level is 4M, it doesn't correspond to any supported
page size.

For the time being, implement use of 16k and 512k pages which is done
at PTE level.

Support of 8M pages will be implemented later, it requires use of
hugepd tables.

Christophe Leroy (4):
  mm/ioremap: Fix iomap_max_page_shift
  mm/hugetlb: Change parameters of arch_make_huge_pte()
  mm/pgtable: Add stubs for {pmd/pub}_{set/clear}_huge
  mm/vmalloc: Add support for huge pages on VMAP and VMALLOC for powerpc
    8xx

 arch/arm64/include/asm/hugetlb.h              |  3 +-
 arch/arm64/mm/hugetlbpage.c                   |  5 +-
 arch/powerpc/Kconfig                          |  3 +-
 .../include/asm/nohash/32/hugetlb-8xx.h       |  5 +-
 arch/sparc/include/asm/pgtable_64.h           |  3 +-
 arch/sparc/mm/hugetlbpage.c                   |  6 +-
 include/linux/hugetlb.h                       |  4 +-
 include/linux/pgtable.h                       | 26 ++++++-
 mm/hugetlb.c                                  |  6 +-
 mm/ioremap.c                                  |  6 +-
 mm/migrate.c                                  |  4 +-
 mm/vmalloc.c                                  | 74 ++++++++++++++++---
 12 files changed, 111 insertions(+), 34 deletions(-)