The weak vmemmap_set_pmd() and vmemmap_check_pmd() hooks are
currently no-ops in the generic code, which leaves architectures that
need PMD-level handling to open-code the same logic locally.

This series provides generic implementations for both helpers in
mm/sparse-vmemmap.c. vmemmap_set_pmd() installs a huge PMD with
PAGE_KERNEL protection, and vmemmap_check_pmd() verifies a present
leaf PMD before reusing the existing vmemmap_verify() helper.

With those generic helpers in place, patches 2-5 remove the now
redundant arch-specific implementations from arm64, riscv, loongarch,
and sparc.

v2 -> v3:
- Replace BUG_ON() with WARN_ON_ONCE() in patch 1
- Add Will Deacon's Acked-by to patch 2

Muchun Song (5):
  mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and
    vmemmap_check_pmd()
  arm64/mm: drop vmemmap_pmd helpers and use generic code
  riscv/mm: drop vmemmap_pmd helpers and use generic code
  loongarch/mm: drop vmemmap_check_pmd helper and use generic code
  sparc/mm: drop vmemmap_check_pmd helper and use generic code

 arch/arm64/mm/mmu.c      | 14 --------------
 arch/loongarch/mm/init.c | 11 -----------
 arch/riscv/mm/init.c     | 13 -------------
 arch/sparc/mm/init_64.c  | 11 -----------
 mm/sparse-vmemmap.c      |  7 ++++++-
 5 files changed, 6 insertions(+), 50 deletions(-)


base-commit: 7da7f07112610a520567421dd2ffcb51beaefbcc
-- 
2.54.0