[PATCH v2 0/5] mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()

Muchun Song songmuchun at bytedance.com
Sat Apr 4 05:20:53 PDT 2026


The two weak functions vmemmap_set_pmd() and vmemmap_check_pmd() are
currently no-ops on every architecture, forcing each platform that needs
them to duplicate the same handful of lines. Provide a generic implementation:

- vmemmap_set_pmd() simply sets a huge PMD with PAGE_KERNEL protection.

- vmemmap_check_pmd() verifies that the PMD is present and leaf,
  then calls the existing vmemmap_verify() helper.

Architectures that need special handling can continue to override the
weak symbols; everyone else gets the standard version for free.

This series drops the custom implementations in arm64, riscv, loongarch,
and sparc, replacing them with the generic implementation introduced
in the first patch.

v1 -> v2:
- Fixed a tooling issue in v1 where duplicate/conflicting patches
  were incorrectly sent to the mailing list. No code changes compared
  to the intended v1.


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(-)

-- 
2.20.1




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