[PATCH v9 0/7] Support page table check

Rohan McLure rmclure at linux.ibm.com
Thu Nov 30 13:53:52 AEDT 2023

Support the page table check sanitiser on all PowerPC platforms. This
sanitiser works by serialising assignments, reassignments and clears of
page table entries at each level in order to ensure that anonymous
mappings have at most one writable consumer, and likewise that
file-backed mappings are not simultaneously also anonymous mappings.

In order to support this infrastructure, a number of stubs must be
defined for all powerpc platforms. Additionally, seperate set_pte_at
and set_pte, to allow for internal, uninstrumented mappings.

 * Adapt to using the set_ptes() API, using __set_pte_at() where we need
   must avoid instrumentation.
 * Use the logic of *_access_permitted() for implementing
   *_user_accessible_page(), which are required routines for page table
 * Even though we no longer need p{m,u,4}d_leaf(), still default
   implement these to assist in refactoring out extant
 * Add p{m,u}_pte() stubs where asm-generic does not provide them, as
   page table check wants all *user_accessible_page() variants, and we
   would like to default implement the variants in terms of
 * Avoid the ugly pmdp_collapse_flush() macro nonsense! Just instrument
   its constituent calls instead for radix and hash.

 * Fix linux/page_table_check.h include in asm/pgtable.h breaking
Link: https://lore.kernel.org/linuxppc-dev/20230215231153.2147454-1-rmclure@linux.ibm.com/

 * Remove use of extern in set_pte prototypes
 * Clean up pmdp_collapse_flush macro
 * Replace set_pte_at with static inline function
 * Fix commit message for patch 7
Link: https://lore.kernel.org/linuxppc-dev/20230215020155.1969194-1-rmclure@linux.ibm.com/

 * Support huge pages and p{m,u}d accounting.
 * Remove instrumentation from set_pte from kernel internal pages.
 * 64s: Implement pmdp_collapse_flush in terms of __pmdp_collapse_flush
   as access to the mm_struct * is required.
Link: https://lore.kernel.org/linuxppc-dev/20230214015939.1853438-1-rmclure@linux.ibm.com/

Link: https://lore.kernel.org/linuxppc-dev/20221118002146.25979-1-rmclure@linux.ibm.com/

Rohan McLure (7):
  powerpc: mm: Replace p{u,m,4}d_is_leaf with p{u,m,4}_leaf
  powerpc: mm: Implement p{m,u,4}d_leaf on all platforms
  powerpc: mm: Add common pud_pfn stub for all platforms
  powerpc: mm: Default p{m,u}d_pte implementations
  poweprc: mm: Implement *_user_accessible_page() for ptes
  powerpc: mm: Use __set_pte_at() for early-boot / internal usages
  powerpc: mm: Support page table check

 arch/powerpc/Kconfig                         |  1 +
 arch/powerpc/include/asm/book3s/32/pgtable.h | 17 ++++-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 57 ++++++++++++----
 arch/powerpc/include/asm/nohash/64/pgtable.h |  8 +++
 arch/powerpc/include/asm/nohash/pgtable.h    |  5 ++
 arch/powerpc/include/asm/pgtable.h           | 68 ++++++++++++++------
 arch/powerpc/kvm/book3s_64_mmu_radix.c       | 12 ++--
 arch/powerpc/mm/book3s64/hash_pgtable.c      |  6 +-
 arch/powerpc/mm/book3s64/pgtable.c           | 17 +++--
 arch/powerpc/mm/book3s64/radix_pgtable.c     | 27 ++++----
 arch/powerpc/mm/nohash/book3e_pgtable.c      |  2 +-
 arch/powerpc/mm/pgtable.c                    | 10 ++-
 arch/powerpc/mm/pgtable_32.c                 |  2 +-
 arch/powerpc/mm/pgtable_64.c                 |  6 +-
 arch/powerpc/xmon/xmon.c                     |  6 +-
 15 files changed, 173 insertions(+), 71 deletions(-)


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