[PATCH v10 00/12] Support page table check PowerPC

[Rohan McLure]

Support page table check on all PowerPC platforms. This 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_at_unchecked(), to allow for internal, uninstrumented mappings.

v10:
 * Revert patches that removed address and mm parameters from page table
   check routines, including consuming code from arm64, x86_64 and
   riscv.
 * Implement *_user_accessible_page() routines in terms of pte_user()
   where available (64-bit, book3s) but otherwise by checking the
   address (on platforms where the pte does not imply whether the
   mapping is for user or kernel) 
 * Internal set_pte_at() calls replaced with set_pte_at_unchecked(), which
   is identical, but prevents double instrumentation.

v9:
 * 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
   check.
 * Even though we no longer need p{m,u,4}d_leaf(), still default
   implement these to assist in refactoring out extant
   p{m,u,4}_is_leaf().
 * 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
   pte_user_accessible_page().
 * Avoid the ugly pmdp_collapse_flush() macro nonsense! Just instrument
   its constituent calls instead for radix and hash.
Link: https://lore.kernel.org/linuxppc-dev/20231130025404.37179-2-rmclure@linux.ibm.com/

v8:
 * Fix linux/page_table_check.h include in asm/pgtable.h breaking
   32-bit.
Link: https://lore.kernel.org/linuxppc-dev/20230215231153.2147454-1-rmclure@linux.ibm.com/

v7:
 * 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/

v6:
 * 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/

v5:
Link: https://lore.kernel.org/linuxppc-dev/20221118002146.25979-1-rmclure@linux.ibm.com/

Rohan McLure (12):
  Revert "mm/page_table_check: remove unused parameter in
    [__]page_table_check_pud_set"
  Revert "mm/page_table_check: remove unused parameter in
    [__]page_table_check_pmd_set"
  mm: Provide addr parameter to page_table_check_pte_set()
  Revert "mm/page_table_check: remove unused parameter in
    [__]page_table_check_pud_clear"
  Revert "mm/page_table_check: remove unused parameter in
    [__]page_table_check_pmd_clear"
  Revert "mm/page_table_check: remove unused parameter in
    [__]page_table_check_pte_clear"
  mm: Provide address parameter to p{te,md,ud}_user_accessible_page()
  powerpc: mm: Replace p{u,m,4}d_is_leaf with p{u,m,4}_leaf
  powerpc: mm: Add common pud_pfn stub for all platforms
  poweprc: mm: Implement *_user_accessible_page() for ptes
  powerpc: mm: Use set_pte_at_unchecked() for early-boot / internal
    usages
  powerpc: mm: Support page table check

 arch/arm64/include/asm/pgtable.h             | 18 ++---
 arch/powerpc/Kconfig                         |  1 +
 arch/powerpc/include/asm/book3s/32/pgtable.h |  7 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h | 74 +++++++++++++++-----
 arch/powerpc/include/asm/pgtable.h           | 66 ++++++++++-------
 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     | 25 ++++---
 arch/powerpc/mm/nohash/book3e_pgtable.c      |  2 +-
 arch/powerpc/mm/pgtable.c                    | 17 ++++-
 arch/powerpc/mm/pgtable_32.c                 |  2 +-
 arch/powerpc/mm/pgtable_64.c                 |  6 +-
 arch/powerpc/xmon/xmon.c                     |  6 +-
 arch/riscv/include/asm/pgtable.h             | 18 ++---
 arch/x86/include/asm/pgtable.h               | 20 +++---
 include/linux/page_table_check.h             | 67 +++++++++++-------
 include/linux/pgtable.h                      |  8 +--
 mm/page_table_check.c                        | 39 ++++++-----
 19 files changed, 261 insertions(+), 150 deletions(-)

-- 
2.44.0