Hi All, (Including wider audience this time since changes touch a fair few subsystems) This is the second half of v3 of a series to improve the encapsulation of pte entries by disallowing non-arch code from directly dereferencing pte_t pointers. Based on earlier feedback, I split the series in 2; the first part, fixes for existing bugs, was already posted at [3] and merged into mm-stable. This second part contains the conversion from direct dereferences to instead use ptep_get()/ptep_get_lockless(). See the v1 cover letter at [1] for rationale for this work. Based on feedback at v2, I've removed the new ptep_deref() helper I originally added, and am now using the existing ptep_get() and ptep_get_lockless() helpers. Testing on Ampere Altra (arm64) showed no difference in performance when using ptep_deref() (*pte) vs ptep_get() (READ_ONCE(*pte)). Patches are based on mm-unstable (49e038b1919e) and a branch is available at [4] (Let me know if this is the wrong branch to target - I'm still not familiar with the details of the mm- dev process!). Note that Hugh Dickins's "mm: allow pte_offset_map[_lock]() to fail" (now in mm-unstable) patch set caused a number of conflicts which I've resolved. But due to that, you won't be able to apply these patches on top of Linus's tree. I have an alternate branch on top of v6.4-rc6 at [5]. Changes since v2 [2]: - Removed ptep_deref() helper - Converted ptep_deref() callsites to use ptep_get[_lockless]() Changes since v1 [1]: - Fixed sh build bug reported by 0-day CI [1] https://lore.kernel.org/linux-mm/20230511132113.80196-1-ryan.roberts@xxxxxxx/ [2] https://lore.kernel.org/linux-mm/20230518110727.2106156-1-ryan.roberts@xxxxxxx/ [3] https://lore.kernel.org/all/20230602092949.545577-1-ryan.roberts@xxxxxxx/ [4] https://gitlab.arm.com/linux-arm/linux-rr/-/tree/features/granule_perf/ptep_get-mm-unstable-lkml_v3 [5] https://gitlab.arm.com/linux-arm/linux-rr/-/tree/features/granule_perf/ptep_get-v6.4-rc6-lkml_v3 Thanks, Ryan Ryan Roberts (3): mm: ptdump should use ptep_get_lockless() mm: Move ptep_get() and pmdp_get() helpers mm: ptep_get() conversion .../drm/i915/gem/selftests/i915_gem_mman.c | 8 +- drivers/misc/sgi-gru/grufault.c | 2 +- drivers/vfio/vfio_iommu_type1.c | 7 +- drivers/xen/privcmd.c | 2 +- fs/proc/task_mmu.c | 33 +++--- fs/userfaultfd.c | 6 +- include/linux/hugetlb.h | 4 + include/linux/mm_inline.h | 2 +- include/linux/pgtable.h | 34 +++--- kernel/events/uprobes.c | 2 +- mm/damon/ops-common.c | 2 +- mm/damon/paddr.c | 2 +- mm/damon/vaddr.c | 10 +- mm/filemap.c | 2 +- mm/gup.c | 21 ++-- mm/highmem.c | 12 ++- mm/hmm.c | 2 +- mm/huge_memory.c | 4 +- mm/hugetlb.c | 2 +- mm/hugetlb_vmemmap.c | 6 +- mm/kasan/init.c | 9 +- mm/kasan/shadow.c | 10 +- mm/khugepaged.c | 22 ++-- mm/ksm.c | 22 ++-- mm/madvise.c | 6 +- mm/mapping_dirty_helpers.c | 4 +- mm/memcontrol.c | 4 +- mm/memory-failure.c | 26 ++--- mm/memory.c | 100 ++++++++++-------- mm/mempolicy.c | 6 +- mm/migrate.c | 14 +-- mm/migrate_device.c | 15 +-- mm/mincore.c | 2 +- mm/mlock.c | 6 +- mm/mprotect.c | 8 +- mm/mremap.c | 2 +- mm/page_table_check.c | 4 +- mm/page_vma_mapped.c | 27 +++-- mm/pgtable-generic.c | 2 +- mm/ptdump.c | 2 +- mm/rmap.c | 34 +++--- mm/sparse-vmemmap.c | 8 +- mm/swap_state.c | 8 +- mm/swapfile.c | 20 ++-- mm/userfaultfd.c | 4 +- mm/vmalloc.c | 6 +- mm/vmscan.c | 14 +-- virt/kvm/kvm_main.c | 11 +- 48 files changed, 316 insertions(+), 243 deletions(-) -- 2.25.1
