• Jérôme Glisse's avatar
    mm/mmu_notifier: contextual information for event triggering invalidation · 6f4f13e8
    Jérôme Glisse authored
    CPU page table update can happens for many reasons, not only as a result
    of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as
    a result of kernel activities (memory compression, reclaim, migration,
    ...).
    
    Users of mmu notifier API track changes to the CPU page table and take
    specific action for them.  While current API only provide range of virtual
    address affected by the change, not why the changes is happening.
    
    This patchset do the initial mechanical convertion of all the places that
    calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP
    event as well as the vma if it is know (most invalidation happens against
    a given vma).  Passing down the vma allows the users of mmu notifier to
    inspect the new vma page protection.
    
    The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier
    should assume that every for the range is going away when that event
    happens.  A latter patch do convert mm call path to use a more appropriate
    events for each call.
    
    This is done as 2 patches so that no call site is forgotten especialy
    as it uses this following coccinelle patch:
    
    %<----------------------------------------------------------------------
    @@
    identifier I1, I2, I3, I4;
    @@
    static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1,
    +enum mmu_notifier_event event,
    +unsigned flags,
    +struct vm_area_struct *vma,
    struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... }
    
    @@
    @@
    -#define mmu_notifier_range_init(range, mm, start, end)
    +#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end)
    
    @@
    expression E1, E3, E4;
    identifier I1;
    @@
    <...
    mmu_notifier_range_init(E1,
    +MMU_NOTIFY_UNMAP, 0, I1,
    I1->vm_mm, E3, E4)
    ...>
    
    @@
    expression E1, E2, E3, E4;
    identifier FN, VMA;
    @@
    FN(..., struct vm_area_struct *VMA, ...) {
    <...
    mmu_notifier_range_init(E1,
    +MMU_NOTIFY_UNMAP, 0, VMA,
    E2, E3, E4)
    ...> }
    
    @@
    expression E1, E2, E3, E4;
    identifier FN, VMA;
    @@
    FN(...) {
    struct vm_area_struct *VMA;
    <...
    mmu_notifier_range_init(E1,
    +MMU_NOTIFY_UNMAP, 0, VMA,
    E2, E3, E4)
    ...> }
    
    @@
    expression E1, E2, E3, E4;
    identifier FN;
    @@
    FN(...) {
    <...
    mmu_notifier_range_init(E1,
    +MMU_NOTIFY_UNMAP, 0, NULL,
    E2, E3, E4)
    ...> }
    ---------------------------------------------------------------------->%
    
    Applied with:
    spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place
    spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place
    spatch --sp-file mmu-notifier.spatch --dir mm --in-place
    
    Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.comSigned-off-by: default avatarJérôme Glisse <jglisse@redhat.com>
    Reviewed-by: default avatarRalph Campbell <rcampbell@nvidia.com>
    Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
    Cc: Christian König <christian.koenig@amd.com>
    Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
    Cc: Jani Nikula <jani.nikula@linux.intel.com>
    Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
    Cc: Jan Kara <jack@suse.cz>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Peter Xu <peterx@redhat.com>
    Cc: Felix Kuehling <Felix.Kuehling@amd.com>
    Cc: Jason Gunthorpe <jgg@mellanox.com>
    Cc: Ross Zwisler <zwisler@kernel.org>
    Cc: Dan Williams <dan.j.williams@intel.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: Radim Krcmar <rkrcmar@redhat.com>
    Cc: Michal Hocko <mhocko@kernel.org>
    Cc: Christian Koenig <christian.koenig@amd.com>
    Cc: John Hubbard <jhubbard@nvidia.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    6f4f13e8
mprotect.c 15.7 KB