Merge remote-tracking branch 'sm8150/lineage-20' into HEAD

* sm8150/lineage-20: (176 commits)
  UPSTREAM: arm64: tlb: Rewrite stale comment in asm/tlbflush.h
  BACKPORT: arm64: tlb: Avoid synchronous TLBIs when freeing page tables
  BACKPORT: arm64: tlb: Adjust stride and type of TLBI according to mmu_gather
  UPSTREAM: arm64: tlb: Remove redundant !CONFIG_HAVE_RCU_TABLE_FREE code
  UPSTREAM: arm64: tlbflush: Allow stride to be specified for __flush_tlb_range()
  UPSTREAM: arm64: tlb: Justify non-leaf invalidation in flush_tlb_range()
  BACKPORT: arm64: pgtable: Implement p[mu]d_valid() and check in set_p[mu]d()
  UPSTREAM: arm64: tlb: Add DSB ISHST prior to TLBI in __flush_tlb_[kernel_]pgtable()
  UPSTREAM: arm64: tlb: Use last-level invalidation in flush_tlb_kernel_range()
  UPSTREAM: MAINTAINERS: Add entry for MMU GATHER AND TLB INVALIDATION
  RELAND: hugetlbfs: flush TLBs correctly after huge_pmd_unshare
  BACKPORT: mm/memory: Move mmu_gather and TLB invalidation code into its own file
  Revert "hugetlbfs: flush TLBs correctly after huge_pmd_unshare"
  UPSTREAM: asm-generic/tlb: Track which levels of the page tables have been cleared
  UPSTREAM: asm-generic/tlb: Track freeing of page-table directories in struct mmu_gather
  UPSTREAM: asm-generic/tlb: Guard with #ifdef CONFIG_MMU
  UPSTREAM: arm64: tlb: Provide forward declaration of tlb_flush() before including tlb.h
  UPSTREAM: mm: mmu_notifier fix for tlb_end_vma
  Revert "mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT"
  Revert "mm: prepare for FAULT_FLAG_SPECULATIVE"
  ...

Change-Id: I31ccaedd41cc02f66129fd8a24dfeb82cf9627ba