linux-dev/include/asm-generic/tlb.h, branch linus/master

mm/mprotect: do not flush when not required architecturally

2022-05-13T14:20:05Z

Currently, using mprotect() to unprotect a memory region or uffd to unprotect a memory region causes a TLB flush. However, in such cases the PTE is often not modified (i.e., remain RO) and therefore not TLB flush is needed. Add an arch-specific pte_needs_flush() which tells whether a TLB flush is needed based on the old PTE and the new one. Implement an x86 pte_needs_flush(). Always flush the TLB when it is architecturally needed even when skipping a TLB flush might only result in a spurious page-faults by skipping the flush. Even with such conservative manner, we can in the future further refine the checks to test whether a PTE is present by only considering the architectural _PAGE_PRESENT flag instead of {pte|pmd}_preesnt(). For not be careful and use the latter. Link: https://lkml.kernel.org/r/20220401180821.1986781-3-namit@vmware.com Signed-off-by: Nadav Amit Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Dave Hansen Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: Yu Zhao Cc: Nick Piggin Cc: Andrew Cooper Cc: Peter Xu Signed-off-by: Andrew Morton

tlb: hugetlb: Add more sizes to tlb_remove_huge_tlb_entry

2022-04-06T11:41:48Z

tlb_remove_huge_tlb_entry only considers PMD_SIZE and PUD_SIZE when updating the mmu_gather structure. Unfortunately on arm64 there are two additional huge page sizes that need to be covered: CONT_PTE_SIZE and CONT_PMD_SIZE. Where an end-user attempts to employ contiguous huge pages, a VM_BUG_ON can be experienced due to the fact that the tlb structure hasn't been correctly updated by the relevant tlb_flush_p.._range() call from tlb_remove_huge_tlb_entry. This patch adds inequality logic to the generic implementation of tlb_remove_huge_tlb_entry s.t. CONT_PTE_SIZE and CONT_PMD_SIZE are effectively covered on arm64. Also, as well as ptes, pmds and puds; p4ds are now considered too. Reported-by: David Hildenbrand Suggested-by: Peter Zijlstra (Intel) Cc: Anshuman Khandual Cc: Catalin Marinas Cc: Will Deacon Link: https://lore.kernel.org/linux-mm/811c5c8e-b3a2-85d2-049c-717f17c3a03a@redhat.com/ Signed-off-by: Steve Capper Acked-by: David Hildenbrand Reviewed-by: Anshuman Khandual Reviewed-by: Catalin Marinas Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220330112543.863-1-steve.capper@arm.com Signed-off-by: Will Deacon

treewide: Replace zero-length arrays with flexible-array members

2022-02-17T13:00:39Z

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. This code was transformed with the help of Coccinelle: (next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch) @@ identifier S, member, array; type T1, T2; @@ struct S { ... T1 member; T2 array[ - 0 ]; }; UAPI and wireless changes were intentionally excluded from this patch and will be sent out separately. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78 Reviewed-by: Kees Cook Signed-off-by: Gustavo A. R. Silva

tlb: mmu_gather: Introduce tlb_gather_mmu_fullmm()

2021-01-29T19:02:29Z

Passing the range '0, -1' to tlb_gather_mmu() sets the 'fullmm' flag, which indicates that the mm_struct being operated on is going away. In this case, some architectures (such as arm64) can elide TLB invalidation by ensuring that the TLB tag (ASID) associated with this mm is not immediately reclaimed. Although this behaviour is documented in asm-generic/tlb.h, it's subtle and easily missed. Introduce tlb_gather_mmu_fullmm() to make it clearer that this is for the entire mm and WARN() if tlb_gather_mmu() is called with the 'fullmm' address range. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Yu Zhao Acked-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/20210127235347.1402-4-will@kernel.org

mm: remove unneeded includes of

2020-08-07T18:33:26Z

Patch series "mm: cleanup usage of " Most architectures have very similar versions of pXd_alloc_one() and pXd_free_one() for intermediate levels of page table. These patches add generic versions of these functions in and enable use of the generic functions where appropriate. In addition, functions declared and defined in headers are used mostly by core mm and early mm initialization in arch and there is no actual reason to have the included all over the place. The first patch in this series removes unneeded includes of In the end it didn't work out as neatly as I hoped and moving pXd_alloc_track() definitions to would require unnecessary changes to arches that have custom page table allocations, so I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local to mm/. This patch (of 8): In most cases header is required only for allocations of page table memory. Most of the .c files that include that header do not use symbols declared in and do not require that header. As for the other header files that used to include , it is possible to move that include into the .c file that actually uses symbols from and drop the include from the header file. The process was somewhat automated using sed -i -E '/[<"]asm\/pgalloc\.h/d' \ $(grep -L -w -f /tmp/xx \ $(git grep -E -l '[<"]asm/pgalloc\.h')) where /tmp/xx contains all the symbols defined in arch/*/include/asm/pgalloc.h. [rppt@linux.ibm.com: fix powerpc warning] Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Reviewed-by: Pekka Enberg Acked-by: Geert Uytterhoeven [m68k] Cc: Abdul Haleem Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Joerg Roedel Cc: Max Filippov Cc: Peter Zijlstra Cc: Satheesh Rajendran Cc: Stafford Horne Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Joerg Roedel Cc: Matthew Wilcox Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org Signed-off-by: Linus Torvalds

tlb: mmu_gather: add tlb_flush_*_range APIs

2020-07-07T10:23:46Z

tlb_flush_{pte|pmd|pud|p4d}_range() adjust the tlb->start and tlb->end, then set corresponding cleared_*. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Zhenyu Ye Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20200625080314.230-5-yezhenyu2@huawei.com Signed-off-by: Catalin Marinas

mm/vma: replace all remaining open encodings with is_vm_hugetlb_page()

2020-04-07T17:43:37Z

This replaces all remaining open encodings with is_vm_hugetlb_page(). Signed-off-by: Anshuman Khandual Signed-off-by: Andrew Morton Acked-by: Vlastimil Babka Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Alexander Viro Cc: Will Deacon Cc: "Aneesh Kumar K.V" Cc: Nick Piggin Cc: Peter Zijlstra Cc: Arnd Bergmann Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Andy Lutomirski Cc: Dave Hansen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Mel Gorman Cc: Paul Burton Cc: Paul Mackerras Cc: Ralf Baechle Cc: Rich Felker Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/1582520593-30704-4-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds

asm-generic/tlb: provide MMU_GATHER_TABLE_FREE

2020-02-04T03:05:26Z

As described in the comment, the correct order for freeing pages is: 1) unhook page 2) TLB invalidate page 3) free page This order equally applies to page directories. Currently there are two correct options: - use tlb_remove_page(), when all page directores are full pages and there are no futher contraints placed by things like software walkers (HAVE_FAST_GUP). - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the architecture does not do IPI based TLB invalidate and has HAVE_FAST_GUP (or software TLB fill). This however leaves architectures that don't have page based directories but don't need RCU in a bind. For those, provide MMU_GATHER_TABLE_FREE, which provides the independent batching for directories without the additional RCU freeing. Link: http://lkml.kernel.org/r/20200116064531.483522-10-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Aneesh Kumar K.V Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

asm-generic/tlb: rename HAVE_MMU_GATHER_NO_GATHER

2020-02-04T03:05:26Z

Towards a more consistent naming scheme. Link: http://lkml.kernel.org/r/20200116064531.483522-9-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Aneesh Kumar K.V Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

asm-generic/tlb: rename HAVE_MMU_GATHER_PAGE_SIZE

2020-02-04T03:05:26Z

Towards a more consistent naming scheme. Link: http://lkml.kernel.org/r/20200116064531.483522-8-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Aneesh Kumar K.V Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds