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2024-05-07mm/gup: fix hugepd handling in hugetlb reworkPeter Xu1-25/+39
Commit a12083d721d7 added hugepd handling for gup-slow, reusing gup-fast functions. follow_hugepd() correctly took the vma pointer in, however didn't pass it over into the lower functions, which was overlooked. The issue is gup_fast_hugepte() uses the vma pointer to make the correct decision on whether an unshare is needed for a FOLL_PIN|FOLL_LONGTERM. Now without vma ponter it will constantly return "true" (needs an unshare) for a page cache, even though in the SHARED case it will be wrong to unshare. The other problem is, even if an unshare is needed, it now returns 0 rather than -EMLINK, which will not trigger a follow up FAULT_FLAG_UNSHARE fault. That will need to be fixed too when the unshare is wanted. gup_longterm test didn't expose this issue in the past because it didn't yet test R/O unshare in this case, another separate patch will enable that in future tests. Fix it by passing vma correctly to the bottom, rename gup_fast_hugepte() back to gup_hugepte() as it is shared between the fast/slow paths, and also allow -EMLINK to be returned properly by gup_hugepte() even though gup-fast will take it the same as zero. Link: https://lkml.kernel.org/r/20240430131303.264331-1-peterx@redhat.com Fixes: a12083d721d7 ("mm/gup: handle hugepd for follow_page()") Signed-off-by: Peter Xu <peterx@redhat.com> Reported-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05gup: use folios for gup_devmapMatthew Wilcox (Oracle)1-9/+8
Use try_grab_folio() instead of try_grab_page() so we get the folio back that we calculated, and then use folio_set_referenced() instead of SetPageReferenced(). Correspondingly, use gup_put_folio() to put any unneeded references. Link: https://lkml.kernel.org/r/20240424191914.361554-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05mm: convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs()Matthew Wilcox (Oracle)1-3/+3
All callers have a folio so we can remove this use of page_ref_sub_return(). Link: https://lkml.kernel.org/r/20240424191914.361554-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/treewide: rename CONFIG_HAVE_FAST_GUP to CONFIG_HAVE_GUP_FASTDavid Hildenbrand1-5/+5
Nowadays, we call it "GUP-fast", the external interface includes functions like "get_user_pages_fast()", and we renamed all internal functions to reflect that as well. Let's make the config option reflect that. Link: https://lkml.kernel.org/r/20240402125516.223131-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: consistently name GUP-fast functionsDavid Hildenbrand1-102/+103
Patch series "mm/gup: consistently call it GUP-fast". Some cleanups around function names, comments and the config option of "GUP-fast" -- GUP without "lock" safety belts on. With this cleanup it's easy to judge which functions are GUP-fast specific. We now consistently call it "GUP-fast", avoiding mixing it with "fast GUP", "lockless", or simply "gup" (which I always considered confusing in the ode). So the magic now happens in functions that contain "gup_fast", whereby gup_fast() is the entry point into that magic. Comments consistently reference either "GUP-fast" or "gup_fast()". This patch (of 3): Let's consistently call the "fast-only" part of GUP "GUP-fast" and rename all relevant internal functions to start with "gup_fast", to make it clearer that this is not ordinary GUP. The current mixture of "lockless", "gup" and "gup_fast" is confusing. Further, avoid the term "huge" when talking about a "leaf" -- for example, we nowadays check pmd_leaf() because pmd_huge() is gone. For the "hugepd"/"hugepte" stuff, it's part of the name ("is_hugepd"), so that stays. What remains is the "external" interface: * get_user_pages_fast_only() * get_user_pages_fast() * pin_user_pages_fast() The high-level internal functions for GUP-fast (+slow fallback) are now: * internal_get_user_pages_fast() -> gup_fast_fallback() * lockless_pages_from_mm() -> gup_fast() The basic GUP-fast walker functions: * gup_pgd_range() -> gup_fast_pgd_range() * gup_p4d_range() -> gup_fast_p4d_range() * gup_pud_range() -> gup_fast_pud_range() * gup_pmd_range() -> gup_fast_pmd_range() * gup_pte_range() -> gup_fast_pte_range() * gup_huge_pgd() -> gup_fast_pgd_leaf() * gup_huge_pud() -> gup_fast_pud_leaf() * gup_huge_pmd() -> gup_fast_pmd_leaf() The weird hugepd stuff: * gup_huge_pd() -> gup_fast_hugepd() * gup_hugepte() -> gup_fast_hugepte() The weird devmap stuff: * __gup_device_huge_pud() -> gup_fast_devmap_pud_leaf() * __gup_device_huge_pmd -> gup_fast_devmap_pmd_leaf() * __gup_device_huge() -> gup_fast_devmap_leaf() * undo_dev_pagemap() -> gup_fast_undo_dev_pagemap() Helper functions: * unpin_user_pages_lockless() -> gup_fast_unpin_user_pages() * gup_fast_folio_allowed() is already properly named * gup_fast_permitted() is already properly named With "gup_fast()", we now even have a function that is referred to in comment in mm/mmu_gather.c. Link: https://lkml.kernel.org/r/20240402125516.223131-1-david@redhat.com Link: https://lkml.kernel.org/r/20240402125516.223131-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: handle hugetlb in the generic follow_page_mask codePeter Xu1-10/+5
Now follow_page() is ready to handle hugetlb pages in whatever form, and over all architectures. Switch to the generic code path. Time to retire hugetlb_follow_page_mask(), following the previous retirement of follow_hugetlb_page() in 4849807114b8. There may be a slight difference of how the loops run when processing slow GUP over a large hugetlb range on cont_pte/cont_pmd supported archs: each loop of __get_user_pages() will resolve one pgtable entry with the patch applied, rather than relying on the size of hugetlb hstate, the latter may cover multiple entries in one loop. A quick performance test on an aarch64 VM on M1 chip shows 15% degrade over a tight loop of slow gup after the path switched. That shouldn't be a problem because slow-gup should not be a hot path for GUP in general: when page is commonly present, fast-gup will already succeed, while when the page is indeed missing and require a follow up page fault, the slow gup degrade will probably buried in the fault paths anyway. It also explains why slow gup for THP used to be very slow before 57edfcfd3419 ("mm/gup: accelerate thp gup even for "pages != NULL"") lands, the latter not part of a performance analysis but a side benefit. If the performance will be a concern, we can consider handle CONT_PTE in follow_page(). Before that is justified to be necessary, keep everything clean and simple. Link: https://lkml.kernel.org/r/20240327152332.950956-14-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: handle hugepd for follow_page()Peter Xu1-106/+163
Hugepd is only used in PowerPC so far on 4K page size kernels where hash mmu is used. follow_page_mask() used to leverage hugetlb APIs to access hugepd entries. Teach follow_page_mask() itself on hugepd. With previous refactors on fast-gup gup_huge_pd(), most of the code can be leveraged. There's something not needed for follow page, for example, gup_hugepte() tries to detect pgtable entry change which will never happen with slow gup (which has the pgtable lock held), but that's not a problem to check. Since follow_page() always only fetch one page, set the end to "address + PAGE_SIZE" should suffice. We will still do the pgtable walk once for each hugetlb page by setting ctx->page_mask properly. One thing worth mentioning is that some level of pgtable's _bad() helper will report is_hugepd() entries as TRUE on Power8 hash MMUs. I think it at least applies to PUD on Power8 with 4K pgsize. It means feeding a hugepd entry to pud_bad() will report a false positive. Let's leave that for now because it can be arch-specific where I am a bit declined to touch. In this patch it's not a problem as long as hugepd is detected before any bad pgtable entries. To allow slow gup like follow_*_page() to access hugepd helpers, hugepd codes are moved to the top. Besides that, the helper record_subpages() will be used by either hugepd or fast-gup now. To avoid "unused function" warnings we must provide a "#ifdef" for it, unfortunately. Link: https://lkml.kernel.org/r/20240327152332.950956-13-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: handle huge pmd for follow_pmd_mask()Peter Xu1-6/+98
Replace pmd_trans_huge() with pmd_leaf() to also cover pmd_huge() as long as enabled. FOLL_TOUCH and FOLL_SPLIT_PMD only apply to THP, not yet huge. Since now follow_trans_huge_pmd() can process hugetlb pages, renaming it into follow_huge_pmd() to match what it does. Move it into gup.c so not depend on CONFIG_THP. When at it, move the ctx->page_mask setup into follow_huge_pmd(), only set it when the page is valid. It was not a bug to set it before even if GUP failed (page==NULL), because follow_page_mask() callers always ignores page_mask if so. But doing so makes the code cleaner. [peterx@redhat.com: allow follow_pmd_mask() to take hugetlb tail pages] Link: https://lkml.kernel.org/r/20240403013249.1418299-3-peterx@redhat.com Link: https://lkml.kernel.org/r/20240327152332.950956-12-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: handle huge pud for follow_pud_mask()Peter Xu1-3/+67
Teach follow_pud_mask() to be able to handle normal PUD pages like hugetlb. Rename follow_devmap_pud() to follow_huge_pud() so that it can process either huge devmap or hugetlb. Move it out of TRANSPARENT_HUGEPAGE_PUD and and huge_memory.c (which relies on CONFIG_THP). Switch to pud_leaf() to detect both cases in the slow gup. In the new follow_huge_pud(), taking care of possible CoR for hugetlb if necessary. touch_pud() needs to be moved out of huge_memory.c to be accessable from gup.c even if !THP. Since at it, optimize the non-present check by adding a pud_present() early check before taking the pgtable lock, failing the follow_page() early if PUD is not present: that is required by both devmap or hugetlb. Use pud_huge() to also cover the pud_devmap() case. One more trivial thing to mention is, introduce "pud_t pud" in the code paths along the way, so the code doesn't dereference *pudp multiple time. Not only because that looks less straightforward, but also because if the dereference really happened, it's not clear whether there can be race to see different *pudp values when it's being modified at the same time. Setting ctx->page_mask properly for a PUD entry. As a side effect, this patch should also be able to optimize devmap GUP on PUD to be able to jump over the whole PUD range, but not yet verified. Hugetlb already can do so prior to this patch. Link: https://lkml.kernel.org/r/20240327152332.950956-11-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: cache *pudp in follow_pud_mask()Peter Xu1-8/+9
Introduce "pud_t pud" in the function, so the code won't dereference *pudp multiple time. Not only because that looks less straightforward, but also because if the dereference really happened, it's not clear whether there can be race to see different *pudp values if it's being modified at the same time. Link: https://lkml.kernel.org/r/20240327152332.950956-10-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: James Houghton <jthoughton@google.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: handle hugetlb for no_page_table()Peter Xu1-18/+26
no_page_table() is not yet used for hugetlb code paths. Make it prepared. The major difference here is hugetlb will return -EFAULT as long as page cache does not exist, even if VM_SHARED. See hugetlb_follow_page_mask(). Pass "address" into no_page_table() too, as hugetlb will need it. Link: https://lkml.kernel.org/r/20240327152332.950956-9-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: refactor record_subpages() to find 1st small pagePeter Xu1-11/+14
All the fast-gup functions take a tail page to operate, always need to do page mask calculations before feeding that into record_subpages(). Merge that logic into record_subpages(), so that it will do the nth_page() calculation. Link: https://lkml.kernel.org/r/20240327152332.950956-8-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: drop gup_fast_folio_allowed() in hugepd processingPeter Xu1-5/+8
Hugepd format for GUP is only used in PowerPC with hugetlbfs. There are some kernel usage of hugepd (can refer to hugepd_populate_kernel() for PPC_8XX), however those pages are not candidates for GUP. Commit a6e79df92e4a ("mm/gup: disallow FOLL_LONGTERM GUP-fast writing to file-backed mappings") added a check to fail gup-fast if there's potential risk of violating GUP over writeback file systems. That should never apply to hugepd. Considering that hugepd is an old format (and even software-only), there's no plan to extend hugepd into other file typed memories that is prone to the same issue. Drop that check, not only because it'll never be true for hugepd per any known plan, but also it paves way for reusing the function outside fast-gup. To make sure we'll still remember this issue just in case hugepd will be extended to support non-hugetlbfs memories, add a rich comment above gup_huge_pd(), explaining the issue with proper references. [akpm@linux-foundation.org: fix comment, per David] Link: https://lkml.kernel.org/r/20240327152332.950956-7-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Tested-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Jones <andrew.jones@linux.dev> Cc: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: "Mike Rapoport (IBM)" <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm: merge folio_is_secretmem() and folio_fast_pin_allowed() into ↵David Hildenbrand1-20/+28
gup_fast_folio_allowed() folio_is_secretmem() is currently only used during GUP-fast. Nowadays, folio_fast_pin_allowed() performs similar checks during GUP-fast and contains a lot of careful handling -- READ_ONCE() -- , sanity checks -- lockdep_assert_irqs_disabled() -- and helpful comments on how this handling is safe and correct. So let's merge folio_is_secretmem() into folio_fast_pin_allowed(). Rename folio_fast_pin_allowed() to gup_fast_folio_allowed(), to better match the new semantics. Link: https://lkml.kernel.org/r/20240326143210.291116-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: xingwei lee <xrivendell7@gmail.com> Cc: yue sun <samsun1006219@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm: record the migration reason for struct migration_target_controlBaolin Wang1-0/+1
Patch series "make the hugetlb migration strategy consistent", v2. As discussed in previous thread [1], there is an inconsistency when handling hugetlb migration. When handling the migration of freed hugetlb, it prevents fallback to other NUMA nodes in alloc_and_dissolve_hugetlb_folio(). However, when dealing with in-use hugetlb, it allows fallback to other NUMA nodes in alloc_hugetlb_folio_nodemask(), which can break the per-node hugetlb pool and might result in unexpected failures when node bound workloads doesn't get what is asssumed available. This patchset tries to make the hugetlb migration strategy more clear and consistent. Please find details in each patch. [1] https://lore.kernel.org/all/6f26ce22d2fcd523418a085f2c588fe0776d46e7.1706794035.git.baolin.wang@linux.alibaba.com/ This patch (of 2): To support different hugetlb allocation strategies during hugetlb migration based on various migration reasons, record the migration reason in the migration_target_control structure as a preparation. Link: https://lkml.kernel.org/r/cover.1709719720.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/7b95d4981e07211f57139fc5b1f7ce91b920cee4.1709719720.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/treewide: replace pXd_huge() with pXd_leaf()Peter Xu1-2/+2
Now after we're sure all pXd_huge() definitions are the same as pXd_leaf(), reuse it. Luckily, pXd_huge() isn't widely used. Link: https://lkml.kernel.org/r/20240318200404.448346-12-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Andersson <andersson@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fabio Estevam <festevam@denx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Konrad Dybcio <konrad.dybcio@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mark Salter <msalter@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: merge pXd huge mapping checksPeter Xu1-4/+3
Huge mapping checks in GUP are slightly redundant and can be simplified. pXd_huge() now is the same as pXd_leaf(). pmd_trans_huge() and pXd_devmap() should both imply pXd_leaf(). Time to merge them into one. Link: https://lkml.kernel.org/r/20240318200404.448346-11-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Andersson <andersson@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fabio Estevam <festevam@denx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konrad Dybcio <konrad.dybcio@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mark Salter <msalter@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: check p4d presence before going onPeter Xu1-2/+2
Currently there should have no p4d swap entries so it may not matter much, however this may help us to rule out swap entries in pXd_huge() API, which will include p4d_huge(). The p4d_present() checks make it 100% clear that we won't rely on p4d_huge() for swap entries. Link: https://lkml.kernel.org/r/20240318200404.448346-4-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Andersson <andersson@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fabio Estevam <festevam@denx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Konrad Dybcio <konrad.dybcio@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mark Salter <msalter@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25mm/gup: cache p4d in follow_p4d_mask()Peter Xu1-6/+7
Add a variable to cache p4d in follow_p4d_mask(). It's a good practise to make sure all the following checks will have a consistent view of the entry. Link: https://lkml.kernel.org/r/20240318200404.448346-3-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andreas Larsson <andreas@gaisler.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Bjorn Andersson <andersson@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Fabio Estevam <festevam@denx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Konrad Dybcio <konrad.dybcio@linaro.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Mark Salter <msalter@redhat.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-16mm/madvise: make MADV_POPULATE_(READ|WRITE) handle VM_FAULT_RETRY properlyDavid Hildenbrand1-22/+32
Darrick reports that in some cases where pread() would fail with -EIO and mmap()+access would generate a SIGBUS signal, MADV_POPULATE_READ / MADV_POPULATE_WRITE will keep retrying forever and not fail with -EFAULT. While the madvise() call can be interrupted by a signal, this is not the desired behavior. MADV_POPULATE_READ / MADV_POPULATE_WRITE should behave like page faults in that case: fail and not retry forever. A reproducer can be found at [1]. The reason is that __get_user_pages(), as called by faultin_vma_page_range(), will not handle VM_FAULT_RETRY in a proper way: it will simply return 0 when VM_FAULT_RETRY happened, making madvise_populate()->faultin_vma_page_range() retry again and again, never setting FOLL_TRIED->FAULT_FLAG_TRIED for __get_user_pages(). __get_user_pages_locked() does what we want, but duplicating that logic in faultin_vma_page_range() feels wrong. So let's use __get_user_pages_locked() instead, that will detect VM_FAULT_RETRY and set FOLL_TRIED when retrying, making the fault handler return VM_FAULT_SIGBUS (VM_FAULT_ERROR) at some point, propagating -EFAULT from faultin_page() to __get_user_pages(), all the way to madvise_populate(). But, there is an issue: __get_user_pages_locked() will end up re-taking the MM lock and then __get_user_pages() will do another VMA lookup. In the meantime, the VMA layout could have changed and we'd fail with different error codes than we'd want to. As __get_user_pages() will currently do a new VMA lookup either way, let it do the VMA handling in a different way, controlled by a new FOLL_MADV_POPULATE flag, effectively moving these checks from madvise_populate() + faultin_page_range() in there. With this change, Darricks reproducer properly fails with -EFAULT, as documented for MADV_POPULATE_READ / MADV_POPULATE_WRITE. [1] https://lore.kernel.org/all/20240313171936.GN1927156@frogsfrogsfrogs/ Link: https://lkml.kernel.org/r/20240314161300.382526-1-david@redhat.com Link: https://lkml.kernel.org/r/20240314161300.382526-2-david@redhat.com Fixes: 4ca9b3859dac ("mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables") Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Darrick J. Wong <djwong@kernel.org> Closes: https://lore.kernel.org/all/20240311223815.GW1927156@frogsfrogsfrogs/ Cc: Darrick J. Wong <djwong@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-29mm: clean up populate_vma_page_range() FOLL_* flag handlingLinus Torvalds1-6/+8
The code wasn't exactly wrong, but it was very odd, and it used FOLL_FORCE together with FOLL_WRITE when it really didn't need to (it only set FOLL_WRITE for writable mappings, so then the FOLL_FORCE was pointless). It also pointlessly called __get_user_pages() even when it knew it wouldn't populate anything because the vma wasn't accessible and it explicitly tested for and did *not* set FOLL_FORCE for inaccessible vma's. This code does need to use FOLL_FORCE, because we want to do fault in writable shared mappings, but then the mapping may not actually be readable. And we don't want to use FOLL_WRITE (which would match the permission of the vma), because that would also dirty the pages, which we don't want to do. For very similar reasons, FOLL_FORCE populates a executable-only mapping with no read permissions. We don't have a FOLL_EXEC flag. Yes, it would probably be cleaner to split FOLL_WRITE into two bits (for separate permission and dirty bit handling), and add a FOLL_EXEC flag for the "GUP executable page" case. That would allow us to avoid FOLL_FORCE entirely here. But that's not how our FOLL_xyz bits have traditionally worked, and that would be a much bigger patch. So this at least avoids the FOLL_FORCE | FOLL_WRITE combination that made one of my experimental validation patches trigger a warning. That warning was a false positive (and my experimental patch was incomplete anyway), but it all made me look at this and decide to clean at least this small case up. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-12-29mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]()David Hildenbrand1-1/+1
Let's convert it like we converted all the other rmap functions. Don't introduce folio_try_share_anon_rmap_ptes() for now, as we don't have a user that wants rmap batching in sight. Pretty easy to add later. All users are easy to convert -- only ksm.c doesn't use folios yet but that is left for future work -- so let's just do it in a single shot. While at it, turn the BUG_ON into a WARN_ON_ONCE. Note that page_try_share_anon_rmap() so far didn't care about pte/pmd mappings (no compound parameter). We're changing that so we can perform better sanity checks and make the code actually more readable/consistent. For example, __folio_rmap_sanity_checks() will make sure that a PMD range actually falls completely into the folio. Link: https://lkml.kernel.org/r/20231220224504.646757-39-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-10mm/gup: fix follow_devmap_p[mu]d() on page==NULL handlingPeter Xu1-0/+2
This is a bug found not by any report but only by code observations. When GUP sees a devpmd/devpud and if page==NULL is returned, it means a fault is probably required. Here falling through when page==NULL can cause unexpected behavior. Fix both cases by catching the page==NULL cases with no_page_table(). Link: https://lkml.kernel.org/r/20231123180222.1048297-1-peterx@redhat.com Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Fixes: 080dbb618b4b ("mm/follow_page_mask: split follow_page_mask to smaller functions.") Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18mm/gup: make failure to pin an error if FOLL_NOWAIT not specifiedLorenzo Stoakes1-0/+11
There really should be no circumstances under which a non-FOLL_NOWAIT GUP operation fails to return any pages, so make this an error and warn on it. To catch the trivial case, simply exit early if nr_pages == 0. This brings __get_user_pages_locked() in line with the behaviour of its nommu variant. Link: https://lkml.kernel.org/r/2a42d96dd1e37163f90a0019a541163dafb7e4c3.1696288092.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCHLorenzo Stoakes1-3/+2
Rather than open-coding a list of internal GUP flags in is_valid_gup_args(), define which ones are internal. In addition, explicitly check to see if the user passed in FOLL_TOUCH somehow, as this appears to have been accidentally excluded. Link: https://lkml.kernel.org/r/971e013dfe20915612ea8b704e801d7aef9a66b6.1696288092.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-31Merge tag 'x86_shstk_for_6.6-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 shadow stack support from Dave Hansen: "This is the long awaited x86 shadow stack support, part of Intel's Control-flow Enforcement Technology (CET). CET consists of two related security features: shadow stacks and indirect branch tracking. This series implements just the shadow stack part of this feature, and just for userspace. The main use case for shadow stack is providing protection against return oriented programming attacks. It works by maintaining a secondary (shadow) stack using a special memory type that has protections against modification. When executing a CALL instruction, the processor pushes the return address to both the normal stack and to the special permission shadow stack. Upon RET, the processor pops the shadow stack copy and compares it to the normal stack copy. For more information, refer to the links below for the earlier versions of this patch set" Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/ Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/ * tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) x86/shstk: Change order of __user in type x86/ibt: Convert IBT selftest to asm x86/shstk: Don't retry vm_munmap() on -EINTR x86/kbuild: Fix Documentation/ reference x86/shstk: Move arch detail comment out of core mm x86/shstk: Add ARCH_SHSTK_STATUS x86/shstk: Add ARCH_SHSTK_UNLOCK x86: Add PTRACE interface for shadow stack selftests/x86: Add shadow stack test x86/cpufeatures: Enable CET CR4 bit for shadow stack x86/shstk: Wire in shadow stack interface x86: Expose thread features in /proc/$PID/status x86/shstk: Support WRSS for userspace x86/shstk: Introduce map_shadow_stack syscall x86/shstk: Check that signal frame is shadow stack mem x86/shstk: Check that SSP is aligned on sigreturn x86/shstk: Handle signals for shadow stack x86/shstk: Introduce routines modifying shstk x86/shstk: Handle thread shadow stack x86/shstk: Add user-mode shadow stack support ...
2023-08-24secretmem: convert page_is_secretmem() to folio_is_secretmem()Matthew Wilcox (Oracle)1-1/+1
The only caller already has a folio, so use it to save calling compound_head() in PageLRU() and remove a use of page->mapping. Link: https://lkml.kernel.org/r/20230822202335.179081-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21mm/gup: don't implicitly set FOLL_HONOR_NUMA_FAULTDavid Hildenbrand1-7/+0
Commit 0b9d705297b2 ("mm: numa: Support NUMA hinting page faults from gup/gup_fast") from 2012 documented as the primary reason why we would want to handle NUMA hinting faults from GUP: KVM secondary MMU page faults will trigger the NUMA hinting page faults through gup_fast -> get_user_pages -> follow_page -> handle_mm_fault. That is still the case today, and relevant KVM code has been converted to manually set FOLL_HONOR_NUMA_FAULT. So let's stop setting FOLL_HONOR_NUMA_FAULT for all GUP users and cross fingers that not that many other ones that really require such handling for autonuma remain. Possible interaction with MMU notifiers: Assume a driver obtains a page using get_user_pages() to map it into a secondary MMU, and uses the MMU notifier framework to get notified on changes. Assume get_user_pages() succeeded on a PROT_NONE-mapped page (because FOLL_HONOR_NUMA_FAULT is not set) in an accessible VMA and the page is mapped into a secondary MMU. Once user space would turn that mapping inaccessible using mprotect(PROT_NONE), the actual PTE in the page table might not change. If the MMU notifier would be smart and optimize for that case "why notify if the PTE didn't change", that could be problematic. At least change_pmd_range() with MMU_NOTIFY_PROTECTION_VMA for now does an unconditional mmu_notifier_invalidate_range_start() -> mmu_notifier_invalidate_range_end() and should be fine. Note that even if a PTE in an accessible VMA is pte_protnone(), the underlying page might be accessed by a secondary MMU that does not set FOLL_HONOR_NUMA_FAULT, and test_young() MMU notifiers would return "true". Link: https://lkml.kernel.org/r/20230803143208.383663-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: liubo <liubo254@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21merge mm-hotfixes-stable into mm-stable to pick up depended-upon changesAndrew Morton1-6/+24
2023-08-21mm/gup: reintroduce FOLL_NUMA as FOLL_HONOR_NUMA_FAULTDavid Hildenbrand1-6/+24
Unfortunately commit 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()") missed that follow_page() and follow_trans_huge_pmd() never implicitly set FOLL_NUMA because they really don't want to fail on PROT_NONE-mapped pages -- either due to NUMA hinting or due to inaccessible (PROT_NONE) VMAs. As spelled out in commit 0b9d705297b2 ("mm: numa: Support NUMA hinting page faults from gup/gup_fast"): "Other follow_page callers like KSM should not use FOLL_NUMA, or they would fail to get the pages if they use follow_page instead of get_user_pages." liubo reported [1] that smaps_rollup results are imprecise, because they miss accounting of pages that are mapped PROT_NONE. Further, it's easy to reproduce that KSM no longer works on inaccessible VMAs on x86-64, because pte_protnone()/pmd_protnone() also indictaes "true" in inaccessible VMAs, and follow_page() refuses to return such pages right now. As KVM really depends on these NUMA hinting faults, removing the pte_protnone()/pmd_protnone() handling in GUP code completely is not really an option. To fix the issues at hand, let's revive FOLL_NUMA as FOLL_HONOR_NUMA_FAULT to restore the original behavior for now and add better comments. Set FOLL_HONOR_NUMA_FAULT independent of FOLL_FORCE in is_valid_gup_args(), to add that flag for all external GUP users. Note that there are three GUP-internal __get_user_pages() users that don't end up calling is_valid_gup_args() and consequently won't get FOLL_HONOR_NUMA_FAULT set. 1) get_dump_page(): we really don't want to handle NUMA hinting faults. It specifies FOLL_FORCE and wouldn't have honored NUMA hinting faults already. 2) populate_vma_page_range(): we really don't want to handle NUMA hinting faults. It specifies FOLL_FORCE on accessible VMAs, so it wouldn't have honored NUMA hinting faults alre