linux/include/asm-generic/pgtable.h, branch v5.5

mm/memory.c: fix a huge pud insertion race during faulting

2019-12-01T14:29:19Z

A huge pud page can theoretically be faulted in racing with pmd_alloc() in __handle_mm_fault(). That will lead to pmd_alloc() returning an invalid pmd pointer. Fix this by adding a pud_trans_unstable() function similar to pmd_trans_unstable() and check whether the pud is really stable before using the pmd pointer. Race: Thread 1: Thread 2: Comment create_huge_pud() Fallback - not taken. create_huge_pud() Taken. pmd_alloc() Returns an invalid pointer. This will result in user-visible huge page data corruption. Note that this was caught during a code audit rather than a real experienced problem. It looks to me like the only implementation that currently creates huge pud pagetable entries is dev_dax_huge_fault() which doesn't appear to care much about private (COW) mappings or write-tracking which is, I believe, a prerequisite for create_huge_pud() falling back on thread 1, but not in thread 2. Link: http://lkml.kernel.org/r/20191115115808.21181-2-thomas_os@shipmail.org Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages") Signed-off-by: Thomas Hellstrom Acked-by: Kirill A. Shutemov Cc: Arnd Bergmann Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move the backup x_devmap() functions to asm-generic/pgtable.h

2019-12-01T14:29:19Z

The asm-generic/pgtable.h include file appears to be the correct place for the backup x_devmap() inline functions. Moving them here is also necessary if we want to include x_devmap() in the [pmd|pud]_unstable functions. So move the x_devmap() functions to asm-generic/pgtable.h Link: http://lkml.kernel.org/r/20191115115808.21181-1-thomas_os@shipmail.org Signed-off-by: Thomas Hellstrom Cc: Arnd Bergmann Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

asm-generic/mm: stub out p{4,u}d_clear_bad() if __PAGETABLE_P{4,U}D_FOLDED

2019-12-01T14:29:19Z

This came up when removing __ARCH_HAS_5LEVEL_HACK for ARC as code bloat. With this patch we see the following code reduction. | bloat-o-meter2 vmlinux-D-elide-p4d_free_tlb vmlinux-E-elide-p?d_clear_bad | add/remove: 0/2 grow/shrink: 0/0 up/down: 0/-40 (-40) | function old new delta | pud_clear_bad 20 - -20 | p4d_clear_bad 20 - -20 | Total: Before=4136930, After=4136890, chg -1.000000% Link: http://lkml.kernel.org/r/20191016162400.14796-6-vgupta@synopsys.com Signed-off-by: Vineet Gupta Acked-by: Kirill A. Shutemov Cc: Arnd Bergmann Cc: Will Deacon Cc: "Aneesh Kumar K . V" Cc: Nick Piggin Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

thp: update split_huge_page_pmd() comment

2019-09-24T22:54:10Z

According to 78ddc5347341 ("thp: rename split_huge_page_pmd() to split_huge_pmd()"), update related comment. Link: http://lkml.kernel.org/r/20190731033406.185285-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: "Kirill A . Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: consolidate pgtable_cache_init() and pgd_cache_init()

2019-09-24T22:54:09Z

Both pgtable_cache_init() and pgd_cache_init() are used to initialize kmem cache for page table allocations on several architectures that do not use PAGE_SIZE tables for one or more levels of the page table hierarchy. Most architectures do not implement these functions and use __weak default NOP implementation of pgd_cache_init(). Since there is no such default for pgtable_cache_init(), its empty stub is duplicated among most architectures. Rename the definitions of pgd_cache_init() to pgtable_cache_init() and drop empty stubs of pgtable_cache_init(). Link: http://lkml.kernel.org/r/1566457046-22637-1-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Acked-by: Will Deacon [arm64] Acked-by: Thomas Gleixner [x86] Cc: Catalin Marinas Cc: Ingo Molnar Cc: Borislav Petkov Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86/mm: Initialize PGD cache during mm initialization

2019-05-05T18:32:46Z

Poking-mm initialization might require to duplicate the PGD in early stage. Initialize the PGD cache earlier to prevent boot failures. Reported-by: kernel test robot Signed-off-by: Nadav Amit Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rick Edgecombe Cc: Rik van Riel Cc: Stephen Rothwell Cc: Thomas Gleixner Fixes: 4fc19708b165 ("x86/alternatives: Initialize temporary mm for patching") Link: http://lkml.kernel.org/r/20190505011124.39692-1-namit@vmware.com Signed-off-by: Ingo Molnar

mm: update ptep_modify_prot_commit to take old pte value as arg

2019-03-06T05:07:18Z

Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Enable that by passing old pte value as the arg. Link: http://lkml.kernel.org/r/20190116085035.29729-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul Mackerras Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: update ptep_modify_prot_start/commit to take vm_area_struct as arg

2019-03-06T05:07:18Z

Patch series "NestMMU pte upgrade workaround for mprotect", v5. We can upgrade pte access (R -> RW transition) via mprotect. We need to make sure we follow the recommended pte update sequence as outlined in commit bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") for such updates. This patch series does that. This patch (of 5): Some architectures may want to call flush_tlb_range from these helpers. Link: http://lkml.kernel.org/r/20190116085035.29729-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Nicholas Piggin Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/ioremap: ensure break-before-make is used for huge p4d mappings

2018-12-28T20:11:50Z

Whilst no architectures actually enable support for huge p4d mappings in the vmap area, the code that is implemented should be using break-before-make, as we do for pud and pmd huge entries. Link: http://lkml.kernel.org/r/1544120495-17438-6-git-send-email-will.deacon@arm.com Signed-off-by: Will Deacon Reviewed-by: Toshi Kani Cc: Chintan Pandya Cc: Toshi Kani Cc: Thomas Gleixner Cc: Michal Hocko Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Sean Christopherson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

generic/pgtable: Introduce set_pte_safe()

2018-12-05T08:03:06Z

Commit: f77084d96355 "x86/mm/pat: Disable preemption around __flush_tlb_all()" introduced a warning to capture cases __flush_tlb_all() is called without pre-emption disabled. It triggers a false positive warning in the memory hotplug path. On investigation it was found that the __flush_tlb_all() calls are not necessary. However, they are only "not necessary" in practice provided the ptes are being initially populated from the !present state. Introduce set_pte_safe() as a sanity check that the pte is being updated in a way that does not require a TLB flush. Forgive the macro, the availability of the various of set_pte() levels is hit and miss across architectures. [ mingo: Minor readability edits. ] Suggested-by: Peter Zijlstra Suggested-by: Dave Hansen Signed-off-by: Dan Williams Acked-by: Peter Zijlstra (Intel) Acked-by: Kirill A. Shutemov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Rik van Riel Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/279dadae-9148-465c-7ec6-3f37e026c6c9@intel.com Signed-off-by: Ingo Molnar