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Signed-off-by: Chen Zhuo Signed-off-by: Yulei Zhang --- arch/x86/include/asm/pgtable.h | 2 +- include/linux/huge_mm.h | 2 +- mm/gup.c | 46 ++++++++++++++++++++++++++++++++++ mm/huge_memory.c | 11 +++++--- mm/memory.c | 4 +-- mm/mprotect.c | 2 ++ 6 files changed, 59 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 313fb4fd6645..c9a3b1f79cd5 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -266,7 +266,7 @@ static inline int pmd_trans_huge(pmd_t pmd) #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static inline int pud_trans_huge(pud_t pud) { - return (pud_val(pud) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE; + return (pud_val(pud) & (_PAGE_PSE|_PAGE_DEVMAP|_PAGE_DMEM)) == _PAGE_PSE; } #endif diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index b7381e5aafe5..ac8eb3e39575 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -254,7 +254,7 @@ static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd, static inline spinlock_t *pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) { - if (pud_trans_huge(*pud) || pud_devmap(*pud)) + if (pud_trans_huge(*pud) || pud_devmap(*pud) || pud_special(*pud)) return __pud_trans_huge_lock(pud, vma); else return NULL; diff --git a/mm/gup.c b/mm/gup.c index a8edbb6a2b2f..fdcaeb163bc4 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -416,6 +416,42 @@ follow_special_pmd(struct vm_area_struct *vma, unsigned long address, return ERR_PTR(-EEXIST); } +static struct page * +follow_special_pud(struct vm_area_struct *vma, unsigned long address, + pud_t *pud, unsigned int flags) +{ + spinlock_t *ptl; + + if (flags & FOLL_DUMP) + /* Avoid special (like zero) pages in core dumps */ + return ERR_PTR(-EFAULT); + + /* No page to get reference */ + if (flags & FOLL_GET) + return ERR_PTR(-EFAULT); + + if (flags & FOLL_TOUCH) { + pud_t _pud; + + ptl = pud_lock(vma->vm_mm, pud); + if (!pud_special(*pud)) { + spin_unlock(ptl); + return NULL; + } + _pud = pud_mkyoung(*pud); + if (flags & FOLL_WRITE) + _pud = pud_mkdirty(_pud); + if (pudp_set_access_flags(vma, address & HPAGE_PMD_MASK, + pud, _pud, + flags & FOLL_WRITE)) + update_mmu_cache_pud(vma, address, pud); + spin_unlock(ptl); + } + + /* Proper page table entry exists, but no corresponding struct page */ + return ERR_PTR(-EEXIST); +} + /* * FOLL_FORCE can write to even unwritable pte's, but only * after we've gone through a COW cycle and they are dirty. @@ -716,6 +752,12 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma, return page; return no_page_table(vma, flags); } + if (pud_special(*pud)) { + page = follow_special_pud(vma, address, pud, flags); + if (page) + return page; + return no_page_table(vma, flags); + } if (is_hugepd(__hugepd(pud_val(*pud)))) { page = follow_huge_pd(vma, address, __hugepd(pud_val(*pud)), flags, @@ -2478,6 +2520,10 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, if (!pud_access_permitted(orig, flags & FOLL_WRITE)) return 0; + /* Bypass dmem pud. It will be handled in outside routine. */ + if (pud_special(orig)) + return 0; + if (pud_devmap(orig)) { if (unlikely(flags & FOLL_LONGTERM)) return 0; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a24601c93713..29e1ab959c90 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -883,6 +883,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, entry = pud_mkhuge(pfn_t_pud(pfn, prot)); if (pfn_t_devmap(pfn)) entry = pud_mkdevmap(entry); + if (pfn_t_dmem(pfn)) + entry = pud_mkdmem(entry); if (write) { entry = pud_mkyoung(pud_mkdirty(entry)); entry = maybe_pud_mkwrite(entry, vma); @@ -919,7 +921,7 @@ vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn, * can't support a 'special' bit. */ BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && - !pfn_t_devmap(pfn)); + !pfn_t_devmap(pfn) && !pfn_t_dmem(pfn)); BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == (VM_PFNMAP|VM_MIXEDMAP)); BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); @@ -1883,7 +1885,7 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) spinlock_t *ptl; ptl = pud_lock(vma->vm_mm, pud); - if (likely(pud_trans_huge(*pud) || pud_devmap(*pud))) + if (likely(pud_trans_huge(*pud) || pud_devmap(*pud) || pud_special(*pud))) return ptl; spin_unlock(ptl); return NULL; @@ -1894,6 +1896,7 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, pud_t *pud, unsigned long addr) { spinlock_t *ptl; + pud_t orig_pud; ptl = __pud_trans_huge_lock(pud, vma); if (!ptl) @@ -1904,9 +1907,9 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, * pgtable_trans_huge_withdraw after finishing pudp related * operations. */ - pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); + orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm); tlb_remove_pud_tlb_entry(tlb, pud, addr); - if (vma_is_special_huge(vma)) { + if (vma_is_special_huge(vma) || pud_special(orig_pud)) { spin_unlock(ptl); /* No zero page support yet */ } else { diff --git a/mm/memory.c b/mm/memory.c index ca42a6e56e9b..3748fab7cc2a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -922,7 +922,7 @@ static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src src_pud = pud_offset(src_p4d, addr); do { next = pud_addr_end(addr, end); - if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) { + if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud) || pud_special(*src_pud)) { int err; VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, vma); @@ -1215,7 +1215,7 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb, pud = pud_offset(p4d, addr); do { next = pud_addr_end(addr, end); - if (pud_trans_huge(*pud) || pud_devmap(*pud)) { + if (pud_trans_huge(*pud) || pud_devmap(*pud) || pud_special(*pud)) { if (next - addr != HPAGE_PUD_SIZE) { mmap_assert_locked(tlb->mm); split_huge_pud(vma, pud, addr); diff --git a/mm/mprotect.c b/mm/mprotect.c index 36f885cbbb30..cae78c0c5160 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -292,6 +292,8 @@ static inline unsigned long change_pud_range(struct vm_area_struct *vma, pud = pud_offset(p4d, addr); do { next = pud_addr_end(addr, end); + if (pud_special(*pud)) + continue; if (pud_none_or_clear_bad(pud)) continue; pages += change_pmd_range(vma, pud, addr, next, newprot, -- 2.28.0