120c8ccb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2c1a4de99SAndrea Arcangeli /* 3c1a4de99SAndrea Arcangeli * mm/userfaultfd.c 4c1a4de99SAndrea Arcangeli * 5c1a4de99SAndrea Arcangeli * Copyright (C) 2015 Red Hat, Inc. 6c1a4de99SAndrea Arcangeli */ 7c1a4de99SAndrea Arcangeli 8c1a4de99SAndrea Arcangeli #include <linux/mm.h> 9174cd4b1SIngo Molnar #include <linux/sched/signal.h> 10c1a4de99SAndrea Arcangeli #include <linux/pagemap.h> 11c1a4de99SAndrea Arcangeli #include <linux/rmap.h> 12c1a4de99SAndrea Arcangeli #include <linux/swap.h> 13c1a4de99SAndrea Arcangeli #include <linux/swapops.h> 14c1a4de99SAndrea Arcangeli #include <linux/userfaultfd_k.h> 15c1a4de99SAndrea Arcangeli #include <linux/mmu_notifier.h> 1660d4d2d2SMike Kravetz #include <linux/hugetlb.h> 1726071cedSMike Rapoport #include <linux/shmem_fs.h> 18c1a4de99SAndrea Arcangeli #include <asm/tlbflush.h> 19c1a4de99SAndrea Arcangeli #include "internal.h" 20c1a4de99SAndrea Arcangeli 21643aa36eSWei Yang static __always_inline 22643aa36eSWei Yang struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm, 23643aa36eSWei Yang unsigned long dst_start, 24643aa36eSWei Yang unsigned long len) 25643aa36eSWei Yang { 26643aa36eSWei Yang /* 27643aa36eSWei Yang * Make sure that the dst range is both valid and fully within a 28643aa36eSWei Yang * single existing vma. 29643aa36eSWei Yang */ 30643aa36eSWei Yang struct vm_area_struct *dst_vma; 31643aa36eSWei Yang 32643aa36eSWei Yang dst_vma = find_vma(dst_mm, dst_start); 33643aa36eSWei Yang if (!dst_vma) 34643aa36eSWei Yang return NULL; 35643aa36eSWei Yang 36643aa36eSWei Yang if (dst_start < dst_vma->vm_start || 37643aa36eSWei Yang dst_start + len > dst_vma->vm_end) 38643aa36eSWei Yang return NULL; 39643aa36eSWei Yang 40643aa36eSWei Yang /* 41643aa36eSWei Yang * Check the vma is registered in uffd, this is required to 42643aa36eSWei Yang * enforce the VM_MAYWRITE check done at uffd registration 43643aa36eSWei Yang * time. 44643aa36eSWei Yang */ 45643aa36eSWei Yang if (!dst_vma->vm_userfaultfd_ctx.ctx) 46643aa36eSWei Yang return NULL; 47643aa36eSWei Yang 48643aa36eSWei Yang return dst_vma; 49643aa36eSWei Yang } 50643aa36eSWei Yang 5115313257SAxel Rasmussen /* 5215313257SAxel Rasmussen * Install PTEs, to map dst_addr (within dst_vma) to page. 5315313257SAxel Rasmussen * 54*7d64ae3aSAxel Rasmussen * This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem 55*7d64ae3aSAxel Rasmussen * and anon, and for both shared and private VMAs. 5615313257SAxel Rasmussen */ 57*7d64ae3aSAxel Rasmussen int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, 5815313257SAxel Rasmussen struct vm_area_struct *dst_vma, 5915313257SAxel Rasmussen unsigned long dst_addr, struct page *page, 6015313257SAxel Rasmussen bool newly_allocated, bool wp_copy) 6115313257SAxel Rasmussen { 6215313257SAxel Rasmussen int ret; 6315313257SAxel Rasmussen pte_t _dst_pte, *dst_pte; 6415313257SAxel Rasmussen bool writable = dst_vma->vm_flags & VM_WRITE; 6515313257SAxel Rasmussen bool vm_shared = dst_vma->vm_flags & VM_SHARED; 6615313257SAxel Rasmussen bool page_in_cache = page->mapping; 6715313257SAxel Rasmussen spinlock_t *ptl; 6815313257SAxel Rasmussen struct inode *inode; 6915313257SAxel Rasmussen pgoff_t offset, max_off; 7015313257SAxel Rasmussen 7115313257SAxel Rasmussen _dst_pte = mk_pte(page, dst_vma->vm_page_prot); 7215313257SAxel Rasmussen if (page_in_cache && !vm_shared) 7315313257SAxel Rasmussen writable = false; 7415313257SAxel Rasmussen if (writable || !page_in_cache) 7515313257SAxel Rasmussen _dst_pte = pte_mkdirty(_dst_pte); 7615313257SAxel Rasmussen if (writable) { 7715313257SAxel Rasmussen if (wp_copy) 7815313257SAxel Rasmussen _dst_pte = pte_mkuffd_wp(_dst_pte); 7915313257SAxel Rasmussen else 8015313257SAxel Rasmussen _dst_pte = pte_mkwrite(_dst_pte); 8115313257SAxel Rasmussen } 8215313257SAxel Rasmussen 8315313257SAxel Rasmussen dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); 8415313257SAxel Rasmussen 8515313257SAxel Rasmussen if (vma_is_shmem(dst_vma)) { 8615313257SAxel Rasmussen /* serialize against truncate with the page table lock */ 8715313257SAxel Rasmussen inode = dst_vma->vm_file->f_inode; 8815313257SAxel Rasmussen offset = linear_page_index(dst_vma, dst_addr); 8915313257SAxel Rasmussen max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 9015313257SAxel Rasmussen ret = -EFAULT; 9115313257SAxel Rasmussen if (unlikely(offset >= max_off)) 9215313257SAxel Rasmussen goto out_unlock; 9315313257SAxel Rasmussen } 9415313257SAxel Rasmussen 9515313257SAxel Rasmussen ret = -EEXIST; 9615313257SAxel Rasmussen if (!pte_none(*dst_pte)) 9715313257SAxel Rasmussen goto out_unlock; 9815313257SAxel Rasmussen 9915313257SAxel Rasmussen if (page_in_cache) 10015313257SAxel Rasmussen page_add_file_rmap(page, false); 10115313257SAxel Rasmussen else 10215313257SAxel Rasmussen page_add_new_anon_rmap(page, dst_vma, dst_addr, false); 10315313257SAxel Rasmussen 10415313257SAxel Rasmussen /* 10515313257SAxel Rasmussen * Must happen after rmap, as mm_counter() checks mapping (via 10615313257SAxel Rasmussen * PageAnon()), which is set by __page_set_anon_rmap(). 10715313257SAxel Rasmussen */ 10815313257SAxel Rasmussen inc_mm_counter(dst_mm, mm_counter(page)); 10915313257SAxel Rasmussen 11015313257SAxel Rasmussen if (newly_allocated) 11115313257SAxel Rasmussen lru_cache_add_inactive_or_unevictable(page, dst_vma); 11215313257SAxel Rasmussen 11315313257SAxel Rasmussen set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); 11415313257SAxel Rasmussen 11515313257SAxel Rasmussen /* No need to invalidate - it was non-present before */ 11615313257SAxel Rasmussen update_mmu_cache(dst_vma, dst_addr, dst_pte); 11715313257SAxel Rasmussen ret = 0; 11815313257SAxel Rasmussen out_unlock: 11915313257SAxel Rasmussen pte_unmap_unlock(dst_pte, ptl); 12015313257SAxel Rasmussen return ret; 12115313257SAxel Rasmussen } 12215313257SAxel Rasmussen 123c1a4de99SAndrea Arcangeli static int mcopy_atomic_pte(struct mm_struct *dst_mm, 124c1a4de99SAndrea Arcangeli pmd_t *dst_pmd, 125c1a4de99SAndrea Arcangeli struct vm_area_struct *dst_vma, 126c1a4de99SAndrea Arcangeli unsigned long dst_addr, 127b6ebaedbSAndrea Arcangeli unsigned long src_addr, 12872981e0eSAndrea Arcangeli struct page **pagep, 12972981e0eSAndrea Arcangeli bool wp_copy) 130c1a4de99SAndrea Arcangeli { 131c1a4de99SAndrea Arcangeli void *page_kaddr; 132c1a4de99SAndrea Arcangeli int ret; 133b6ebaedbSAndrea Arcangeli struct page *page; 134c1a4de99SAndrea Arcangeli 135b6ebaedbSAndrea Arcangeli if (!*pagep) { 136c1a4de99SAndrea Arcangeli ret = -ENOMEM; 137c1a4de99SAndrea Arcangeli page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, dst_vma, dst_addr); 138c1a4de99SAndrea Arcangeli if (!page) 139c1a4de99SAndrea Arcangeli goto out; 140c1a4de99SAndrea Arcangeli 141b6ebaedbSAndrea Arcangeli page_kaddr = kmap_atomic(page); 142b6ebaedbSAndrea Arcangeli ret = copy_from_user(page_kaddr, 143b6ebaedbSAndrea Arcangeli (const void __user *) src_addr, 144b6ebaedbSAndrea Arcangeli PAGE_SIZE); 145b6ebaedbSAndrea Arcangeli kunmap_atomic(page_kaddr); 146b6ebaedbSAndrea Arcangeli 147c1e8d7c6SMichel Lespinasse /* fallback to copy_from_user outside mmap_lock */ 148b6ebaedbSAndrea Arcangeli if (unlikely(ret)) { 1499e368259SAndrea Arcangeli ret = -ENOENT; 150b6ebaedbSAndrea Arcangeli *pagep = page; 151b6ebaedbSAndrea Arcangeli /* don't free the page */ 152b6ebaedbSAndrea Arcangeli goto out; 153b6ebaedbSAndrea Arcangeli } 154b6ebaedbSAndrea Arcangeli } else { 155b6ebaedbSAndrea Arcangeli page = *pagep; 156b6ebaedbSAndrea Arcangeli *pagep = NULL; 157b6ebaedbSAndrea Arcangeli } 158c1a4de99SAndrea Arcangeli 159c1a4de99SAndrea Arcangeli /* 160c1a4de99SAndrea Arcangeli * The memory barrier inside __SetPageUptodate makes sure that 161f4f5329dSWei Yang * preceding stores to the page contents become visible before 162c1a4de99SAndrea Arcangeli * the set_pte_at() write. 163c1a4de99SAndrea Arcangeli */ 164c1a4de99SAndrea Arcangeli __SetPageUptodate(page); 165c1a4de99SAndrea Arcangeli 166c1a4de99SAndrea Arcangeli ret = -ENOMEM; 167d9eb1ea2SJohannes Weiner if (mem_cgroup_charge(page, dst_mm, GFP_KERNEL)) 168c1a4de99SAndrea Arcangeli goto out_release; 169c1a4de99SAndrea Arcangeli 17015313257SAxel Rasmussen ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, 17115313257SAxel Rasmussen page, true, wp_copy); 17215313257SAxel Rasmussen if (ret) 17315313257SAxel Rasmussen goto out_release; 174c1a4de99SAndrea Arcangeli out: 175c1a4de99SAndrea Arcangeli return ret; 176c1a4de99SAndrea Arcangeli out_release: 17709cbfeafSKirill A. Shutemov put_page(page); 178c1a4de99SAndrea Arcangeli goto out; 179c1a4de99SAndrea Arcangeli } 180c1a4de99SAndrea Arcangeli 181c1a4de99SAndrea Arcangeli static int mfill_zeropage_pte(struct mm_struct *dst_mm, 182c1a4de99SAndrea Arcangeli pmd_t *dst_pmd, 183c1a4de99SAndrea Arcangeli struct vm_area_struct *dst_vma, 184c1a4de99SAndrea Arcangeli unsigned long dst_addr) 185c1a4de99SAndrea Arcangeli { 186c1a4de99SAndrea Arcangeli pte_t _dst_pte, *dst_pte; 187c1a4de99SAndrea Arcangeli spinlock_t *ptl; 188c1a4de99SAndrea Arcangeli int ret; 189e2a50c1fSAndrea Arcangeli pgoff_t offset, max_off; 190e2a50c1fSAndrea Arcangeli struct inode *inode; 191c1a4de99SAndrea Arcangeli 192c1a4de99SAndrea Arcangeli _dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr), 193c1a4de99SAndrea Arcangeli dst_vma->vm_page_prot)); 194c1a4de99SAndrea Arcangeli dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); 195e2a50c1fSAndrea Arcangeli if (dst_vma->vm_file) { 196e2a50c1fSAndrea Arcangeli /* the shmem MAP_PRIVATE case requires checking the i_size */ 197e2a50c1fSAndrea Arcangeli inode = dst_vma->vm_file->f_inode; 198e2a50c1fSAndrea Arcangeli offset = linear_page_index(dst_vma, dst_addr); 199e2a50c1fSAndrea Arcangeli max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 200e2a50c1fSAndrea Arcangeli ret = -EFAULT; 201e2a50c1fSAndrea Arcangeli if (unlikely(offset >= max_off)) 202e2a50c1fSAndrea Arcangeli goto out_unlock; 203e2a50c1fSAndrea Arcangeli } 204e2a50c1fSAndrea Arcangeli ret = -EEXIST; 205c1a4de99SAndrea Arcangeli if (!pte_none(*dst_pte)) 206c1a4de99SAndrea Arcangeli goto out_unlock; 207c1a4de99SAndrea Arcangeli set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); 208c1a4de99SAndrea Arcangeli /* No need to invalidate - it was non-present before */ 209c1a4de99SAndrea Arcangeli update_mmu_cache(dst_vma, dst_addr, dst_pte); 210c1a4de99SAndrea Arcangeli ret = 0; 211c1a4de99SAndrea Arcangeli out_unlock: 212c1a4de99SAndrea Arcangeli pte_unmap_unlock(dst_pte, ptl); 213c1a4de99SAndrea Arcangeli return ret; 214c1a4de99SAndrea Arcangeli } 215c1a4de99SAndrea Arcangeli 21615313257SAxel Rasmussen /* Handles UFFDIO_CONTINUE for all shmem VMAs (shared or private). */ 21715313257SAxel Rasmussen static int mcontinue_atomic_pte(struct mm_struct *dst_mm, 21815313257SAxel Rasmussen pmd_t *dst_pmd, 21915313257SAxel Rasmussen struct vm_area_struct *dst_vma, 22015313257SAxel Rasmussen unsigned long dst_addr, 22115313257SAxel Rasmussen bool wp_copy) 22215313257SAxel Rasmussen { 22315313257SAxel Rasmussen struct inode *inode = file_inode(dst_vma->vm_file); 22415313257SAxel Rasmussen pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); 22515313257SAxel Rasmussen struct page *page; 22615313257SAxel Rasmussen int ret; 22715313257SAxel Rasmussen 22815313257SAxel Rasmussen ret = shmem_getpage(inode, pgoff, &page, SGP_READ); 22915313257SAxel Rasmussen if (ret) 23015313257SAxel Rasmussen goto out; 23115313257SAxel Rasmussen if (!page) { 23215313257SAxel Rasmussen ret = -EFAULT; 23315313257SAxel Rasmussen goto out; 23415313257SAxel Rasmussen } 23515313257SAxel Rasmussen 23615313257SAxel Rasmussen ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr, 23715313257SAxel Rasmussen page, false, wp_copy); 23815313257SAxel Rasmussen if (ret) 23915313257SAxel Rasmussen goto out_release; 24015313257SAxel Rasmussen 24115313257SAxel Rasmussen unlock_page(page); 24215313257SAxel Rasmussen ret = 0; 24315313257SAxel Rasmussen out: 24415313257SAxel Rasmussen return ret; 24515313257SAxel Rasmussen out_release: 24615313257SAxel Rasmussen unlock_page(page); 24715313257SAxel Rasmussen put_page(page); 24815313257SAxel Rasmussen goto out; 24915313257SAxel Rasmussen } 25015313257SAxel Rasmussen 251c1a4de99SAndrea Arcangeli static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address) 252c1a4de99SAndrea Arcangeli { 253c1a4de99SAndrea Arcangeli pgd_t *pgd; 254c2febafcSKirill A. Shutemov p4d_t *p4d; 255c1a4de99SAndrea Arcangeli pud_t *pud; 256c1a4de99SAndrea Arcangeli 257c1a4de99SAndrea Arcangeli pgd = pgd_offset(mm, address); 258c2febafcSKirill A. Shutemov p4d = p4d_alloc(mm, pgd, address); 259c2febafcSKirill A. Shutemov if (!p4d) 260c2febafcSKirill A. Shutemov return NULL; 261c2febafcSKirill A. Shutemov pud = pud_alloc(mm, p4d, address); 262c2febafcSKirill A. Shutemov if (!pud) 263c2febafcSKirill A. Shutemov return NULL; 264c1a4de99SAndrea Arcangeli /* 265c1a4de99SAndrea Arcangeli * Note that we didn't run this because the pmd was 266c1a4de99SAndrea Arcangeli * missing, the *pmd may be already established and in 267c1a4de99SAndrea Arcangeli * turn it may also be a trans_huge_pmd. 268c1a4de99SAndrea Arcangeli */ 269c2febafcSKirill A. Shutemov return pmd_alloc(mm, pud, address); 270c1a4de99SAndrea Arcangeli } 271c1a4de99SAndrea Arcangeli 27260d4d2d2SMike Kravetz #ifdef CONFIG_HUGETLB_PAGE 27360d4d2d2SMike Kravetz /* 27460d4d2d2SMike Kravetz * __mcopy_atomic processing for HUGETLB vmas. Note that this routine is 275c1e8d7c6SMichel Lespinasse * called with mmap_lock held, it will release mmap_lock before returning. 27660d4d2d2SMike Kravetz */ 27760d4d2d2SMike Kravetz static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, 27860d4d2d2SMike Kravetz struct vm_area_struct *dst_vma, 27960d4d2d2SMike Kravetz unsigned long dst_start, 28060d4d2d2SMike Kravetz unsigned long src_start, 28160d4d2d2SMike Kravetz unsigned long len, 282f6191471SAxel Rasmussen enum mcopy_atomic_mode mode) 28360d4d2d2SMike Kravetz { 2841c9e8defSMike Kravetz int vm_shared = dst_vma->vm_flags & VM_SHARED; 28560d4d2d2SMike Kravetz ssize_t err; 28660d4d2d2SMike Kravetz pte_t *dst_pte; 28760d4d2d2SMike Kravetz unsigned long src_addr, dst_addr; 28860d4d2d2SMike Kravetz long copied; 28960d4d2d2SMike Kravetz struct page *page; 29060d4d2d2SMike Kravetz unsigned long vma_hpagesize; 29160d4d2d2SMike Kravetz pgoff_t idx; 29260d4d2d2SMike Kravetz u32 hash; 29360d4d2d2SMike Kravetz struct address_space *mapping; 29460d4d2d2SMike Kravetz 29560d4d2d2SMike Kravetz /* 29660d4d2d2SMike Kravetz * There is no default zero huge page for all huge page sizes as 29760d4d2d2SMike Kravetz * supported by hugetlb. A PMD_SIZE huge pages may exist as used 29860d4d2d2SMike Kravetz * by THP. Since we can not reliably insert a zero page, this 29960d4d2d2SMike Kravetz * feature is not supported. 30060d4d2d2SMike Kravetz */ 301f6191471SAxel Rasmussen if (mode == MCOPY_ATOMIC_ZEROPAGE) { 302d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 30360d4d2d2SMike Kravetz return -EINVAL; 30460d4d2d2SMike Kravetz } 30560d4d2d2SMike Kravetz 30660d4d2d2SMike Kravetz src_addr = src_start; 30760d4d2d2SMike Kravetz dst_addr = dst_start; 30860d4d2d2SMike Kravetz copied = 0; 30960d4d2d2SMike Kravetz page = NULL; 31060d4d2d2SMike Kravetz vma_hpagesize = vma_kernel_pagesize(dst_vma); 31160d4d2d2SMike Kravetz 31260d4d2d2SMike Kravetz /* 31360d4d2d2SMike Kravetz * Validate alignment based on huge page size 31460d4d2d2SMike Kravetz */ 31560d4d2d2SMike Kravetz err = -EINVAL; 31660d4d2d2SMike Kravetz if (dst_start & (vma_hpagesize - 1) || len & (vma_hpagesize - 1)) 31760d4d2d2SMike Kravetz goto out_unlock; 31860d4d2d2SMike Kravetz 31960d4d2d2SMike Kravetz retry: 32060d4d2d2SMike Kravetz /* 321c1e8d7c6SMichel Lespinasse * On routine entry dst_vma is set. If we had to drop mmap_lock and 32260d4d2d2SMike Kravetz * retry, dst_vma will be set to NULL and we must lookup again. 32360d4d2d2SMike Kravetz */ 32460d4d2d2SMike Kravetz if (!dst_vma) { 32527d02568SMike Rapoport err = -ENOENT; 326643aa36eSWei Yang dst_vma = find_dst_vma(dst_mm, dst_start, len); 32760d4d2d2SMike Kravetz if (!dst_vma || !is_vm_hugetlb_page(dst_vma)) 32860d4d2d2SMike Kravetz goto out_unlock; 3291c9e8defSMike Kravetz 33027d02568SMike Rapoport err = -EINVAL; 33127d02568SMike Rapoport if (vma_hpagesize != vma_kernel_pagesize(dst_vma)) 33227d02568SMike Rapoport goto out_unlock; 33327d02568SMike Rapoport 3341c9e8defSMike Kravetz vm_shared = dst_vma->vm_flags & VM_SHARED; 33560d4d2d2SMike Kravetz } 33660d4d2d2SMike Kravetz 33760d4d2d2SMike Kravetz /* 3381c9e8defSMike Kravetz * If not shared, ensure the dst_vma has a anon_vma. 33960d4d2d2SMike Kravetz */ 34060d4d2d2SMike Kravetz err = -ENOMEM; 3411c9e8defSMike Kravetz if (!vm_shared) { 34260d4d2d2SMike Kravetz if (unlikely(anon_vma_prepare(dst_vma))) 34360d4d2d2SMike Kravetz goto out_unlock; 3441c9e8defSMike Kravetz } 34560d4d2d2SMike Kravetz 34660d4d2d2SMike Kravetz while (src_addr < src_start + len) { 34760d4d2d2SMike Kravetz BUG_ON(dst_addr >= dst_start + len); 34860d4d2d2SMike Kravetz 34960d4d2d2SMike Kravetz /* 350c0d0381aSMike Kravetz * Serialize via i_mmap_rwsem and hugetlb_fault_mutex. 351c0d0381aSMike Kravetz * i_mmap_rwsem ensures the dst_pte remains valid even 352c0d0381aSMike Kravetz * in the case of shared pmds. fault mutex prevents 353c0d0381aSMike Kravetz * races with other faulting threads. 35460d4d2d2SMike Kravetz */ 355ddeaab32SMike Kravetz mapping = dst_vma->vm_file->f_mapping; 356c0d0381aSMike Kravetz i_mmap_lock_read(mapping); 357c0d0381aSMike Kravetz idx = linear_page_index(dst_vma, dst_addr); 358188b04a7SWei Yang hash = hugetlb_fault_mutex_hash(mapping, idx); 35960d4d2d2SMike Kravetz mutex_lock(&hugetlb_fault_mutex_table[hash]); 36060d4d2d2SMike Kravetz 36160d4d2d2SMike Kravetz err = -ENOMEM; 362aec44e0fSPeter Xu dst_pte = huge_pte_alloc(dst_mm, dst_vma, dst_addr, vma_hpagesize); 36360d4d2d2SMike Kravetz if (!dst_pte) { 36460d4d2d2SMike Kravetz mutex_unlock(&hugetlb_fault_mutex_table[hash]); 365c0d0381aSMike Kravetz i_mmap_unlock_read(mapping); 36660d4d2d2SMike Kravetz goto out_unlock; 36760d4d2d2SMike Kravetz } 36860d4d2d2SMike Kravetz 369f6191471SAxel Rasmussen if (mode != MCOPY_ATOMIC_CONTINUE && 370f6191471SAxel Rasmussen !huge_pte_none(huge_ptep_get(dst_pte))) { 37160d4d2d2SMike Kravetz err = -EEXIST; 37260d4d2d2SMike Kravetz mutex_unlock(&hugetlb_fault_mutex_table[hash]); 373c0d0381aSMike Kravetz i_mmap_unlock_read(mapping); 37460d4d2d2SMike Kravetz goto out_unlock; 37560d4d2d2SMike Kravetz } 37660d4d2d2SMike Kravetz 37760d4d2d2SMike Kravetz err = hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, 378f6191471SAxel Rasmussen dst_addr, src_addr, mode, &page); 37960d4d2d2SMike Kravetz 38060d4d2d2SMike Kravetz mutex_unlock(&hugetlb_fault_mutex_table[hash]); 381c0d0381aSMike Kravetz i_mmap_unlock_read(mapping); 38260d4d2d2SMike Kravetz 38360d4d2d2SMike Kravetz cond_resched(); 38460d4d2d2SMike Kravetz 3859e368259SAndrea Arcangeli if (unlikely(err == -ENOENT)) { 386d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 38760d4d2d2SMike Kravetz BUG_ON(!page); 38860d4d2d2SMike Kravetz 38960d4d2d2SMike Kravetz err = copy_huge_page_from_user(page, 39060d4d2d2SMike Kravetz (const void __user *)src_addr, 3914fb07ee6SWei Yang vma_hpagesize / PAGE_SIZE, 3924fb07ee6SWei Yang true); 39360d4d2d2SMike Kravetz if (unlikely(err)) { 39460d4d2d2SMike Kravetz err = -EFAULT; 39560d4d2d2SMike Kravetz goto out; 39660d4d2d2SMike Kravetz } 397d8ed45c5SMichel Lespinasse mmap_read_lock(dst_mm); 39860d4d2d2SMike Kravetz 39960d4d2d2SMike Kravetz dst_vma = NULL; 40060d4d2d2SMike Kravetz goto retry; 40160d4d2d2SMike Kravetz } else 40260d4d2d2SMike Kravetz BUG_ON(page); 40360d4d2d2SMike Kravetz 40460d4d2d2SMike Kravetz if (!err) { 40560d4d2d2SMike Kravetz dst_addr += vma_hpagesize; 40660d4d2d2SMike Kravetz src_addr += vma_hpagesize; 40760d4d2d2SMike Kravetz copied += vma_hpagesize; 40860d4d2d2SMike Kravetz 40960d4d2d2SMike Kravetz if (fatal_signal_pending(current)) 41060d4d2d2SMike Kravetz err = -EINTR; 41160d4d2d2SMike Kravetz } 41260d4d2d2SMike Kravetz if (err) 41360d4d2d2SMike Kravetz break; 41460d4d2d2SMike Kravetz } 41560d4d2d2SMike Kravetz 41660d4d2d2SMike Kravetz out_unlock: 417d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 41860d4d2d2SMike Kravetz out: 4198cc5fcbbSMina Almasry if (page) 42060d4d2d2SMike Kravetz put_page(page); 42160d4d2d2SMike Kravetz BUG_ON(copied < 0); 42260d4d2d2SMike Kravetz BUG_ON(err > 0); 42360d4d2d2SMike Kravetz BUG_ON(!copied && !err); 42460d4d2d2SMike Kravetz return copied ? copied : err; 42560d4d2d2SMike Kravetz } 42660d4d2d2SMike Kravetz #else /* !CONFIG_HUGETLB_PAGE */ 42760d4d2d2SMike Kravetz /* fail at build time if gcc attempts to use this */ 42860d4d2d2SMike Kravetz extern ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm, 42960d4d2d2SMike Kravetz struct vm_area_struct *dst_vma, 43060d4d2d2SMike Kravetz unsigned long dst_start, 43160d4d2d2SMike Kravetz unsigned long src_start, 43260d4d2d2SMike Kravetz unsigned long len, 433f6191471SAxel Rasmussen enum mcopy_atomic_mode mode); 43460d4d2d2SMike Kravetz #endif /* CONFIG_HUGETLB_PAGE */ 43560d4d2d2SMike Kravetz 4363217d3c7SMike Rapoport static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm, 4373217d3c7SMike Rapoport pmd_t *dst_pmd, 4383217d3c7SMike Rapoport struct vm_area_struct *dst_vma, 4393217d3c7SMike Rapoport unsigned long dst_addr, 4403217d3c7SMike Rapoport unsigned long src_addr, 4413217d3c7SMike Rapoport struct page **page, 44215313257SAxel Rasmussen enum mcopy_atomic_mode mode, 44372981e0eSAndrea Arcangeli bool wp_copy) 4443217d3c7SMike Rapoport { 4453217d3c7SMike Rapoport ssize_t err; 4463217d3c7SMike Rapoport 44715313257SAxel Rasmussen if (mode == MCOPY_ATOMIC_CONTINUE) { 44815313257SAxel Rasmussen return mcontinue_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, 44915313257SAxel Rasmussen wp_copy); 45015313257SAxel Rasmussen } 45115313257SAxel Rasmussen 4525b51072eSAndrea Arcangeli /* 4535b51072eSAndrea Arcangeli * The normal page fault path for a shmem will invoke the 4545b51072eSAndrea Arcangeli * fault, fill the hole in the file and COW it right away. The 4555b51072eSAndrea Arcangeli * result generates plain anonymous memory. So when we are 4565b51072eSAndrea Arcangeli * asked to fill an hole in a MAP_PRIVATE shmem mapping, we'll 4575b51072eSAndrea Arcangeli * generate anonymous memory directly without actually filling 4585b51072eSAndrea Arcangeli * the hole. For the MAP_PRIVATE case the robustness check 4595b51072eSAndrea Arcangeli * only happens in the pagetable (to verify it's still none) 4605b51072eSAndrea Arcangeli * and not in the radix tree. 4615b51072eSAndrea Arcangeli */ 4625b51072eSAndrea Arcangeli if (!(dst_vma->vm_flags & VM_SHARED)) { 46315313257SAxel Rasmussen if (mode == MCOPY_ATOMIC_NORMAL) 4643217d3c7SMike Rapoport err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma, 46572981e0eSAndrea Arcangeli dst_addr, src_addr, page, 46672981e0eSAndrea Arcangeli wp_copy); 4673217d3c7SMike Rapoport else 4683217d3c7SMike Rapoport err = mfill_zeropage_pte(dst_mm, dst_pmd, 4693217d3c7SMike Rapoport dst_vma, dst_addr); 4703217d3c7SMike Rapoport } else { 47172981e0eSAndrea Arcangeli VM_WARN_ON_ONCE(wp_copy); 4723460f6e5SAxel Rasmussen err = shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, 47315313257SAxel Rasmussen dst_addr, src_addr, 47415313257SAxel Rasmussen mode != MCOPY_ATOMIC_NORMAL, 4753460f6e5SAxel Rasmussen page); 4763217d3c7SMike Rapoport } 4773217d3c7SMike Rapoport 4783217d3c7SMike Rapoport return err; 4793217d3c7SMike Rapoport } 4803217d3c7SMike Rapoport 481c1a4de99SAndrea Arcangeli static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm, 482c1a4de99SAndrea Arcangeli unsigned long dst_start, 483c1a4de99SAndrea Arcangeli unsigned long src_start, 484c1a4de99SAndrea Arcangeli unsigned long len, 485f6191471SAxel Rasmussen enum mcopy_atomic_mode mcopy_mode, 48672981e0eSAndrea Arcangeli bool *mmap_changing, 48772981e0eSAndrea Arcangeli __u64 mode) 488c1a4de99SAndrea Arcangeli { 489c1a4de99SAndrea Arcangeli struct vm_area_struct *dst_vma; 490c1a4de99SAndrea Arcangeli ssize_t err; 491c1a4de99SAndrea Arcangeli pmd_t *dst_pmd; 492c1a4de99SAndrea Arcangeli unsigned long src_addr, dst_addr; 493b6ebaedbSAndrea Arcangeli long copied; 494b6ebaedbSAndrea Arcangeli struct page *page; 49572981e0eSAndrea Arcangeli bool wp_copy; 496c1a4de99SAndrea Arcangeli 497c1a4de99SAndrea Arcangeli /* 498c1a4de99SAndrea Arcangeli * Sanitize the command parameters: 499c1a4de99SAndrea Arcangeli */ 500c1a4de99SAndrea Arcangeli BUG_ON(dst_start & ~PAGE_MASK); 501c1a4de99SAndrea Arcangeli BUG_ON(len & ~PAGE_MASK); 502c1a4de99SAndrea Arcangeli 503c1a4de99SAndrea Arcangeli /* Does the address range wrap, or is the span zero-sized? */ 504c1a4de99SAndrea Arcangeli BUG_ON(src_start + len <= src_start); 505c1a4de99SAndrea Arcangeli BUG_ON(dst_start + len <= dst_start); 506c1a4de99SAndrea Arcangeli 507b6ebaedbSAndrea Arcangeli src_addr = src_start; 508b6ebaedbSAndrea Arcangeli dst_addr = dst_start; 509b6ebaedbSAndrea Arcangeli copied = 0; 510b6ebaedbSAndrea Arcangeli page = NULL; 511b6ebaedbSAndrea Arcangeli retry: 512d8ed45c5SMichel Lespinasse mmap_read_lock(dst_mm); 513c1a4de99SAndrea Arcangeli 514c1a4de99SAndrea Arcangeli /* 515df2cc96eSMike Rapoport * If memory mappings are changing because of non-cooperative 516df2cc96eSMike Rapoport * operation (e.g. mremap) running in parallel, bail out and 517df2cc96eSMike Rapoport * request the user to retry later 518df2cc96eSMike Rapoport */ 519df2cc96eSMike Rapoport err = -EAGAIN; 520df2cc96eSMike Rapoport if (mmap_changing && READ_ONCE(*mmap_changing)) 521df2cc96eSMike Rapoport goto out_unlock; 522df2cc96eSMike Rapoport 523df2cc96eSMike Rapoport /* 524c1a4de99SAndrea Arcangeli * Make sure the vma is not shared, that the dst range is 525c1a4de99SAndrea Arcangeli * both valid and fully within a single existing vma. 526c1a4de99SAndrea Arcangeli */ 52727d02568SMike Rapoport err = -ENOENT; 528643aa36eSWei Yang dst_vma = find_dst_vma(dst_mm, dst_start, len); 52926071cedSMike Rapoport if (!dst_vma) 53026071cedSMike Rapoport goto out_unlock; 53127d02568SMike Rapoport 53227d02568SMike Rapoport err = -EINVAL; 53327d02568SMike Rapoport /* 53427d02568SMike Rapoport * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but 53527d02568SMike Rapoport * it will overwrite vm_ops, so vma_is_anonymous must return false. 53627d02568SMike Rapoport */ 53727d02568SMike Rapoport if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) && 53827d02568SMike Rapoport dst_vma->vm_flags & VM_SHARED)) 53927d02568SMike Rapoport goto out_unlock; 54027d02568SMike Rapoport 54127d02568SMike Rapoport /* 54272981e0eSAndrea Arcangeli * validate 'mode' now that we know the dst_vma: don't allow 54372981e0eSAndrea Arcangeli * a wrprotect copy if the userfaultfd didn't register as WP. 54472981e0eSAndrea Arcangeli */ 54572981e0eSAndrea Arcangeli wp_copy = mode & UFFDIO_COPY_MODE_WP; 54672981e0eSAndrea Arcangeli if (wp_copy && !(dst_vma->vm_flags & VM_UFFD_WP)) 54772981e0eSAndrea Arcangeli goto out_unlock; 54872981e0eSAndrea Arcangeli 54972981e0eSAndrea Arcangeli /* 55027d02568SMike Rapoport * If this is a HUGETLB vma, pass off to appropriate routine 55127d02568SMike Rapoport */ 55227d02568SMike Rapoport if (is_vm_hugetlb_page(dst_vma)) 55327d02568SMike Rapoport return __mcopy_atomic_hugetlb(dst_mm, dst_vma, dst_start, 554f6191471SAxel Rasmussen src_start, len, mcopy_mode); 55527d02568SMike Rapoport 55626071cedSMike Rapoport if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) 557b6ebaedbSAndrea Arcangeli goto out_unlock; 55815313257SAxel Rasmussen if (!vma_is_shmem(dst_vma) && mcopy_mode == MCOPY_ATOMIC_CONTINUE) 559f6191471SAxel Rasmussen goto out_unlock; 560c1a4de99SAndrea Arcangeli 561c1a4de99SAndrea Arcangeli /* 562c1a4de99SAndrea Arcangeli * Ensure the dst_vma has a anon_vma or this page 563c1a4de99SAndrea Arcangeli * would get a NULL anon_vma when moved in the 564c1a4de99SAndrea Arcangeli * dst_vma. 565c1a4de99SAndrea Arcangeli */ 566c1a4de99SAndrea Arcangeli err = -ENOMEM; 5675b51072eSAndrea Arcangeli if (!(dst_vma->vm_flags & VM_SHARED) && 5685b51072eSAndrea Arcangeli unlikely(anon_vma_prepare(dst_vma))) 569b6ebaedbSAndrea Arcangeli goto out_unlock; 570c1a4de99SAndrea Arcangeli 571b6ebaedbSAndrea Arcangeli while (src_addr < src_start + len) { 572c1a4de99SAndrea Arcangeli pmd_t dst_pmdval; 573b6ebaedbSAndrea Arcangeli 574c1a4de99SAndrea Arcangeli BUG_ON(dst_addr >= dst_start + len); 575b6ebaedbSAndrea Arcangeli 576c1a4de99SAndrea Arcangeli dst_pmd = mm_alloc_pmd(dst_mm, dst_addr); 577c1a4de99SAndrea Arcangeli if (unlikely(!dst_pmd)) { 578c1a4de99SAndrea Arcangeli err = -ENOMEM; 579c1a4de99SAndrea Arcangeli break; 580c1a4de99SAndrea Arcangeli } 581c1a4de99SAndrea Arcangeli 582c1a4de99SAndrea Arcangeli dst_pmdval = pmd_read_atomic(dst_pmd); 583c1a4de99SAndrea Arcangeli /* 584c1a4de99SAndrea Arcangeli * If the dst_pmd is mapped as THP don't 585c1a4de99SAndrea Arcangeli * override it and just be strict. 586c1a4de99SAndrea Arcangeli */ 587c1a4de99SAndrea Arcangeli if (unlikely(pmd_trans_huge(dst_pmdval))) { 588c1a4de99SAndrea Arcangeli err = -EEXIST; 589c1a4de99SAndrea Arcangeli break; 590c1a4de99SAndrea Arcangeli } 591c1a4de99SAndrea Arcangeli if (unlikely(pmd_none(dst_pmdval)) && 5924cf58924SJoel Fernandes (Google) unlikely(__pte_alloc(dst_mm, dst_pmd))) { 593c1a4de99SAndrea Arcangeli err = -ENOMEM; 594c1a4de99SAndrea Arcangeli break; 595c1a4de99SAndrea Arcangeli } 596c1a4de99SAndrea Arcangeli /* If an huge pmd materialized from under us fail */ 597c1a4de99SAndrea Arcangeli if (unlikely(pmd_trans_huge(*dst_pmd))) { 598c1a4de99SAndrea Arcangeli err = -EFAULT; 599c1a4de99SAndrea Arcangeli break; 600c1a4de99SAndrea Arcangeli } 601c1a4de99SAndrea Arcangeli 602c1a4de99SAndrea Arcangeli BUG_ON(pmd_none(*dst_pmd)); 603c1a4de99SAndrea Arcangeli BUG_ON(pmd_trans_huge(*dst_pmd)); 604c1a4de99SAndrea Arcangeli 6053217d3c7SMike Rapoport err = mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, 60615313257SAxel Rasmussen src_addr, &page, mcopy_mode, wp_copy); 607c1a4de99SAndrea Arcangeli cond_resched(); 608c1a4de99SAndrea Arcangeli 6099e368259SAndrea Arcangeli if (unlikely(err == -ENOENT)) { 610b6ebaedbSAndrea Arcangeli void *page_kaddr; 611b6ebaedbSAndrea Arcangeli 612d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 613b6ebaedbSAndrea Arcangeli BUG_ON(!page); 614b6ebaedbSAndrea Arcangeli 615b6ebaedbSAndrea Arcangeli page_kaddr = kmap(page); 616b6ebaedbSAndrea Arcangeli err = copy_from_user(page_kaddr, 617b6ebaedbSAndrea Arcangeli (const void __user *) src_addr, 618b6ebaedbSAndrea Arcangeli PAGE_SIZE); 619b6ebaedbSAndrea Arcangeli kunmap(page); 620b6ebaedbSAndrea Arcangeli if (unlikely(err)) { 621b6ebaedbSAndrea Arcangeli err = -EFAULT; 622b6ebaedbSAndrea Arcangeli goto out; 623b6ebaedbSAndrea Arcangeli } 624b6ebaedbSAndrea Arcangeli goto retry; 625b6ebaedbSAndrea Arcangeli } else 626b6ebaedbSAndrea Arcangeli BUG_ON(page); 627b6ebaedbSAndrea Arcangeli 628c1a4de99SAndrea Arcangeli if (!err) { 629c1a4de99SAndrea Arcangeli dst_addr += PAGE_SIZE; 630c1a4de99SAndrea Arcangeli src_addr += PAGE_SIZE; 631c1a4de99SAndrea Arcangeli copied += PAGE_SIZE; 632c1a4de99SAndrea Arcangeli 633c1a4de99SAndrea Arcangeli if (fatal_signal_pending(current)) 634c1a4de99SAndrea Arcangeli err = -EINTR; 635c1a4de99SAndrea Arcangeli } 636c1a4de99SAndrea Arcangeli if (err) 637c1a4de99SAndrea Arcangeli break; 638c1a4de99SAndrea Arcangeli } 639c1a4de99SAndrea Arcangeli 640b6ebaedbSAndrea Arcangeli out_unlock: 641d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 642b6ebaedbSAndrea Arcangeli out: 643b6ebaedbSAndrea Arcangeli if (page) 64409cbfeafSKirill A. Shutemov put_page(page); 645c1a4de99SAndrea Arcangeli BUG_ON(copied < 0); 646c1a4de99SAndrea Arcangeli BUG_ON(err > 0); 647c1a4de99SAndrea Arcangeli BUG_ON(!copied && !err); 648c1a4de99SAndrea Arcangeli return copied ? copied : err; 649c1a4de99SAndrea Arcangeli } 650c1a4de99SAndrea Arcangeli 651c1a4de99SAndrea Arcangeli ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start, 652df2cc96eSMike Rapoport unsigned long src_start, unsigned long len, 65372981e0eSAndrea Arcangeli bool *mmap_changing, __u64 mode) 654c1a4de99SAndrea Arcangeli { 655f6191471SAxel Rasmussen return __mcopy_atomic(dst_mm, dst_start, src_start, len, 656f6191471SAxel Rasmussen MCOPY_ATOMIC_NORMAL, mmap_changing, mode); 657c1a4de99SAndrea Arcangeli } 658c1a4de99SAndrea Arcangeli 659c1a4de99SAndrea Arcangeli ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start, 660df2cc96eSMike Rapoport unsigned long len, bool *mmap_changing) 661c1a4de99SAndrea Arcangeli { 662f6191471SAxel Rasmussen return __mcopy_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_ZEROPAGE, 663f6191471SAxel Rasmussen mmap_changing, 0); 664f6191471SAxel Rasmussen } 665f6191471SAxel Rasmussen 666f6191471SAxel Rasmussen ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long start, 667f6191471SAxel Rasmussen unsigned long len, bool *mmap_changing) 668f6191471SAxel Rasmussen { 669f6191471SAxel Rasmussen return __mcopy_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_CONTINUE, 670f6191471SAxel Rasmussen mmap_changing, 0); 671c1a4de99SAndrea Arcangeli } 672ffd05793SShaohua Li 673ffd05793SShaohua Li int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, 674ffd05793SShaohua Li unsigned long len, bool enable_wp, bool *mmap_changing) 675ffd05793SShaohua Li { 676ffd05793SShaohua Li struct vm_area_struct *dst_vma; 677ffd05793SShaohua Li pgprot_t newprot; 678ffd05793SShaohua Li int err; 679ffd05793SShaohua Li 680ffd05793SShaohua Li /* 681ffd05793SShaohua Li * Sanitize the command parameters: 682ffd05793SShaohua Li */ 683ffd05793SShaohua Li BUG_ON(start & ~PAGE_MASK); 684ffd05793SShaohua Li BUG_ON(len & ~PAGE_MASK); 685ffd05793SShaohua Li 686ffd05793SShaohua Li /* Does the address range wrap, or is the span zero-sized? */ 687ffd05793SShaohua Li BUG_ON(start + len <= start); 688ffd05793SShaohua Li 689d8ed45c5SMichel Lespinasse mmap_read_lock(dst_mm); 690ffd05793SShaohua Li 691ffd05793SShaohua Li /* 692ffd05793SShaohua Li * If memory mappings are changing because of non-cooperative 693ffd05793SShaohua Li * operation (e.g. mremap) running in parallel, bail out and 694ffd05793SShaohua Li * request the user to retry later 695ffd05793SShaohua Li */ 696ffd05793SShaohua Li err = -EAGAIN; 697ffd05793SShaohua Li if (mmap_changing && READ_ONCE(*mmap_changing)) 698ffd05793SShaohua Li goto out_unlock; 699ffd05793SShaohua Li 700ffd05793SShaohua Li err = -ENOENT; 701ffd05793SShaohua Li dst_vma = find_dst_vma(dst_mm, start, len); 702ffd05793SShaohua Li /* 703ffd05793SShaohua Li * Make sure the vma is not shared, that the dst range is 704ffd05793SShaohua Li * both valid and fully within a single existing vma. 705ffd05793SShaohua Li */ 706ffd05793SShaohua Li if (!dst_vma || (dst_vma->vm_flags & VM_SHARED)) 707ffd05793SShaohua Li goto out_unlock; 708ffd05793SShaohua Li if (!userfaultfd_wp(dst_vma)) 709ffd05793SShaohua Li goto out_unlock; 710ffd05793SShaohua Li if (!vma_is_anonymous(dst_vma)) 711ffd05793SShaohua Li goto out_unlock; 712ffd05793SShaohua Li 713ffd05793SShaohua Li if (enable_wp) 714ffd05793SShaohua Li newprot = vm_get_page_prot(dst_vma->vm_flags & ~(VM_WRITE)); 715ffd05793SShaohua Li else 716ffd05793SShaohua Li newprot = vm_get_page_prot(dst_vma->vm_flags); 717ffd05793SShaohua Li 718ffd05793SShaohua Li change_protection(dst_vma, start, start + len, newprot, 719ffd05793SShaohua Li enable_wp ? MM_CP_UFFD_WP : MM_CP_UFFD_WP_RESOLVE); 720ffd05793SShaohua Li 721ffd05793SShaohua Li err = 0; 722ffd05793SShaohua Li out_unlock: 723d8ed45c5SMichel Lespinasse mmap_read_unlock(dst_mm); 724ffd05793SShaohua Li return err; 725ffd05793SShaohua Li } 726