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- #include <linux/kernel.h>
- #include <linux/errno.h>
- #include <linux/err.h>
- #include <linux/spinlock.h>
- #include <linux/mm.h>
- #include <linux/memremap.h>
- #include <linux/pagemap.h>
- #include <linux/rmap.h>
- #include <linux/swap.h>
- #include <linux/swapops.h>
- #include <linux/secretmem.h>
- #include <linux/sched/signal.h>
- #include <linux/rwsem.h>
- #include <linux/hugetlb.h>
- #include <linux/migrate.h>
- #include <linux/mm_inline.h>
- #include <linux/sched/mm.h>
- #include <asm/mmu_context.h>
- #include <asm/tlbflush.h>
- #include "internal.h"
- struct follow_page_context {
- struct dev_pagemap *pgmap;
- unsigned int page_mask;
- };
- static inline void sanity_check_pinned_pages(struct page **pages,
- unsigned long npages)
- {
- if (!IS_ENABLED(CONFIG_DEBUG_VM))
- return;
-
- for (; npages; npages--, pages++) {
- struct page *page = *pages;
- struct folio *folio = page_folio(page);
- if (!folio_test_anon(folio))
- continue;
- if (!folio_test_large(folio) || folio_test_hugetlb(folio))
- VM_BUG_ON_PAGE(!PageAnonExclusive(&folio->page), page);
- else
-
- VM_BUG_ON_PAGE(!PageAnonExclusive(&folio->page) &&
- !PageAnonExclusive(page), page);
- }
- }
- static inline struct folio *try_get_folio(struct page *page, int refs)
- {
- struct folio *folio;
- retry:
- folio = page_folio(page);
- if (WARN_ON_ONCE(folio_ref_count(folio) < 0))
- return NULL;
- if (unlikely(!folio_ref_try_add_rcu(folio, refs)))
- return NULL;
-
- if (unlikely(page_folio(page) != folio)) {
- if (!put_devmap_managed_page_refs(&folio->page, refs))
- folio_put_refs(folio, refs);
- goto retry;
- }
- return folio;
- }
- struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
- {
- if (flags & FOLL_GET)
- return try_get_folio(page, refs);
- else if (flags & FOLL_PIN) {
- struct folio *folio;
-
- if (unlikely((flags & FOLL_LONGTERM) &&
- !is_longterm_pinnable_page(page)))
- return NULL;
-
- folio = try_get_folio(page, refs);
- if (!folio)
- return NULL;
-
- if (folio_test_large(folio))
- atomic_add(refs, folio_pincount_ptr(folio));
- else
- folio_ref_add(folio,
- refs * (GUP_PIN_COUNTING_BIAS - 1));
-
- smp_mb__after_atomic();
- node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, refs);
- return folio;
- }
- WARN_ON_ONCE(1);
- return NULL;
- }
- static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
- {
- if (flags & FOLL_PIN) {
- node_stat_mod_folio(folio, NR_FOLL_PIN_RELEASED, refs);
- if (folio_test_large(folio))
- atomic_sub(refs, folio_pincount_ptr(folio));
- else
- refs *= GUP_PIN_COUNTING_BIAS;
- }
- if (!put_devmap_managed_page_refs(&folio->page, refs))
- folio_put_refs(folio, refs);
- }
- bool __must_check try_grab_page(struct page *page, unsigned int flags)
- {
- struct folio *folio = page_folio(page);
- WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == (FOLL_GET | FOLL_PIN));
- if (WARN_ON_ONCE(folio_ref_count(folio) <= 0))
- return false;
- if (flags & FOLL_GET)
- folio_ref_inc(folio);
- else if (flags & FOLL_PIN) {
-
- if (folio_test_large(folio)) {
- folio_ref_add(folio, 1);
- atomic_add(1, folio_pincount_ptr(folio));
- } else {
- folio_ref_add(folio, GUP_PIN_COUNTING_BIAS);
- }
- node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, 1);
- }
- return true;
- }
- void unpin_user_page(struct page *page)
- {
- sanity_check_pinned_pages(&page, 1);
- gup_put_folio(page_folio(page), 1, FOLL_PIN);
- }
- EXPORT_SYMBOL(unpin_user_page);
- static inline struct folio *gup_folio_range_next(struct page *start,
- unsigned long npages, unsigned long i, unsigned int *ntails)
- {
- struct page *next = nth_page(start, i);
- struct folio *folio = page_folio(next);
- unsigned int nr = 1;
- if (folio_test_large(folio))
- nr = min_t(unsigned int, npages - i,
- folio_nr_pages(folio) - folio_page_idx(folio, next));
- *ntails = nr;
- return folio;
- }
- static inline struct folio *gup_folio_next(struct page **list,
- unsigned long npages, unsigned long i, unsigned int *ntails)
- {
- struct folio *folio = page_folio(list[i]);
- unsigned int nr;
- for (nr = i + 1; nr < npages; nr++) {
- if (page_folio(list[nr]) != folio)
- break;
- }
- *ntails = nr - i;
- return folio;
- }
- void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
- bool make_dirty)
- {
- unsigned long i;
- struct folio *folio;
- unsigned int nr;
- if (!make_dirty) {
- unpin_user_pages(pages, npages);
- return;
- }
- sanity_check_pinned_pages(pages, npages);
- for (i = 0; i < npages; i += nr) {
- folio = gup_folio_next(pages, npages, i, &nr);
-
- if (!folio_test_dirty(folio)) {
- folio_lock(folio);
- folio_mark_dirty(folio);
- folio_unlock(folio);
- }
- gup_put_folio(folio, nr, FOLL_PIN);
- }
- }
- EXPORT_SYMBOL(unpin_user_pages_dirty_lock);
- void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
- bool make_dirty)
- {
- unsigned long i;
- struct folio *folio;
- unsigned int nr;
- for (i = 0; i < npages; i += nr) {
- folio = gup_folio_range_next(page, npages, i, &nr);
- if (make_dirty && !folio_test_dirty(folio)) {
- folio_lock(folio);
- folio_mark_dirty(folio);
- folio_unlock(folio);
- }
- gup_put_folio(folio, nr, FOLL_PIN);
- }
- }
- EXPORT_SYMBOL(unpin_user_page_range_dirty_lock);
- static void unpin_user_pages_lockless(struct page **pages, unsigned long npages)
- {
- unsigned long i;
- struct folio *folio;
- unsigned int nr;
-
- for (i = 0; i < npages; i += nr) {
- folio = gup_folio_next(pages, npages, i, &nr);
- gup_put_folio(folio, nr, FOLL_PIN);
- }
- }
- void unpin_user_pages(struct page **pages, unsigned long npages)
- {
- unsigned long i;
- struct folio *folio;
- unsigned int nr;
-
- if (WARN_ON(IS_ERR_VALUE(npages)))
- return;
- sanity_check_pinned_pages(pages, npages);
- for (i = 0; i < npages; i += nr) {
- folio = gup_folio_next(pages, npages, i, &nr);
- gup_put_folio(folio, nr, FOLL_PIN);
- }
- }
- EXPORT_SYMBOL(unpin_user_pages);
- static inline void mm_set_has_pinned_flag(unsigned long *mm_flags)
- {
- if (!test_bit(MMF_HAS_PINNED, mm_flags))
- set_bit(MMF_HAS_PINNED, mm_flags);
- }
- #ifdef CONFIG_MMU
- static struct page *no_page_table(struct vm_area_struct *vma,
- unsigned int flags)
- {
-
- if ((flags & FOLL_DUMP) &&
- (vma_is_anonymous(vma) || !vma->vm_ops->fault))
- return ERR_PTR(-EFAULT);
- return NULL;
- }
- static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
- pte_t *pte, unsigned int flags)
- {
- if (flags & FOLL_TOUCH) {
- pte_t entry = *pte;
- if (flags & FOLL_WRITE)
- entry = pte_mkdirty(entry);
- entry = pte_mkyoung(entry);
- if (!pte_same(*pte, entry)) {
- set_pte_at(vma->vm_mm, address, pte, entry);
- update_mmu_cache(vma, address, pte);
- }
- }
-
- return -EEXIST;
- }
- static inline bool can_follow_write_pte(pte_t pte, struct page *page,
- struct vm_area_struct *vma,
- unsigned int flags)
- {
-
- if (pte_write(pte))
- return true;
-
- if (!(flags & FOLL_FORCE))
- return false;
-
- if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED))
- return false;
-
- if (!(vma->vm_flags & VM_MAYWRITE))
- return false;
-
- if (vma->vm_flags & VM_WRITE)
- return false;
-
- if (!page || !PageAnon(page) || !PageAnonExclusive(page))
- return false;
-
- if (vma_soft_dirty_enabled(vma) && !pte_soft_dirty(pte))
- return false;
- return !userfaultfd_pte_wp(vma, pte);
- }
- static struct page *follow_page_pte(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd, unsigned int flags,
- struct dev_pagemap **pgmap)
- {
- struct mm_struct *mm = vma->vm_mm;
- struct page *page;
- spinlock_t *ptl;
- pte_t *ptep, pte;
- int ret;
-
- if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
- (FOLL_PIN | FOLL_GET)))
- return ERR_PTR(-EINVAL);
-
- if (is_vm_hugetlb_page(vma)) {
- page = follow_huge_pmd_pte(vma, address, flags);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- retry:
- if (unlikely(pmd_bad(*pmd)))
- return no_page_table(vma, flags);
- ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
- pte = *ptep;
- if (!pte_present(pte)) {
- swp_entry_t entry;
-
- if (likely(!(flags & FOLL_MIGRATION)))
- goto no_page;
- if (pte_none(pte))
- goto no_page;
- entry = pte_to_swp_entry(pte);
- if (!is_migration_entry(entry))
- goto no_page;
- pte_unmap_unlock(ptep, ptl);
- migration_entry_wait(mm, pmd, address);
- goto retry;
- }
- if (pte_protnone(pte) && !gup_can_follow_protnone(flags))
- goto no_page;
- page = vm_normal_page(vma, address, pte);
-
- if ((flags & FOLL_WRITE) &&
- !can_follow_write_pte(pte, page, vma, flags)) {
- page = NULL;
- goto out;
- }
- if (!page && pte_devmap(pte) && (flags & (FOLL_GET | FOLL_PIN))) {
-
- *pgmap = get_dev_pagemap(pte_pfn(pte), *pgmap);
- if (*pgmap)
- page = pte_page(pte);
- else
- goto no_page;
- } else if (unlikely(!page)) {
- if (flags & FOLL_DUMP) {
-
- page = ERR_PTR(-EFAULT);
- goto out;
- }
- if (is_zero_pfn(pte_pfn(pte))) {
- page = pte_page(pte);
- } else {
- ret = follow_pfn_pte(vma, address, ptep, flags);
- page = ERR_PTR(ret);
- goto out;
- }
- }
- if (!pte_write(pte) && gup_must_unshare(flags, page)) {
- page = ERR_PTR(-EMLINK);
- goto out;
- }
- VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) &&
- !PageAnonExclusive(page), page);
-
- if (unlikely(!try_grab_page(page, flags))) {
- page = ERR_PTR(-ENOMEM);
- goto out;
- }
-
- if (flags & FOLL_PIN) {
- ret = arch_make_page_accessible(page);
- if (ret) {
- unpin_user_page(page);
- page = ERR_PTR(ret);
- goto out;
- }
- }
- if (flags & FOLL_TOUCH) {
- if ((flags & FOLL_WRITE) &&
- !pte_dirty(pte) && !PageDirty(page))
- set_page_dirty(page);
-
- mark_page_accessed(page);
- }
- out:
- pte_unmap_unlock(ptep, ptl);
- return page;
- no_page:
- pte_unmap_unlock(ptep, ptl);
- if (!pte_none(pte))
- return NULL;
- return no_page_table(vma, flags);
- }
- static struct page *follow_pmd_mask(struct vm_area_struct *vma,
- unsigned long address, pud_t *pudp,
- unsigned int flags,
- struct follow_page_context *ctx)
- {
- pmd_t *pmd, pmdval;
- spinlock_t *ptl;
- struct page *page;
- struct mm_struct *mm = vma->vm_mm;
- pmd = pmd_offset(pudp, address);
-
- pmdval = READ_ONCE(*pmd);
- if (pmd_none(pmdval))
- return no_page_table(vma, flags);
- if (pmd_huge(pmdval) && is_vm_hugetlb_page(vma)) {
- page = follow_huge_pmd_pte(vma, address, flags);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- if (is_hugepd(__hugepd(pmd_val(pmdval)))) {
- page = follow_huge_pd(vma, address,
- __hugepd(pmd_val(pmdval)), flags,
- PMD_SHIFT);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- retry:
- if (!pmd_present(pmdval)) {
-
- VM_BUG_ON(!thp_migration_supported() ||
- !is_pmd_migration_entry(pmdval));
- if (likely(!(flags & FOLL_MIGRATION)))
- return no_page_table(vma, flags);
- pmd_migration_entry_wait(mm, pmd);
- pmdval = READ_ONCE(*pmd);
-
- if (pmd_none(pmdval))
- return no_page_table(vma, flags);
- goto retry;
- }
- if (pmd_devmap(pmdval)) {
- ptl = pmd_lock(mm, pmd);
- page = follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap);
- spin_unlock(ptl);
- if (page)
- return page;
- }
- if (likely(!pmd_trans_huge(pmdval)))
- return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
- if (pmd_protnone(pmdval) && !gup_can_follow_protnone(flags))
- return no_page_table(vma, flags);
- retry_locked:
- ptl = pmd_lock(mm, pmd);
- if (unlikely(pmd_none(*pmd))) {
- spin_unlock(ptl);
- return no_page_table(vma, flags);
- }
- if (unlikely(!pmd_present(*pmd))) {
- spin_unlock(ptl);
- if (likely(!(flags & FOLL_MIGRATION)))
- return no_page_table(vma, flags);
- pmd_migration_entry_wait(mm, pmd);
- goto retry_locked;
- }
- if (unlikely(!pmd_trans_huge(*pmd))) {
- spin_unlock(ptl);
- return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
- }
- if (flags & FOLL_SPLIT_PMD) {
- int ret;
- page = pmd_page(*pmd);
- if (is_huge_zero_page(page)) {
- spin_unlock(ptl);
- ret = 0;
- split_huge_pmd(vma, pmd, address);
- if (pmd_trans_unstable(pmd))
- ret = -EBUSY;
- } else {
- spin_unlock(ptl);
- split_huge_pmd(vma, pmd, address);
- ret = pte_alloc(mm, pmd) ? -ENOMEM : 0;
- }
- return ret ? ERR_PTR(ret) :
- follow_page_pte(vma, address, pmd, flags, &ctx->pgmap);
- }
- page = follow_trans_huge_pmd(vma, address, pmd, flags);
- spin_unlock(ptl);
- ctx->page_mask = HPAGE_PMD_NR - 1;
- return page;
- }
- static struct page *follow_pud_mask(struct vm_area_struct *vma,
- unsigned long address, p4d_t *p4dp,
- unsigned int flags,
- struct follow_page_context *ctx)
- {
- pud_t *pud;
- spinlock_t *ptl;
- struct page *page;
- struct mm_struct *mm = vma->vm_mm;
- pud = pud_offset(p4dp, address);
- if (pud_none(*pud))
- return no_page_table(vma, flags);
- if (pud_huge(*pud) && is_vm_hugetlb_page(vma)) {
- page = follow_huge_pud(mm, 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,
- PUD_SHIFT);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- if (pud_devmap(*pud)) {
- ptl = pud_lock(mm, pud);
- page = follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap);
- spin_unlock(ptl);
- if (page)
- return page;
- }
- if (unlikely(pud_bad(*pud)))
- return no_page_table(vma, flags);
- return follow_pmd_mask(vma, address, pud, flags, ctx);
- }
- static struct page *follow_p4d_mask(struct vm_area_struct *vma,
- unsigned long address, pgd_t *pgdp,
- unsigned int flags,
- struct follow_page_context *ctx)
- {
- p4d_t *p4d;
- struct page *page;
- p4d = p4d_offset(pgdp, address);
- if (p4d_none(*p4d))
- return no_page_table(vma, flags);
- BUILD_BUG_ON(p4d_huge(*p4d));
- if (unlikely(p4d_bad(*p4d)))
- return no_page_table(vma, flags);
- if (is_hugepd(__hugepd(p4d_val(*p4d)))) {
- page = follow_huge_pd(vma, address,
- __hugepd(p4d_val(*p4d)), flags,
- P4D_SHIFT);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- return follow_pud_mask(vma, address, p4d, flags, ctx);
- }
- static struct page *follow_page_mask(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags,
- struct follow_page_context *ctx)
- {
- pgd_t *pgd;
- struct page *page;
- struct mm_struct *mm = vma->vm_mm;
- ctx->page_mask = 0;
-
- page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
- if (!IS_ERR(page)) {
- WARN_ON_ONCE(flags & (FOLL_GET | FOLL_PIN));
- return page;
- }
- pgd = pgd_offset(mm, address);
- if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- return no_page_table(vma, flags);
- if (pgd_huge(*pgd)) {
- page = follow_huge_pgd(mm, address, pgd, flags);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- if (is_hugepd(__hugepd(pgd_val(*pgd)))) {
- page = follow_huge_pd(vma, address,
- __hugepd(pgd_val(*pgd)), flags,
- PGDIR_SHIFT);
- if (page)
- return page;
- return no_page_table(vma, flags);
- }
- return follow_p4d_mask(vma, address, pgd, flags, ctx);
- }
- struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
- unsigned int foll_flags)
- {
- struct follow_page_context ctx = { NULL };
- struct page *page;
- if (vma_is_secretmem(vma))
- return NULL;
- if (foll_flags & FOLL_PIN)
- return NULL;
- page = follow_page_mask(vma, address, foll_flags, &ctx);
- if (ctx.pgmap)
- put_dev_pagemap(ctx.pgmap);
- return page;
- }
- static int get_gate_page(struct mm_struct *mm, unsigned long address,
- unsigned int gup_flags, struct vm_area_struct **vma,
- struct page **page)
- {
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int ret = -EFAULT;
-
- if (gup_flags & FOLL_WRITE)
- return -EFAULT;
- if (address > TASK_SIZE)
- pgd = pgd_offset_k(address);
- else
- pgd = pgd_offset_gate(mm, address);
- if (pgd_none(*pgd))
- return -EFAULT;
- p4d = p4d_offset(pgd, address);
- if (p4d_none(*p4d))
- return -EFAULT;
- pud = pud_offset(p4d, address);
- if (pud_none(*pud))
- return -EFAULT;
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
- return -EFAULT;
- VM_BUG_ON(pmd_trans_huge(*pmd));
- pte = pte_offset_map(pmd, address);
- if (pte_none(*pte))
- goto unmap;
- *vma = get_gate_vma(mm);
- if (!page)
- goto out;
- *page = vm_normal_page(*vma, address, *pte);
- if (!*page) {
- if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte)))
- goto unmap;
- *page = pte_page(*pte);
- }
- if (unlikely(!try_grab_page(*page, gup_flags))) {
- ret = -ENOMEM;
- goto unmap;
- }
- out:
- ret = 0;
- unmap:
- pte_unmap(pte);
- return ret;
- }
- static int faultin_page(struct vm_area_struct *vma,
- unsigned long address, unsigned int *flags, bool unshare,
- int *locked)
- {
- unsigned int fault_flags = 0;
- vm_fault_t ret;
- if (*flags & FOLL_NOFAULT)
- return -EFAULT;
- if (*flags & FOLL_WRITE)
- fault_flags |= FAULT_FLAG_WRITE;
- if (*flags & FOLL_REMOTE)
- fault_flags |= FAULT_FLAG_REMOTE;
- if (locked)
- fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
- if (*flags & FOLL_NOWAIT)
- fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
- if (*flags & FOLL_TRIED) {
-
- fault_flags |= FAULT_FLAG_TRIED;
- }
- if (unshare) {
- fault_flags |= FAULT_FLAG_UNSHARE;
-
- VM_BUG_ON(fault_flags & FAULT_FLAG_WRITE);
- }
- ret = handle_mm_fault(vma, address, fault_flags, NULL);
- if (ret & VM_FAULT_COMPLETED) {
-
- WARN_ON_ONCE(fault_flags & FAULT_FLAG_RETRY_NOWAIT);
- if (locked)
- *locked = 0;
-
- return -EAGAIN;
- }
- if (ret & VM_FAULT_ERROR) {
- int err = vm_fault_to_errno(ret, *flags);
- if (err)
- return err;
- BUG();
- }
- if (ret & VM_FAULT_RETRY) {
- if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
- *locked = 0;
- return -EBUSY;
- }
- return 0;
- }
- static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
- {
- vm_flags_t vm_flags = vma->vm_flags;
- int write = (gup_flags & FOLL_WRITE);
- int foreign = (gup_flags & FOLL_REMOTE);
- if (vm_flags & (VM_IO | VM_PFNMAP))
- return -EFAULT;
- if (gup_flags & FOLL_ANON && !vma_is_anonymous(vma))
- return -EFAULT;
- if ((gup_flags & FOLL_LONGTERM) && vma_is_fsdax(vma))
- return -EOPNOTSUPP;
- if (vma_is_secretmem(vma))
- return -EFAULT;
- if (write) {
- if (!(vm_flags & VM_WRITE)) {
- if (!(gup_flags & FOLL_FORCE))
- return -EFAULT;
-
- if (is_vm_hugetlb_page(vma))
- return -EFAULT;
-
- if (!is_cow_mapping(vm_flags))
- return -EFAULT;
- }
- } else if (!(vm_flags & VM_READ)) {
- if (!(gup_flags & FOLL_FORCE))
- return -EFAULT;
-
- if (!(vm_flags & VM_MAYREAD))
- return -EFAULT;
- }
-
- if (!arch_vma_access_permitted(vma, write, false, foreign))
- return -EFAULT;
- return 0;
- }
- static long __get_user_pages(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
- long ret = 0, i = 0;
- struct vm_area_struct *vma = NULL;
- struct follow_page_context ctx = { NULL };
- if (!nr_pages)
- return 0;
- start = untagged_addr(start);
- VM_BUG_ON(!!pages != !!(gup_flags & (FOLL_GET | FOLL_PIN)));
- do {
- struct page *page;
- unsigned int foll_flags = gup_flags;
- unsigned int page_increm;
-
- if (!vma || start >= vma->vm_end) {
- vma = vma_lookup(mm, start);
- if (!vma && in_gate_area(mm, start)) {
- ret = get_gate_page(mm, start & PAGE_MASK,
- gup_flags, &vma,
- pages ? &pages[i] : NULL);
- if (ret)
- goto out;
- ctx.page_mask = 0;
- goto next_page;
- }
- if (!vma) {
- ret = -EFAULT;
- goto out;
- }
- ret = check_vma_flags(vma, gup_flags);
- if (ret)
- goto out;
- if (is_vm_hugetlb_page(vma)) {
- i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &nr_pages, i,
- gup_flags, locked);
- if (locked && *locked == 0) {
-
- BUG_ON(gup_flags & FOLL_NOWAIT);
- goto out;
- }
- continue;
- }
- }
- retry:
-
- if (fatal_signal_pending(current)) {
- ret = -EINTR;
- goto out;
- }
- cond_resched();
- page = follow_page_mask(vma, start, foll_flags, &ctx);
- if (!page || PTR_ERR(page) == -EMLINK) {
- ret = faultin_page(vma, start, &foll_flags,
- PTR_ERR(page) == -EMLINK, locked);
- switch (ret) {
- case 0:
- goto retry;
- case -EBUSY:
- case -EAGAIN:
- ret = 0;
- fallthrough;
- case -EFAULT:
- case -ENOMEM:
- case -EHWPOISON:
- goto out;
- }
- BUG();
- } else if (PTR_ERR(page) == -EEXIST) {
-
- if (pages) {
- ret = PTR_ERR(page);
- goto out;
- }
- goto next_page;
- } else if (IS_ERR(page)) {
- ret = PTR_ERR(page);
- goto out;
- }
- if (pages) {
- pages[i] = page;
- flush_anon_page(vma, page, start);
- flush_dcache_page(page);
- ctx.page_mask = 0;
- }
- next_page:
- if (vmas) {
- vmas[i] = vma;
- ctx.page_mask = 0;
- }
- page_increm = 1 + (~(start >> PAGE_SHIFT) & ctx.page_mask);
- if (page_increm > nr_pages)
- page_increm = nr_pages;
- i += page_increm;
- start += page_increm * PAGE_SIZE;
- nr_pages -= page_increm;
- } while (nr_pages);
- out:
- if (ctx.pgmap)
- put_dev_pagemap(ctx.pgmap);
- return i ? i : ret;
- }
- static bool vma_permits_fault(struct vm_area_struct *vma,
- unsigned int fault_flags)
- {
- bool write = !!(fault_flags & FAULT_FLAG_WRITE);
- bool foreign = !!(fault_flags & FAULT_FLAG_REMOTE);
- vm_flags_t vm_flags = write ? VM_WRITE : VM_READ;
- if (!(vm_flags & vma->vm_flags))
- return false;
-
- if (!arch_vma_access_permitted(vma, write, false, foreign))
- return false;
- return true;
- }
- int fixup_user_fault(struct mm_struct *mm,
- unsigned long address, unsigned int fault_flags,
- bool *unlocked)
- {
- struct vm_area_struct *vma;
- vm_fault_t ret;
- address = untagged_addr(address);
- if (unlocked)
- fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
- retry:
- vma = vma_lookup(mm, address);
- if (!vma)
- return -EFAULT;
- if (!vma_permits_fault(vma, fault_flags))
- return -EFAULT;
- if ((fault_flags & FAULT_FLAG_KILLABLE) &&
- fatal_signal_pending(current))
- return -EINTR;
- ret = handle_mm_fault(vma, address, fault_flags, NULL);
- if (ret & VM_FAULT_COMPLETED) {
-
- mmap_read_lock(mm);
- *unlocked = true;
- return 0;
- }
- if (ret & VM_FAULT_ERROR) {
- int err = vm_fault_to_errno(ret, 0);
- if (err)
- return err;
- BUG();
- }
- if (ret & VM_FAULT_RETRY) {
- mmap_read_lock(mm);
- *unlocked = true;
- fault_flags |= FAULT_FLAG_TRIED;
- goto retry;
- }
- return 0;
- }
- EXPORT_SYMBOL_GPL(fixup_user_fault);
- static __always_inline long __get_user_pages_locked(struct mm_struct *mm,
- unsigned long start,
- unsigned long nr_pages,
- struct page **pages,
- struct vm_area_struct **vmas,
- int *locked,
- unsigned int flags)
- {
- long ret, pages_done;
- bool lock_dropped;
- if (locked) {
-
- BUG_ON(vmas);
-
- BUG_ON(*locked != 1);
- }
- if (flags & FOLL_PIN)
- mm_set_has_pinned_flag(&mm->flags);
-
- if (pages && !(flags & FOLL_PIN))
- flags |= FOLL_GET;
- pages_done = 0;
- lock_dropped = false;
- for (;;) {
- ret = __get_user_pages(mm, start, nr_pages, flags, pages,
- vmas, locked);
- if (!locked)
-
- return ret;
-
- if (!*locked) {
- BUG_ON(ret < 0);
- BUG_ON(ret >= nr_pages);
- }
- if (ret > 0) {
- nr_pages -= ret;
- pages_done += ret;
- if (!nr_pages)
- break;
- }
- if (*locked) {
-
- if (!pages_done)
- pages_done = ret;
- break;
- }
-
- if (likely(pages))
- pages += ret;
- start += ret << PAGE_SHIFT;
- lock_dropped = true;
- retry:
-
- if (fatal_signal_pending(current)) {
- if (!pages_done)
- pages_done = -EINTR;
- break;
- }
- ret = mmap_read_lock_killable(mm);
- if (ret) {
- BUG_ON(ret > 0);
- if (!pages_done)
- pages_done = ret;
- break;
- }
- *locked = 1;
- ret = __get_user_pages(mm, start, 1, flags | FOLL_TRIED,
- pages, NULL, locked);
- if (!*locked) {
-
- BUG_ON(ret != 0);
- goto retry;
- }
- if (ret != 1) {
- BUG_ON(ret > 1);
- if (!pages_done)
- pages_done = ret;
- break;
- }
- nr_pages--;
- pages_done++;
- if (!nr_pages)
- break;
- if (likely(pages))
- pages++;
- start += PAGE_SIZE;
- }
- if (lock_dropped && *locked) {
-
- mmap_read_unlock(mm);
- *locked = 0;
- }
- return pages_done;
- }
- long populate_vma_page_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end, int *locked)
- {
- struct mm_struct *mm = vma->vm_mm;
- unsigned long nr_pages = (end - start) / PAGE_SIZE;
- int gup_flags;
- long ret;
- VM_BUG_ON(!PAGE_ALIGNED(start));
- VM_BUG_ON(!PAGE_ALIGNED(end));
- VM_BUG_ON_VMA(start < vma->vm_start, vma);
- VM_BUG_ON_VMA(end > vma->vm_end, vma);
- mmap_assert_locked(mm);
-
- if (vma->vm_flags & VM_LOCKONFAULT)
- return nr_pages;
- gup_flags = FOLL_TOUCH;
-
- if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
- gup_flags |= FOLL_WRITE;
-
- if (vma_is_accessible(vma))
- gup_flags |= FOLL_FORCE;
-
- ret = __get_user_pages(mm, start, nr_pages, gup_flags,
- NULL, NULL, locked);
- lru_add_drain();
- return ret;
- }
- long faultin_vma_page_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, bool write, int *locked)
- {
- struct mm_struct *mm = vma->vm_mm;
- unsigned long nr_pages = (end - start) / PAGE_SIZE;
- int gup_flags;
- long ret;
- VM_BUG_ON(!PAGE_ALIGNED(start));
- VM_BUG_ON(!PAGE_ALIGNED(end));
- VM_BUG_ON_VMA(start < vma->vm_start, vma);
- VM_BUG_ON_VMA(end > vma->vm_end, vma);
- mmap_assert_locked(mm);
-
- gup_flags = FOLL_TOUCH | FOLL_HWPOISON;
- if (write)
- gup_flags |= FOLL_WRITE;
-
- if (check_vma_flags(vma, gup_flags))
- return -EINVAL;
- ret = __get_user_pages(mm, start, nr_pages, gup_flags,
- NULL, NULL, locked);
- lru_add_drain();
- return ret;
- }
- int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
- {
- struct mm_struct *mm = current->mm;
- unsigned long end, nstart, nend;
- struct vm_area_struct *vma = NULL;
- int locked = 0;
- long ret = 0;
- end = start + len;
- for (nstart = start; nstart < end; nstart = nend) {
-
- if (!locked) {
- locked = 1;
- mmap_read_lock(mm);
- vma = find_vma_intersection(mm, nstart, end);
- } else if (nstart >= vma->vm_end)
- vma = find_vma_intersection(mm, vma->vm_end, end);
- if (!vma)
- break;
-
- nend = min(end, vma->vm_end);
- if (vma->vm_flags & (VM_IO | VM_PFNMAP))
- continue;
- if (nstart < vma->vm_start)
- nstart = vma->vm_start;
-
- ret = populate_vma_page_range(vma, nstart, nend, &locked);
- if (ret < 0) {
- if (ignore_errors) {
- ret = 0;
- continue;
- }
- break;
- }
- nend = nstart + ret * PAGE_SIZE;
- ret = 0;
- }
- if (locked)
- mmap_read_unlock(mm);
- return ret;
- }
- #else
- static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,
- unsigned long nr_pages, struct page **pages,
- struct vm_area_struct **vmas, int *locked,
- unsigned int foll_flags)
- {
- struct vm_area_struct *vma;
- unsigned long vm_flags;
- long i;
-
- vm_flags = (foll_flags & FOLL_WRITE) ?
- (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= (foll_flags & FOLL_FORCE) ?
- (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
- for (i = 0; i < nr_pages; i++) {
- vma = find_vma(mm, start);
- if (!vma)
- goto finish_or_fault;
-
- if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
- !(vm_flags & vma->vm_flags))
- goto finish_or_fault;
- if (pages) {
- pages[i] = virt_to_page((void *)start);
- if (pages[i])
- get_page(pages[i]);
- }
- if (vmas)
- vmas[i] = vma;
- start = (start + PAGE_SIZE) & PAGE_MASK;
- }
- return i;
- finish_or_fault:
- return i ? : -EFAULT;
- }
- #endif
- size_t fault_in_writeable(char __user *uaddr, size_t size)
- {
- char __user *start = uaddr, *end;
- if (unlikely(size == 0))
- return 0;
- if (!user_write_access_begin(uaddr, size))
- return size;
- if (!PAGE_ALIGNED(uaddr)) {
- unsafe_put_user(0, uaddr, out);
- uaddr = (char __user *)PAGE_ALIGN((unsigned long)uaddr);
- }
- end = (char __user *)PAGE_ALIGN((unsigned long)start + size);
- if (unlikely(end < start))
- end = NULL;
- while (uaddr != end) {
- unsafe_put_user(0, uaddr, out);
- uaddr += PAGE_SIZE;
- }
- out:
- user_write_access_end();
- if (size > uaddr - start)
- return size - (uaddr - start);
- return 0;
- }
- EXPORT_SYMBOL(fault_in_writeable);
- size_t fault_in_subpage_writeable(char __user *uaddr, size_t size)
- {
- size_t faulted_in;
-
- faulted_in = size - fault_in_writeable(uaddr, size);
- if (faulted_in)
- faulted_in -= probe_subpage_writeable(uaddr, faulted_in);
- return size - faulted_in;
- }
- EXPORT_SYMBOL(fault_in_subpage_writeable);
- size_t fault_in_safe_writeable(const char __user *uaddr, size_t size)
- {
- unsigned long start = (unsigned long)uaddr, end;
- struct mm_struct *mm = current->mm;
- bool unlocked = false;
- if (unlikely(size == 0))
- return 0;
- end = PAGE_ALIGN(start + size);
- if (end < start)
- end = 0;
- mmap_read_lock(mm);
- do {
- if (fixup_user_fault(mm, start, FAULT_FLAG_WRITE, &unlocked))
- break;
- start = (start + PAGE_SIZE) & PAGE_MASK;
- } while (start != end);
- mmap_read_unlock(mm);
- if (size > (unsigned long)uaddr - start)
- return size - ((unsigned long)uaddr - start);
- return 0;
- }
- EXPORT_SYMBOL(fault_in_safe_writeable);
- size_t fault_in_readable(const char __user *uaddr, size_t size)
- {
- const char __user *start = uaddr, *end;
- volatile char c;
- if (unlikely(size == 0))
- return 0;
- if (!user_read_access_begin(uaddr, size))
- return size;
- if (!PAGE_ALIGNED(uaddr)) {
- unsafe_get_user(c, uaddr, out);
- uaddr = (const char __user *)PAGE_ALIGN((unsigned long)uaddr);
- }
- end = (const char __user *)PAGE_ALIGN((unsigned long)start + size);
- if (unlikely(end < start))
- end = NULL;
- while (uaddr != end) {
- unsafe_get_user(c, uaddr, out);
- uaddr += PAGE_SIZE;
- }
- out:
- user_read_access_end();
- (void)c;
- if (size > uaddr - start)
- return size - (uaddr - start);
- return 0;
- }
- EXPORT_SYMBOL(fault_in_readable);
- #ifdef CONFIG_ELF_CORE
- struct page *get_dump_page(unsigned long addr)
- {
- struct mm_struct *mm = current->mm;
- struct page *page;
- int locked = 1;
- int ret;
- if (mmap_read_lock_killable(mm))
- return NULL;
- ret = __get_user_pages_locked(mm, addr, 1, &page, NULL, &locked,
- FOLL_FORCE | FOLL_DUMP | FOLL_GET);
- if (locked)
- mmap_read_unlock(mm);
- return (ret == 1) ? page : NULL;
- }
- #endif
- #ifdef CONFIG_MIGRATION
- static unsigned long collect_longterm_unpinnable_pages(
- struct list_head *movable_page_list,
- unsigned long nr_pages,
- struct page **pages)
- {
- unsigned long i, collected = 0;
- struct folio *prev_folio = NULL;
- bool drain_allow = true;
- for (i = 0; i < nr_pages; i++) {
- struct folio *folio = page_folio(pages[i]);
- if (folio == prev_folio)
- continue;
- prev_folio = folio;
- if (folio_is_longterm_pinnable(folio))
- continue;
- collected++;
- if (folio_is_device_coherent(folio))
- continue;
- if (folio_test_hugetlb(folio)) {
- isolate_hugetlb(&folio->page, movable_page_list);
- continue;
- }
- if (!folio_test_lru(folio) && drain_allow) {
- lru_add_drain_all();
- drain_allow = false;
- }
- if (folio_isolate_lru(folio))
- continue;
- list_add_tail(&folio->lru, movable_page_list);
- node_stat_mod_folio(folio,
- NR_ISOLATED_ANON + folio_is_file_lru(folio),
- folio_nr_pages(folio));
- }
- return collected;
- }
- static int migrate_longterm_unpinnable_pages(
- struct list_head *movable_page_list,
- unsigned long nr_pages,
- struct page **pages)
- {
- int ret;
- unsigned long i;
- for (i = 0; i < nr_pages; i++) {
- struct folio *folio = page_folio(pages[i]);
- if (folio_is_device_coherent(folio)) {
-
- pages[i] = NULL;
- folio_get(folio);
- gup_put_folio(folio, 1, FOLL_PIN);
- if (migrate_device_coherent_page(&folio->page)) {
- ret = -EBUSY;
- goto err;
- }
- continue;
- }
-
- unpin_user_page(pages[i]);
- pages[i] = NULL;
- }
- if (!list_empty(movable_page_list)) {
- struct migration_target_control mtc = {
- .nid = NUMA_NO_NODE,
- .gfp_mask = GFP_USER | __GFP_NOWARN,
- };
- if (migrate_pages(movable_page_list, alloc_migration_target,
- NULL, (unsigned long)&mtc, MIGRATE_SYNC,
- MR_LONGTERM_PIN, NULL)) {
- ret = -ENOMEM;
- goto err;
- }
- }
- putback_movable_pages(movable_page_list);
- return -EAGAIN;
- err:
- for (i = 0; i < nr_pages; i++)
- if (pages[i])
- unpin_user_page(pages[i]);
- putback_movable_pages(movable_page_list);
- return ret;
- }
- static long check_and_migrate_movable_pages(unsigned long nr_pages,
- struct page **pages)
- {
- unsigned long collected;
- LIST_HEAD(movable_page_list);
- collected = collect_longterm_unpinnable_pages(&movable_page_list,
- nr_pages, pages);
- if (!collected)
- return 0;
- return migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages,
- pages);
- }
- #else
- static long check_and_migrate_movable_pages(unsigned long nr_pages,
- struct page **pages)
- {
- return 0;
- }
- #endif
- static long __gup_longterm_locked(struct mm_struct *mm,
- unsigned long start,
- unsigned long nr_pages,
- struct page **pages,
- struct vm_area_struct **vmas,
- unsigned int gup_flags)
- {
- unsigned int flags;
- long rc, nr_pinned_pages;
- if (!(gup_flags & FOLL_LONGTERM))
- return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
- NULL, gup_flags);
-
- if (WARN_ON(!(gup_flags & FOLL_PIN)))
- return -EINVAL;
- flags = memalloc_pin_save();
- do {
- nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages,
- pages, vmas, NULL,
- gup_flags);
- if (nr_pinned_pages <= 0) {
- rc = nr_pinned_pages;
- break;
- }
- rc = check_and_migrate_movable_pages(nr_pinned_pages, pages);
- } while (rc == -EAGAIN);
- memalloc_pin_restore(flags);
- return rc ? rc : nr_pinned_pages;
- }
- static bool is_valid_gup_flags(unsigned int gup_flags)
- {
-
- if (WARN_ON_ONCE(gup_flags & FOLL_PIN))
- return false;
-
- if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
- return false;
- return true;
- }
- #ifdef CONFIG_MMU
- static long __get_user_pages_remote(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
-
- if (gup_flags & FOLL_LONGTERM) {
- if (WARN_ON_ONCE(locked))
- return -EINVAL;
-
- return __gup_longterm_locked(mm, start, nr_pages, pages,
- vmas, gup_flags | FOLL_TOUCH |
- FOLL_REMOTE);
- }
- return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
- locked,
- gup_flags | FOLL_TOUCH | FOLL_REMOTE);
- }
- long get_user_pages_remote(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
- if (!is_valid_gup_flags(gup_flags))
- return -EINVAL;
- return __get_user_pages_remote(mm, start, nr_pages, gup_flags,
- pages, vmas, locked);
- }
- EXPORT_SYMBOL(get_user_pages_remote);
- #else
- long get_user_pages_remote(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
- return 0;
- }
- static long __get_user_pages_remote(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
- return 0;
- }
- #endif
- long get_user_pages(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
- {
- if (!is_valid_gup_flags(gup_flags))
- return -EINVAL;
- return __gup_longterm_locked(current->mm, start, nr_pages,
- pages, vmas, gup_flags | FOLL_TOUCH);
- }
- EXPORT_SYMBOL(get_user_pages);
- long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
- struct page **pages, unsigned int gup_flags)
- {
- struct mm_struct *mm = current->mm;
- int locked = 1;
- long ret;
-
- if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
- return -EINVAL;
- mmap_read_lock(mm);
- ret = __get_user_pages_locked(mm, start, nr_pages, pages, NULL,
- &locked, gup_flags | FOLL_TOUCH);
- if (locked)
- mmap_read_unlock(mm);
- return ret;
- }
- EXPORT_SYMBOL(get_user_pages_unlocked);
- #ifdef CONFIG_HAVE_FAST_GUP
- static void __maybe_unused undo_dev_pagemap(int *nr, int nr_start,
- unsigned int flags,
- struct page **pages)
- {
- while ((*nr) - nr_start) {
- struct page *page = pages[--(*nr)];
- ClearPageReferenced(page);
- if (flags & FOLL_PIN)
- unpin_user_page(page);
- else
- put_page(page);
- }
- }
- #ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
- static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- struct dev_pagemap *pgmap = NULL;
- int nr_start = *nr, ret = 0;
- pte_t *ptep, *ptem;
- ptem = ptep = pte_offset_map(&pmd, addr);
- do {
- pte_t pte = ptep_get_lockless(ptep);
- struct page *page;
- struct folio *folio;
- if (pte_protnone(pte) && !gup_can_follow_protnone(flags))
- goto pte_unmap;
- if (!pte_access_permitted(pte, flags & FOLL_WRITE))
- goto pte_unmap;
- if (pte_devmap(pte)) {
- if (unlikely(flags & FOLL_LONGTERM))
- goto pte_unmap;
- pgmap = get_dev_pagemap(pte_pfn(pte), pgmap);
- if (unlikely(!pgmap)) {
- undo_dev_pagemap(nr, nr_start, flags, pages);
- goto pte_unmap;
- }
- } else if (pte_special(pte))
- goto pte_unmap;
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
- page = pte_page(pte);
- folio = try_grab_folio(page, 1, flags);
- if (!folio)
- goto pte_unmap;
- if (unlikely(page_is_secretmem(page))) {
- gup_put_folio(folio, 1, flags);
- goto pte_unmap;
- }
- if (unlikely(pmd_val(pmd) != pmd_val(*pmdp)) ||
- unlikely(pte_val(pte) != pte_val(*ptep))) {
- gup_put_folio(folio, 1, flags);
- goto pte_unmap;
- }
- if (!pte_write(pte) && gup_must_unshare(flags, page)) {
- gup_put_folio(folio, 1, flags);
- goto pte_unmap;
- }
-
- if (flags & FOLL_PIN) {
- ret = arch_make_page_accessible(page);
- if (ret) {
- gup_put_folio(folio, 1, flags);
- goto pte_unmap;
- }
- }
- folio_set_referenced(folio);
- pages[*nr] = page;
- (*nr)++;
- } while (ptep++, addr += PAGE_SIZE, addr != end);
- ret = 1;
- pte_unmap:
- if (pgmap)
- put_dev_pagemap(pgmap);
- pte_unmap(ptem);
- return ret;
- }
- #else
- static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- return 0;
- }
- #endif
- #if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
- static int __gup_device_huge(unsigned long pfn, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- int nr_start = *nr;
- struct dev_pagemap *pgmap = NULL;
- do {
- struct page *page = pfn_to_page(pfn);
- pgmap = get_dev_pagemap(pfn, pgmap);
- if (unlikely(!pgmap)) {
- undo_dev_pagemap(nr, nr_start, flags, pages);
- break;
- }
- SetPageReferenced(page);
- pages[*nr] = page;
- if (unlikely(!try_grab_page(page, flags))) {
- undo_dev_pagemap(nr, nr_start, flags, pages);
- break;
- }
- (*nr)++;
- pfn++;
- } while (addr += PAGE_SIZE, addr != end);
- put_dev_pagemap(pgmap);
- return addr == end;
- }
- static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- unsigned long fault_pfn;
- int nr_start = *nr;
- fault_pfn = pmd_pfn(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
- if (!__gup_device_huge(fault_pfn, addr, end, flags, pages, nr))
- return 0;
- if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
- undo_dev_pagemap(nr, nr_start, flags, pages);
- return 0;
- }
- return 1;
- }
- static int __gup_device_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- unsigned long fault_pfn;
- int nr_start = *nr;
- fault_pfn = pud_pfn(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
- if (!__gup_device_huge(fault_pfn, addr, end, flags, pages, nr))
- return 0;
- if (unlikely(pud_val(orig) != pud_val(*pudp))) {
- undo_dev_pagemap(nr, nr_start, flags, pages);
- return 0;
- }
- return 1;
- }
- #else
- static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- BUILD_BUG();
- return 0;
- }
- static int __gup_device_huge_pud(pud_t pud, pud_t *pudp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- BUILD_BUG();
- return 0;
- }
- #endif
- static int record_subpages(struct page *page, unsigned long addr,
- unsigned long end, struct page **pages)
- {
- int nr;
- for (nr = 0; addr != end; nr++, addr += PAGE_SIZE)
- pages[nr] = nth_page(page, nr);
- return nr;
- }
- #ifdef CONFIG_ARCH_HAS_HUGEPD
- static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
- unsigned long sz)
- {
- unsigned long __boundary = (addr + sz) & ~(sz-1);
- return (__boundary - 1 < end - 1) ? __boundary : end;
- }
- static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- unsigned long pte_end;
- struct page *page;
- struct folio *folio;
- pte_t pte;
- int refs;
- pte_end = (addr + sz) & ~(sz-1);
- if (pte_end < end)
- end = pte_end;
- pte = huge_ptep_get(ptep);
- if (!pte_access_permitted(pte, flags & FOLL_WRITE))
- return 0;
-
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
- page = nth_page(pte_page(pte), (addr & (sz - 1)) >> PAGE_SHIFT);
- refs = record_subpages(page, addr, end, pages + *nr);
- folio = try_grab_folio(page, refs, flags);
- if (!folio)
- return 0;
- if (unlikely(pte_val(pte) != pte_val(*ptep))) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- if (!pte_write(pte) && gup_must_unshare(flags, &folio->page)) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- *nr += refs;
- folio_set_referenced(folio);
- return 1;
- }
- static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
- unsigned int pdshift, unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- pte_t *ptep;
- unsigned long sz = 1UL << hugepd_shift(hugepd);
- unsigned long next;
- ptep = hugepte_offset(hugepd, addr, pdshift);
- do {
- next = hugepte_addr_end(addr, end, sz);
- if (!gup_hugepte(ptep, sz, addr, end, flags, pages, nr))
- return 0;
- } while (ptep++, addr = next, addr != end);
- return 1;
- }
- #else
- static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
- unsigned int pdshift, unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- return 0;
- }
- #endif
- static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- struct page *page;
- struct folio *folio;
- int refs;
- if (!pmd_access_permitted(orig, flags & FOLL_WRITE))
- return 0;
- if (pmd_devmap(orig)) {
- if (unlikely(flags & FOLL_LONGTERM))
- return 0;
- return __gup_device_huge_pmd(orig, pmdp, addr, end, flags,
- pages, nr);
- }
- page = nth_page(pmd_page(orig), (addr & ~PMD_MASK) >> PAGE_SHIFT);
- refs = record_subpages(page, addr, end, pages + *nr);
- folio = try_grab_folio(page, refs, flags);
- if (!folio)
- return 0;
- if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- if (!pmd_write(orig) && gup_must_unshare(flags, &folio->page)) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- *nr += refs;
- folio_set_referenced(folio);
- return 1;
- }
- static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- struct page *page;
- struct folio *folio;
- int refs;
- if (!pud_access_permitted(orig, flags & FOLL_WRITE))
- return 0;
- if (pud_devmap(orig)) {
- if (unlikely(flags & FOLL_LONGTERM))
- return 0;
- return __gup_device_huge_pud(orig, pudp, addr, end, flags,
- pages, nr);
- }
- page = nth_page(pud_page(orig), (addr & ~PUD_MASK) >> PAGE_SHIFT);
- refs = record_subpages(page, addr, end, pages + *nr);
- folio = try_grab_folio(page, refs, flags);
- if (!folio)
- return 0;
- if (unlikely(pud_val(orig) != pud_val(*pudp))) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- if (!pud_write(orig) && gup_must_unshare(flags, &folio->page)) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- *nr += refs;
- folio_set_referenced(folio);
- return 1;
- }
- static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
- unsigned long end, unsigned int flags,
- struct page **pages, int *nr)
- {
- int refs;
- struct page *page;
- struct folio *folio;
- if (!pgd_access_permitted(orig, flags & FOLL_WRITE))
- return 0;
- BUILD_BUG_ON(pgd_devmap(orig));
- page = nth_page(pgd_page(orig), (addr & ~PGDIR_MASK) >> PAGE_SHIFT);
- refs = record_subpages(page, addr, end, pages + *nr);
- folio = try_grab_folio(page, refs, flags);
- if (!folio)
- return 0;
- if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) {
- gup_put_folio(folio, refs, flags);
- return 0;
- }
- *nr += refs;
- folio_set_referenced(folio);
- return 1;
- }
- static int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
- {
- unsigned long next;
- pmd_t *pmdp;
- pmdp = pmd_offset_lockless(pudp, pud, addr);
- do {
- pmd_t pmd = READ_ONCE(*pmdp);
- next = pmd_addr_end(addr, end);
- if (!pmd_present(pmd))
- return 0;
- if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) ||
- pmd_devmap(pmd))) {
- if (pmd_protnone(pmd) &&
- !gup_can_follow_protnone(flags))
- return 0;
- if (!gup_huge_pmd(pmd, pmdp, addr, next, flags,
- pages, nr))
- return 0;
- } else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) {
-
- if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr,
- PMD_SHIFT, next, flags, pages, nr))
- return 0;
- } else if (!gup_pte_range(pmd, pmdp, addr, next, flags, pages, nr))
- return 0;
- } while (pmdp++, addr = next, addr != end);
- return 1;
- }
- static int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
- {
- unsigned long next;
- pud_t *pudp;
- pudp = pud_offset_lockless(p4dp, p4d, addr);
- do {
- pud_t pud = READ_ONCE(*pudp);
- next = pud_addr_end(addr, end);
- if (unlikely(!pud_present(pud)))
- return 0;
- if (unlikely(pud_huge(pud) || pud_devmap(pud))) {
- if (!gup_huge_pud(pud, pudp, addr, next, flags,
- pages, nr))
- return 0;
- } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) {
- if (!gup_huge_pd(__hugepd(pud_val(pud)), addr,
- PUD_SHIFT, next, flags, pages, nr))
- return 0;
- } else if (!gup_pmd_range(pudp, pud, addr, next, flags, pages, nr))
- return 0;
- } while (pudp++, addr = next, addr != end);
- return 1;
- }
- static int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
- {
- unsigned long next;
- p4d_t *p4dp;
- p4dp = p4d_offset_lockless(pgdp, pgd, addr);
- do {
- p4d_t p4d = READ_ONCE(*p4dp);
- next = p4d_addr_end(addr, end);
- if (p4d_none(p4d))
- return 0;
- BUILD_BUG_ON(p4d_huge(p4d));
- if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) {
- if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr,
- P4D_SHIFT, next, flags, pages, nr))
- return 0;
- } else if (!gup_pud_range(p4dp, p4d, addr, next, flags, pages, nr))
- return 0;
- } while (p4dp++, addr = next, addr != end);
- return 1;
- }
- static void gup_pgd_range(unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
- {
- unsigned long next;
- pgd_t *pgdp;
- pgdp = pgd_offset(current->mm, addr);
- do {
- pgd_t pgd = READ_ONCE(*pgdp);
- next = pgd_addr_end(addr, end);
- if (pgd_none(pgd))
- return;
- if (unlikely(pgd_huge(pgd))) {
- if (!gup_huge_pgd(pgd, pgdp, addr, next, flags,
- pages, nr))
- return;
- } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) {
- if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
- PGDIR_SHIFT, next, flags, pages, nr))
- return;
- } else if (!gup_p4d_range(pgdp, pgd, addr, next, flags, pages, nr))
- return;
- } while (pgdp++, addr = next, addr != end);
- }
- #else
- static inline void gup_pgd_range(unsigned long addr, unsigned long end,
- unsigned int flags, struct page **pages, int *nr)
- {
- }
- #endif
- #ifndef gup_fast_permitted
- static bool gup_fast_permitted(unsigned long start, unsigned long end)
- {
- return true;
- }
- #endif
- static int __gup_longterm_unlocked(unsigned long start, int nr_pages,
- unsigned int gup_flags, struct page **pages)
- {
- int ret;
-
- if (gup_flags & FOLL_LONGTERM) {
- mmap_read_lock(current->mm);
- ret = __gup_longterm_locked(current->mm,
- start, nr_pages,
- pages, NULL, gup_flags);
- mmap_read_unlock(current->mm);
- } else {
- ret = get_user_pages_unlocked(start, nr_pages,
- pages, gup_flags);
- }
- return ret;
- }
- static unsigned long lockless_pages_from_mm(unsigned long start,
- unsigned long end,
- unsigned int gup_flags,
- struct page **pages)
- {
- unsigned long flags;
- int nr_pinned = 0;
- unsigned seq;
- if (!IS_ENABLED(CONFIG_HAVE_FAST_GUP) ||
- !gup_fast_permitted(start, end))
- return 0;
- if (gup_flags & FOLL_PIN) {
- seq = raw_read_seqcount(¤t->mm->write_protect_seq);
- if (seq & 1)
- return 0;
- }
-
- local_irq_save(flags);
- gup_pgd_range(start, end, gup_flags, pages, &nr_pinned);
- local_irq_restore(flags);
-
- if (gup_flags & FOLL_PIN) {
- if (read_seqcount_retry(¤t->mm->write_protect_seq, seq)) {
- unpin_user_pages_lockless(pages, nr_pinned);
- return 0;
- } else {
- sanity_check_pinned_pages(pages, nr_pinned);
- }
- }
- return nr_pinned;
- }
- static int internal_get_user_pages_fast(unsigned long start,
- unsigned long nr_pages,
- unsigned int gup_flags,
- struct page **pages)
- {
- unsigned long len, end;
- unsigned long nr_pinned;
- int ret;
- if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM |
- FOLL_FORCE | FOLL_PIN | FOLL_GET |
- FOLL_FAST_ONLY | FOLL_NOFAULT)))
- return -EINVAL;
- if (gup_flags & FOLL_PIN)
- mm_set_has_pinned_flag(¤t->mm->flags);
- if (!(gup_flags & FOLL_FAST_ONLY))
- might_lock_read(¤t->mm->mmap_lock);
- start = untagged_addr(start) & PAGE_MASK;
- len = nr_pages << PAGE_SHIFT;
- if (check_add_overflow(start, len, &end))
- return 0;
- if (unlikely(!access_ok((void __user *)start, len)))
- return -EFAULT;
- nr_pinned = lockless_pages_from_mm(start, end, gup_flags, pages);
- if (nr_pinned == nr_pages || gup_flags & FOLL_FAST_ONLY)
- return nr_pinned;
-
- start += nr_pinned << PAGE_SHIFT;
- pages += nr_pinned;
- ret = __gup_longterm_unlocked(start, nr_pages - nr_pinned, gup_flags,
- pages);
- if (ret < 0) {
-
- if (nr_pinned)
- return nr_pinned;
- return ret;
- }
- return ret + nr_pinned;
- }
- int get_user_pages_fast_only(unsigned long start, int nr_pages,
- unsigned int gup_flags, struct page **pages)
- {
- int nr_pinned;
-
- gup_flags |= FOLL_GET | FOLL_FAST_ONLY;
- nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
- pages);
-
- if (nr_pinned < 0)
- nr_pinned = 0;
- return nr_pinned;
- }
- EXPORT_SYMBOL_GPL(get_user_pages_fast_only);
- int get_user_pages_fast(unsigned long start, int nr_pages,
- unsigned int gup_flags, struct page **pages)
- {
- if (!is_valid_gup_flags(gup_flags))
- return -EINVAL;
-
- gup_flags |= FOLL_GET;
- return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
- }
- EXPORT_SYMBOL_GPL(get_user_pages_fast);
- int pin_user_pages_fast(unsigned long start, int nr_pages,
- unsigned int gup_flags, struct page **pages)
- {
-
- if (WARN_ON_ONCE(gup_flags & FOLL_GET))
- return -EINVAL;
- if (WARN_ON_ONCE(!pages))
- return -EINVAL;
- gup_flags |= FOLL_PIN;
- return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
- }
- EXPORT_SYMBOL_GPL(pin_user_pages_fast);
- int pin_user_pages_fast_only(unsigned long start, int nr_pages,
- unsigned int gup_flags, struct page **pages)
- {
- int nr_pinned;
-
- if (WARN_ON_ONCE(gup_flags & FOLL_GET))
- return 0;
- if (WARN_ON_ONCE(!pages))
- return 0;
-
- gup_flags |= (FOLL_PIN | FOLL_FAST_ONLY);
- nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
- pages);
-
- if (nr_pinned < 0)
- nr_pinned = 0;
- return nr_pinned;
- }
- EXPORT_SYMBOL_GPL(pin_user_pages_fast_only);
- long pin_user_pages_remote(struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas, int *locked)
- {
-
- if (WARN_ON_ONCE(gup_flags & FOLL_GET))
- return -EINVAL;
- if (WARN_ON_ONCE(!pages))
- return -EINVAL;
- gup_flags |= FOLL_PIN;
- return __get_user_pages_remote(mm, start, nr_pages, gup_flags,
- pages, vmas, locked);
- }
- EXPORT_SYMBOL(pin_user_pages_remote);
- long pin_user_pages(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
- {
-
- if (WARN_ON_ONCE(gup_flags & FOLL_GET))
- return -EINVAL;
- if (WARN_ON_ONCE(!pages))
- return -EINVAL;
- gup_flags |= FOLL_PIN;
- return __gup_longterm_locked(current->mm, start, nr_pages,
- pages, vmas, gup_flags);
- }
- EXPORT_SYMBOL(pin_user_pages);
- long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
- struct page **pages, unsigned int gup_flags)
- {
-
- if (WARN_ON_ONCE(gup_flags & FOLL_GET))
- return -EINVAL;
- if (WARN_ON_ONCE(!pages))
- return -EINVAL;
- gup_flags |= FOLL_PIN;
- return get_user_pages_unlocked(start, nr_pages, pages, gup_flags);
- }
- EXPORT_SYMBOL(pin_user_pages_unlocked);
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