linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  mm/mprotect.c

 *

 *  (C) Copyright 1994 Linus Torvalds

 *  (C) Copyright 2002 Christoph Hellwig

 *

 *  Address space accounting code   <alan@lxorguk.ukuu.org.uk>

 *  (C) Copyright 2002 Red Hat Inc, All Rights Reserved

 */

​

#include <linux/mm.h>

#include <linux/hugetlb.h>

#include <linux/shm.h>

#include <linux/mman.h>

#include <linux/fs.h>

#include <linux/highmem.h>

#include <linux/security.h>

#include <linux/mempolicy.h>

#include <linux/personality.h>

#include <linux/syscalls.h>

#include <linux/swap.h>

#include <linux/swapops.h>

#include <linux/mmu_notifier.h>

#include <linux/migrate.h>

#include <linux/perf_event.h>

#include <linux/pkeys.h>

#include <linux/ksm.h>

#include <linux/uaccess.h>

#include <linux/mm_inline.h>

#include <asm/pgtable.h>

#include <asm/cacheflush.h>

#include <asm/mmu_context.h>

#include <asm/tlbflush.h>

​

#include "internal.h"

​

static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,

        unsigned long addr, unsigned long end, pgprot_t newprot,

        int dirty_accountable, int prot_numa)

{

    struct mm_struct *mm = vma->vm_mm;

    pte_t *pte, oldpte;

    spinlock_t *ptl;

    unsigned long pages = 0;

    int target_node = NUMA_NO_NODE;

​

    /*

     * Can be called with only the mmap_sem for reading by

     * prot_numa so we must check the pmd isn't constantly

     * changing from under us from pmd_none to pmd_trans_huge

     * and/or the other way around.

     */

    if (pmd_trans_unstable(pmd))

        return 0;

​

    /*

     * The pmd points to a regular pte so the pmd can't change

     * from under us even if the mmap_sem is only hold for

     * reading.

     */

    pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);

​

    /* Get target node for single threaded private VMAs */

    if (prot_numa && !(vma->vm_flags & VM_SHARED) &&

        atomic_read(&vma->vm_mm->mm_users) == 1)

        target_node = numa_node_id();

​

    flush_tlb_batched_pending(vma->vm_mm);

    arch_enter_lazy_mmu_mode();

    do {

        oldpte = *pte;

        if (pte_present(oldpte)) {

            pte_t ptent;

            bool preserve_write = prot_numa && pte_write(oldpte);

​

            /*

             * Avoid trapping faults against the zero or KSM

             * pages. See similar comment in change_huge_pmd.

             */

            if (prot_numa) {

                struct page *page;

​

                page = vm_normal_page(vma, addr, oldpte);

                if (!page || PageKsm(page))

                    continue;

​

                /* Also skip shared copy-on-write pages */

                if (is_cow_mapping(vma->vm_flags) &&

                    page_mapcount(page) != 1)

                    continue;

​