linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  linux/mm/mincore.c

 *

 * Copyright (C) 1994-2006  Linus Torvalds

 */

​

/*

 * The mincore() system call.

 */

#include <linux/pagemap.h>

#include <linux/gfp.h>

#include <linux/mm.h>

#include <linux/mman.h>

#include <linux/syscalls.h>

#include <linux/swap.h>

#include <linux/swapops.h>

#include <linux/shmem_fs.h>

#include <linux/hugetlb.h>

​

#include <linux/uaccess.h>

#include <asm/pgtable.h>

​

static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,

            unsigned long end, struct mm_walk *walk)

{

#ifdef CONFIG_HUGETLB_PAGE

    unsigned char present;

    unsigned char *vec = walk->private;

​

    /*

     * Hugepages under user process are always in RAM and never

     * swapped out, but theoretically it needs to be checked.

     */

    present = pte && !huge_pte_none(huge_ptep_get(pte));

    for (; addr != end; vec++, addr += PAGE_SIZE)

        *vec = present;

    walk->private = vec;

#else

    BUG();

#endif

    return 0;

}

​

/*

 * Later we can get more picky about what "in core" means precisely.

 * For now, simply check to see if the page is in the page cache,

 * and is up to date; i.e. that no page-in operation would be required

 * at this time if an application were to map and access this page.

 */

static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)

{

    unsigned char present = 0;

    struct page *page;

​

    /*

     * When tmpfs swaps out a page from a file, any process mapping that

     * file will not get a swp_entry_t in its pte, but rather it is like

     * any other file mapping (ie. marked !present and faulted in with

     * tmpfs's .fault). So swapped out tmpfs mappings are tested here.

     */

#ifdef CONFIG_SWAP

    if (shmem_mapping(mapping)) {