// SPDX-License-Identifier: GPL-2.0-or-later
/* nommu.c: mmu-less memory info files
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>
#include <asm/tlb.h>
#include <asm/div64.h>
#include "internal.h"

/*
 * display a single region to a sequenced file
 */
static int nommu_region_show(struct seq_file *m, struct vm_region *region)
{
        unsigned long ino = 0;
        struct file *file;
        dev_t dev = 0;
        int flags;

        flags = region->vm_flags;
        file = region->vm_file;

        if (file) {
                struct inode *inode = file_inode(region->vm_file);
                dev = inode->i_sb->s_dev;
                ino = inode->i_ino;
        }

        seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
        seq_printf(m,
                   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
                   region->vm_start,
                   region->vm_end,
                   flags & VM_READ ? 'r' : '-',
                   flags & VM_WRITE ? 'w' : '-',
                   flags & VM_EXEC ? 'x' : '-',
                   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
                   ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
                   MAJOR(dev), MINOR(dev), ino);

        if (file) {
                seq_pad(m, ' ');
                seq_path(m, file_user_path(file), "");
        }

        seq_putc(m, '\n');
        return 0;
}

/*
 * display a list of all the REGIONs the kernel knows about
 * - nommu kernels have a single flat list
 */
static int nommu_region_list_show(struct seq_file *m, void *_p)
{
        struct rb_node *p = _p;

        return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
}

static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
{
        struct rb_node *p;
        loff_t pos = *_pos;

        down_read(&nommu_region_sem);

        for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
                if (pos-- == 0)
                        return p;
        return NULL;
}

static void nommu_region_list_stop(struct seq_file *m, void *v)
{
        up_read(&nommu_region_sem);
}

static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
{
        (*pos)++;
        return rb_next((struct rb_node *) v);
}

static const struct seq_operations proc_nommu_region_list_seqop = {
        .start  = nommu_region_list_start,
        .next   = nommu_region_list_next,
        .stop   = nommu_region_list_stop,
        .show   = nommu_region_list_show
};

static int __init proc_nommu_init(void)
{
        proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop);
        return 0;
}

fs_initcall(proc_nommu_init);