// 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 <linux/uaccess.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_file_path(m, file, "");

  	}
  
  	seq_putc(m, '
  ');
  	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);