1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /* nommu.c: mmu-less memory info files
3   *
4   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
5   * Written by David Howells (dhowells@redhat.com)
6   */
7  
8  #include <linux/init.h>
9  #include <linux/module.h>
10  #include <linux/errno.h>
11  #include <linux/time.h>
12  #include <linux/kernel.h>
13  #include <linux/string.h>
14  #include <linux/mman.h>
15  #include <linux/proc_fs.h>
16  #include <linux/mm.h>
17  #include <linux/mmzone.h>
18  #include <linux/pagemap.h>
19  #include <linux/swap.h>
20  #include <linux/smp.h>
21  #include <linux/seq_file.h>
22  #include <linux/hugetlb.h>
23  #include <linux/vmalloc.h>
24  #include <asm/tlb.h>
25  #include <asm/div64.h>
26  #include "internal.h"
27  
28  /*
29   * display a single region to a sequenced file
30   */
nommu_region_show(struct seq_file * m,struct vm_region * region)31  static int nommu_region_show(struct seq_file *m, struct vm_region *region)
32  {
33  	unsigned long ino = 0;
34  	struct file *file;
35  	dev_t dev = 0;
36  	int flags;
37  
38  	flags = region->vm_flags;
39  	file = region->vm_file;
40  
41  	if (file) {
42  		struct inode *inode = file_inode(region->vm_file);
43  		dev = inode->i_sb->s_dev;
44  		ino = inode->i_ino;
45  	}
46  
47  	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
48  	seq_printf(m,
49  		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
50  		   region->vm_start,
51  		   region->vm_end,
52  		   flags & VM_READ ? 'r' : '-',
53  		   flags & VM_WRITE ? 'w' : '-',
54  		   flags & VM_EXEC ? 'x' : '-',
55  		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
56  		   ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
57  		   MAJOR(dev), MINOR(dev), ino);
58  
59  	if (file) {
60  		seq_pad(m, ' ');
61  		seq_path(m, file_user_path(file), "");
62  	}
63  
64  	seq_putc(m, '\n');
65  	return 0;
66  }
67  
68  /*
69   * display a list of all the REGIONs the kernel knows about
70   * - nommu kernels have a single flat list
71   */
nommu_region_list_show(struct seq_file * m,void * _p)72  static int nommu_region_list_show(struct seq_file *m, void *_p)
73  {
74  	struct rb_node *p = _p;
75  
76  	return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
77  }
78  
nommu_region_list_start(struct seq_file * m,loff_t * _pos)79  static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
80  {
81  	struct rb_node *p;
82  	loff_t pos = *_pos;
83  
84  	down_read(&nommu_region_sem);
85  
86  	for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
87  		if (pos-- == 0)
88  			return p;
89  	return NULL;
90  }
91  
nommu_region_list_stop(struct seq_file * m,void * v)92  static void nommu_region_list_stop(struct seq_file *m, void *v)
93  {
94  	up_read(&nommu_region_sem);
95  }
96  
nommu_region_list_next(struct seq_file * m,void * v,loff_t * pos)97  static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
98  {
99  	(*pos)++;
100  	return rb_next((struct rb_node *) v);
101  }
102  
103  static const struct seq_operations proc_nommu_region_list_seqop = {
104  	.start	= nommu_region_list_start,
105  	.next	= nommu_region_list_next,
106  	.stop	= nommu_region_list_stop,
107  	.show	= nommu_region_list_show
108  };
109  
proc_nommu_init(void)110  static int __init proc_nommu_init(void)
111  {
112  	proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop);
113  	return 0;
114  }
115  
116  fs_initcall(proc_nommu_init);
117