xref: /kernel/linux/linux-5.10/fs/proc/nommu.c (revision 8c2ecf20) 
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 <linux/uaccess.h>
25#include <asm/tlb.h>
26#include <asm/div64.h>
27#include "internal.h"
28
29/*
30 * display a single region to a sequenced file
31 */
32static int nommu_region_show(struct seq_file *m, struct vm_region *region)
33{
34	unsigned long ino = 0;
35	struct file *file;
36	dev_t dev = 0;
37	int flags;
38
39	flags = region->vm_flags;
40	file = region->vm_file;
41
42	if (file) {
43		struct inode *inode = file_inode(region->vm_file);
44		dev = inode->i_sb->s_dev;
45		ino = inode->i_ino;
46	}
47
48	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
49	seq_printf(m,
50		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
51		   region->vm_start,
52		   region->vm_end,
53		   flags & VM_READ ? 'r' : '-',
54		   flags & VM_WRITE ? 'w' : '-',
55		   flags & VM_EXEC ? 'x' : '-',
56		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
57		   ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
58		   MAJOR(dev), MINOR(dev), ino);
59
60	if (file) {
61		seq_pad(m, ' ');
62		seq_file_path(m, file, "");
63	}
64
65	seq_putc(m, '\n');
66	return 0;
67}
68
69/*
70 * display a list of all the REGIONs the kernel knows about
71 * - nommu kernels have a single flat list
72 */
73static int nommu_region_list_show(struct seq_file *m, void *_p)
74{
75	struct rb_node *p = _p;
76
77	return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
78}
79
80static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
81{
82	struct rb_node *p;
83	loff_t pos = *_pos;
84
85	down_read(&nommu_region_sem);
86
87	for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
88		if (pos-- == 0)
89			return p;
90	return NULL;
91}
92
93static void nommu_region_list_stop(struct seq_file *m, void *v)
94{
95	up_read(&nommu_region_sem);
96}
97
98static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
99{
100	(*pos)++;
101	return rb_next((struct rb_node *) v);
102}
103
104static const struct seq_operations proc_nommu_region_list_seqop = {
105	.start	= nommu_region_list_start,
106	.next	= nommu_region_list_next,
107	.stop	= nommu_region_list_stop,
108	.show	= nommu_region_list_show
109};
110
111static int __init proc_nommu_init(void)
112{
113	proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop);
114	return 0;
115}
116
117fs_initcall(proc_nommu_init);
118