fs/proc/nommu.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /* nommu.c: mmu-less memory info files
0003  *
0004  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
0005  * Written by David Howells (dhowells@redhat.com)
0006  */
0007
0008 #include <linux/init.h>
0009 #include <linux/module.h>
0010 #include <linux/errno.h>
0011 #include <linux/time.h>
0012 #include <linux/kernel.h>
0013 #include <linux/string.h>
0014 #include <linux/mman.h>
0015 #include <linux/proc_fs.h>
0016 #include <linux/mm.h>
0017 #include <linux/mmzone.h>
0018 #include <linux/pagemap.h>
0019 #include <linux/swap.h>
0020 #include <linux/smp.h>
0021 #include <linux/seq_file.h>
0022 #include <linux/hugetlb.h>
0023 #include <linux/vmalloc.h>
0024 #include <asm/tlb.h>
0025 #include <asm/div64.h>
0026 #include "internal.h"
0027
0028 /*
0029  * display a single region to a sequenced file
0030  */
0031 static int nommu_region_show(struct seq_file *m, struct vm_region *region)
0032 {
0033     unsigned long ino = 0;
0034     struct file *file;
0035     dev_t dev = 0;
0036     int flags;
0037
0038     flags = region->vm_flags;
0039     file = region->vm_file;
0040
0041     if (file) {
0042         struct inode *inode = file_inode(region->vm_file);
0043         dev = inode->i_sb->s_dev;
0044         ino = inode->i_ino;
0045     }
0046
0047     seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
0048     seq_printf(m,
0049            "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
0050            region->vm_start,
0051            region->vm_end,
0052            flags & VM_READ ? 'r' : '-',
0053            flags & VM_WRITE ? 'w' : '-',
0054            flags & VM_EXEC ? 'x' : '-',
0055            flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
0056            ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
0057            MAJOR(dev), MINOR(dev), ino);
0058
0059     if (file) {
0060         seq_pad(m, ' ');
0061         seq_file_path(m, file, "");
0062     }
0063
0064     seq_putc(m, '\n');
0065     return 0;
0066 }
0067
0068 /*
0069  * display a list of all the REGIONs the kernel knows about
0070  * - nommu kernels have a single flat list
0071  */
0072 static int nommu_region_list_show(struct seq_file *m, void *_p)
0073 {
0074     struct rb_node *p = _p;
0075
0076     return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
0077 }
0078
0079 static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
0080 {
0081     struct rb_node *p;
0082     loff_t pos = *_pos;
0083
0084     down_read(&nommu_region_sem);
0085
0086     for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
0087         if (pos-- == 0)
0088             return p;
0089     return NULL;
0090 }
0091
0092 static void nommu_region_list_stop(struct seq_file *m, void *v)
0093 {
0094     up_read(&nommu_region_sem);
0095 }
0096
0097 static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
0098 {
0099     (*pos)++;
0100     return rb_next((struct rb_node *) v);
0101 }
0102
0103 static const struct seq_operations proc_nommu_region_list_seqop = {
0104     .start  = nommu_region_list_start,
0105     .next   = nommu_region_list_next,
0106     .stop   = nommu_region_list_stop,
0107     .show   = nommu_region_list_show
0108 };
0109
0110 static int __init proc_nommu_init(void)
0111 {
0112     proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop);
0113     return 0;
0114 }
0115
0116 fs_initcall(proc_nommu_init);