fs/proc/nommu.c

   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  */
  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  */
  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
  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
  92 static void nommu_region_list_stop(struct seq_file *m, void *v)
  93 {
  94         up_read(&nommu_region_sem);
  95 }
  96
  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
 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);