1 /*
2 * debugfs ops for process ASIDs
3 *
4 * Copyright (C) 2000, 2001 Paolo Alberelli
5 * Copyright (C) 2003 - 2008 Paul Mundt
6 * Copyright (C) 2003, 2004 Richard Curnow
7 *
8 * Provides a debugfs file that lists out the ASIDs currently associated
9 * with the processes.
10 *
11 * In the SH-5 case, if the DM.PC register is examined through the debug
12 * link, this shows ASID + PC. To make use of this, the PID->ASID
13 * relationship needs to be known. This is primarily for debugging.
14 *
15 * This file is subject to the terms and conditions of the GNU General Public
16 * License. See the file "COPYING" in the main directory of this archive
17 * for more details.
18 */
19 #include <linux/init.h>
20 #include <linux/debugfs.h>
21 #include <linux/seq_file.h>
22 #include <linux/spinlock.h>
23 #include <linux/sched/signal.h>
24 #include <linux/sched/task.h>
25
26 #include <asm/processor.h>
27 #include <asm/mmu_context.h>
28
asids_seq_show(struct seq_file * file,void * iter)29 static int asids_seq_show(struct seq_file *file, void *iter)
30 {
31 struct task_struct *p;
32
33 read_lock(&tasklist_lock);
34
35 for_each_process(p) {
36 int pid = p->pid;
37
38 if (unlikely(!pid))
39 continue;
40
41 if (p->mm)
42 seq_printf(file, "%5d : %04lx\n", pid,
43 cpu_asid(smp_processor_id(), p->mm));
44 }
45
46 read_unlock(&tasklist_lock);
47
48 return 0;
49 }
50
asids_debugfs_open(struct inode * inode,struct file * file)51 static int asids_debugfs_open(struct inode *inode, struct file *file)
52 {
53 return single_open(file, asids_seq_show, inode->i_private);
54 }
55
56 static const struct file_operations asids_debugfs_fops = {
57 .owner = THIS_MODULE,
58 .open = asids_debugfs_open,
59 .read = seq_read,
60 .llseek = seq_lseek,
61 .release = single_release,
62 };
63
asids_debugfs_init(void)64 static int __init asids_debugfs_init(void)
65 {
66 struct dentry *asids_dentry;
67
68 asids_dentry = debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir,
69 NULL, &asids_debugfs_fops);
70 if (!asids_dentry)
71 return -ENOMEM;
72
73 return PTR_ERR_OR_ZERO(asids_dentry);
74 }
75 device_initcall(asids_debugfs_init);
76
