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
29static int asids_debugfs_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(m: file, fmt: "%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
51DEFINE_SHOW_ATTRIBUTE(asids_debugfs);
52
53static int __init asids_debugfs_init(void)
54{
55 debugfs_create_file(name: "asids", S_IRUSR, parent: arch_debugfs_dir, NULL,
56 fops: &asids_debugfs_fops);
57 return 0;
58}
59device_initcall(asids_debugfs_init);
60

source code of linux/arch/sh/mm/asids-debugfs.c