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_debugfs_show(struct seq_file * file,void * iter)29 static 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(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 
51 DEFINE_SHOW_ATTRIBUTE(asids_debugfs);
52 
asids_debugfs_init(void)53 static int __init asids_debugfs_init(void)
54 {
55 	debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir, NULL,
56 			    &asids_debugfs_fops);
57 	return 0;
58 }
59 device_initcall(asids_debugfs_init);
60