1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright 2018, Christophe Leroy CS S.I.
4  * <christophe.leroy@c-s.fr>
5  *
6  * This dumps the content of Segment Registers
7  */
8 
9 #include <asm/debugfs.h>
10 
11 static void seg_show(struct seq_file *m, int i)
12 {
13 	u32 val = mfsrin(i << 28);
14 
15 	seq_printf(m, "0x%01x0000000-0x%01xfffffff ", i, i);
16 	seq_printf(m, "Kern key %d ", (val >> 30) & 1);
17 	seq_printf(m, "User key %d ", (val >> 29) & 1);
18 	if (val & 0x80000000) {
19 		seq_printf(m, "Device 0x%03x", (val >> 20) & 0x1ff);
20 		seq_printf(m, "-0x%05x", val & 0xfffff);
21 	} else {
22 		if (val & 0x10000000)
23 			seq_puts(m, "No Exec ");
24 		seq_printf(m, "VSID 0x%06x", val & 0xffffff);
25 	}
26 	seq_puts(m, "\n");
27 }
28 
29 static int sr_show(struct seq_file *m, void *v)
30 {
31 	int i;
32 
33 	seq_puts(m, "---[ User Segments ]---\n");
34 	for (i = 0; i < TASK_SIZE >> 28; i++)
35 		seg_show(m, i);
36 
37 	seq_puts(m, "\n---[ Kernel Segments ]---\n");
38 	for (; i < 16; i++)
39 		seg_show(m, i);
40 
41 	return 0;
42 }
43 
44 static int sr_open(struct inode *inode, struct file *file)
45 {
46 	return single_open(file, sr_show, NULL);
47 }
48 
49 static const struct file_operations sr_fops = {
50 	.open		= sr_open,
51 	.read		= seq_read,
52 	.llseek		= seq_lseek,
53 	.release	= single_release,
54 };
55 
56 static int __init sr_init(void)
57 {
58 	struct dentry *debugfs_file;
59 
60 	debugfs_file = debugfs_create_file("segment_registers", 0400,
61 					   powerpc_debugfs_root, NULL, &sr_fops);
62 	return debugfs_file ? 0 : -ENOMEM;
63 }
64 device_initcall(sr_init);
65