xref: /openbmc/linux/arch/x86/kernel/kdebugfs.c (revision 19503d38)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Architecture specific debugfs files
4  *
5  * Copyright (C) 2007, Intel Corp.
6  *	Huang Ying <ying.huang@intel.com>
7  */
8 #include <linux/debugfs.h>
9 #include <linux/uaccess.h>
10 #include <linux/export.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <linux/stat.h>
14 #include <linux/io.h>
15 #include <linux/mm.h>
16 
17 #include <asm/setup.h>
18 
19 struct dentry *arch_debugfs_dir;
20 EXPORT_SYMBOL(arch_debugfs_dir);
21 
22 #ifdef CONFIG_DEBUG_BOOT_PARAMS
23 struct setup_data_node {
24 	u64 paddr;
25 	u32 type;
26 	u32 len;
27 };
28 
setup_data_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)29 static ssize_t setup_data_read(struct file *file, char __user *user_buf,
30 			       size_t count, loff_t *ppos)
31 {
32 	struct setup_data_node *node = file->private_data;
33 	unsigned long remain;
34 	loff_t pos = *ppos;
35 	void *p;
36 	u64 pa;
37 
38 	if (pos < 0)
39 		return -EINVAL;
40 
41 	if (pos >= node->len)
42 		return 0;
43 
44 	if (count > node->len - pos)
45 		count = node->len - pos;
46 
47 	pa = node->paddr + pos;
48 
49 	/* Is it direct data or invalid indirect one? */
50 	if (!(node->type & SETUP_INDIRECT) || node->type == SETUP_INDIRECT)
51 		pa += sizeof(struct setup_data);
52 
53 	p = memremap(pa, count, MEMREMAP_WB);
54 	if (!p)
55 		return -ENOMEM;
56 
57 	remain = copy_to_user(user_buf, p, count);
58 
59 	memunmap(p);
60 
61 	if (remain)
62 		return -EFAULT;
63 
64 	*ppos = pos + count;
65 
66 	return count;
67 }
68 
69 static const struct file_operations fops_setup_data = {
70 	.read		= setup_data_read,
71 	.open		= simple_open,
72 	.llseek		= default_llseek,
73 };
74 
75 static void __init
create_setup_data_node(struct dentry * parent,int no,struct setup_data_node * node)76 create_setup_data_node(struct dentry *parent, int no,
77 		       struct setup_data_node *node)
78 {
79 	struct dentry *d;
80 	char buf[16];
81 
82 	sprintf(buf, "%d", no);
83 	d = debugfs_create_dir(buf, parent);
84 
85 	debugfs_create_x32("type", S_IRUGO, d, &node->type);
86 	debugfs_create_file("data", S_IRUGO, d, node, &fops_setup_data);
87 }
88 
create_setup_data_nodes(struct dentry * parent)89 static int __init create_setup_data_nodes(struct dentry *parent)
90 {
91 	struct setup_indirect *indirect;
92 	struct setup_data_node *node;
93 	struct setup_data *data;
94 	u64 pa_data, pa_next;
95 	struct dentry *d;
96 	int error;
97 	u32 len;
98 	int no = 0;
99 
100 	d = debugfs_create_dir("setup_data", parent);
101 
102 	pa_data = boot_params.hdr.setup_data;
103 
104 	while (pa_data) {
105 		node = kmalloc(sizeof(*node), GFP_KERNEL);
106 		if (!node) {
107 			error = -ENOMEM;
108 			goto err_dir;
109 		}
110 
111 		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
112 		if (!data) {
113 			kfree(node);
114 			error = -ENOMEM;
115 			goto err_dir;
116 		}
117 		pa_next = data->next;
118 
119 		if (data->type == SETUP_INDIRECT) {
120 			len = sizeof(*data) + data->len;
121 			memunmap(data);
122 			data = memremap(pa_data, len, MEMREMAP_WB);
123 			if (!data) {
124 				kfree(node);
125 				error = -ENOMEM;
126 				goto err_dir;
127 			}
128 
129 			indirect = (struct setup_indirect *)data->data;
130 
131 			if (indirect->type != SETUP_INDIRECT) {
132 				node->paddr = indirect->addr;
133 				node->type  = indirect->type;
134 				node->len   = indirect->len;
135 			} else {
136 				node->paddr = pa_data;
137 				node->type  = data->type;
138 				node->len   = data->len;
139 			}
140 		} else {
141 			node->paddr = pa_data;
142 			node->type  = data->type;
143 			node->len   = data->len;
144 		}
145 
146 		create_setup_data_node(d, no, node);
147 		pa_data = pa_next;
148 
149 		memunmap(data);
150 		no++;
151 	}
152 
153 	return 0;
154 
155 err_dir:
156 	debugfs_remove_recursive(d);
157 	return error;
158 }
159 
160 static struct debugfs_blob_wrapper boot_params_blob = {
161 	.data		= &boot_params,
162 	.size		= sizeof(boot_params),
163 };
164 
boot_params_kdebugfs_init(void)165 static int __init boot_params_kdebugfs_init(void)
166 {
167 	struct dentry *dbp;
168 	int error;
169 
170 	dbp = debugfs_create_dir("boot_params", arch_debugfs_dir);
171 
172 	debugfs_create_x16("version", S_IRUGO, dbp, &boot_params.hdr.version);
173 	debugfs_create_blob("data", S_IRUGO, dbp, &boot_params_blob);
174 
175 	error = create_setup_data_nodes(dbp);
176 	if (error)
177 		debugfs_remove_recursive(dbp);
178 
179 	return error;
180 }
181 #endif /* CONFIG_DEBUG_BOOT_PARAMS */
182 
arch_kdebugfs_init(void)183 static int __init arch_kdebugfs_init(void)
184 {
185 	int error = 0;
186 
187 	arch_debugfs_dir = debugfs_create_dir("x86", NULL);
188 
189 #ifdef CONFIG_DEBUG_BOOT_PARAMS
190 	error = boot_params_kdebugfs_init();
191 #endif
192 
193 	return error;
194 }
195 arch_initcall(arch_kdebugfs_init);
196