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