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Commit | Line | Data |
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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
526b4af4 | 2 | /* |
5baa1be1 | 3 | * custom_method.c - debugfs interface for customizing ACPI control method |
526b4af4 TR |
4 | */ |
5 | ||
6 | #include <linux/init.h> | |
7 | #include <linux/module.h> | |
8 | #include <linux/kernel.h> | |
9 | #include <linux/uaccess.h> | |
10 | #include <linux/debugfs.h> | |
8b48463f | 11 | #include <linux/acpi.h> |
526b4af4 TR |
12 | |
13 | #include "internal.h" | |
14 | ||
15 | #define _COMPONENT ACPI_SYSTEM_COMPONENT | |
16 | ACPI_MODULE_NAME("custom_method"); | |
17 | MODULE_LICENSE("GPL"); | |
18 | ||
19 | static struct dentry *cm_dentry; | |
20 | ||
21 | /* /sys/kernel/debug/acpi/custom_method */ | |
22 | ||
23 | static ssize_t cm_write(struct file *file, const char __user * user_buf, | |
24 | size_t count, loff_t *ppos) | |
25 | { | |
26 | static char *buf; | |
27 | static u32 max_size; | |
28 | static u32 uncopied_bytes; | |
29 | ||
30 | struct acpi_table_header table; | |
31 | acpi_status status; | |
32 | ||
33 | if (!(*ppos)) { | |
34 | /* parse the table header to get the table length */ | |
35 | if (count <= sizeof(struct acpi_table_header)) | |
36 | return -EINVAL; | |
37 | if (copy_from_user(&table, user_buf, | |
38 | sizeof(struct acpi_table_header))) | |
39 | return -EFAULT; | |
40 | uncopied_bytes = max_size = table.length; | |
41 | buf = kzalloc(max_size, GFP_KERNEL); | |
42 | if (!buf) | |
43 | return -ENOMEM; | |
44 | } | |
45 | ||
46 | if (buf == NULL) | |
47 | return -EINVAL; | |
48 | ||
49 | if ((*ppos > max_size) || | |
50 | (*ppos + count > max_size) || | |
51 | (*ppos + count < count) || | |
52 | (count > uncopied_bytes)) | |
53 | return -EINVAL; | |
54 | ||
55 | if (copy_from_user(buf + (*ppos), user_buf, count)) { | |
56 | kfree(buf); | |
57 | buf = NULL; | |
58 | return -EFAULT; | |
59 | } | |
60 | ||
61 | uncopied_bytes -= count; | |
62 | *ppos += count; | |
63 | ||
64 | if (!uncopied_bytes) { | |
65 | status = acpi_install_method(buf); | |
66 | kfree(buf); | |
67 | buf = NULL; | |
68 | if (ACPI_FAILURE(status)) | |
69 | return -EINVAL; | |
373d4d09 | 70 | add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE); |
526b4af4 TR |
71 | } |
72 | ||
73 | return count; | |
74 | } | |
75 | ||
76 | static const struct file_operations cm_fops = { | |
77 | .write = cm_write, | |
78 | .llseek = default_llseek, | |
79 | }; | |
80 | ||
81 | static int __init acpi_custom_method_init(void) | |
82 | { | |
526b4af4 TR |
83 | cm_dentry = debugfs_create_file("custom_method", S_IWUSR, |
84 | acpi_debugfs_dir, NULL, &cm_fops); | |
526b4af4 TR |
85 | return 0; |
86 | } | |
87 | ||
88 | static void __exit acpi_custom_method_exit(void) | |
89 | { | |
7e79a692 | 90 | debugfs_remove(cm_dentry); |
447a5647 | 91 | } |
526b4af4 TR |
92 | |
93 | module_init(acpi_custom_method_init); | |
94 | module_exit(acpi_custom_method_exit); |