projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 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); |