projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 9d5438f4 MS |
1 | /* |
| 2 | * Copyright 2014 Google, Inc. | |
| 3 | * | |
| 4 | * This software is licensed under the terms of the GNU General Public | |
| 5 | * License version 2, as published by the Free Software Foundation, and | |
| 6 | * may be copied, distributed, and modified under those terms. | |
| 7 | * | |
| 8 | * This program is distributed in the hope that it will be useful, | |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 11 | * GNU General Public License for more details. | |
| 12 | */ | |
| 13 | ||
| 14 | #include <linux/cdev.h> | |
| 15 | #include <linux/device.h> | |
| 16 | #include <linux/fs.h> | |
| 17 | #include <linux/uaccess.h> | |
| 9d5438f4 MS |
18 | #include "internal.h" |
| 19 | ||
| 20 | static DEFINE_MUTEX(pmsg_lock); | |
| 9d5438f4 MS |
21 | |
| 22 | static ssize_t write_pmsg(struct file *file, const char __user *buf, | |
| 23 | size_t count, loff_t *ppos) | |
| 24 | { | |
| e581ca81 | 25 | struct pstore_record record; |
| 5bf6d1b9 | 26 | int ret; |
| 9d5438f4 MS |
27 | |
| 28 | if (!count) | |
| 29 | return 0; | |
| 30 | ||
| e581ca81 KC |
31 | pstore_record_init(&record, psinfo); |
| 32 | record.type = PSTORE_TYPE_PMSG; | |
| 33 | record.size = count; | |
| 34 | ||
| 4c9ec219 | 35 | /* check outside lock, page in any data. write_user also checks */ |
| 9d5438f4 MS |
36 | if (!access_ok(VERIFY_READ, buf, count)) |
| 37 | return -EFAULT; | |
| 38 | ||
| 9d5438f4 | 39 | mutex_lock(&pmsg_lock); |
| 4c9ec219 | 40 | ret = psinfo->write_user(&record, buf); |
| 9d5438f4 | 41 | mutex_unlock(&pmsg_lock); |
| 5bf6d1b9 | 42 | return ret ? ret : count; |
| 9d5438f4 MS |
43 | } |
| 44 | ||
| 45 | static const struct file_operations pmsg_fops = { | |
| 46 | .owner = THIS_MODULE, | |
| 47 | .llseek = noop_llseek, | |
| 48 | .write = write_pmsg, | |
| 49 | }; | |
| 50 | ||
| 51 | static struct class *pmsg_class; | |
| 52 | static int pmsg_major; | |
| 53 | #define PMSG_NAME "pmsg" | |
| 54 | #undef pr_fmt | |
| 55 | #define pr_fmt(fmt) PMSG_NAME ": " fmt | |
| 56 | ||
| 57 | static char *pmsg_devnode(struct device *dev, umode_t *mode) | |
| 58 | { | |
| 59 | if (mode) | |
| 60 | *mode = 0220; | |
| 61 | return NULL; | |
| 62 | } | |
| 63 | ||
| 64 | void pstore_register_pmsg(void) | |
| 65 | { | |
| 66 | struct device *pmsg_device; | |
| 67 | ||
| 68 | pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops); | |
| 69 | if (pmsg_major < 0) { | |
| 70 | pr_err("register_chrdev failed\n"); | |
| 71 | goto err; | |
| 72 | } | |
| 73 | ||
| 74 | pmsg_class = class_create(THIS_MODULE, PMSG_NAME); | |
| 75 | if (IS_ERR(pmsg_class)) { | |
| 76 | pr_err("device class file already in use\n"); | |
| 77 | goto err_class; | |
| 78 | } | |
| 79 | pmsg_class->devnode = pmsg_devnode; | |
| 80 | ||
| 81 | pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0), | |
| 82 | NULL, "%s%d", PMSG_NAME, 0); | |
| 83 | if (IS_ERR(pmsg_device)) { | |
| 84 | pr_err("failed to create device\n"); | |
| 85 | goto err_device; | |
| 86 | } | |
| 87 | return; | |
| 88 | ||
| 89 | err_device: | |
| 90 | class_destroy(pmsg_class); | |
| 91 | err_class: | |
| 92 | unregister_chrdev(pmsg_major, PMSG_NAME); | |
| 93 | err: | |
| 94 | return; | |
| 95 | } | |
| ee1d2674 GT |
96 | |
| 97 | void pstore_unregister_pmsg(void) | |
| 98 | { | |
| 99 | device_destroy(pmsg_class, MKDEV(pmsg_major, 0)); | |
| 100 | class_destroy(pmsg_class); | |
| 101 | unregister_chrdev(pmsg_major, PMSG_NAME); | |
| 102 | } |