projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 9c92ab61 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 9d5438f4 MS |
2 | /* |
| 3 | * Copyright 2014 Google, Inc. | |
| 9d5438f4 MS |
4 | */ |
| 5 | ||
| 6 | #include <linux/cdev.h> | |
| 7 | #include <linux/device.h> | |
| 8 | #include <linux/fs.h> | |
| 9 | #include <linux/uaccess.h> | |
| 9d5438f4 MS |
10 | #include "internal.h" |
| 11 | ||
| 12 | static DEFINE_MUTEX(pmsg_lock); | |
| 9d5438f4 MS |
13 | |
| 14 | static ssize_t write_pmsg(struct file *file, const char __user *buf, | |
| 15 | size_t count, loff_t *ppos) | |
| 16 | { | |
| e581ca81 | 17 | struct pstore_record record; |
| 5bf6d1b9 | 18 | int ret; |
| 9d5438f4 MS |
19 | |
| 20 | if (!count) | |
| 21 | return 0; | |
| 22 | ||
| e581ca81 KC |
23 | pstore_record_init(&record, psinfo); |
| 24 | record.type = PSTORE_TYPE_PMSG; | |
| 25 | record.size = count; | |
| 26 | ||
| 4c9ec219 | 27 | /* check outside lock, page in any data. write_user also checks */ |
| 96d4f267 | 28 | if (!access_ok(buf, count)) |
| 9d5438f4 MS |
29 | return -EFAULT; |
| 30 | ||
| 9d5438f4 | 31 | mutex_lock(&pmsg_lock); |
| 4c9ec219 | 32 | ret = psinfo->write_user(&record, buf); |
| 9d5438f4 | 33 | mutex_unlock(&pmsg_lock); |
| 5bf6d1b9 | 34 | return ret ? ret : count; |
| 9d5438f4 MS |
35 | } |
| 36 | ||
| 37 | static const struct file_operations pmsg_fops = { | |
| 38 | .owner = THIS_MODULE, | |
| 39 | .llseek = noop_llseek, | |
| 40 | .write = write_pmsg, | |
| 41 | }; | |
| 42 | ||
| 43 | static struct class *pmsg_class; | |
| 44 | static int pmsg_major; | |
| 45 | #define PMSG_NAME "pmsg" | |
| 46 | #undef pr_fmt | |
| 47 | #define pr_fmt(fmt) PMSG_NAME ": " fmt | |
| 48 | ||
| 49 | static char *pmsg_devnode(struct device *dev, umode_t *mode) | |
| 50 | { | |
| 51 | if (mode) | |
| 52 | *mode = 0220; | |
| 53 | return NULL; | |
| 54 | } | |
| 55 | ||
| 56 | void pstore_register_pmsg(void) | |
| 57 | { | |
| 58 | struct device *pmsg_device; | |
| 59 | ||
| 60 | pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops); | |
| 61 | if (pmsg_major < 0) { | |
| 62 | pr_err("register_chrdev failed\n"); | |
| 63 | goto err; | |
| 64 | } | |
| 65 | ||
| 66 | pmsg_class = class_create(THIS_MODULE, PMSG_NAME); | |
| 67 | if (IS_ERR(pmsg_class)) { | |
| 68 | pr_err("device class file already in use\n"); | |
| 69 | goto err_class; | |
| 70 | } | |
| 71 | pmsg_class->devnode = pmsg_devnode; | |
| 72 | ||
| 73 | pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0), | |
| 74 | NULL, "%s%d", PMSG_NAME, 0); | |
| 75 | if (IS_ERR(pmsg_device)) { | |
| 76 | pr_err("failed to create device\n"); | |
| 77 | goto err_device; | |
| 78 | } | |
| 79 | return; | |
| 80 | ||
| 81 | err_device: | |
| 82 | class_destroy(pmsg_class); | |
| 83 | err_class: | |
| 84 | unregister_chrdev(pmsg_major, PMSG_NAME); | |
| 85 | err: | |
| 86 | return; | |
| 87 | } | |
| ee1d2674 GT |
88 | |
| 89 | void pstore_unregister_pmsg(void) | |
| 90 | { | |
| 91 | device_destroy(pmsg_class, MKDEV(pmsg_major, 0)); | |
| 92 | class_destroy(pmsg_class); | |
| 93 | unregister_chrdev(pmsg_major, PMSG_NAME); | |
| 94 | } |