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Commit | Line | Data |
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0a8adf58 KC |
1 | /* |
2 | * This module provides an interface to trigger and test firmware loading. | |
3 | * | |
4 | * It is designed to be used for basic evaluation of the firmware loading | |
5 | * subsystem (for example when validating firmware verification). It lacks | |
6 | * any extra dependencies, and will not normally be loaded by the system | |
7 | * unless explicitly requested by name. | |
8 | */ | |
9 | ||
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
11 | ||
12 | #include <linux/init.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/printk.h> | |
15 | #include <linux/firmware.h> | |
16 | #include <linux/device.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/miscdevice.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/uaccess.h> | |
21 | ||
22 | static DEFINE_MUTEX(test_fw_mutex); | |
23 | static const struct firmware *test_firmware; | |
24 | ||
25 | static ssize_t test_fw_misc_read(struct file *f, char __user *buf, | |
26 | size_t size, loff_t *offset) | |
27 | { | |
28 | ssize_t rc = 0; | |
29 | ||
30 | mutex_lock(&test_fw_mutex); | |
31 | if (test_firmware) | |
32 | rc = simple_read_from_buffer(buf, size, offset, | |
33 | test_firmware->data, | |
34 | test_firmware->size); | |
35 | mutex_unlock(&test_fw_mutex); | |
36 | return rc; | |
37 | } | |
38 | ||
39 | static const struct file_operations test_fw_fops = { | |
40 | .owner = THIS_MODULE, | |
41 | .read = test_fw_misc_read, | |
42 | }; | |
43 | ||
44 | static struct miscdevice test_fw_misc_device = { | |
45 | .minor = MISC_DYNAMIC_MINOR, | |
46 | .name = "test_firmware", | |
47 | .fops = &test_fw_fops, | |
48 | }; | |
49 | ||
50 | static ssize_t trigger_request_store(struct device *dev, | |
51 | struct device_attribute *attr, | |
52 | const char *buf, size_t count) | |
53 | { | |
54 | int rc; | |
55 | char *name; | |
56 | ||
be4a1326 | 57 | name = kstrndup(buf, count, GFP_KERNEL); |
0a8adf58 KC |
58 | if (!name) |
59 | return -ENOSPC; | |
0a8adf58 KC |
60 | |
61 | pr_info("loading '%s'\n", name); | |
62 | ||
63 | mutex_lock(&test_fw_mutex); | |
64 | release_firmware(test_firmware); | |
65 | test_firmware = NULL; | |
66 | rc = request_firmware(&test_firmware, name, dev); | |
47e0bbb7 | 67 | if (rc) { |
0a8adf58 | 68 | pr_info("load of '%s' failed: %d\n", name, rc); |
47e0bbb7 BN |
69 | goto out; |
70 | } | |
71 | pr_info("loaded: %zu\n", test_firmware->size); | |
72 | rc = count; | |
73 | ||
74 | out: | |
0a8adf58 KC |
75 | mutex_unlock(&test_fw_mutex); |
76 | ||
77 | kfree(name); | |
78 | ||
47e0bbb7 | 79 | return rc; |
0a8adf58 KC |
80 | } |
81 | static DEVICE_ATTR_WO(trigger_request); | |
82 | ||
83 | static int __init test_firmware_init(void) | |
84 | { | |
85 | int rc; | |
86 | ||
87 | rc = misc_register(&test_fw_misc_device); | |
88 | if (rc) { | |
89 | pr_err("could not register misc device: %d\n", rc); | |
90 | return rc; | |
91 | } | |
92 | rc = device_create_file(test_fw_misc_device.this_device, | |
93 | &dev_attr_trigger_request); | |
94 | if (rc) { | |
95 | pr_err("could not create sysfs interface: %d\n", rc); | |
96 | goto dereg; | |
97 | } | |
98 | ||
99 | pr_warn("interface ready\n"); | |
100 | ||
101 | return 0; | |
102 | dereg: | |
103 | misc_deregister(&test_fw_misc_device); | |
104 | return rc; | |
105 | } | |
106 | ||
107 | module_init(test_firmware_init); | |
108 | ||
109 | static void __exit test_firmware_exit(void) | |
110 | { | |
111 | release_firmware(test_firmware); | |
112 | device_remove_file(test_fw_misc_device.this_device, | |
113 | &dev_attr_trigger_request); | |
114 | misc_deregister(&test_fw_misc_device); | |
115 | pr_warn("removed interface\n"); | |
116 | } | |
117 | ||
118 | module_exit(test_firmware_exit); | |
119 | ||
120 | MODULE_AUTHOR("Kees Cook <keescook@chromium.org>"); | |
121 | MODULE_LICENSE("GPL"); |