118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
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/*
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* This module provides an interface to trigger and test firmware loading.
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*
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* It is designed to be used for basic evaluation of the firmware loading
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* subsystem (for example when validating firmware verification). It lacks
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* any extra dependencies, and will not normally be loaded by the system
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* unless explicitly requested by name.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/printk.h>
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#include <linux/firmware.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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static DEFINE_MUTEX(test_fw_mutex);
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static const struct firmware *test_firmware;
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static ssize_t test_fw_misc_read(struct file *f, char __user *buf,
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size_t size, loff_t *offset)
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{
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ssize_t rc = 0;
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mutex_lock(&test_fw_mutex);
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if (test_firmware)
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rc = simple_read_from_buffer(buf, size, offset,
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test_firmware->data,
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test_firmware->size);
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mutex_unlock(&test_fw_mutex);
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return rc;
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}
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static const struct file_operations test_fw_fops = {
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.owner = THIS_MODULE,
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.read = test_fw_misc_read,
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};
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static struct miscdevice test_fw_misc_device = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = "test_firmware",
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.fops = &test_fw_fops,
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};
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static ssize_t trigger_request_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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int rc;
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char *name;
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name = kzalloc(count + 1, GFP_KERNEL);
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if (!name)
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return -ENOSPC;
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memcpy(name, buf, count);
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pr_info("loading '%s'\n", name);
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mutex_lock(&test_fw_mutex);
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release_firmware(test_firmware);
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test_firmware = NULL;
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rc = request_firmware(&test_firmware, name, dev);
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if (rc)
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pr_info("load of '%s' failed: %d\n", name, rc);
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pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
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mutex_unlock(&test_fw_mutex);
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kfree(name);
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return count;
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}
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static DEVICE_ATTR_WO(trigger_request);
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static int __init test_firmware_init(void)
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{
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int rc;
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rc = misc_register(&test_fw_misc_device);
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if (rc) {
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pr_err("could not register misc device: %d\n", rc);
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return rc;
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}
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rc = device_create_file(test_fw_misc_device.this_device,
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&dev_attr_trigger_request);
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if (rc) {
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pr_err("could not create sysfs interface: %d\n", rc);
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goto dereg;
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}
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pr_warn("interface ready\n");
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return 0;
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dereg:
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misc_deregister(&test_fw_misc_device);
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return rc;
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}
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module_init(test_firmware_init);
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static void __exit test_firmware_exit(void)
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{
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release_firmware(test_firmware);
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device_remove_file(test_fw_misc_device.this_device,
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&dev_attr_trigger_request);
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misc_deregister(&test_fw_misc_device);
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pr_warn("removed interface\n");
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}
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module_exit(test_firmware_exit);
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MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
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MODULE_LICENSE("GPL");
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