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94 lines
1.9 KiB
94 lines
1.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright 2014 Google, Inc. |
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*/ |
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#include <linux/cdev.h> |
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#include <linux/device.h> |
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#include <linux/fs.h> |
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#include <linux/uaccess.h> |
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#include "internal.h" |
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static DEFINE_MUTEX(pmsg_lock); |
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static ssize_t write_pmsg(struct file *file, const char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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struct pstore_record record; |
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int ret; |
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if (!count) |
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return 0; |
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pstore_record_init(&record, psinfo); |
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record.type = PSTORE_TYPE_PMSG; |
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record.size = count; |
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/* check outside lock, page in any data. write_user also checks */ |
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if (!access_ok(buf, count)) |
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return -EFAULT; |
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mutex_lock(&pmsg_lock); |
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ret = psinfo->write_user(&record, buf); |
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mutex_unlock(&pmsg_lock); |
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return ret ? ret : count; |
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} |
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static const struct file_operations pmsg_fops = { |
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.owner = THIS_MODULE, |
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.llseek = noop_llseek, |
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.write = write_pmsg, |
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}; |
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static struct class *pmsg_class; |
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static int pmsg_major; |
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#define PMSG_NAME "pmsg" |
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#undef pr_fmt |
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#define pr_fmt(fmt) PMSG_NAME ": " fmt |
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static char *pmsg_devnode(struct device *dev, umode_t *mode) |
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{ |
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if (mode) |
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*mode = 0220; |
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return NULL; |
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} |
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void pstore_register_pmsg(void) |
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{ |
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struct device *pmsg_device; |
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pmsg_major = register_chrdev(0, PMSG_NAME, &pmsg_fops); |
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if (pmsg_major < 0) { |
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pr_err("register_chrdev failed\n"); |
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goto err; |
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} |
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pmsg_class = class_create(THIS_MODULE, PMSG_NAME); |
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if (IS_ERR(pmsg_class)) { |
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pr_err("device class file already in use\n"); |
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goto err_class; |
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} |
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pmsg_class->devnode = pmsg_devnode; |
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pmsg_device = device_create(pmsg_class, NULL, MKDEV(pmsg_major, 0), |
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NULL, "%s%d", PMSG_NAME, 0); |
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if (IS_ERR(pmsg_device)) { |
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pr_err("failed to create device\n"); |
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goto err_device; |
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} |
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return; |
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err_device: |
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class_destroy(pmsg_class); |
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err_class: |
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unregister_chrdev(pmsg_major, PMSG_NAME); |
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err: |
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return; |
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} |
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void pstore_unregister_pmsg(void) |
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{ |
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device_destroy(pmsg_class, MKDEV(pmsg_major, 0)); |
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class_destroy(pmsg_class); |
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unregister_chrdev(pmsg_major, PMSG_NAME); |
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}
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