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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
Now that the SPDX tag is in all driver core files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
357 lines
9.3 KiB
C
357 lines
9.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright(c) 2014 Intel Mobile Communications GmbH
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* Copyright(c) 2015 Intel Deutschland GmbH
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*
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* Contact Information:
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* Intel Linux Wireless <ilw@linux.intel.com>
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* Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
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*
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* Author: Johannes Berg <johannes@sipsolutions.net>
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/devcoredump.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/workqueue.h>
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static struct class devcd_class;
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/* global disable flag, for security purposes */
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static bool devcd_disabled;
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/* if data isn't read by userspace after 5 minutes then delete it */
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#define DEVCD_TIMEOUT (HZ * 60 * 5)
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struct devcd_entry {
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struct device devcd_dev;
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void *data;
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size_t datalen;
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struct module *owner;
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ssize_t (*read)(char *buffer, loff_t offset, size_t count,
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void *data, size_t datalen);
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void (*free)(void *data);
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struct delayed_work del_wk;
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struct device *failing_dev;
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};
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static struct devcd_entry *dev_to_devcd(struct device *dev)
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{
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return container_of(dev, struct devcd_entry, devcd_dev);
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}
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static void devcd_dev_release(struct device *dev)
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{
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struct devcd_entry *devcd = dev_to_devcd(dev);
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devcd->free(devcd->data);
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module_put(devcd->owner);
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/*
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* this seems racy, but I don't see a notifier or such on
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* a struct device to know when it goes away?
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*/
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if (devcd->failing_dev->kobj.sd)
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sysfs_delete_link(&devcd->failing_dev->kobj, &dev->kobj,
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"devcoredump");
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put_device(devcd->failing_dev);
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kfree(devcd);
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}
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static void devcd_del(struct work_struct *wk)
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{
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struct devcd_entry *devcd;
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devcd = container_of(wk, struct devcd_entry, del_wk.work);
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device_del(&devcd->devcd_dev);
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put_device(&devcd->devcd_dev);
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}
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static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr,
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char *buffer, loff_t offset, size_t count)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct devcd_entry *devcd = dev_to_devcd(dev);
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return devcd->read(buffer, offset, count, devcd->data, devcd->datalen);
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}
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static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr,
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char *buffer, loff_t offset, size_t count)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct devcd_entry *devcd = dev_to_devcd(dev);
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mod_delayed_work(system_wq, &devcd->del_wk, 0);
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return count;
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}
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static struct bin_attribute devcd_attr_data = {
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.attr = { .name = "data", .mode = S_IRUSR | S_IWUSR, },
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.size = 0,
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.read = devcd_data_read,
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.write = devcd_data_write,
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};
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static struct bin_attribute *devcd_dev_bin_attrs[] = {
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&devcd_attr_data, NULL,
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};
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static const struct attribute_group devcd_dev_group = {
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.bin_attrs = devcd_dev_bin_attrs,
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};
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static const struct attribute_group *devcd_dev_groups[] = {
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&devcd_dev_group, NULL,
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};
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static int devcd_free(struct device *dev, void *data)
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{
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struct devcd_entry *devcd = dev_to_devcd(dev);
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flush_delayed_work(&devcd->del_wk);
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return 0;
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}
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static ssize_t disabled_show(struct class *class, struct class_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%d\n", devcd_disabled);
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}
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static ssize_t disabled_store(struct class *class, struct class_attribute *attr,
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const char *buf, size_t count)
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{
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long tmp = simple_strtol(buf, NULL, 10);
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/*
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* This essentially makes the attribute write-once, since you can't
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* go back to not having it disabled. This is intentional, it serves
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* as a system lockdown feature.
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*/
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if (tmp != 1)
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return -EINVAL;
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devcd_disabled = true;
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class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
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return count;
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}
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static CLASS_ATTR_RW(disabled);
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static struct attribute *devcd_class_attrs[] = {
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&class_attr_disabled.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(devcd_class);
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static struct class devcd_class = {
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.name = "devcoredump",
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.owner = THIS_MODULE,
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.dev_release = devcd_dev_release,
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.dev_groups = devcd_dev_groups,
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.class_groups = devcd_class_groups,
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};
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static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
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void *data, size_t datalen)
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{
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if (offset > datalen)
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return -EINVAL;
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if (offset + count > datalen)
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count = datalen - offset;
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if (count)
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memcpy(buffer, ((u8 *)data) + offset, count);
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return count;
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}
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static void devcd_freev(void *data)
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{
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vfree(data);
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}
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/**
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* dev_coredumpv - create device coredump with vmalloc data
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* @dev: the struct device for the crashed device
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* @data: vmalloc data containing the device coredump
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* @datalen: length of the data
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* @gfp: allocation flags
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*
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* This function takes ownership of the vmalloc'ed data and will free
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* it when it is no longer used. See dev_coredumpm() for more information.
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*/
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void dev_coredumpv(struct device *dev, void *data, size_t datalen,
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gfp_t gfp)
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{
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dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, devcd_freev);
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}
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EXPORT_SYMBOL_GPL(dev_coredumpv);
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static int devcd_match_failing(struct device *dev, const void *failing)
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{
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struct devcd_entry *devcd = dev_to_devcd(dev);
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return devcd->failing_dev == failing;
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}
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/**
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* devcd_free_sgtable - free all the memory of the given scatterlist table
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* (i.e. both pages and scatterlist instances)
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* NOTE: if two tables allocated with devcd_alloc_sgtable and then chained
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* using the sg_chain function then that function should be called only once
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* on the chained table
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* @table: pointer to sg_table to free
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*/
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static void devcd_free_sgtable(void *data)
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{
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_devcd_free_sgtable(data);
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}
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/**
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* devcd_read_from_table - copy data from sg_table to a given buffer
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* and return the number of bytes read
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* @buffer: the buffer to copy the data to it
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* @buf_len: the length of the buffer
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* @data: the scatterlist table to copy from
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* @offset: start copy from @offset@ bytes from the head of the data
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* in the given scatterlist
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* @data_len: the length of the data in the sg_table
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*/
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static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
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size_t buf_len, void *data,
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size_t data_len)
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{
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struct scatterlist *table = data;
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if (offset > data_len)
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return -EINVAL;
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if (offset + buf_len > data_len)
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buf_len = data_len - offset;
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return sg_pcopy_to_buffer(table, sg_nents(table), buffer, buf_len,
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offset);
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}
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/**
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* dev_coredumpm - create device coredump with read/free methods
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* @dev: the struct device for the crashed device
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* @owner: the module that contains the read/free functions, use %THIS_MODULE
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* @data: data cookie for the @read/@free functions
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* @datalen: length of the data
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* @gfp: allocation flags
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* @read: function to read from the given buffer
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* @free: function to free the given buffer
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*
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* Creates a new device coredump for the given device. If a previous one hasn't
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* been read yet, the new coredump is discarded. The data lifetime is determined
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* by the device coredump framework and when it is no longer needed the @free
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* function will be called to free the data.
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*/
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void dev_coredumpm(struct device *dev, struct module *owner,
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void *data, size_t datalen, gfp_t gfp,
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ssize_t (*read)(char *buffer, loff_t offset, size_t count,
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void *data, size_t datalen),
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void (*free)(void *data))
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{
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static atomic_t devcd_count = ATOMIC_INIT(0);
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struct devcd_entry *devcd;
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struct device *existing;
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if (devcd_disabled)
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goto free;
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existing = class_find_device(&devcd_class, NULL, dev,
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devcd_match_failing);
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if (existing) {
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put_device(existing);
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goto free;
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}
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if (!try_module_get(owner))
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goto free;
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devcd = kzalloc(sizeof(*devcd), gfp);
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if (!devcd)
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goto put_module;
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devcd->owner = owner;
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devcd->data = data;
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devcd->datalen = datalen;
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devcd->read = read;
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devcd->free = free;
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devcd->failing_dev = get_device(dev);
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device_initialize(&devcd->devcd_dev);
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dev_set_name(&devcd->devcd_dev, "devcd%d",
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atomic_inc_return(&devcd_count));
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devcd->devcd_dev.class = &devcd_class;
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if (device_add(&devcd->devcd_dev))
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goto put_device;
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if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
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"failing_device"))
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/* nothing - symlink will be missing */;
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if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
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"devcoredump"))
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/* nothing - symlink will be missing */;
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INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
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schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
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return;
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put_device:
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put_device(&devcd->devcd_dev);
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put_module:
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module_put(owner);
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free:
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free(data);
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}
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EXPORT_SYMBOL_GPL(dev_coredumpm);
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/**
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* dev_coredumpmsg - create device coredump that uses scatterlist as data
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* parameter
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* @dev: the struct device for the crashed device
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* @table: the dump data
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* @datalen: length of the data
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* @gfp: allocation flags
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*
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* Creates a new device coredump for the given device. If a previous one hasn't
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* been read yet, the new coredump is discarded. The data lifetime is determined
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* by the device coredump framework and when it is no longer needed
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* it will free the data.
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*/
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void dev_coredumpsg(struct device *dev, struct scatterlist *table,
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size_t datalen, gfp_t gfp)
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{
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dev_coredumpm(dev, NULL, table, datalen, gfp, devcd_read_from_sgtable,
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devcd_free_sgtable);
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}
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EXPORT_SYMBOL_GPL(dev_coredumpsg);
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static int __init devcoredump_init(void)
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{
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return class_register(&devcd_class);
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}
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__initcall(devcoredump_init);
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static void __exit devcoredump_exit(void)
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{
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class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
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class_unregister(&devcd_class);
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}
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__exitcall(devcoredump_exit);
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