linux/drivers/uio/uio.c
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00

914 lines
20 KiB
C

/*
* drivers/uio/uio.c
*
* Copyright(C) 2005, Benedikt Spranger <b.spranger@linutronix.de>
* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
* Copyright(C) 2006, Hans J. Koch <hjk@hansjkoch.de>
* Copyright(C) 2006, Greg Kroah-Hartman <greg@kroah.com>
*
* Userspace IO
*
* Base Functions
*
* Licensed under the GPLv2 only.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/idr.h>
#include <linux/sched/signal.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/cdev.h>
#include <linux/uio_driver.h>
#define UIO_MAX_DEVICES (1U << MINORBITS)
static int uio_major;
static struct cdev *uio_cdev;
static DEFINE_IDR(uio_idr);
static const struct file_operations uio_fops;
/* Protect idr accesses */
static DEFINE_MUTEX(minor_lock);
/*
* attributes
*/
struct uio_map {
struct kobject kobj;
struct uio_mem *mem;
};
#define to_map(map) container_of(map, struct uio_map, kobj)
static ssize_t map_name_show(struct uio_mem *mem, char *buf)
{
if (unlikely(!mem->name))
mem->name = "";
return sprintf(buf, "%s\n", mem->name);
}
static ssize_t map_addr_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "%pa\n", &mem->addr);
}
static ssize_t map_size_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "%pa\n", &mem->size);
}
static ssize_t map_offset_show(struct uio_mem *mem, char *buf)
{
return sprintf(buf, "0x%llx\n", (unsigned long long)mem->offs);
}
struct map_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct uio_mem *, char *);
ssize_t (*store)(struct uio_mem *, const char *, size_t);
};
static struct map_sysfs_entry name_attribute =
__ATTR(name, S_IRUGO, map_name_show, NULL);
static struct map_sysfs_entry addr_attribute =
__ATTR(addr, S_IRUGO, map_addr_show, NULL);
static struct map_sysfs_entry size_attribute =
__ATTR(size, S_IRUGO, map_size_show, NULL);
static struct map_sysfs_entry offset_attribute =
__ATTR(offset, S_IRUGO, map_offset_show, NULL);
static struct attribute *attrs[] = {
&name_attribute.attr,
&addr_attribute.attr,
&size_attribute.attr,
&offset_attribute.attr,
NULL, /* need to NULL terminate the list of attributes */
};
static void map_release(struct kobject *kobj)
{
struct uio_map *map = to_map(kobj);
kfree(map);
}
static ssize_t map_type_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct uio_map *map = to_map(kobj);
struct uio_mem *mem = map->mem;
struct map_sysfs_entry *entry;
entry = container_of(attr, struct map_sysfs_entry, attr);
if (!entry->show)
return -EIO;
return entry->show(mem, buf);
}
static const struct sysfs_ops map_sysfs_ops = {
.show = map_type_show,
};
static struct kobj_type map_attr_type = {
.release = map_release,
.sysfs_ops = &map_sysfs_ops,
.default_attrs = attrs,
};
struct uio_portio {
struct kobject kobj;
struct uio_port *port;
};
#define to_portio(portio) container_of(portio, struct uio_portio, kobj)
static ssize_t portio_name_show(struct uio_port *port, char *buf)
{
if (unlikely(!port->name))
port->name = "";
return sprintf(buf, "%s\n", port->name);
}
static ssize_t portio_start_show(struct uio_port *port, char *buf)
{
return sprintf(buf, "0x%lx\n", port->start);
}
static ssize_t portio_size_show(struct uio_port *port, char *buf)
{
return sprintf(buf, "0x%lx\n", port->size);
}
static ssize_t portio_porttype_show(struct uio_port *port, char *buf)
{
const char *porttypes[] = {"none", "x86", "gpio", "other"};
if ((port->porttype < 0) || (port->porttype > UIO_PORT_OTHER))
return -EINVAL;
return sprintf(buf, "port_%s\n", porttypes[port->porttype]);
}
struct portio_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct uio_port *, char *);
ssize_t (*store)(struct uio_port *, const char *, size_t);
};
static struct portio_sysfs_entry portio_name_attribute =
__ATTR(name, S_IRUGO, portio_name_show, NULL);
static struct portio_sysfs_entry portio_start_attribute =
__ATTR(start, S_IRUGO, portio_start_show, NULL);
static struct portio_sysfs_entry portio_size_attribute =
__ATTR(size, S_IRUGO, portio_size_show, NULL);
static struct portio_sysfs_entry portio_porttype_attribute =
__ATTR(porttype, S_IRUGO, portio_porttype_show, NULL);
static struct attribute *portio_attrs[] = {
&portio_name_attribute.attr,
&portio_start_attribute.attr,
&portio_size_attribute.attr,
&portio_porttype_attribute.attr,
NULL,
};
static void portio_release(struct kobject *kobj)
{
struct uio_portio *portio = to_portio(kobj);
kfree(portio);
}
static ssize_t portio_type_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct uio_portio *portio = to_portio(kobj);
struct uio_port *port = portio->port;
struct portio_sysfs_entry *entry;
entry = container_of(attr, struct portio_sysfs_entry, attr);
if (!entry->show)
return -EIO;
return entry->show(port, buf);
}
static const struct sysfs_ops portio_sysfs_ops = {
.show = portio_type_show,
};
static struct kobj_type portio_attr_type = {
.release = portio_release,
.sysfs_ops = &portio_sysfs_ops,
.default_attrs = portio_attrs,
};
static ssize_t name_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", idev->info->name);
}
static DEVICE_ATTR_RO(name);
static ssize_t version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", idev->info->version);
}
static DEVICE_ATTR_RO(version);
static ssize_t event_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct uio_device *idev = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", (unsigned int)atomic_read(&idev->event));
}
static DEVICE_ATTR_RO(event);
static struct attribute *uio_attrs[] = {
&dev_attr_name.attr,
&dev_attr_version.attr,
&dev_attr_event.attr,
NULL,
};
ATTRIBUTE_GROUPS(uio);
/* UIO class infrastructure */
static struct class uio_class = {
.name = "uio",
.dev_groups = uio_groups,
};
/*
* device functions
*/
static int uio_dev_add_attributes(struct uio_device *idev)
{
int ret;
int mi, pi;
int map_found = 0;
int portio_found = 0;
struct uio_mem *mem;
struct uio_map *map;
struct uio_port *port;
struct uio_portio *portio;
for (mi = 0; mi < MAX_UIO_MAPS; mi++) {
mem = &idev->info->mem[mi];
if (mem->size == 0)
break;
if (!map_found) {
map_found = 1;
idev->map_dir = kobject_create_and_add("maps",
&idev->dev->kobj);
if (!idev->map_dir) {
ret = -ENOMEM;
goto err_map;
}
}
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (!map) {
ret = -ENOMEM;
goto err_map;
}
kobject_init(&map->kobj, &map_attr_type);
map->mem = mem;
mem->map = map;
ret = kobject_add(&map->kobj, idev->map_dir, "map%d", mi);
if (ret)
goto err_map_kobj;
ret = kobject_uevent(&map->kobj, KOBJ_ADD);
if (ret)
goto err_map_kobj;
}
for (pi = 0; pi < MAX_UIO_PORT_REGIONS; pi++) {
port = &idev->info->port[pi];
if (port->size == 0)
break;
if (!portio_found) {
portio_found = 1;
idev->portio_dir = kobject_create_and_add("portio",
&idev->dev->kobj);
if (!idev->portio_dir) {
ret = -ENOMEM;
goto err_portio;
}
}
portio = kzalloc(sizeof(*portio), GFP_KERNEL);
if (!portio) {
ret = -ENOMEM;
goto err_portio;
}
kobject_init(&portio->kobj, &portio_attr_type);
portio->port = port;
port->portio = portio;
ret = kobject_add(&portio->kobj, idev->portio_dir,
"port%d", pi);
if (ret)
goto err_portio_kobj;
ret = kobject_uevent(&portio->kobj, KOBJ_ADD);
if (ret)
goto err_portio_kobj;
}
return 0;
err_portio:
pi--;
err_portio_kobj:
for (; pi >= 0; pi--) {
port = &idev->info->port[pi];
portio = port->portio;
kobject_put(&portio->kobj);
}
kobject_put(idev->portio_dir);
err_map:
mi--;
err_map_kobj:
for (; mi >= 0; mi--) {
mem = &idev->info->mem[mi];
map = mem->map;
kobject_put(&map->kobj);
}
kobject_put(idev->map_dir);
dev_err(idev->dev, "error creating sysfs files (%d)\n", ret);
return ret;
}
static void uio_dev_del_attributes(struct uio_device *idev)
{
int i;
struct uio_mem *mem;
struct uio_port *port;
for (i = 0; i < MAX_UIO_MAPS; i++) {
mem = &idev->info->mem[i];
if (mem->size == 0)
break;
kobject_put(&mem->map->kobj);
}
kobject_put(idev->map_dir);
for (i = 0; i < MAX_UIO_PORT_REGIONS; i++) {
port = &idev->info->port[i];
if (port->size == 0)
break;
kobject_put(&port->portio->kobj);
}
kobject_put(idev->portio_dir);
}
static int uio_get_minor(struct uio_device *idev)
{
int retval = -ENOMEM;
mutex_lock(&minor_lock);
retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
if (retval >= 0) {
idev->minor = retval;
retval = 0;
} else if (retval == -ENOSPC) {
dev_err(idev->dev, "too many uio devices\n");
retval = -EINVAL;
}
mutex_unlock(&minor_lock);
return retval;
}
static void uio_free_minor(struct uio_device *idev)
{
mutex_lock(&minor_lock);
idr_remove(&uio_idr, idev->minor);
mutex_unlock(&minor_lock);
}
/**
* uio_event_notify - trigger an interrupt event
* @info: UIO device capabilities
*/
void uio_event_notify(struct uio_info *info)
{
struct uio_device *idev = info->uio_dev;
atomic_inc(&idev->event);
wake_up_interruptible(&idev->wait);
kill_fasync(&idev->async_queue, SIGIO, POLL_IN);
}
EXPORT_SYMBOL_GPL(uio_event_notify);
/**
* uio_interrupt - hardware interrupt handler
* @irq: IRQ number, can be UIO_IRQ_CYCLIC for cyclic timer
* @dev_id: Pointer to the devices uio_device structure
*/
static irqreturn_t uio_interrupt(int irq, void *dev_id)
{
struct uio_device *idev = (struct uio_device *)dev_id;
irqreturn_t ret = idev->info->handler(irq, idev->info);
if (ret == IRQ_HANDLED)
uio_event_notify(idev->info);
return ret;
}
struct uio_listener {
struct uio_device *dev;
s32 event_count;
};
static int uio_open(struct inode *inode, struct file *filep)
{
struct uio_device *idev;
struct uio_listener *listener;
int ret = 0;
mutex_lock(&minor_lock);
idev = idr_find(&uio_idr, iminor(inode));
mutex_unlock(&minor_lock);
if (!idev) {
ret = -ENODEV;
goto out;
}
if (!try_module_get(idev->owner)) {
ret = -ENODEV;
goto out;
}
listener = kmalloc(sizeof(*listener), GFP_KERNEL);
if (!listener) {
ret = -ENOMEM;
goto err_alloc_listener;
}
listener->dev = idev;
listener->event_count = atomic_read(&idev->event);
filep->private_data = listener;
if (idev->info->open) {
ret = idev->info->open(idev->info, inode);
if (ret)
goto err_infoopen;
}
return 0;
err_infoopen:
kfree(listener);
err_alloc_listener:
module_put(idev->owner);
out:
return ret;
}
static int uio_fasync(int fd, struct file *filep, int on)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
return fasync_helper(fd, filep, on, &idev->async_queue);
}
static int uio_release(struct inode *inode, struct file *filep)
{
int ret = 0;
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
if (idev->info->release)
ret = idev->info->release(idev->info, inode);
module_put(idev->owner);
kfree(listener);
return ret;
}
static __poll_t uio_poll(struct file *filep, poll_table *wait)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
if (!idev->info->irq)
return -EIO;
poll_wait(filep, &idev->wait, wait);
if (listener->event_count != atomic_read(&idev->event))
return EPOLLIN | EPOLLRDNORM;
return 0;
}
static ssize_t uio_read(struct file *filep, char __user *buf,
size_t count, loff_t *ppos)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
DECLARE_WAITQUEUE(wait, current);
ssize_t retval;
s32 event_count;
if (!idev->info->irq)
return -EIO;
if (count != sizeof(s32))
return -EINVAL;
add_wait_queue(&idev->wait, &wait);
do {
set_current_state(TASK_INTERRUPTIBLE);
event_count = atomic_read(&idev->event);
if (event_count != listener->event_count) {
__set_current_state(TASK_RUNNING);
if (copy_to_user(buf, &event_count, count))
retval = -EFAULT;
else {
listener->event_count = event_count;
retval = count;
}
break;
}
if (filep->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
break;
}
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
} while (1);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&idev->wait, &wait);
return retval;
}
static ssize_t uio_write(struct file *filep, const char __user *buf,
size_t count, loff_t *ppos)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
ssize_t retval;
s32 irq_on;
if (!idev->info->irq)
return -EIO;
if (count != sizeof(s32))
return -EINVAL;
if (!idev->info->irqcontrol)
return -ENOSYS;
if (copy_from_user(&irq_on, buf, count))
return -EFAULT;
retval = idev->info->irqcontrol(idev->info, irq_on);
return retval ? retval : sizeof(s32);
}
static int uio_find_mem_index(struct vm_area_struct *vma)
{
struct uio_device *idev = vma->vm_private_data;
if (vma->vm_pgoff < MAX_UIO_MAPS) {
if (idev->info->mem[vma->vm_pgoff].size == 0)
return -1;
return (int)vma->vm_pgoff;
}
return -1;
}
static int uio_vma_fault(struct vm_fault *vmf)
{
struct uio_device *idev = vmf->vma->vm_private_data;
struct page *page;
unsigned long offset;
void *addr;
int mi = uio_find_mem_index(vmf->vma);
if (mi < 0)
return VM_FAULT_SIGBUS;
/*
* We need to subtract mi because userspace uses offset = N*PAGE_SIZE
* to use mem[N].
*/
offset = (vmf->pgoff - mi) << PAGE_SHIFT;
addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset;
if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL)
page = virt_to_page(addr);
else
page = vmalloc_to_page(addr);
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct uio_logical_vm_ops = {
.fault = uio_vma_fault,
};
static int uio_mmap_logical(struct vm_area_struct *vma)
{
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &uio_logical_vm_ops;
return 0;
}
static const struct vm_operations_struct uio_physical_vm_ops = {
#ifdef CONFIG_HAVE_IOREMAP_PROT
.access = generic_access_phys,
#endif
};
static int uio_mmap_physical(struct vm_area_struct *vma)
{
struct uio_device *idev = vma->vm_private_data;
int mi = uio_find_mem_index(vma);
struct uio_mem *mem;
if (mi < 0)
return -EINVAL;
mem = idev->info->mem + mi;
if (mem->addr & ~PAGE_MASK)
return -ENODEV;
if (vma->vm_end - vma->vm_start > mem->size)
return -EINVAL;
vma->vm_ops = &uio_physical_vm_ops;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
/*
* We cannot use the vm_iomap_memory() helper here,
* because vma->vm_pgoff is the map index we looked
* up above in uio_find_mem_index(), rather than an
* actual page offset into the mmap.
*
* So we just do the physical mmap without a page
* offset.
*/
return remap_pfn_range(vma,
vma->vm_start,
mem->addr >> PAGE_SHIFT,
vma->vm_end - vma->vm_start,
vma->vm_page_prot);
}
static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
{
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
int mi;
unsigned long requested_pages, actual_pages;
int ret = 0;
if (vma->vm_end < vma->vm_start)
return -EINVAL;
vma->vm_private_data = idev;
mi = uio_find_mem_index(vma);
if (mi < 0)
return -EINVAL;
requested_pages = vma_pages(vma);
actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
+ idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
if (requested_pages > actual_pages)
return -EINVAL;
if (idev->info->mmap) {
ret = idev->info->mmap(idev->info, vma);
return ret;
}
switch (idev->info->mem[mi].memtype) {
case UIO_MEM_PHYS:
return uio_mmap_physical(vma);
case UIO_MEM_LOGICAL:
case UIO_MEM_VIRTUAL:
return uio_mmap_logical(vma);
default:
return -EINVAL;
}
}
static const struct file_operations uio_fops = {
.owner = THIS_MODULE,
.open = uio_open,
.release = uio_release,
.read = uio_read,
.write = uio_write,
.mmap = uio_mmap,
.poll = uio_poll,
.fasync = uio_fasync,
.llseek = noop_llseek,
};
static int uio_major_init(void)
{
static const char name[] = "uio";
struct cdev *cdev = NULL;
dev_t uio_dev = 0;
int result;
result = alloc_chrdev_region(&uio_dev, 0, UIO_MAX_DEVICES, name);
if (result)
goto out;
result = -ENOMEM;
cdev = cdev_alloc();
if (!cdev)
goto out_unregister;
cdev->owner = THIS_MODULE;
cdev->ops = &uio_fops;
kobject_set_name(&cdev->kobj, "%s", name);
result = cdev_add(cdev, uio_dev, UIO_MAX_DEVICES);
if (result)
goto out_put;
uio_major = MAJOR(uio_dev);
uio_cdev = cdev;
return 0;
out_put:
kobject_put(&cdev->kobj);
out_unregister:
unregister_chrdev_region(uio_dev, UIO_MAX_DEVICES);
out:
return result;
}
static void uio_major_cleanup(void)
{
unregister_chrdev_region(MKDEV(uio_major, 0), UIO_MAX_DEVICES);
cdev_del(uio_cdev);
}
static int init_uio_class(void)
{
int ret;
/* This is the first time in here, set everything up properly */
ret = uio_major_init();
if (ret)
goto exit;
ret = class_register(&uio_class);
if (ret) {
printk(KERN_ERR "class_register failed for uio\n");
goto err_class_register;
}
return 0;
err_class_register:
uio_major_cleanup();
exit:
return ret;
}
static void release_uio_class(void)
{
class_unregister(&uio_class);
uio_major_cleanup();
}
/**
* uio_register_device - register a new userspace IO device
* @owner: module that creates the new device
* @parent: parent device
* @info: UIO device capabilities
*
* returns zero on success or a negative error code.
*/
int __uio_register_device(struct module *owner,
struct device *parent,
struct uio_info *info)
{
struct uio_device *idev;
int ret = 0;
if (!parent || !info || !info->name || !info->version)
return -EINVAL;
info->uio_dev = NULL;
idev = devm_kzalloc(parent, sizeof(*idev), GFP_KERNEL);
if (!idev) {
return -ENOMEM;
}
idev->owner = owner;
idev->info = info;
init_waitqueue_head(&idev->wait);
atomic_set(&idev->event, 0);
ret = uio_get_minor(idev);
if (ret)
return ret;
idev->dev = device_create(&uio_class, parent,
MKDEV(uio_major, idev->minor), idev,
"uio%d", idev->minor);
if (IS_ERR(idev->dev)) {
printk(KERN_ERR "UIO: device register failed\n");
ret = PTR_ERR(idev->dev);
goto err_device_create;
}
ret = uio_dev_add_attributes(idev);
if (ret)
goto err_uio_dev_add_attributes;
info->uio_dev = idev;
if (info->irq && (info->irq != UIO_IRQ_CUSTOM)) {
/*
* Note that we deliberately don't use devm_request_irq
* here. The parent module can unregister the UIO device
* and call pci_disable_msi, which requires that this
* irq has been freed. However, the device may have open
* FDs at the time of unregister and therefore may not be
* freed until they are released.
*/
ret = request_irq(info->irq, uio_interrupt,
info->irq_flags, info->name, idev);
if (ret)
goto err_request_irq;
}
return 0;
err_request_irq:
uio_dev_del_attributes(idev);
err_uio_dev_add_attributes:
device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
err_device_create:
uio_free_minor(idev);
return ret;
}
EXPORT_SYMBOL_GPL(__uio_register_device);
/**
* uio_unregister_device - unregister a industrial IO device
* @info: UIO device capabilities
*
*/
void uio_unregister_device(struct uio_info *info)
{
struct uio_device *idev;
if (!info || !info->uio_dev)
return;
idev = info->uio_dev;
uio_free_minor(idev);
uio_dev_del_attributes(idev);
if (info->irq && info->irq != UIO_IRQ_CUSTOM)
free_irq(info->irq, idev);
device_destroy(&uio_class, MKDEV(uio_major, idev->minor));
return;
}
EXPORT_SYMBOL_GPL(uio_unregister_device);
static int __init uio_init(void)
{
return init_uio_class();
}
static void __exit uio_exit(void)
{
release_uio_class();
idr_destroy(&uio_idr);
}
module_init(uio_init)
module_exit(uio_exit)
MODULE_LICENSE("GPL v2");