kernel-fxtec-pro1x/drivers/gpu/drm/drm_file.c
Chris Wilson 00734a9e73 drm: Wake up next in drm_read() chain if we are forced to putback the event
[ Upstream commit 60b801999c48b6c1dd04e653a38e2e613664264e ]

After an event is sent, we try to copy it into the user buffer of the
first waiter in drm_read() and if the user buffer doesn't have enough
room we put it back onto the list. However, we didn't wake up any
subsequent waiter, so that event may sit on the list until either a new
vblank event is sent or a new waiter appears. Rare, but in the worst
case may lead to a stuck process.

Testcase: igt/drm_read/short-buffer-wakeup
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170804082328.17173-1-chris@chris-wilson.co.uk
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-31 06:46:34 -07:00

793 lines
22 KiB
C

/*
* \author Rickard E. (Rik) Faith <faith@valinux.com>
* \author Daryll Strauss <daryll@valinux.com>
* \author Gareth Hughes <gareth@valinux.com>
*/
/*
* Created: Mon Jan 4 08:58:31 1999 by faith@valinux.com
*
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <drm/drm_client.h>
#include <drm/drm_file.h>
#include <drm/drmP.h>
#include "drm_legacy.h"
#include "drm_internal.h"
#include "drm_crtc_internal.h"
/* from BKL pushdown */
DEFINE_MUTEX(drm_global_mutex);
/**
* DOC: file operations
*
* Drivers must define the file operations structure that forms the DRM
* userspace API entry point, even though most of those operations are
* implemented in the DRM core. The resulting &struct file_operations must be
* stored in the &drm_driver.fops field. The mandatory functions are drm_open(),
* drm_read(), drm_ioctl() and drm_compat_ioctl() if CONFIG_COMPAT is enabled
* Note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n, so there's no
* need to sprinkle #ifdef into the code. Drivers which implement private ioctls
* that require 32/64 bit compatibility support must provide their own
* &file_operations.compat_ioctl handler that processes private ioctls and calls
* drm_compat_ioctl() for core ioctls.
*
* In addition drm_read() and drm_poll() provide support for DRM events. DRM
* events are a generic and extensible means to send asynchronous events to
* userspace through the file descriptor. They are used to send vblank event and
* page flip completions by the KMS API. But drivers can also use it for their
* own needs, e.g. to signal completion of rendering.
*
* For the driver-side event interface see drm_event_reserve_init() and
* drm_send_event() as the main starting points.
*
* The memory mapping implementation will vary depending on how the driver
* manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
* function, modern drivers should use one of the provided memory-manager
* specific implementations. For GEM-based drivers this is drm_gem_mmap(), and
* for drivers which use the CMA GEM helpers it's drm_gem_cma_mmap().
*
* No other file operations are supported by the DRM userspace API. Overall the
* following is an example &file_operations structure::
*
* static const example_drm_fops = {
* .owner = THIS_MODULE,
* .open = drm_open,
* .release = drm_release,
* .unlocked_ioctl = drm_ioctl,
* .compat_ioctl = drm_compat_ioctl, // NULL if CONFIG_COMPAT=n
* .poll = drm_poll,
* .read = drm_read,
* .llseek = no_llseek,
* .mmap = drm_gem_mmap,
* };
*
* For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
* CMA based drivers there is the DEFINE_DRM_GEM_CMA_FOPS() macro to make this
* simpler.
*
* The driver's &file_operations must be stored in &drm_driver.fops.
*
* For driver-private IOCTL handling see the more detailed discussion in
* :ref:`IOCTL support in the userland interfaces chapter<drm_driver_ioctl>`.
*/
static int drm_open_helper(struct file *filp, struct drm_minor *minor);
/**
* drm_file_alloc - allocate file context
* @minor: minor to allocate on
*
* This allocates a new DRM file context. It is not linked into any context and
* can be used by the caller freely. Note that the context keeps a pointer to
* @minor, so it must be freed before @minor is.
*
* RETURNS:
* Pointer to newly allocated context, ERR_PTR on failure.
*/
struct drm_file *drm_file_alloc(struct drm_minor *minor)
{
struct drm_device *dev = minor->dev;
struct drm_file *file;
int ret;
file = kzalloc(sizeof(*file), GFP_KERNEL);
if (!file)
return ERR_PTR(-ENOMEM);
file->pid = get_pid(task_pid(current));
file->minor = minor;
/* for compatibility root is always authenticated */
file->authenticated = capable(CAP_SYS_ADMIN);
file->lock_count = 0;
INIT_LIST_HEAD(&file->lhead);
INIT_LIST_HEAD(&file->fbs);
mutex_init(&file->fbs_lock);
INIT_LIST_HEAD(&file->blobs);
INIT_LIST_HEAD(&file->pending_event_list);
INIT_LIST_HEAD(&file->event_list);
init_waitqueue_head(&file->event_wait);
file->event_space = 4096; /* set aside 4k for event buffer */
mutex_init(&file->event_read_lock);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_open(dev, file);
if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
drm_syncobj_open(file);
if (drm_core_check_feature(dev, DRIVER_PRIME))
drm_prime_init_file_private(&file->prime);
if (dev->driver->open) {
ret = dev->driver->open(dev, file);
if (ret < 0)
goto out_prime_destroy;
}
return file;
out_prime_destroy:
if (drm_core_check_feature(dev, DRIVER_PRIME))
drm_prime_destroy_file_private(&file->prime);
if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
drm_syncobj_release(file);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_release(dev, file);
put_pid(file->pid);
kfree(file);
return ERR_PTR(ret);
}
static void drm_events_release(struct drm_file *file_priv)
{
struct drm_device *dev = file_priv->minor->dev;
struct drm_pending_event *e, *et;
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
/* Unlink pending events */
list_for_each_entry_safe(e, et, &file_priv->pending_event_list,
pending_link) {
list_del(&e->pending_link);
e->file_priv = NULL;
}
/* Remove unconsumed events */
list_for_each_entry_safe(e, et, &file_priv->event_list, link) {
list_del(&e->link);
kfree(e);
}
spin_unlock_irqrestore(&dev->event_lock, flags);
}
/**
* drm_file_free - free file context
* @file: context to free, or NULL
*
* This destroys and deallocates a DRM file context previously allocated via
* drm_file_alloc(). The caller must make sure to unlink it from any contexts
* before calling this.
*
* If NULL is passed, this is a no-op.
*
* RETURNS:
* 0 on success, or error code on failure.
*/
void drm_file_free(struct drm_file *file)
{
struct drm_device *dev;
if (!file)
return;
dev = file->minor->dev;
DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
task_pid_nr(current),
(long)old_encode_dev(file->minor->kdev->devt),
dev->open_count);
if (drm_core_check_feature(dev, DRIVER_LEGACY) &&
dev->driver->preclose)
dev->driver->preclose(dev, file);
if (drm_core_check_feature(dev, DRIVER_LEGACY))
drm_legacy_lock_release(dev, file->filp);
if (drm_core_check_feature(dev, DRIVER_HAVE_DMA))
drm_legacy_reclaim_buffers(dev, file);
drm_events_release(file);
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
drm_fb_release(file);
drm_property_destroy_user_blobs(dev, file);
}
if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
drm_syncobj_release(file);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_release(dev, file);
drm_legacy_ctxbitmap_flush(dev, file);
if (drm_is_primary_client(file))
drm_master_release(file);
if (dev->driver->postclose)
dev->driver->postclose(dev, file);
if (drm_core_check_feature(dev, DRIVER_PRIME))
drm_prime_destroy_file_private(&file->prime);
WARN_ON(!list_empty(&file->event_list));
put_pid(file->pid);
kfree(file);
}
static int drm_setup(struct drm_device * dev)
{
int ret;
if (dev->driver->firstopen &&
drm_core_check_feature(dev, DRIVER_LEGACY)) {
ret = dev->driver->firstopen(dev);
if (ret != 0)
return ret;
}
ret = drm_legacy_dma_setup(dev);
if (ret < 0)
return ret;
DRM_DEBUG("\n");
return 0;
}
/**
* drm_open - open method for DRM file
* @inode: device inode
* @filp: file pointer.
*
* This function must be used by drivers as their &file_operations.open method.
* It looks up the correct DRM device and instantiates all the per-file
* resources for it. It also calls the &drm_driver.open driver callback.
*
* RETURNS:
*
* 0 on success or negative errno value on falure.
*/
int drm_open(struct inode *inode, struct file *filp)
{
struct drm_device *dev;
struct drm_minor *minor;
int retcode;
int need_setup = 0;
minor = drm_minor_acquire(iminor(inode));
if (IS_ERR(minor))
return PTR_ERR(minor);
dev = minor->dev;
if (!dev->open_count++)
need_setup = 1;
/* share address_space across all char-devs of a single device */
filp->f_mapping = dev->anon_inode->i_mapping;
retcode = drm_open_helper(filp, minor);
if (retcode)
goto err_undo;
if (need_setup) {
retcode = drm_setup(dev);
if (retcode)
goto err_undo;
}
return 0;
err_undo:
dev->open_count--;
drm_minor_release(minor);
return retcode;
}
EXPORT_SYMBOL(drm_open);
/*
* Check whether DRI will run on this CPU.
*
* \return non-zero if the DRI will run on this CPU, or zero otherwise.
*/
static int drm_cpu_valid(void)
{
#if defined(__sparc__) && !defined(__sparc_v9__)
return 0; /* No cmpxchg before v9 sparc. */
#endif
return 1;
}
/*
* Called whenever a process opens /dev/drm.
*
* \param filp file pointer.
* \param minor acquired minor-object.
* \return zero on success or a negative number on failure.
*
* Creates and initializes a drm_file structure for the file private data in \p
* filp and add it into the double linked list in \p dev.
*/
static int drm_open_helper(struct file *filp, struct drm_minor *minor)
{
struct drm_device *dev = minor->dev;
struct drm_file *priv;
int ret;
if (filp->f_flags & O_EXCL)
return -EBUSY; /* No exclusive opens */
if (!drm_cpu_valid())
return -EINVAL;
if (dev->switch_power_state != DRM_SWITCH_POWER_ON && dev->switch_power_state != DRM_SWITCH_POWER_DYNAMIC_OFF)
return -EINVAL;
DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor->index);
priv = drm_file_alloc(minor);
if (IS_ERR(priv))
return PTR_ERR(priv);
if (drm_is_primary_client(priv)) {
ret = drm_master_open(priv);
if (ret) {
drm_file_free(priv);
return ret;
}
}
filp->private_data = priv;
filp->f_mode |= FMODE_UNSIGNED_OFFSET;
priv->filp = filp;
mutex_lock(&dev->filelist_mutex);
list_add(&priv->lhead, &dev->filelist);
mutex_unlock(&dev->filelist_mutex);
#ifdef __alpha__
/*
* Default the hose
*/
if (!dev->hose) {
struct pci_dev *pci_dev;
pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
if (pci_dev) {
dev->hose = pci_dev->sysdata;
pci_dev_put(pci_dev);
}
if (!dev->hose) {
struct pci_bus *b = list_entry(pci_root_buses.next,
struct pci_bus, node);
if (b)
dev->hose = b->sysdata;
}
}
#endif
return 0;
}
static void drm_legacy_dev_reinit(struct drm_device *dev)
{
if (dev->irq_enabled)
drm_irq_uninstall(dev);
mutex_lock(&dev->struct_mutex);
drm_legacy_agp_clear(dev);
drm_legacy_sg_cleanup(dev);
drm_legacy_vma_flush(dev);
drm_legacy_dma_takedown(dev);
mutex_unlock(&dev->struct_mutex);
dev->sigdata.lock = NULL;
dev->context_flag = 0;
dev->last_context = 0;
dev->if_version = 0;
DRM_DEBUG("lastclose completed\n");
}
void drm_lastclose(struct drm_device * dev)
{
DRM_DEBUG("\n");
if (dev->driver->lastclose)
dev->driver->lastclose(dev);
DRM_DEBUG("driver lastclose completed\n");
if (drm_core_check_feature(dev, DRIVER_LEGACY))
drm_legacy_dev_reinit(dev);
drm_client_dev_restore(dev);
}
/**
* drm_release - release method for DRM file
* @inode: device inode
* @filp: file pointer.
*
* This function must be used by drivers as their &file_operations.release
* method. It frees any resources associated with the open file, and calls the
* &drm_driver.postclose driver callback. If this is the last open file for the
* DRM device also proceeds to call the &drm_driver.lastclose driver callback.
*
* RETURNS:
*
* Always succeeds and returns 0.
*/
int drm_release(struct inode *inode, struct file *filp)
{
struct drm_file *file_priv = filp->private_data;
struct drm_minor *minor = file_priv->minor;
struct drm_device *dev = minor->dev;
mutex_lock(&drm_global_mutex);
DRM_DEBUG("open_count = %d\n", dev->open_count);
mutex_lock(&dev->filelist_mutex);
list_del(&file_priv->lhead);
mutex_unlock(&dev->filelist_mutex);
drm_file_free(file_priv);
if (!--dev->open_count)
drm_lastclose(dev);
mutex_unlock(&drm_global_mutex);
drm_minor_release(minor);
return 0;
}
EXPORT_SYMBOL(drm_release);
/**
* drm_read - read method for DRM file
* @filp: file pointer
* @buffer: userspace destination pointer for the read
* @count: count in bytes to read
* @offset: offset to read
*
* This function must be used by drivers as their &file_operations.read
* method iff they use DRM events for asynchronous signalling to userspace.
* Since events are used by the KMS API for vblank and page flip completion this
* means all modern display drivers must use it.
*
* @offset is ignored, DRM events are read like a pipe. Therefore drivers also
* must set the &file_operation.llseek to no_llseek(). Polling support is
* provided by drm_poll().
*
* This function will only ever read a full event. Therefore userspace must
* supply a big enough buffer to fit any event to ensure forward progress. Since
* the maximum event space is currently 4K it's recommended to just use that for
* safety.
*
* RETURNS:
*
* Number of bytes read (always aligned to full events, and can be 0) or a
* negative error code on failure.
*/
ssize_t drm_read(struct file *filp, char __user *buffer,
size_t count, loff_t *offset)
{
struct drm_file *file_priv = filp->private_data;
struct drm_device *dev = file_priv->minor->dev;
ssize_t ret;
if (!access_ok(VERIFY_WRITE, buffer, count))
return -EFAULT;
ret = mutex_lock_interruptible(&file_priv->event_read_lock);
if (ret)
return ret;
for (;;) {
struct drm_pending_event *e = NULL;
spin_lock_irq(&dev->event_lock);
if (!list_empty(&file_priv->event_list)) {
e = list_first_entry(&file_priv->event_list,
struct drm_pending_event, link);
file_priv->event_space += e->event->length;
list_del(&e->link);
}
spin_unlock_irq(&dev->event_lock);
if (e == NULL) {
if (ret)
break;
if (filp->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
mutex_unlock(&file_priv->event_read_lock);
ret = wait_event_interruptible(file_priv->event_wait,
!list_empty(&file_priv->event_list));
if (ret >= 0)
ret = mutex_lock_interruptible(&file_priv->event_read_lock);
if (ret)
return ret;
} else {
unsigned length = e->event->length;
if (length > count - ret) {
put_back_event:
spin_lock_irq(&dev->event_lock);
file_priv->event_space -= length;
list_add(&e->link, &file_priv->event_list);
spin_unlock_irq(&dev->event_lock);
wake_up_interruptible(&file_priv->event_wait);
break;
}
if (copy_to_user(buffer + ret, e->event, length)) {
if (ret == 0)
ret = -EFAULT;
goto put_back_event;
}
ret += length;
kfree(e);
}
}
mutex_unlock(&file_priv->event_read_lock);
return ret;
}
EXPORT_SYMBOL(drm_read);
/**
* drm_poll - poll method for DRM file
* @filp: file pointer
* @wait: poll waiter table
*
* This function must be used by drivers as their &file_operations.read method
* iff they use DRM events for asynchronous signalling to userspace. Since
* events are used by the KMS API for vblank and page flip completion this means
* all modern display drivers must use it.
*
* See also drm_read().
*
* RETURNS:
*
* Mask of POLL flags indicating the current status of the file.
*/
__poll_t drm_poll(struct file *filp, struct poll_table_struct *wait)
{
struct drm_file *file_priv = filp->private_data;
__poll_t mask = 0;
poll_wait(filp, &file_priv->event_wait, wait);
if (!list_empty(&file_priv->event_list))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
EXPORT_SYMBOL(drm_poll);
/**
* drm_event_reserve_init_locked - init a DRM event and reserve space for it
* @dev: DRM device
* @file_priv: DRM file private data
* @p: tracking structure for the pending event
* @e: actual event data to deliver to userspace
*
* This function prepares the passed in event for eventual delivery. If the event
* doesn't get delivered (because the IOCTL fails later on, before queuing up
* anything) then the even must be cancelled and freed using
* drm_event_cancel_free(). Successfully initialized events should be sent out
* using drm_send_event() or drm_send_event_locked() to signal completion of the
* asynchronous event to userspace.
*
* If callers embedded @p into a larger structure it must be allocated with
* kmalloc and @p must be the first member element.
*
* This is the locked version of drm_event_reserve_init() for callers which
* already hold &drm_device.event_lock.
*
* RETURNS:
*
* 0 on success or a negative error code on failure.
*/
int drm_event_reserve_init_locked(struct drm_device *dev,
struct drm_file *file_priv,
struct drm_pending_event *p,
struct drm_event *e)
{
if (file_priv->event_space < e->length)
return -ENOMEM;
file_priv->event_space -= e->length;
p->event = e;
list_add(&p->pending_link, &file_priv->pending_event_list);
p->file_priv = file_priv;
return 0;
}
EXPORT_SYMBOL(drm_event_reserve_init_locked);
/**
* drm_event_reserve_init - init a DRM event and reserve space for it
* @dev: DRM device
* @file_priv: DRM file private data
* @p: tracking structure for the pending event
* @e: actual event data to deliver to userspace
*
* This function prepares the passed in event for eventual delivery. If the event
* doesn't get delivered (because the IOCTL fails later on, before queuing up
* anything) then the even must be cancelled and freed using
* drm_event_cancel_free(). Successfully initialized events should be sent out
* using drm_send_event() or drm_send_event_locked() to signal completion of the
* asynchronous event to userspace.
*
* If callers embedded @p into a larger structure it must be allocated with
* kmalloc and @p must be the first member element.
*
* Callers which already hold &drm_device.event_lock should use
* drm_event_reserve_init_locked() instead.
*
* RETURNS:
*
* 0 on success or a negative error code on failure.
*/
int drm_event_reserve_init(struct drm_device *dev,
struct drm_file *file_priv,
struct drm_pending_event *p,
struct drm_event *e)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&dev->event_lock, flags);
ret = drm_event_reserve_init_locked(dev, file_priv, p, e);
spin_unlock_irqrestore(&dev->event_lock, flags);
return ret;
}
EXPORT_SYMBOL(drm_event_reserve_init);
/**
* drm_event_cancel_free - free a DRM event and release it's space
* @dev: DRM device
* @p: tracking structure for the pending event
*
* This function frees the event @p initialized with drm_event_reserve_init()
* and releases any allocated space. It is used to cancel an event when the
* nonblocking operation could not be submitted and needed to be aborted.
*/
void drm_event_cancel_free(struct drm_device *dev,
struct drm_pending_event *p)
{
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
if (p->file_priv) {
p->file_priv->event_space += p->event->length;
list_del(&p->pending_link);
}
spin_unlock_irqrestore(&dev->event_lock, flags);
if (p->fence)
dma_fence_put(p->fence);
kfree(p);
}
EXPORT_SYMBOL(drm_event_cancel_free);
/**
* drm_send_event_locked - send DRM event to file descriptor
* @dev: DRM device
* @e: DRM event to deliver
*
* This function sends the event @e, initialized with drm_event_reserve_init(),
* to its associated userspace DRM file. Callers must already hold
* &drm_device.event_lock, see drm_send_event() for the unlocked version.
*
* Note that the core will take care of unlinking and disarming events when the
* corresponding DRM file is closed. Drivers need not worry about whether the
* DRM file for this event still exists and can call this function upon
* completion of the asynchronous work unconditionally.
*/
void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
{
assert_spin_locked(&dev->event_lock);
if (e->completion) {
complete_all(e->completion);
e->completion_release(e->completion);
e->completion = NULL;
}
if (e->fence) {
dma_fence_signal(e->fence);
dma_fence_put(e->fence);
}
if (!e->file_priv) {
kfree(e);
return;
}
list_del(&e->pending_link);
list_add_tail(&e->link,
&e->file_priv->event_list);
wake_up_interruptible(&e->file_priv->event_wait);
}
EXPORT_SYMBOL(drm_send_event_locked);
/**
* drm_send_event - send DRM event to file descriptor
* @dev: DRM device
* @e: DRM event to deliver
*
* This function sends the event @e, initialized with drm_event_reserve_init(),
* to its associated userspace DRM file. This function acquires
* &drm_device.event_lock, see drm_send_event_locked() for callers which already
* hold this lock.
*
* Note that the core will take care of unlinking and disarming events when the
* corresponding DRM file is closed. Drivers need not worry about whether the
* DRM file for this event still exists and can call this function upon
* completion of the asynchronous work unconditionally.
*/
void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
{
unsigned long irqflags;
spin_lock_irqsave(&dev->event_lock, irqflags);
drm_send_event_locked(dev, e);
spin_unlock_irqrestore(&dev->event_lock, irqflags);
}
EXPORT_SYMBOL(drm_send_event);