linux/drivers/gpu/drm/drm_file.c

/*
 * \author Rickard E. (Rik) Faith <[email protected]>
 * \author Daryll Strauss <[email protected]>
 * \author Gareth Hughes <[email protected]>
 */

/*
 * Created: Mon Jan  4 08:58:31 1999 by [email protected]
 *
 * 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/anon_inodes.h>
#include <linux/dma-fence.h>
#include <linux/file.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/vga_switcheroo.h>

#include <drm/drm_client.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_gem.h>
#include <drm/drm_print.h>

#include "drm_crtc_internal.h"
#include "drm_internal.h"

/* from BKL pushdown */
DEFINE_MUTEX();

bool drm_dev_needs_global_mutex(struct drm_device *dev)
{}

/**
 * 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. For GEM-based drivers this is drm_gem_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,
 *             .mmap = drm_gem_mmap,
 *     };
 *
 * For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
 * DMA based drivers there is the DEFINE_DRM_GEM_DMA_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>`.
 */

/**
 * 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)
{}

static void drm_events_release(struct drm_file *file_priv)
{}

/**
 * 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.
 */
void drm_file_free(struct drm_file *file)
{}

static void drm_close_helper(struct file *filp)
{}

/*
 * 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)
{}

/*
 * Called whenever a process opens a drm node
 *
 * \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.
 */
int drm_open_helper(struct file *filp, struct drm_minor *minor)
{}

/**
 * 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 failure.
 */
int drm_open(struct inode *inode, struct file *filp)
{}
EXPORT_SYMBOL();

static void drm_lastclose(struct drm_device *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. If this
 * is the last open file for the DRM device, it also restores the active
 * in-kernel DRM client.
 *
 * RETURNS:
 * Always succeeds and returns 0.
 */
int drm_release(struct inode *inode, struct file *filp)
{}
EXPORT_SYMBOL();

void drm_file_update_pid(struct drm_file *filp)
{}

/**
 * drm_release_noglobal - release method for DRM file
 * @inode: device inode
 * @filp: file pointer.
 *
 * This function may be used by drivers as their &file_operations.release
 * method. It frees any resources associated with the open file prior to taking
 * the drm_global_mutex. If this is the last open file for the DRM device, it
 * then restores the active in-kernel DRM client.
 *
 * RETURNS:
 * Always succeeds and returns 0.
 */
int drm_release_noglobal(struct inode *inode, struct file *filp)
{}
EXPORT_SYMBOL();

/**
 * 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 if 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. 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)
{}
EXPORT_SYMBOL();

/**
 * 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
 * if 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)
{}
EXPORT_SYMBOL();

/**
 * 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)
{}
EXPORT_SYMBOL();

/**
 * 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)
{}
EXPORT_SYMBOL();

/**
 * drm_event_cancel_free - free a DRM event and release its 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)
{}
EXPORT_SYMBOL();

static void drm_send_event_helper(struct drm_device *dev,
			   struct drm_pending_event *e, ktime_t timestamp)
{}

/**
 * drm_send_event_timestamp_locked - send DRM event to file descriptor
 * @dev: DRM device
 * @e: DRM event to deliver
 * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
 * time domain
 *
 * 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.
 *
 * 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_timestamp_locked(struct drm_device *dev,
				     struct drm_pending_event *e, ktime_t timestamp)
{}
EXPORT_SYMBOL();

/**
 * 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)
{}
EXPORT_SYMBOL();

/**
 * 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)
{}
EXPORT_SYMBOL();

static void print_size(struct drm_printer *p, const char *stat,
		       const char *region, u64 sz)
{}

/**
 * drm_print_memory_stats - A helper to print memory stats
 * @p: The printer to print output to
 * @stats: The collected memory stats
 * @supported_status: Bitmask of optional stats which are available
 * @region: The memory region
 *
 */
void drm_print_memory_stats(struct drm_printer *p,
			    const struct drm_memory_stats *stats,
			    enum drm_gem_object_status supported_status,
			    const char *region)
{}
EXPORT_SYMBOL();

/**
 * drm_show_memory_stats - Helper to collect and show standard fdinfo memory stats
 * @p: the printer to print output to
 * @file: the DRM file
 *
 * Helper to iterate over GEM objects with a handle allocated in the specified
 * file.
 */
void drm_show_memory_stats(struct drm_printer *p, struct drm_file *file)
{}
EXPORT_SYMBOL();

/**
 * drm_show_fdinfo - helper for drm file fops
 * @m: output stream
 * @f: the device file instance
 *
 * Helper to implement fdinfo, for userspace to query usage stats, etc, of a
 * process using the GPU.  See also &drm_driver.show_fdinfo.
 *
 * For text output format description please see Documentation/gpu/drm-usage-stats.rst
 */
void drm_show_fdinfo(struct seq_file *m, struct file *f)
{}
EXPORT_SYMBOL();

/**
 * mock_drm_getfile - Create a new struct file for the drm device
 * @minor: drm minor to wrap (e.g. #drm_device.primary)
 * @flags: file creation mode (O_RDWR etc)
 *
 * This create a new struct file that wraps a DRM file context around a
 * DRM minor. This mimicks userspace opening e.g. /dev/dri/card0, but without
 * invoking userspace. The struct file may be operated on using its f_op
 * (the drm_device.driver.fops) to mimick userspace operations, or be supplied
 * to userspace facing functions as an internal/anonymous client.
 *
 * RETURNS:
 * Pointer to newly created struct file, ERR_PTR on failure.
 */
struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags)
{}
EXPORT_SYMBOL_FOR_TESTS_ONLY();