drm: document drm_ioctl.[hc]

Also unify/merge with the existing stuff.

I was a bit torn where to put this, but in the end I decided to put
all the ioctl/sysfs/debugfs stuff into drm-uapi.rst. That means we
have a bit a split with the other uapi related stuff used internally,
like drm_file.[hc], but I think overall this makes more sense.

If it's too confusing we can always add more cross-links to make it
more discoverable. But the auto-sprinkling of links kernel-doc already
does seems sufficient.

Also for prettier docs and more cross-links, switch the internal
defines over to an enum, as usual.

v2: Update kerneldoc fro drm_compat_ioctl too (caught by 0day), plus a
bit more drive-by polish.

v3: Fix typo, spotted by xerpi on irc (Sergi).

v4: Add missing space in comment (Neil).

Cc: Sergi Granell <xerpi.g.12@gmail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170404095304.17599-4-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter 2017-04-04 11:52:57 +02:00
parent e22717046a
commit 2640981f36
5 changed files with 203 additions and 103 deletions

View File

@ -255,56 +255,6 @@ File Operations
.. kernel-doc:: drivers/gpu/drm/drm_file.c
:export:
IOCTLs
------
struct drm_ioctl_desc \*ioctls; int num_ioctls;
Driver-specific ioctls descriptors table.
Driver-specific ioctls numbers start at DRM_COMMAND_BASE. The ioctls
descriptors table is indexed by the ioctl number offset from the base
value. Drivers can use the DRM_IOCTL_DEF_DRV() macro to initialize
the table entries.
::
DRM_IOCTL_DEF_DRV(ioctl, func, flags)
``ioctl`` is the ioctl name. Drivers must define the DRM_##ioctl and
DRM_IOCTL_##ioctl macros to the ioctl number offset from
DRM_COMMAND_BASE and the ioctl number respectively. The first macro is
private to the device while the second must be exposed to userspace in a
public header.
``func`` is a pointer to the ioctl handler function compatible with the
``drm_ioctl_t`` type.
::
typedef int drm_ioctl_t(struct drm_device *dev, void *data,
struct drm_file *file_priv);
``flags`` is a bitmask combination of the following values. It restricts
how the ioctl is allowed to be called.
- DRM_AUTH - Only authenticated callers allowed
- DRM_MASTER - The ioctl can only be called on the master file handle
- DRM_ROOT_ONLY - Only callers with the SYSADMIN capability allowed
- DRM_CONTROL_ALLOW - The ioctl can only be called on a control
device
- DRM_UNLOCKED - The ioctl handler will be called without locking the
DRM global mutex. This is the enforced default for kms drivers (i.e.
using the DRIVER_MODESET flag) and hence shouldn't be used any more
for new drivers.
.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
:export:
Misc Utilities
==============

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@ -160,6 +160,20 @@ other hand, a driver requires shared state between clients which is
visible to user-space and accessible beyond open-file boundaries, they
cannot support render nodes.
IOCTL Support on Device Nodes
=============================
.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
:doc: driver specific ioctls
.. kernel-doc:: include/drm/drm_ioctl.h
:internal:
.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
:export:
.. kernel-doc:: drivers/gpu/drm/drm_ioc32.c
:export:
Testing and validation
======================

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@ -1,4 +1,4 @@
/**
/*
* \file drm_ioc32.c
*
* 32-bit ioctl compatibility routines for the DRM.
@ -72,15 +72,15 @@
#define DRM_IOCTL_MODE_ADDFB232 DRM_IOWR(0xb8, drm_mode_fb_cmd232_t)
typedef struct drm_version_32 {
int version_major; /**< Major version */
int version_minor; /**< Minor version */
int version_patchlevel; /**< Patch level */
u32 name_len; /**< Length of name buffer */
u32 name; /**< Name of driver */
u32 date_len; /**< Length of date buffer */
u32 date; /**< User-space buffer to hold date */
u32 desc_len; /**< Length of desc buffer */
u32 desc; /**< User-space buffer to hold desc */
int version_major; /* Major version */
int version_minor; /* Minor version */
int version_patchlevel; /* Patch level */
u32 name_len; /* Length of name buffer */
u32 name; /* Name of driver */
u32 date_len; /* Length of date buffer */
u32 date; /* User-space buffer to hold date */
u32 desc_len; /* Length of desc buffer */
u32 desc; /* User-space buffer to hold desc */
} drm_version32_t;
static int compat_drm_version(struct file *file, unsigned int cmd,
@ -126,8 +126,8 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
}
typedef struct drm_unique32 {
u32 unique_len; /**< Length of unique */
u32 unique; /**< Unique name for driver instantiation */
u32 unique_len; /* Length of unique */
u32 unique; /* Unique name for driver instantiation */
} drm_unique32_t;
static int compat_drm_getunique(struct file *file, unsigned int cmd,
@ -180,12 +180,12 @@ static int compat_drm_setunique(struct file *file, unsigned int cmd,
}
typedef struct drm_map32 {
u32 offset; /**< Requested physical address (0 for SAREA)*/
u32 size; /**< Requested physical size (bytes) */
enum drm_map_type type; /**< Type of memory to map */
enum drm_map_flags flags; /**< Flags */
u32 handle; /**< User-space: "Handle" to pass to mmap() */
int mtrr; /**< MTRR slot used */
u32 offset; /* Requested physical address (0 for SAREA) */
u32 size; /* Requested physical size (bytes) */
enum drm_map_type type; /* Type of memory to map */
enum drm_map_flags flags; /* Flags */
u32 handle; /* User-space: "Handle" to pass to mmap() */
int mtrr; /* MTRR slot used */
} drm_map32_t;
static int compat_drm_getmap(struct file *file, unsigned int cmd,
@ -286,12 +286,12 @@ static int compat_drm_rmmap(struct file *file, unsigned int cmd,
}
typedef struct drm_client32 {
int idx; /**< Which client desired? */
int auth; /**< Is client authenticated? */
u32 pid; /**< Process ID */
u32 uid; /**< User ID */
u32 magic; /**< Magic */
u32 iocs; /**< Ioctl count */
int idx; /* Which client desired? */
int auth; /* Is client authenticated? */
u32 pid; /* Process ID */
u32 uid; /* User ID */
u32 magic; /* Magic */
u32 iocs; /* Ioctl count */
} drm_client32_t;
static int compat_drm_getclient(struct file *file, unsigned int cmd,
@ -366,12 +366,12 @@ static int compat_drm_getstats(struct file *file, unsigned int cmd,
}
typedef struct drm_buf_desc32 {
int count; /**< Number of buffers of this size */
int size; /**< Size in bytes */
int low_mark; /**< Low water mark */
int high_mark; /**< High water mark */
int count; /* Number of buffers of this size */
int size; /* Size in bytes */
int low_mark; /* Low water mark */
int high_mark; /* High water mark */
int flags;
u32 agp_start; /**< Start address in the AGP aperture */
u32 agp_start; /* Start address in the AGP aperture */
} drm_buf_desc32_t;
static int compat_drm_addbufs(struct file *file, unsigned int cmd,
@ -1111,13 +1111,18 @@ static drm_ioctl_compat_t *drm_compat_ioctls[] = {
};
/**
* Called whenever a 32-bit process running under a 64-bit kernel
* performs an ioctl on /dev/drm.
* drm_compat_ioctl - 32bit IOCTL compatibility handler for DRM drivers
* @filp: file this ioctl is called on
* @cmd: ioctl cmd number
* @arg: user argument
*
* \param file_priv DRM file private.
* \param cmd command.
* \param arg user argument.
* \return zero on success or negative number on failure.
* Compatibility handler for 32 bit userspace running on 64 kernels. All actual
* IOCTL handling is forwarded to drm_ioctl(), while marshalling structures as
* appropriate. Note that this only handles DRM core IOCTLs, if the driver has
* botched IOCTL itself, it must handle those by wrapping this function.
*
* Returns:
* Zero on success, negative error code on failure.
*/
long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
@ -1141,5 +1146,4 @@ long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return ret;
}
EXPORT_SYMBOL(drm_compat_ioctl);

View File

@ -646,14 +646,60 @@ static const struct drm_ioctl_desc drm_ioctls[] = {
#define DRM_CORE_IOCTL_COUNT ARRAY_SIZE( drm_ioctls )
/**
* DOC: driver specific ioctls
*
* First things first, driver private IOCTLs should only be needed for drivers
* supporting rendering. Kernel modesetting is all standardized, and extended
* through properties. There are a few exceptions in some existing drivers,
* which define IOCTL for use by the display DRM master, but they all predate
* properties.
*
* Now if you do have a render driver you always have to support it through
* driver private properties. There's a few steps needed to wire all the things
* up.
*
* First you need to define the structure for your IOCTL in your driver private
* UAPI header in ``include/uapi/drm/my_driver_drm.h``::
*
* struct my_driver_operation {
* u32 some_thing;
* u32 another_thing;
* };
*
* Please make sure that you follow all the best practices from
* ``Documentation/ioctl/botching-up-ioctls.txt``. Note that drm_ioctl()
* automatically zero-extends structures, hence make sure you can add more stuff
* at the end, i.e. don't put a variable sized array there.
*
* Then you need to define your IOCTL number, using one of DRM_IO(), DRM_IOR(),
* DRM_IOW() or DRM_IOWR(). It must start with the DRM_IOCTL\_ prefix::
*
* ##define DRM_IOCTL_MY_DRIVER_OPERATION \
* DRM_IOW(DRM_COMMAND_BASE, struct my_driver_operation)
*
* DRM driver private IOCTL must be in the range from DRM_COMMAND_BASE to
* DRM_COMMAND_END. Finally you need an array of &struct drm_ioctl_desc to wire
* up the handlers and set the access rights:
*
* static const struct drm_ioctl_desc my_driver_ioctls[] = {
* DRM_IOCTL_DEF_DRV(MY_DRIVER_OPERATION, my_driver_operation,
* DRM_AUTH|DRM_RENDER_ALLOW),
* };
*
* And then assign this to the &drm_driver.ioctls field in your driver
* structure.
*/
/**
* drm_ioctl - ioctl callback implementation for DRM drivers
* @filp: file this ioctl is called on
* @cmd: ioctl cmd number
* @arg: user argument
*
* Looks up the ioctl function in the ::ioctls table, checking for root
* previleges if so required, and dispatches to the respective function.
* Looks up the ioctl function in the DRM core and the driver dispatch table,
* stored in &drm_driver.ioctls. It checks for necessary permission by calling
* drm_ioctl_permit(), and dispatches to the respective function.
*
* Returns:
* Zero on success, negative error code on failure.

View File

@ -33,6 +33,7 @@
#define _DRM_IOCTL_H_
#include <linux/types.h>
#include <linux/bitops.h>
#include <asm/ioctl.h>
@ -41,41 +42,126 @@ struct drm_file;
struct file;
/**
* Ioctl function type.
* drm_ioctl_t - DRM ioctl function type.
* @dev: DRM device inode
* @data: private pointer of the ioctl call
* @file_priv: DRM file this ioctl was made on
*
* \param inode device inode.
* \param file_priv DRM file private pointer.
* \param cmd command.
* \param arg argument.
* This is the DRM ioctl typedef. Note that drm_ioctl() has alrady copied @data
* into kernel-space, and will also copy it back, depending upon the read/write
* settings in the ioctl command code.
*/
typedef int drm_ioctl_t(struct drm_device *dev, void *data,
struct drm_file *file_priv);
/**
* drm_ioctl_compat_t - compatibility DRM ioctl function type.
* @filp: file pointer
* @cmd: ioctl command code
* @arg: DRM file this ioctl was made on
*
* Just a typedef to make declaring an array of compatibility handlers easier.
* New drivers shouldn't screw up the structure layout for their ioctl
* structures and hence never need this.
*/
typedef int drm_ioctl_compat_t(struct file *filp, unsigned int cmd,
unsigned long arg);
#define DRM_IOCTL_NR(n) _IOC_NR(n)
#define DRM_MAJOR 226
#define DRM_AUTH 0x1
#define DRM_MASTER 0x2
#define DRM_ROOT_ONLY 0x4
#define DRM_CONTROL_ALLOW 0x8
#define DRM_UNLOCKED 0x10
#define DRM_RENDER_ALLOW 0x20
/**
* enum drm_ioctl_flags - DRM ioctl flags
*
* Various flags that can be set in &drm_ioctl_desc.flags to control how
* userspace can use a given ioctl.
*/
enum drm_ioctl_flags {
/**
* @DRM_AUTH:
*
* This is for ioctl which are used for rendering, and require that the
* file descriptor is either for a render node, or if it's a
* legacy/primary node, then it must be authenticated.
*/
DRM_AUTH = BIT(0),
/**
* @DRM_MASTER:
*
* This must be set for any ioctl which can change the modeset or
* display state. Userspace must call the ioctl through a primary node,
* while it is the active master.
*
* Note that read-only modeset ioctl can also be called by
* unauthenticated clients, or when a master is not the currently active
* one.
*/
DRM_MASTER = BIT(1),
/**
* @DRM_ROOT_ONLY:
*
* Anything that could potentially wreak a master file descriptor needs
* to have this flag set. Current that's only for the SETMASTER and
* DROPMASTER ioctl, which e.g. logind can call to force a non-behaving
* master (display compositor) into compliance.
*
* This is equivalent to callers with the SYSADMIN capability.
*/
DRM_ROOT_ONLY = BIT(2),
/**
* @DRM_CONTROL_ALLOW:
*
* Deprecated, do not use. Control nodes are in the process of getting
* removed.
*/
DRM_CONTROL_ALLOW = BIT(3),
/**
* @DRM_UNLOCKED:
*
* Whether &drm_ioctl_desc.func should be called with the DRM BKL held
* or not. Enforced as the default for all modern drivers, hence there
* should never be a need to set this flag.
*/
DRM_UNLOCKED = BIT(4),
/**
* @DRM_RENDER_ALLOW:
*
* This is used for all ioctl needed for rendering only, for drivers
* which support render nodes. This should be all new render drivers,
* and hence it should be always set for any ioctl with DRM_AUTH set.
* Note though that read-only query ioctl might have this set, but have
* not set DRM_AUTH because they do not require authentication.
*/
DRM_RENDER_ALLOW = BIT(5),
};
/**
* struct drm_ioctl_desc - DRM driver ioctl entry
* @cmd: ioctl command number, without flags
* @flags: a bitmask of &enum drm_ioctl_flags
* @func: handler for this ioctl
* @name: user-readable name for debug output
*
* For convenience it's easier to create these using the DRM_IOCTL_DEF_DRV()
* macro.
*/
struct drm_ioctl_desc {
unsigned int cmd;
int flags;
enum drm_ioctl_flags flags;
drm_ioctl_t *func;
const char *name;
};
/**
* Creates a driver or general drm_ioctl_desc array entry for the given
* ioctl, for use by drm_ioctl().
* DRM_IOCTL_DEF_DRV() - helper macro to fill out a &struct drm_ioctl_desc
* @ioctl: ioctl command suffix
* @_func: handler for the ioctl
* @_flags: a bitmask of &enum drm_ioctl_flags
*
* Small helper macro to create a &struct drm_ioctl_desc entry. The ioctl
* command number is constructed by prepending ``DRM_IOCTL\_`` and passing that
* to DRM_IOCTL_NR().
*/
#define DRM_IOCTL_DEF_DRV(ioctl, _func, _flags) \
[DRM_IOCTL_NR(DRM_IOCTL_##ioctl) - DRM_COMMAND_BASE] = { \
.cmd = DRM_IOCTL_##ioctl, \