Commit 1a6c0b36 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Mauro Carvalho Chehab
Browse files

media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI 



The v4l2_event structure contains a 'struct timespec' member that is
defined by the user space C library, creating an ABI incompatibility
when that gets updated to a 64-bit time_t.

While passing a 32-bit time_t here would be sufficient for CLOCK_MONOTONIC
timestamps, simply redefining the structure to use the kernel's
__kernel_old_timespec would not work for any library that uses a copy
of the linux/videodev2.h header file rather than including the copy from
the latest kernel headers.

This means the kernel has to be changed to handle both versions of the
structure layout on a 32-bit architecture. The easiest way to do this
is during the copy from/to user space.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent c8ef1a60

drivers/media/v4l2-core/v4l2-event.c

+4 −1
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx) 
static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)

{

	struct v4l2_kevent *kev;

	struct timespec64 ts;

	unsigned long flags;



	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
@@ -44,7 +45,9 @@ static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event) 


	kev->event.pending = fh->navailable;

	*event = kev->event;

	event->timestamp = ns_to_timespec(kev->ts);

	ts = ns_to_timespec64(kev->ts);

	event->timestamp.tv_sec = ts.tv_sec;

	event->timestamp.tv_nsec = ts.tv_nsec;

	kev->sev->first = sev_pos(kev->sev, 1);

	kev->sev->in_use--;

drivers/media/v4l2-core/v4l2-ioctl.c

+28 −1
Original line number Diff line number Diff line
@@ -821,7 +821,7 @@ static void v4l_print_event(const void *arg, bool write_only) 
	const struct v4l2_event *p = arg;

	const struct v4l2_event_ctrl *c;



	pr_cont("type=0x%x, pending=%u, sequence=%u, id=%u, timestamp=%lu.%9.9lu\n",

	pr_cont("type=0x%x, pending=%u, sequence=%u, id=%u, timestamp=%llu.%9.9llu\n",

			p->type, p->pending, p->sequence, p->id,

			p->timestamp.tv_sec, p->timestamp.tv_nsec);

	switch (p->type) {
@@ -3025,6 +3025,13 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size, 


static unsigned int video_translate_cmd(unsigned int cmd)

{

	switch (cmd) {

#ifdef CONFIG_COMPAT_32BIT_TIME

	case VIDIOC_DQEVENT_TIME32:

		return VIDIOC_DQEVENT;

#endif

	}



	return cmd;

}
@@ -3074,6 +3081,26 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd) 
		return 0;



	switch (cmd) {

#ifdef CONFIG_COMPAT_32BIT_TIME

	case VIDIOC_DQEVENT_TIME32: {

		struct v4l2_event *ev = parg;

		struct v4l2_event_time32 ev32 = {

			.type		= ev->type,

			.pending	= ev->pending,

			.sequence	= ev->sequence,

			.timestamp.tv_sec  = ev->timestamp.tv_sec,

			.timestamp.tv_nsec = ev->timestamp.tv_nsec,

			.id		= ev->id,

		};



		memcpy(&ev32.u, &ev->u, sizeof(ev->u));

		memcpy(&ev32.reserved, &ev->reserved, sizeof(ev->reserved));



		if (copy_to_user(arg, &ev32, sizeof(ev32)))

			return -EFAULT;

		break;

	}

#endif

	default:

		/*  Copy results into user buffer  */

		if (copy_to_user(arg, parg, _IOC_SIZE(cmd)))

drivers/media/v4l2-core/v4l2-subdev.c

+25 −1
Original line number Diff line number Diff line
@@ -331,8 +331,8 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 
	struct v4l2_fh *vfh = file->private_data;

#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)

	struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);

	int rval;

#endif

	int rval;



	switch (cmd) {

	case VIDIOC_QUERYCTRL:
@@ -392,6 +392,30 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) 


		return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK);



	case VIDIOC_DQEVENT_TIME32: {

		struct v4l2_event_time32 *ev32 = arg;

		struct v4l2_event ev;



		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))

			return -ENOIOCTLCMD;



		rval = v4l2_event_dequeue(vfh, &ev, file->f_flags & O_NONBLOCK);



		*ev32 = (struct v4l2_event_time32) {

			.type		= ev.type,

			.pending	= ev.pending,

			.sequence	= ev.sequence,

			.timestamp.tv_sec  = ev.timestamp.tv_sec,

			.timestamp.tv_nsec = ev.timestamp.tv_nsec,

			.id		= ev.id,

		};



		memcpy(&ev32->u, &ev.u, sizeof(ev.u));

		memcpy(&ev32->reserved, &ev.reserved, sizeof(ev.reserved));



		return rval;

	}



	case VIDIOC_SUBSCRIBE_EVENT:

		return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);

include/media/v4l2-ioctl.h

+25 −0
Original line number Diff line number Diff line
@@ -724,4 +724,29 @@ long int video_usercopy(struct file *file, unsigned int cmd, 
long int video_ioctl2(struct file *file,

		      unsigned int cmd, unsigned long int arg);



/*

 * The user space interpretation of the 'v4l2_event' differs

 * based on the 'time_t' definition on 32-bit architectures, so

 * the kernel has to handle both.

 * This is the old version for 32-bit architectures.

 */

struct v4l2_event_time32 {

	__u32				type;

	union {

		struct v4l2_event_vsync		vsync;

		struct v4l2_event_ctrl		ctrl;

		struct v4l2_event_frame_sync	frame_sync;

		struct v4l2_event_src_change	src_change;

		struct v4l2_event_motion_det	motion_det;

		__u8				data[64];

	} u;

	__u32				pending;

	__u32				sequence;

	struct old_timespec32		timestamp;

	__u32				id;

	__u32				reserved[8];

};



#define	VIDIOC_DQEVENT_TIME32	 _IOR('V', 89, struct v4l2_event_time32)



#endif /* _V4L2_IOCTL_H */

include/uapi/linux/videodev2.h

+4 −0
Original line number Diff line number Diff line
@@ -2341,7 +2341,11 @@ struct v4l2_event { 
	} u;

	__u32				pending;

	__u32				sequence;

#ifdef __KERNEL__

	struct __kernel_timespec	timestamp;

#else

	struct timespec			timestamp;

#endif

	__u32				id;

	__u32				reserved[8];

};

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