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[v2,8/9,media] handle 64-bit time_t in v4l2_buffer

Message ID 1442524780-781677-9-git-send-email-arnd@arndb.de (mailing list archive)
State New, archived
Headers show

Commit Message

Arnd Bergmann Sept. 17, 2015, 9:19 p.m. UTC
This is the final change to enable user space with 64-bit time_t
in the core v4l2 code.

Four ioctls are affected here: VIDIOC_QUERYBUF, VIDIOC_QBUF,
VIDIOC_DQBUF, and VIDIOC_PREPARE_BUF. All of them pass a
struct v4l2_buffer, which can either contain a 32-bit time_t
or a 64-bit time on 32-bit architectures.

In this patch, we redefine the in-kernel version of this structure
to use the 64-bit __s64 type through the use of v4l2_timeval.
This means the normal ioctl handling now assumes 64-bit time_t
and so we have to add support for 32-bit time_t in new handlers.

This is somewhat similar to the 32-bit compat handling on 64-bit
architectures, but those also have to modify other fields of
the structure. For now, I leave that compat code alone, as it
handles the normal case (32-bit compat_time_t) correctly, this
has to be done as a follow-up.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/media/v4l2-core/v4l2-ioctl.c | 174 +++++++++++++++++++++++++++++++++--
 include/uapi/linux/videodev2.h       |  34 ++++++-
 2 files changed, 199 insertions(+), 9 deletions(-)

Comments

Hans Verkuil Sept. 18, 2015, 7:18 a.m. UTC | #1
Hi Arnd,

Thanks once again for working on this! Unfortunately, this approach won't
work, see my comments below.

BTW, I would expect to see compile errors when compiling for 32 bit. Did
you try that?

On 09/17/2015 11:19 PM, Arnd Bergmann wrote:
> This is the final change to enable user space with 64-bit time_t
> in the core v4l2 code.
> 
> Four ioctls are affected here: VIDIOC_QUERYBUF, VIDIOC_QBUF,
> VIDIOC_DQBUF, and VIDIOC_PREPARE_BUF. All of them pass a
> struct v4l2_buffer, which can either contain a 32-bit time_t
> or a 64-bit time on 32-bit architectures.
> 
> In this patch, we redefine the in-kernel version of this structure
> to use the 64-bit __s64 type through the use of v4l2_timeval.
> This means the normal ioctl handling now assumes 64-bit time_t
> and so we have to add support for 32-bit time_t in new handlers.
> 
> This is somewhat similar to the 32-bit compat handling on 64-bit
> architectures, but those also have to modify other fields of
> the structure. For now, I leave that compat code alone, as it
> handles the normal case (32-bit compat_time_t) correctly, this
> has to be done as a follow-up.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/media/v4l2-core/v4l2-ioctl.c | 174 +++++++++++++++++++++++++++++++++--
>  include/uapi/linux/videodev2.h       |  34 ++++++-
>  2 files changed, 199 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 7aab18dd2ca5..137475c28e8f 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -438,15 +438,14 @@ static void v4l_print_buffer(const void *arg, bool write_only)
>  	const struct v4l2_timecode *tc = &p->timecode;
>  	const struct v4l2_plane *plane;
>  	int i;
> +	/* y2038 safe because of monotonic time */
> +	unsigned int seconds = p->timestamp.tv_sec;
>  
> -	pr_cont("%02ld:%02d:%02d.%08ld index=%d, type=%s, "
> +	pr_cont("%02d:%02d:%02d.%08ld index=%d, type=%s, "
>  		"flags=0x%08x, field=%s, sequence=%d, memory=%s",
> -			p->timestamp.tv_sec / 3600,
> -			(int)(p->timestamp.tv_sec / 60) % 60,
> -			(int)(p->timestamp.tv_sec % 60),
> -			(long)p->timestamp.tv_usec,
> -			p->index,
> -			prt_names(p->type, v4l2_type_names),
> +			seconds / 3600, (seconds / 60) % 60,
> +			seconds % 60, (long)p->timestamp.tv_usec,
> +			p->index, prt_names(p->type, v4l2_type_names),
>  			p->flags, prt_names(p->field, v4l2_field_names),
>  			p->sequence, prt_names(p->memory, v4l2_memory_names));
>  
> @@ -1846,6 +1845,123 @@ static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
>  	return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
>  }
>  
> +#ifndef CONFIG_64BIT
> +static void v4l_get_buffer_time32(struct v4l2_buffer *to,
> +				  const struct v4l2_buffer_time32 *from)
> +{
> +	to->index		= from->index;
> +	to->type		= from->type;
> +	to->bytesused		= from->bytesused;
> +	to->flags		= from->flags;
> +	to->field		= from->field;
> +	to->timestamp.tv_sec	= from->timestamp.tv_sec;
> +	to->timestamp.tv_usec	= from->timestamp.tv_usec;
> +	to->timecode		= from->timecode;
> +	to->sequence		= from->sequence;
> +	to->memory		= from->memory;
> +	to->m.offset		= from->m.offset;
> +	to->length		= from->length;
> +	to->reserved2		= from->reserved2;
> +	to->reserved		= from->reserved;
> +}
> +
> +static void v4l_put_buffer_time32(struct v4l2_buffer_time32 *to,
> +				  const struct v4l2_buffer *from)
> +{
> +	to->index		= from->index;
> +	to->type		= from->type;
> +	to->bytesused		= from->bytesused;
> +	to->flags		= from->flags;
> +	to->field		= from->field;
> +	to->timestamp.tv_sec	= from->timestamp.tv_sec;
> +	to->timestamp.tv_usec	= from->timestamp.tv_usec;
> +	to->timecode		= from->timecode;
> +	to->sequence		= from->sequence;
> +	to->memory		= from->memory;
> +	to->m.offset		= from->m.offset;
> +	to->length		= from->length;
> +	to->reserved2		= from->reserved2;
> +	to->reserved		= from->reserved;
> +}

Is there a reason why you didn't use memcpy like you did for VIDIOC_DQEVENT (path 5/9)?
I would prefer that over these explicit assignments.

> +
> +static int v4l_querybuf_time32(const struct v4l2_ioctl_ops *ops,
> +				struct file *file, void *fh, void *arg)
> +{
> +	struct v4l2_buffer buffer;
> +	int ret;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	ret = v4l_querybuf(ops, file, fh, &buffer);
> +	v4l_put_buffer_time32(arg, &buffer);
> +
> +	return ret;
> +}
> +
> +static int v4l_qbuf_time32(const struct v4l2_ioctl_ops *ops,
> +				struct file *file, void *fh, void *arg)
> +{
> +	struct v4l2_buffer buffer;
> +	int ret;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	ret = v4l_qbuf(ops, file, fh, &buffer);
> +	v4l_put_buffer_time32(arg, &buffer);
> +
> +	return ret;
> +}
> +
> +static int v4l_dqbuf_time32(const struct v4l2_ioctl_ops *ops,
> +				struct file *file, void *fh, void *arg)
> +{
> +	struct v4l2_buffer buffer;
> +	int ret;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	ret = v4l_dqbuf(ops, file, fh, &buffer);
> +	v4l_put_buffer_time32(arg, &buffer);
> +
> +	return ret;
> +}
> +
> +static int v4l_prepare_buf_time32(const struct v4l2_ioctl_ops *ops,
> +				struct file *file, void *fh, void *arg)
> +{
> +	struct v4l2_buffer buffer;
> +	int ret;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	ret = v4l_prepare_buf(ops, file, fh, &buffer);
> +
> +	return ret;
> +}
> +
> +static void v4l_print_buffer_time32(const void *arg, bool write_only)
> +{
> +	struct v4l2_buffer buffer;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	v4l_print_buffer(&buffer, write_only);
> +}
> +
> +#ifdef CONFIG_TRACEPOINTS
> +static void trace_v4l2_dqbuf_time32(int minor, const struct v4l2_buffer_time32 *arg)
> +{
> +	struct v4l2_buffer buffer;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	trace_v4l2_dqbuf(minor, &buffer);
> +}
> +
> +static void trace_v4l2_qbuf_time32(int minor, const struct v4l2_buffer_time32 *arg)
> +{
> +	struct v4l2_buffer buffer;
> +
> +	v4l_get_buffer_time32(&buffer, arg);
> +	trace_v4l2_qbuf(minor, &buffer);
> +}
> +#endif
> +#endif
> +
>  static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
>  				struct file *file, void *fh, void *arg)
>  {
> @@ -2408,12 +2524,21 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
>  	IOCTL_INFO_FNC(VIDIOC_S_FMT, v4l_s_fmt, v4l_print_format, INFO_FL_PRIO),
>  	IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>  	IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
> +#ifndef CONFIG_64BIT
> +	IOCTL_INFO_FNC(VIDIOC_QUERYBUF_TIME32, v4l_querybuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
> +#endif

This doesn't work. These IOCTL macros use the ioctl nr as the index in the array. Since
VIDIOC_QUERYBUF and VIDIOC_QUERYBUF_TIME32 have the same index, this will fail.

I think (not 100% certain, there may be better suggestions) that the conversion is best
done in video_usercopy(): just before func() is called have a switch for the TIME32
variants, convert to the regular variant, call func() and convert back.

My only concern here is that an additional v4l2_buffer struct (68 bytes) is needed on the
stack. I don't see any way around that, though.

>  	IOCTL_INFO_STD(VIDIOC_G_FBUF, vidioc_g_fbuf, v4l_print_framebuffer, 0),
>  	IOCTL_INFO_STD(VIDIOC_S_FBUF, vidioc_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
>  	IOCTL_INFO_FNC(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),
>  	IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
> +#ifndef CONFIG_64BIT
> +	IOCTL_INFO_FNC(VIDIOC_QBUF_TIME32, v4l_qbuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
> +#endif
>  	IOCTL_INFO_STD(VIDIOC_EXPBUF, vidioc_expbuf, v4l_print_exportbuffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_exportbuffer, flags)),
>  	IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
> +#ifndef CONFIG_64BIT
> +	IOCTL_INFO_FNC(VIDIOC_DQBUF_TIME32, v4l_dqbuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
> +#endif
>  	IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
>  	IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
>  	IOCTL_INFO_FNC(VIDIOC_G_PARM, v4l_g_parm, v4l_print_streamparm, INFO_FL_CLEAR(v4l2_streamparm, type)),
> @@ -2479,6 +2604,9 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
>  	IOCTL_INFO_FNC(VIDIOC_UNSUBSCRIBE_EVENT, v4l_unsubscribe_event, v4l_print_event_subscription, 0),
>  	IOCTL_INFO_FNC(VIDIOC_CREATE_BUFS, v4l_create_bufs, v4l_print_create_buffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>  	IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF, v4l_prepare_buf, v4l_print_buffer, INFO_FL_QUEUE),
> +#ifndef CONFIG_64BIT
> +	IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF_TIME32, v4l_prepare_buf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
> +#endif
>  	IOCTL_INFO_STD(VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings, v4l_print_enum_dv_timings, 0),
>  	IOCTL_INFO_STD(VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings, v4l_print_dv_timings, 0),
>  	IOCTL_INFO_STD(VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap, v4l_print_dv_timings_cap, INFO_FL_CLEAR(v4l2_dv_timings_cap, type)),
> @@ -2608,6 +2736,12 @@ done:
>  		    (cmd == VIDIOC_QBUF || cmd == VIDIOC_DQBUF))
>  			return ret;
>  
> +#ifndef CONFIG_64BIT
> +		if (!(dev_debug & V4L2_DEV_DEBUG_STREAMING) &&
> +		    (cmd == VIDIOC_QBUF_TIME32 || cmd == VIDIOC_DQBUF_TIME32))
> +			return ret;
> +#endif
> +
>  		v4l_printk_ioctl(video_device_node_name(vfd), cmd);
>  		if (ret < 0)
>  			pr_cont(": error %ld", ret);
> @@ -2630,6 +2764,26 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
>  	int ret = 0;
>  
>  	switch (cmd) {
> +#ifndef CONFIG_64BIT
> +	case VIDIOC_PREPARE_BUF_TIME32:
> +	case VIDIOC_QUERYBUF_TIME32:
> +	case VIDIOC_QBUF_TIME32:
> +	case VIDIOC_DQBUF_TIME32: {
> +		struct v4l2_buffer_time32 *buf = parg;
> +
> +		if (V4L2_TYPE_IS_MULTIPLANAR(buf->type) && buf->length > 0) {
> +			if (buf->length > VIDEO_MAX_PLANES) {
> +				ret = -EINVAL;
> +				break;
> +			}
> +			*user_ptr = (void __user *)buf->m.planes;
> +			*kernel_ptr = (void **)&buf->m.planes;
> +			*array_size = sizeof(struct v4l2_plane) * buf->length;
> +			ret = 1;
> +		}
> +		break;
> +	}
> +#endif
>  	case VIDIOC_PREPARE_BUF:
>  	case VIDIOC_QUERYBUF:
>  	case VIDIOC_QBUF:
> @@ -2774,6 +2928,12 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
>  			trace_v4l2_dqbuf(video_devdata(file)->minor, parg);
>  		else if (cmd == VIDIOC_QBUF)
>  			trace_v4l2_qbuf(video_devdata(file)->minor, parg);
> +#ifndef CONFIG_64BIT
> +		else if (cmd == VIDIOC_DQBUF_TIME32)
> +			trace_v4l2_dqbuf_time32(video_devdata(file)->minor, parg);
> +		else if (cmd == VIDIOC_QBUF_TIME32)
> +			trace_v4l2_qbuf_time32(video_devdata(file)->minor, parg);
> +#endif
>  	}
>  
>  	if (has_array_args) {
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 450b3249ba30..0d3688a97ab8 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -811,8 +811,8 @@ struct v4l2_plane {
>   * time_t, so we have to convert it when accessing user data.
>   */
>  struct v4l2_timeval {
> -	long tv_sec;
> -	long tv_usec;
> +	__s64 tv_sec;
> +	__s64 tv_usec;
>  };
>  #endif
>  
> @@ -873,6 +873,32 @@ struct v4l2_buffer {
>  	__u32			reserved;
>  };
>  
> +struct v4l2_buffer_time32 {
> +	__u32			index;
> +	__u32			type;
> +	__u32			bytesused;
> +	__u32			flags;
> +	__u32			field;
> +	struct {
> +		__s32		tv_sec;
> +		__s32		tv_usec;
> +	}			timestamp;
> +	struct v4l2_timecode	timecode;
> +	__u32			sequence;
> +
> +	/* memory location */
> +	__u32			memory;
> +	union {
> +		__u32           offset;
> +		unsigned long   userptr;
> +		struct v4l2_plane *planes;
> +		__s32		fd;
> +	} m;
> +	__u32			length;
> +	__u32			reserved2;
> +	__u32			reserved;
> +};

Should this be part of a public API at all? Userspace will never use this struct
or the TIME32 ioctls in the source code, right? This would be more appropriate for
v4l2-ioctl.h.

> +
>  /*  Flags for 'flags' field */
>  /* Buffer is mapped (flag) */
>  #define V4L2_BUF_FLAG_MAPPED			0x00000001
> @@ -2216,12 +2242,15 @@ struct v4l2_create_buffers {
>  #define VIDIOC_S_FMT		_IOWR('V',  5, struct v4l2_format)
>  #define VIDIOC_REQBUFS		_IOWR('V',  8, struct v4l2_requestbuffers)
>  #define VIDIOC_QUERYBUF		_IOWR('V',  9, struct v4l2_buffer)
> +#define VIDIOC_QUERYBUF_TIME32	_IOWR('V',  9, struct v4l2_buffer_time32)
>  #define VIDIOC_G_FBUF		 _IOR('V', 10, struct v4l2_framebuffer)
>  #define VIDIOC_S_FBUF		 _IOW('V', 11, struct v4l2_framebuffer)
>  #define VIDIOC_OVERLAY		 _IOW('V', 14, int)
>  #define VIDIOC_QBUF		_IOWR('V', 15, struct v4l2_buffer)
> +#define VIDIOC_QBUF_TIME32	_IOWR('V', 15, struct v4l2_buffer_time32)
>  #define VIDIOC_EXPBUF		_IOWR('V', 16, struct v4l2_exportbuffer)
>  #define VIDIOC_DQBUF		_IOWR('V', 17, struct v4l2_buffer)
> +#define VIDIOC_DQBUF_TIME32	_IOWR('V', 17, struct v4l2_buffer_time32)
>  #define VIDIOC_STREAMON		 _IOW('V', 18, int)
>  #define VIDIOC_STREAMOFF	 _IOW('V', 19, int)
>  #define VIDIOC_G_PARM		_IOWR('V', 21, struct v4l2_streamparm)
> @@ -2292,6 +2321,7 @@ struct v4l2_create_buffers {
>     versions */
>  #define VIDIOC_CREATE_BUFS	_IOWR('V', 92, struct v4l2_create_buffers)
>  #define VIDIOC_PREPARE_BUF	_IOWR('V', 93, struct v4l2_buffer)
> +#define VIDIOC_PREPARE_BUF_TIME32 _IOWR('V', 93, struct v4l2_buffer_time32)
>  
>  /* Experimental selection API */
>  #define VIDIOC_G_SELECTION	_IOWR('V', 94, struct v4l2_selection)
> 

Regards,

	Hans
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Arnd Bergmann Sept. 18, 2015, 9:26 a.m. UTC | #2
On Friday 18 September 2015 09:18:45 Hans Verkuil wrote:
> Hi Arnd,
> 
> Thanks once again for working on this! Unfortunately, this approach won't
> work, see my comments below.
> 
> BTW, I would expect to see compile errors when compiling for 32 bit. Did
> you try that?

I only tested on 32-bit, both ARM and x86, but had a longer set of patches
applied below.

> > +static void v4l_put_buffer_time32(struct v4l2_buffer_time32 *to,
> > +				  const struct v4l2_buffer *from)
> > +{
> > +	to->index		= from->index;
> > +	to->type		= from->type;
> > +	to->bytesused		= from->bytesused;
> > +	to->flags		= from->flags;
> > +	to->field		= from->field;
> > +	to->timestamp.tv_sec	= from->timestamp.tv_sec;
> > +	to->timestamp.tv_usec	= from->timestamp.tv_usec;
> > +	to->timecode		= from->timecode;
> > +	to->sequence		= from->sequence;
> > +	to->memory		= from->memory;
> > +	to->m.offset		= from->m.offset;
> > +	to->length		= from->length;
> > +	to->reserved2		= from->reserved2;
> > +	to->reserved		= from->reserved;
> > +}
> 
> Is there a reason why you didn't use memcpy like you did for VIDIOC_DQEVENT (path 5/9)?
> I would prefer that over these explicit assignments.

No strong reason. I went back and forth a bit on the m.offset field that
is part of a union: In a previous version, I planned to move all the
compat handling here, and doing the conversion one field at a time would
make it easier to share the code between 32-bit and 64-bit kernels
handling old 32-bit user space. This version doesn't do that, so I can
use the memcpy approach instead.

> >  static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
> >  				struct file *file, void *fh, void *arg)
> >  {
> > @@ -2408,12 +2524,21 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
> >  	IOCTL_INFO_FNC(VIDIOC_S_FMT, v4l_s_fmt, v4l_print_format, INFO_FL_PRIO),
> >  	IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
> >  	IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
> > +#ifndef CONFIG_64BIT
> > +	IOCTL_INFO_FNC(VIDIOC_QUERYBUF_TIME32, v4l_querybuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
> > +#endif
> 
> This doesn't work. These IOCTL macros use the ioctl nr as the index in the array. Since
> VIDIOC_QUERYBUF and VIDIOC_QUERYBUF_TIME32 have the same index, this will fail.

Ah, I see. No idea why that did not cause a compile-time error. I got some
errors for duplicate 'case' values when the structures are the same size
(that's why we need the '#ifdef CONFIG_64BIT' in some places) but not here.

> I think (not 100% certain, there may be better suggestions) that the conversion is best
> done in video_usercopy(): just before func() is called have a switch for the TIME32
> variants, convert to the regular variant, call func() and convert back.

Does the handler have access to the _IOC_SIZE() value that was passed? If
it does, we could add a conditional inside of v4l_querybuf().
I did not see an easy way to do that though.

> My only concern here is that an additional v4l2_buffer struct (68 bytes) is needed on the
> stack. I don't see any way around that, though.

Agreed.

> > +struct v4l2_buffer_time32 {
> > +	__u32			index;
> > +	__u32			type;
> > +	__u32			bytesused;
> > +	__u32			flags;
> > +	__u32			field;
> > +	struct {
> > +		__s32		tv_sec;
> > +		__s32		tv_usec;
> > +	}			timestamp;
> > +	struct v4l2_timecode	timecode;
> > +	__u32			sequence;
> > +
> > +	/* memory location */
> > +	__u32			memory;
> > +	union {
> > +		__u32           offset;
> > +		unsigned long   userptr;
> > +		struct v4l2_plane *planes;
> > +		__s32		fd;
> > +	} m;
> > +	__u32			length;
> > +	__u32			reserved2;
> > +	__u32			reserved;
> > +};
> 
> Should this be part of a public API at all? Userspace will never use this struct
> or the TIME32 ioctls in the source code, right? This would be more appropriate for
> v4l2-ioctl.h.

Yes, makes sense. I think for the other structures I just enclosed them
inside #ifdef __KERNEL__ so they get stripped at 'make headers_install'
time, but I forgot to do that here.

My intention was to keep the structure close to the other one, so any
changes to them would be more likely to make it into both versions.

Let me know if you prefer to have an #ifdef added here, or if I should
move all three structures to v4l2-ioctl.h.

Thanks a lot for the review!

	Arnd
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Hans Verkuil Sept. 18, 2015, 9:49 a.m. UTC | #3
On 09/18/15 11:26, Arnd Bergmann wrote:
> On Friday 18 September 2015 09:18:45 Hans Verkuil wrote:
>> Hi Arnd,
>>
>> Thanks once again for working on this! Unfortunately, this approach won't
>> work, see my comments below.
>>
>> BTW, I would expect to see compile errors when compiling for 32 bit. Did
>> you try that?
> 
> I only tested on 32-bit, both ARM and x86, but had a longer set of patches
> applied below.
> 
>>> +static void v4l_put_buffer_time32(struct v4l2_buffer_time32 *to,
>>> +				  const struct v4l2_buffer *from)
>>> +{
>>> +	to->index		= from->index;
>>> +	to->type		= from->type;
>>> +	to->bytesused		= from->bytesused;
>>> +	to->flags		= from->flags;
>>> +	to->field		= from->field;
>>> +	to->timestamp.tv_sec	= from->timestamp.tv_sec;
>>> +	to->timestamp.tv_usec	= from->timestamp.tv_usec;
>>> +	to->timecode		= from->timecode;
>>> +	to->sequence		= from->sequence;
>>> +	to->memory		= from->memory;
>>> +	to->m.offset		= from->m.offset;
>>> +	to->length		= from->length;
>>> +	to->reserved2		= from->reserved2;
>>> +	to->reserved		= from->reserved;
>>> +}
>>
>> Is there a reason why you didn't use memcpy like you did for VIDIOC_DQEVENT (path 5/9)?
>> I would prefer that over these explicit assignments.
> 
> No strong reason. I went back and forth a bit on the m.offset field that
> is part of a union: In a previous version, I planned to move all the
> compat handling here, and doing the conversion one field at a time would
> make it easier to share the code between 32-bit and 64-bit kernels
> handling old 32-bit user space. This version doesn't do that, so I can
> use the memcpy approach instead.
> 
>>>  static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
>>>  				struct file *file, void *fh, void *arg)
>>>  {
>>> @@ -2408,12 +2524,21 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
>>>  	IOCTL_INFO_FNC(VIDIOC_S_FMT, v4l_s_fmt, v4l_print_format, INFO_FL_PRIO),
>>>  	IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>>>  	IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
>>> +#ifndef CONFIG_64BIT
>>> +	IOCTL_INFO_FNC(VIDIOC_QUERYBUF_TIME32, v4l_querybuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
>>> +#endif
>>
>> This doesn't work. These IOCTL macros use the ioctl nr as the index in the array. Since
>> VIDIOC_QUERYBUF and VIDIOC_QUERYBUF_TIME32 have the same index, this will fail.
> 
> Ah, I see. No idea why that did not cause a compile-time error. I got some
> errors for duplicate 'case' values when the structures are the same size
> (that's why we need the '#ifdef CONFIG_64BIT' in some places) but not here.
> 
>> I think (not 100% certain, there may be better suggestions) that the conversion is best
>> done in video_usercopy(): just before func() is called have a switch for the TIME32
>> variants, convert to the regular variant, call func() and convert back.
> 
> Does the handler have access to the _IOC_SIZE() value that was passed? If
> it does, we could add a conditional inside of v4l_querybuf().
> I did not see an easy way to do that though.

No, the v4l_ handlers don't have access to that. But I think it is much easier to
do the conversion at the first opportunity (video_usercopy), so no other code
needs to be modified. Easier to review and maintain that way.

>> My only concern here is that an additional v4l2_buffer struct (68 bytes) is needed on the
>> stack. I don't see any way around that, though.
> 
> Agreed.
> 
>>> +struct v4l2_buffer_time32 {
>>> +	__u32			index;
>>> +	__u32			type;
>>> +	__u32			bytesused;
>>> +	__u32			flags;
>>> +	__u32			field;
>>> +	struct {
>>> +		__s32		tv_sec;
>>> +		__s32		tv_usec;
>>> +	}			timestamp;
>>> +	struct v4l2_timecode	timecode;
>>> +	__u32			sequence;
>>> +
>>> +	/* memory location */
>>> +	__u32			memory;
>>> +	union {
>>> +		__u32           offset;
>>> +		unsigned long   userptr;
>>> +		struct v4l2_plane *planes;
>>> +		__s32		fd;
>>> +	} m;
>>> +	__u32			length;
>>> +	__u32			reserved2;
>>> +	__u32			reserved;
>>> +};
>>
>> Should this be part of a public API at all? Userspace will never use this struct
>> or the TIME32 ioctls in the source code, right? This would be more appropriate for
>> v4l2-ioctl.h.
> 
> Yes, makes sense. I think for the other structures I just enclosed them
> inside #ifdef __KERNEL__ so they get stripped at 'make headers_install'
> time, but I forgot to do that here.
> 
> My intention was to keep the structure close to the other one, so any
> changes to them would be more likely to make it into both versions.
> 
> Let me know if you prefer to have an #ifdef added here, or if I should
> move all three structures to v4l2-ioctl.h.

*If* the conversion takes place only in v4l2-ioctl.c, then it makes sense
have these structs + ioctls moved to v4l2-ioctl.h.

I noticed that v4l2-compat-ioctl32.c wasn't changed. Is that right? I have
unfortunately no time to double-check that, but it surprised me.

Regards,

	Hans

> Thanks a lot for the review!
> 
> 	Arnd
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Arnd Bergmann Sept. 18, 2015, 10:14 a.m. UTC | #4
On Friday 18 September 2015 11:49:50 Hans Verkuil wrote:
> *If* the conversion takes place only in v4l2-ioctl.c, then it makes sense
> have these structs + ioctls moved to v4l2-ioctl.h.

Ok.
 
> I noticed that v4l2-compat-ioctl32.c wasn't changed. Is that right? I have
> unfortunately no time to double-check that, but it surprised me.

Yes, I pointed that out in the cover letter as something that is still
left to be done. If we end up taking the current approach (plus the
change to the location of the conversion), the compat code would
basically be duplicated.

Alternatively, the video_usercopy() function could just be changed
to handle both 32-bit formats directly (including conversion of the
multiplane array) and then we can remove that compat handler for
all eight ioctls.

	Arnd
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diff mbox

Patch

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 7aab18dd2ca5..137475c28e8f 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -438,15 +438,14 @@  static void v4l_print_buffer(const void *arg, bool write_only)
 	const struct v4l2_timecode *tc = &p->timecode;
 	const struct v4l2_plane *plane;
 	int i;
+	/* y2038 safe because of monotonic time */
+	unsigned int seconds = p->timestamp.tv_sec;
 
-	pr_cont("%02ld:%02d:%02d.%08ld index=%d, type=%s, "
+	pr_cont("%02d:%02d:%02d.%08ld index=%d, type=%s, "
 		"flags=0x%08x, field=%s, sequence=%d, memory=%s",
-			p->timestamp.tv_sec / 3600,
-			(int)(p->timestamp.tv_sec / 60) % 60,
-			(int)(p->timestamp.tv_sec % 60),
-			(long)p->timestamp.tv_usec,
-			p->index,
-			prt_names(p->type, v4l2_type_names),
+			seconds / 3600, (seconds / 60) % 60,
+			seconds % 60, (long)p->timestamp.tv_usec,
+			p->index, prt_names(p->type, v4l2_type_names),
 			p->flags, prt_names(p->field, v4l2_field_names),
 			p->sequence, prt_names(p->memory, v4l2_memory_names));
 
@@ -1846,6 +1845,123 @@  static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
 	return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
 }
 
+#ifndef CONFIG_64BIT
+static void v4l_get_buffer_time32(struct v4l2_buffer *to,
+				  const struct v4l2_buffer_time32 *from)
+{
+	to->index		= from->index;
+	to->type		= from->type;
+	to->bytesused		= from->bytesused;
+	to->flags		= from->flags;
+	to->field		= from->field;
+	to->timestamp.tv_sec	= from->timestamp.tv_sec;
+	to->timestamp.tv_usec	= from->timestamp.tv_usec;
+	to->timecode		= from->timecode;
+	to->sequence		= from->sequence;
+	to->memory		= from->memory;
+	to->m.offset		= from->m.offset;
+	to->length		= from->length;
+	to->reserved2		= from->reserved2;
+	to->reserved		= from->reserved;
+}
+
+static void v4l_put_buffer_time32(struct v4l2_buffer_time32 *to,
+				  const struct v4l2_buffer *from)
+{
+	to->index		= from->index;
+	to->type		= from->type;
+	to->bytesused		= from->bytesused;
+	to->flags		= from->flags;
+	to->field		= from->field;
+	to->timestamp.tv_sec	= from->timestamp.tv_sec;
+	to->timestamp.tv_usec	= from->timestamp.tv_usec;
+	to->timecode		= from->timecode;
+	to->sequence		= from->sequence;
+	to->memory		= from->memory;
+	to->m.offset		= from->m.offset;
+	to->length		= from->length;
+	to->reserved2		= from->reserved2;
+	to->reserved		= from->reserved;
+}
+
+static int v4l_querybuf_time32(const struct v4l2_ioctl_ops *ops,
+				struct file *file, void *fh, void *arg)
+{
+	struct v4l2_buffer buffer;
+	int ret;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	ret = v4l_querybuf(ops, file, fh, &buffer);
+	v4l_put_buffer_time32(arg, &buffer);
+
+	return ret;
+}
+
+static int v4l_qbuf_time32(const struct v4l2_ioctl_ops *ops,
+				struct file *file, void *fh, void *arg)
+{
+	struct v4l2_buffer buffer;
+	int ret;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	ret = v4l_qbuf(ops, file, fh, &buffer);
+	v4l_put_buffer_time32(arg, &buffer);
+
+	return ret;
+}
+
+static int v4l_dqbuf_time32(const struct v4l2_ioctl_ops *ops,
+				struct file *file, void *fh, void *arg)
+{
+	struct v4l2_buffer buffer;
+	int ret;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	ret = v4l_dqbuf(ops, file, fh, &buffer);
+	v4l_put_buffer_time32(arg, &buffer);
+
+	return ret;
+}
+
+static int v4l_prepare_buf_time32(const struct v4l2_ioctl_ops *ops,
+				struct file *file, void *fh, void *arg)
+{
+	struct v4l2_buffer buffer;
+	int ret;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	ret = v4l_prepare_buf(ops, file, fh, &buffer);
+
+	return ret;
+}
+
+static void v4l_print_buffer_time32(const void *arg, bool write_only)
+{
+	struct v4l2_buffer buffer;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	v4l_print_buffer(&buffer, write_only);
+}
+
+#ifdef CONFIG_TRACEPOINTS
+static void trace_v4l2_dqbuf_time32(int minor, const struct v4l2_buffer_time32 *arg)
+{
+	struct v4l2_buffer buffer;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	trace_v4l2_dqbuf(minor, &buffer);
+}
+
+static void trace_v4l2_qbuf_time32(int minor, const struct v4l2_buffer_time32 *arg)
+{
+	struct v4l2_buffer buffer;
+
+	v4l_get_buffer_time32(&buffer, arg);
+	trace_v4l2_qbuf(minor, &buffer);
+}
+#endif
+#endif
+
 static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
@@ -2408,12 +2524,21 @@  static struct v4l2_ioctl_info v4l2_ioctls[] = {
 	IOCTL_INFO_FNC(VIDIOC_S_FMT, v4l_s_fmt, v4l_print_format, INFO_FL_PRIO),
 	IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
+#ifndef CONFIG_64BIT
+	IOCTL_INFO_FNC(VIDIOC_QUERYBUF_TIME32, v4l_querybuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
+#endif
 	IOCTL_INFO_STD(VIDIOC_G_FBUF, vidioc_g_fbuf, v4l_print_framebuffer, 0),
 	IOCTL_INFO_STD(VIDIOC_S_FBUF, vidioc_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
 	IOCTL_INFO_FNC(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),
 	IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
+#ifndef CONFIG_64BIT
+	IOCTL_INFO_FNC(VIDIOC_QBUF_TIME32, v4l_qbuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
+#endif
 	IOCTL_INFO_STD(VIDIOC_EXPBUF, vidioc_expbuf, v4l_print_exportbuffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_exportbuffer, flags)),
 	IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
+#ifndef CONFIG_64BIT
+	IOCTL_INFO_FNC(VIDIOC_DQBUF_TIME32, v4l_dqbuf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
+#endif
 	IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_G_PARM, v4l_g_parm, v4l_print_streamparm, INFO_FL_CLEAR(v4l2_streamparm, type)),
@@ -2479,6 +2604,9 @@  static struct v4l2_ioctl_info v4l2_ioctls[] = {
 	IOCTL_INFO_FNC(VIDIOC_UNSUBSCRIBE_EVENT, v4l_unsubscribe_event, v4l_print_event_subscription, 0),
 	IOCTL_INFO_FNC(VIDIOC_CREATE_BUFS, v4l_create_bufs, v4l_print_create_buffers, INFO_FL_PRIO | INFO_FL_QUEUE),
 	IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF, v4l_prepare_buf, v4l_print_buffer, INFO_FL_QUEUE),
+#ifndef CONFIG_64BIT
+	IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF_TIME32, v4l_prepare_buf_time32, v4l_print_buffer_time32, INFO_FL_QUEUE),
+#endif
 	IOCTL_INFO_STD(VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings, v4l_print_enum_dv_timings, 0),
 	IOCTL_INFO_STD(VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings, v4l_print_dv_timings, 0),
 	IOCTL_INFO_STD(VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap, v4l_print_dv_timings_cap, INFO_FL_CLEAR(v4l2_dv_timings_cap, type)),
@@ -2608,6 +2736,12 @@  done:
 		    (cmd == VIDIOC_QBUF || cmd == VIDIOC_DQBUF))
 			return ret;
 
+#ifndef CONFIG_64BIT
+		if (!(dev_debug & V4L2_DEV_DEBUG_STREAMING) &&
+		    (cmd == VIDIOC_QBUF_TIME32 || cmd == VIDIOC_DQBUF_TIME32))
+			return ret;
+#endif
+
 		v4l_printk_ioctl(video_device_node_name(vfd), cmd);
 		if (ret < 0)
 			pr_cont(": error %ld", ret);
@@ -2630,6 +2764,26 @@  static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 	int ret = 0;
 
 	switch (cmd) {
+#ifndef CONFIG_64BIT
+	case VIDIOC_PREPARE_BUF_TIME32:
+	case VIDIOC_QUERYBUF_TIME32:
+	case VIDIOC_QBUF_TIME32:
+	case VIDIOC_DQBUF_TIME32: {
+		struct v4l2_buffer_time32 *buf = parg;
+
+		if (V4L2_TYPE_IS_MULTIPLANAR(buf->type) && buf->length > 0) {
+			if (buf->length > VIDEO_MAX_PLANES) {
+				ret = -EINVAL;
+				break;
+			}
+			*user_ptr = (void __user *)buf->m.planes;
+			*kernel_ptr = (void **)&buf->m.planes;
+			*array_size = sizeof(struct v4l2_plane) * buf->length;
+			ret = 1;
+		}
+		break;
+	}
+#endif
 	case VIDIOC_PREPARE_BUF:
 	case VIDIOC_QUERYBUF:
 	case VIDIOC_QBUF:
@@ -2774,6 +2928,12 @@  video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
 			trace_v4l2_dqbuf(video_devdata(file)->minor, parg);
 		else if (cmd == VIDIOC_QBUF)
 			trace_v4l2_qbuf(video_devdata(file)->minor, parg);
+#ifndef CONFIG_64BIT
+		else if (cmd == VIDIOC_DQBUF_TIME32)
+			trace_v4l2_dqbuf_time32(video_devdata(file)->minor, parg);
+		else if (cmd == VIDIOC_QBUF_TIME32)
+			trace_v4l2_qbuf_time32(video_devdata(file)->minor, parg);
+#endif
 	}
 
 	if (has_array_args) {
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 450b3249ba30..0d3688a97ab8 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -811,8 +811,8 @@  struct v4l2_plane {
  * time_t, so we have to convert it when accessing user data.
  */
 struct v4l2_timeval {
-	long tv_sec;
-	long tv_usec;
+	__s64 tv_sec;
+	__s64 tv_usec;
 };
 #endif
 
@@ -873,6 +873,32 @@  struct v4l2_buffer {
 	__u32			reserved;
 };
 
+struct v4l2_buffer_time32 {
+	__u32			index;
+	__u32			type;
+	__u32			bytesused;
+	__u32			flags;
+	__u32			field;
+	struct {
+		__s32		tv_sec;
+		__s32		tv_usec;
+	}			timestamp;
+	struct v4l2_timecode	timecode;
+	__u32			sequence;
+
+	/* memory location */
+	__u32			memory;
+	union {
+		__u32           offset;
+		unsigned long   userptr;
+		struct v4l2_plane *planes;
+		__s32		fd;
+	} m;
+	__u32			length;
+	__u32			reserved2;
+	__u32			reserved;
+};
+
 /*  Flags for 'flags' field */
 /* Buffer is mapped (flag) */
 #define V4L2_BUF_FLAG_MAPPED			0x00000001
@@ -2216,12 +2242,15 @@  struct v4l2_create_buffers {
 #define VIDIOC_S_FMT		_IOWR('V',  5, struct v4l2_format)
 #define VIDIOC_REQBUFS		_IOWR('V',  8, struct v4l2_requestbuffers)
 #define VIDIOC_QUERYBUF		_IOWR('V',  9, struct v4l2_buffer)
+#define VIDIOC_QUERYBUF_TIME32	_IOWR('V',  9, struct v4l2_buffer_time32)
 #define VIDIOC_G_FBUF		 _IOR('V', 10, struct v4l2_framebuffer)
 #define VIDIOC_S_FBUF		 _IOW('V', 11, struct v4l2_framebuffer)
 #define VIDIOC_OVERLAY		 _IOW('V', 14, int)
 #define VIDIOC_QBUF		_IOWR('V', 15, struct v4l2_buffer)
+#define VIDIOC_QBUF_TIME32	_IOWR('V', 15, struct v4l2_buffer_time32)
 #define VIDIOC_EXPBUF		_IOWR('V', 16, struct v4l2_exportbuffer)
 #define VIDIOC_DQBUF		_IOWR('V', 17, struct v4l2_buffer)
+#define VIDIOC_DQBUF_TIME32	_IOWR('V', 17, struct v4l2_buffer_time32)
 #define VIDIOC_STREAMON		 _IOW('V', 18, int)
 #define VIDIOC_STREAMOFF	 _IOW('V', 19, int)
 #define VIDIOC_G_PARM		_IOWR('V', 21, struct v4l2_streamparm)
@@ -2292,6 +2321,7 @@  struct v4l2_create_buffers {
    versions */
 #define VIDIOC_CREATE_BUFS	_IOWR('V', 92, struct v4l2_create_buffers)
 #define VIDIOC_PREPARE_BUF	_IOWR('V', 93, struct v4l2_buffer)
+#define VIDIOC_PREPARE_BUF_TIME32 _IOWR('V', 93, struct v4l2_buffer_time32)
 
 /* Experimental selection API */
 #define VIDIOC_G_SELECTION	_IOWR('V', 94, struct v4l2_selection)