media: v4l2-core: fix v4l2_buffer handling for time64 ABI

The v4l2_buffer structure contains a 'struct timeval' member that is
defined by the user space C library, creating an ABI incompatibility
when that gets updated to a 64-bit time_t.

As in v4l2_event, handle this with a special case in video_put_user()
and video_get_user() to replace the memcpy there.

Since the structure also contains a pointer, there are now two
native versions (on 32-bit systems) as well as two compat versions
(on 64-bit systems), which unfortunately complicates the compat
handler quite a bit.

Duplicating the existing handlers for the new types is a safe
conversion for now, but unfortunately this may turn into a
maintenance burden later. A larger-scale rework of the
compat code might be a better alternative, but is out of scope
of the y2038 work.

Sparc64 needs a special case because of their special suseconds_t
definition.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index caf156d45842..5f9357dcb060 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -912,6 +912,25 @@ struct v4l2_jpegcompression {
 /*
  *	M E M O R Y - M A P P I N G   B U F F E R S
  */
+
+#ifdef __KERNEL__
+/*
+ * This corresponds to the user space version of timeval
+ * for 64-bit time_t. sparc64 is different from everyone
+ * else, using the microseconds in the wrong half of the
+ * second 64-bit word.
+ */
+struct __kernel_v4l2_timeval {
+	long long	tv_sec;
+#if defined(__sparc__) && defined(__arch64__)
+	int		tv_usec;
+	int		__pad;
+#else
+	long long	tv_usec;
+#endif
+};
+#endif
+
 struct v4l2_requestbuffers {
 	__u32			count;
 	__u32			type;		/* enum v4l2_buf_type */
@@ -997,7 +1016,11 @@ struct v4l2_buffer {
 	__u32			bytesused;
 	__u32			flags;
 	__u32			field;
+#ifdef __KERNEL__
+	struct __kernel_v4l2_timeval timestamp;
+#else
 	struct timeval		timestamp;
+#endif
 	struct v4l2_timecode	timecode;
 	__u32			sequence;