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Subject[PATCH v6 6/8] media: v4l2-core: fix v4l2_buffer handling for time64 ABI
Date
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>
---
drivers/media/v4l2-core/v4l2-ioctl.c | 74 ++++++++++++++++++++++++++--
include/media/v4l2-ioctl.h | 30 +++++++++++
include/uapi/linux/videodev2.h | 23 +++++++++
3 files changed, 123 insertions(+), 4 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index b066e27e99a2..667225712343 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -474,10 +474,10 @@ static void v4l_print_buffer(const void *arg, bool write_only)
const struct v4l2_plane *plane;
int i;

- pr_cont("%02ld:%02d:%02d.%08ld index=%d, type=%s, request_fd=%d, 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),
+ pr_cont("%02d:%02d:%02d.%09ld index=%d, type=%s, request_fd=%d, flags=0x%08x, field=%s, sequence=%d, memory=%s",
+ (int)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), p->request_fd,
@@ -3029,6 +3029,14 @@ static unsigned int video_translate_cmd(unsigned int cmd)
#ifdef CONFIG_COMPAT_32BIT_TIME
case VIDIOC_DQEVENT_TIME32:
return VIDIOC_DQEVENT;
+ case VIDIOC_QUERYBUF_TIME32:
+ return VIDIOC_QUERYBUF;
+ case VIDIOC_QBUF_TIME32:
+ return VIDIOC_QBUF;
+ case VIDIOC_DQBUF_TIME32:
+ return VIDIOC_DQBUF;
+ case VIDIOC_PREPARE_BUF_TIME32:
+ return VIDIOC_PREPARE_BUF;
#endif
}

@@ -3047,6 +3055,39 @@ static int video_get_user(void __user *arg, void *parg, unsigned int cmd,
}

switch (cmd) {
+#ifdef CONFIG_COMPAT_32BIT_TIME
+ case VIDIOC_QUERYBUF_TIME32:
+ case VIDIOC_QBUF_TIME32:
+ case VIDIOC_DQBUF_TIME32:
+ case VIDIOC_PREPARE_BUF_TIME32: {
+ struct v4l2_buffer_time32 vb32;
+ struct v4l2_buffer *vb = parg;
+
+ if (copy_from_user(&vb32, arg, sizeof(vb32)))
+ return -EFAULT;
+
+ *vb = (struct v4l2_buffer) {
+ .index = vb32.index,
+ .type = vb32.type,
+ .bytesused = vb32.bytesused,
+ .flags = vb32.flags,
+ .field = vb32.field,
+ .timestamp.tv_sec = vb32.timestamp.tv_sec,
+ .timestamp.tv_usec = vb32.timestamp.tv_usec,
+ .timecode = vb32.timecode,
+ .sequence = vb32.sequence,
+ .memory = vb32.memory,
+ .m.userptr = vb32.m.userptr,
+ .length = vb32.length,
+ .request_fd = vb32.request_fd,
+ };
+
+ if (cmd == VIDIOC_QUERYBUF_TIME32)
+ vb->request_fd = 0;
+
+ break;
+ }
+#endif
default:
/*
* In some cases, only a few fields are used as input,
@@ -3100,6 +3141,31 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd)
return -EFAULT;
break;
}
+ case VIDIOC_QUERYBUF_TIME32:
+ case VIDIOC_QBUF_TIME32:
+ case VIDIOC_DQBUF_TIME32:
+ case VIDIOC_PREPARE_BUF_TIME32: {
+ struct v4l2_buffer *vb = parg;
+ struct v4l2_buffer_time32 vb32 = {
+ .index = vb->index,
+ .type = vb->type,
+ .bytesused = vb->bytesused,
+ .flags = vb->flags,
+ .field = vb->field,
+ .timestamp.tv_sec = vb->timestamp.tv_sec,
+ .timestamp.tv_usec = vb->timestamp.tv_usec,
+ .timecode = vb->timecode,
+ .sequence = vb->sequence,
+ .memory = vb->memory,
+ .m.userptr = vb->m.userptr,
+ .length = vb->length,
+ .request_fd = vb->request_fd,
+ };
+
+ if (copy_to_user(arg, &vb32, sizeof(vb32)))
+ return -EFAULT;
+ break;
+ }
#endif
default:
/* Copy results into user buffer */
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index 05c1ec93a911..86878fba332b 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -749,4 +749,34 @@ struct v4l2_event_time32 {

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

+struct v4l2_buffer_time32 {
+ __u32 index;
+ __u32 type;
+ __u32 bytesused;
+ __u32 flags;
+ __u32 field;
+ struct old_timeval32 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;
+ union {
+ __s32 request_fd;
+ __u32 reserved;
+ };
+};
+#define VIDIOC_QUERYBUF_TIME32 _IOWR('V', 9, struct v4l2_buffer_time32)
+#define VIDIOC_QBUF_TIME32 _IOWR('V', 15, struct v4l2_buffer_time32)
+#define VIDIOC_DQBUF_TIME32 _IOWR('V', 17, struct v4l2_buffer_time32)
+#define VIDIOC_PREPARE_BUF_TIME32 _IOWR('V', 93, struct v4l2_buffer_time32)
+
#endif /* _V4L2_IOCTL_H */
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;

--
2.20.0
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