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

diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c
index 9d673d113d7acd7b41cec2bfb2eec4b9a70ee58c..290c6b2131797c2d1229a027c5fef050b5553d8e 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-event.c
+++ b/drivers/media/v4l2-core/v4l2-event.c
@@ -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--;
 

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 1f22b135577847c488d7130bd2d7760219174852..f13b232e6c3169cc1d8c3ac2404238170281285c 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -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)))

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 9e987c0f840ec1a53c4ea767d1bda9a70ad62880..de926e3113486f2eed89b605718596ca99f7b74b 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -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);
 

diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index 4bba65a59d466ff39b9b8d45b7000a1e1b162a71..05c1ec93a91153bb2b3f76c4a525ff753a0f805c 100644 (file)
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -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 */

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 6ef4a5b787a4654145e69631849feed8a96ebcf5..caf156d45842faed65296e3a3c024ead39045469 100644 (file)
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -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];
 };