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Message-Id: <20191106194715.2238044-6-arnd@arndb.de>
Date: Wed, 6 Nov 2019 20:47:12 +0100
From: Arnd Bergmann <arnd@...db.de>
To: Hans Verkuil <hverkuil@...all.nl>,
Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
y2038@...ts.linaro.org,
Boris Brezillon <boris.brezillon@...labora.com>,
Maxime Ripard <maxime.ripard@...tlin.com>,
Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
Tiffany Lin <tiffany.lin@...iatek.com>,
Daniel Mentz <danielmentz@...gle.com>,
Arnd Bergmann <arnd@...db.de>
Subject: [PATCH v3 5/8] 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@...db.de>
---
drivers/media/v4l2-core/v4l2-event.c | 5 ++++-
drivers/media/v4l2-core/v4l2-ioctl.c | 22 ++++++++++++++++++++
drivers/media/v4l2-core/v4l2-subdev.c | 20 +++++++++++++++++-
include/uapi/linux/videodev2.h | 30 +++++++++++++++++++++++++++
4 files changed, 75 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c
index 9d673d113d7a..290c6b213179 100644
--- 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 50612b4749d3..b8aca0d174bd 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -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 +3081,21 @@ 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_time32 ev32;
+ struct v4l2_event *ev = parg;
+
+ memcpy(&ev32, ev, offsetof(struct v4l2_event, timestamp));
+ ev32.timestamp.tv_sec = ev->timestamp.tv_sec;
+ ev32.timestamp.tv_nsec = ev->timestamp.tv_nsec;
+ memcpy(&ev32.id, &ev->id, sizeof(*ev) - offsetof(struct v4l2_event, id));
+
+ 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 9e987c0f840e..77b77807aaca 100644
--- 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 +392,24 @@ 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);
+
+ memcpy(ev32, &ev, offsetof(struct v4l2_event, timestamp));
+ ev32->timestamp.tv_sec = ev.timestamp.tv_sec;
+ ev32->timestamp.tv_nsec = ev.timestamp.tv_nsec;
+ memcpy(&ev32->id, &ev.id,
+ sizeof(ev) - offsetof(struct v4l2_event, id));
+
+ return rval;
+ }
+
case VIDIOC_SUBSCRIBE_EVENT:
return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 5de1e37995c0..e38afa71a327 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -2340,11 +2340,40 @@ struct v4l2_event {
} u;
__u32 pending;
__u32 sequence;
+#ifdef __KERNEL__
+ struct __kernel_timespec timestamp;
+#else
struct timespec timestamp;
+#endif
__u32 id;
__u32 reserved[8];
};
+#ifdef __KERNEL__
+/*
+ * 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];
+};
+#endif
+
#define V4L2_EVENT_SUB_FL_SEND_INITIAL (1 << 0)
#define V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK (1 << 1)
@@ -2497,6 +2526,7 @@ struct v4l2_create_buffers {
#define VIDIOC_S_DV_TIMINGS _IOWR('V', 87, struct v4l2_dv_timings)
#define VIDIOC_G_DV_TIMINGS _IOWR('V', 88, struct v4l2_dv_timings)
#define VIDIOC_DQEVENT _IOR('V', 89, struct v4l2_event)
+#define VIDIOC_DQEVENT_TIME32 _IOR('V', 89, struct v4l2_event_time32)
#define VIDIOC_SUBSCRIBE_EVENT _IOW('V', 90, struct v4l2_event_subscription)
#define VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 91, struct v4l2_event_subscription)
#define VIDIOC_CREATE_BUFS _IOWR('V', 92, struct v4l2_create_buffers)
--
2.20.0
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